diff --git a/spring-boot-project/spring-boot-docs/build.gradle b/spring-boot-project/spring-boot-docs/build.gradle index 2ecfb58208..4bb899895b 100644 --- a/spring-boot-project/spring-boot-docs/build.gradle +++ b/spring-boot-project/spring-boot-docs/build.gradle @@ -181,33 +181,33 @@ task aggregatedJavadoc(type: Javadoc) { task documentTestSlices(type: org.springframework.boot.build.test.autoconfigure.DocumentTestSlices) { testSlices = configurations.testSlices - outputFile = file("${buildDir}/docs/generated/test-slice-auto-configuration.adoc") + outputFile = file("${buildDir}/docs/generated/test-auto-configuration/documented-slices.adoc") } task documentStarters(type: org.springframework.boot.build.starters.DocumentStarters) { - outputDir = file("${buildDir}/docs/generated/starters/") + outputDir = file("${buildDir}/docs/generated/using/starters/") } task documentAutoConfigurationClasses(type: org.springframework.boot.build.autoconfigure.DocumentAutoConfigurationClasses) { autoConfiguration = configurations.autoConfiguration - outputDir = file("${buildDir}/docs/generated/auto-configuration-classes/") + outputDir = file("${buildDir}/docs/generated/auto-configuration-classes/documented-auto-configuration-classes/") } task documentDependencyVersions(type: org.springframework.boot.build.constraints.DocumentConstrainedVersions) { dependsOn dependencyVersions constrainedVersions.set(providers.provider { dependencyVersions.constrainedVersions }) - outputFile = file("${buildDir}/docs/generated/generated-dependency-versions.adoc") + outputFile = file("${buildDir}/docs/generated/dependency-versions/documented-coordinates.adoc") } task documentVersionProperties(type: org.springframework.boot.build.constraints.DocumentVersionProperties) { dependsOn dependencyVersions versionProperties.set(providers.provider { dependencyVersions.versionProperties}) - outputFile = file("${buildDir}/docs/generated/generated-version-properties.adoc") + outputFile = file("${buildDir}/docs/generated/dependency-versions/documented-properties.adoc") } task documentConfigurationProperties(type: org.springframework.boot.build.context.properties.DocumentConfigurationProperties) { configurationPropertyMetadata = configurations.configurationProperties - outputDir = file("${buildDir}/docs/generated/config-docs/") + outputDir = file("${buildDir}/docs/generated/application-properties/documented-application-properties/") } tasks.withType(org.asciidoctor.gradle.jvm.AbstractAsciidoctorTask) { diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator.adoc index 3ec946013a..f9e97e30b2 100644 --- a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator.adoc +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator.adoc @@ -2,2868 +2,32 @@ = Spring Boot Actuator: Production-ready Features include::attributes.adoc[] + + Spring Boot includes a number of additional features to help you monitor and manage your application when you push it to production. You can choose to manage and monitor your application by using HTTP endpoints or with JMX. Auditing, health, and metrics gathering can also be automatically applied to your application. -[[actuator.enabling]] -== Enabling Production-ready Features -The {spring-boot-code}/spring-boot-project/spring-boot-actuator[`spring-boot-actuator`] module provides all of Spring Boot's production-ready features. -The recommended way to enable the features is to add a dependency on the `spring-boot-starter-actuator` '`Starter`'. +include::actuator/enabling.adoc[] -.Definition of Actuator -**** -An actuator is a manufacturing term that refers to a mechanical device for moving or controlling something. -Actuators can generate a large amount of motion from a small change. -**** +include::actuator/endpoints.adoc[] -To add the actuator to a Maven based project, add the following '`Starter`' dependency: +include::actuator/monitoring.adoc[] -[source,xml,indent=0] ----- - - - org.springframework.boot - spring-boot-starter-actuator - - ----- +include::actuator/jmx.adoc[] -For Gradle, use the following declaration: +include::actuator/loggers.adoc[] -[source,groovy,indent=0] ----- - dependencies { - implementation 'org.springframework.boot:spring-boot-starter-actuator' - } ----- +include::actuator/metrics.adoc[] +include::actuator/auditing.adoc[] +include::actuator/tracing.adoc[] -[[actuator.endpoints]] -== Endpoints -Actuator endpoints let you monitor and interact with your application. -Spring Boot includes a number of built-in endpoints and lets you add your own. -For example, the `health` endpoint provides basic application health information. +include::actuator/process-monitoring.adoc[] -Each individual endpoint can be <> and <>. -An endpoint is considered to be available when it is both enabled and exposed. -The built-in endpoints will only be auto-configured when they are available. -Most applications choose exposure via HTTP, where the ID of the endpoint along with a prefix of `/actuator` is mapped to a URL. -For example, by default, the `health` endpoint is mapped to `/actuator/health`. +include::actuator/cloud-foundry.adoc[] -TIP: To learn more about the Actuator's endpoints and their request and response formats, please refer to the separate API documentation ({spring-boot-actuator-restapi-docs}[HTML] or {spring-boot-actuator-restapi-pdfdocs}[PDF]). - -The following technology-agnostic endpoints are available: - -[cols="2,5"] -|=== -| ID | Description - -| `auditevents` -| Exposes audit events information for the current application. - Requires an `AuditEventRepository` bean. - -| `beans` -| Displays a complete list of all the Spring beans in your application. - -| `caches` -| Exposes available caches. - -| `conditions` -| Shows the conditions that were evaluated on configuration and auto-configuration classes and the reasons why they did or did not match. - -| `configprops` -| Displays a collated list of all `@ConfigurationProperties`. - -| `env` -| Exposes properties from Spring's `ConfigurableEnvironment`. - -| `flyway` -| Shows any Flyway database migrations that have been applied. - Requires one or more `Flyway` beans. - -| `health` -| Shows application health information. - -| `httptrace` -| Displays HTTP trace information (by default, the last 100 HTTP request-response exchanges). - Requires an `HttpTraceRepository` bean. - -| `info` -| Displays arbitrary application info. - -| `integrationgraph` -| Shows the Spring Integration graph. - Requires a dependency on `spring-integration-core`. - -| `loggers` -| Shows and modifies the configuration of loggers in the application. - -| `liquibase` -| Shows any Liquibase database migrations that have been applied. - Requires one or more `Liquibase` beans. - -| `metrics` -| Shows '`metrics`' information for the current application. - -| `mappings` -| Displays a collated list of all `@RequestMapping` paths. - -|`quartz` -|Shows information about Quartz Scheduler jobs. - -| `scheduledtasks` -| Displays the scheduled tasks in your application. - -| `sessions` -| Allows retrieval and deletion of user sessions from a Spring Session-backed session store. - Requires a Servlet-based web application using Spring Session. - -| `shutdown` -| Lets the application be gracefully shutdown. - Disabled by default. - -| `startup` -| Shows the <> collected by the `ApplicationStartup`. - Requires the `SpringApplication` to be configured with a `BufferingApplicationStartup`. - -| `threaddump` -| Performs a thread dump. -|=== - -If your application is a web application (Spring MVC, Spring WebFlux, or Jersey), you can use the following additional endpoints: - -[cols="2,5"] -|=== -| ID | Description - -| `heapdump` -| Returns an `hprof` heap dump file. - -| `jolokia` -| Exposes JMX beans over HTTP (when Jolokia is on the classpath, not available for WebFlux). - Requires a dependency on `jolokia-core`. - -| `logfile` -| Returns the contents of the logfile (if `logging.file.name` or `logging.file.path` properties have been set). - Supports the use of the HTTP `Range` header to retrieve part of the log file's content. - -| `prometheus` -| Exposes metrics in a format that can be scraped by a Prometheus server. - Requires a dependency on `micrometer-registry-prometheus`. -|=== - - - -[[actuator.endpoints.enabling]] -=== Enabling Endpoints -By default, all endpoints except for `shutdown` are enabled. -To configure the enablement of an endpoint, use its `management.endpoint..enabled` property. -The following example enables the `shutdown` endpoint: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - endpoint: - shutdown: - enabled: true ----- - -If you prefer endpoint enablement to be opt-in rather than opt-out, set the configprop:management.endpoints.enabled-by-default[] property to `false` and use individual endpoint `enabled` properties to opt back in. -The following example enables the `info` endpoint and disables all other endpoints: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - endpoints: - enabled-by-default: false - endpoint: - info: - enabled: true ----- - -NOTE: Disabled endpoints are removed entirely from the application context. -If you want to change only the technologies over which an endpoint is exposed, use the <> instead. - - - -[[actuator.endpoints.exposing]] -=== Exposing Endpoints -Since Endpoints may contain sensitive information, careful consideration should be given about when to expose them. -The following table shows the default exposure for the built-in endpoints: - -[cols="1,1,1"] -|=== -| ID | JMX | Web - -| `auditevents` -| Yes -| No - -| `beans` -| Yes -| No - -| `caches` -| Yes -| No - -| `conditions` -| Yes -| No - -| `configprops` -| Yes -| No - -| `env` -| Yes -| No - -| `flyway` -| Yes -| No - -| `health` -| Yes -| Yes - -| `heapdump` -| N/A -| No - -| `httptrace` -| Yes -| No - -| `info` -| Yes -| Yes - -| `integrationgraph` -| Yes -| No - -| `jolokia` -| N/A -| No - -| `logfile` -| N/A -| No - -| `loggers` -| Yes -| No - -| `liquibase` -| Yes -| No - -| `metrics` -| Yes -| No - -| `mappings` -| Yes -| No - -| `prometheus` -| N/A -| No - -| `quartz` -| Yes -| No - -| `scheduledtasks` -| Yes -| No - -| `sessions` -| Yes -| No - -| `shutdown` -| Yes -| No - -| `startup` -| Yes -| No - -| `threaddump` -| Yes -| No -|=== - -To change which endpoints are exposed, use the following technology-specific `include` and `exclude` properties: - -[cols="3,1"] -|=== -| Property | Default - -| configprop:management.endpoints.jmx.exposure.exclude[] -| - -| configprop:management.endpoints.jmx.exposure.include[] -| `*` - -| configprop:management.endpoints.web.exposure.exclude[] -| - -| configprop:management.endpoints.web.exposure.include[] -| `info, health` -|=== - -The `include` property lists the IDs of the endpoints that are exposed. -The `exclude` property lists the IDs of the endpoints that should not be exposed. -The `exclude` property takes precedence over the `include` property. -Both `include` and `exclude` properties can be configured with a list of endpoint IDs. - -For example, to stop exposing all endpoints over JMX and only expose the `health` and `info` endpoints, use the following property: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - endpoints: - jmx: - exposure: - include: "health,info" ----- - -`*` can be used to select all endpoints. -For example, to expose everything over HTTP except the `env` and `beans` endpoints, use the following properties: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - endpoints: - web: - exposure: - include: "*" - exclude: "env,beans" ----- - -NOTE: `*` has a special meaning in YAML, so be sure to add quotes if you want to include (or exclude) all endpoints. - -NOTE: If your application is exposed publicly, we strongly recommend that you also <>. - -TIP: If you want to implement your own strategy for when endpoints are exposed, you can register an `EndpointFilter` bean. - - - -[[actuator.endpoints.security]] -=== Securing HTTP Endpoints -You should take care to secure HTTP endpoints in the same way that you would any other sensitive URL. -If Spring Security is present, endpoints are secured by default using Spring Security’s content-negotiation strategy. -If you wish to configure custom security for HTTP endpoints, for example, only allow users with a certain role to access them, Spring Boot provides some convenient `RequestMatcher` objects that can be used in combination with Spring Security. - -A typical Spring Security configuration might look something like the following example: - -[source,java,pending-extract=true,indent=0] ----- - @Bean - public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception { - http.requestMatcher(EndpointRequest.toAnyEndpoint()).authorizeRequests((requests) -> - requests.anyRequest().hasRole("ENDPOINT_ADMIN")); - http.httpBasic(); - return http.build(); - } ----- - -The preceding example uses `EndpointRequest.toAnyEndpoint()` to match a request to any endpoint and then ensures that all have the `ENDPOINT_ADMIN` role. -Several other matcher methods are also available on `EndpointRequest`. -See the API documentation ({spring-boot-actuator-restapi-docs}[HTML] or {spring-boot-actuator-restapi-pdfdocs}[PDF]) for details. - -If you deploy applications behind a firewall, you may prefer that all your actuator endpoints can be accessed without requiring authentication. -You can do so by changing the configprop:management.endpoints.web.exposure.include[] property, as follows: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - endpoints: - web: - exposure: - include: "*" ----- - -Additionally, if Spring Security is present, you would need to add custom security configuration that allows unauthenticated access to the endpoints as shown in the following example: - -[source,java,pending-extract=true,indent=0] ----- - @Bean - public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception { - http.requestMatcher(EndpointRequest.toAnyEndpoint()).authorizeRequests((requests) -> - requests.anyRequest().permitAll()); - return http.build(); - } ----- - -NOTE: In both the examples above, the configuration applies only to the actuator endpoints. -Since Spring Boot's security configuration backs off completely in the presence of any `SecurityFilterChain` bean, you will need to configure an additional `SecurityFilterChain` bean with rules that apply to the rest of the application. - - - -[[actuator.endpoints.caching]] -=== Configuring Endpoints -Endpoints automatically cache responses to read operations that do not take any parameters. -To configure the amount of time for which an endpoint will cache a response, use its `cache.time-to-live` property. -The following example sets the time-to-live of the `beans` endpoint's cache to 10 seconds: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - endpoint: - beans: - cache: - time-to-live: "10s" ----- - -NOTE: The prefix `management.endpoint.` is used to uniquely identify the endpoint that is being configured. - - - -[[actuator.endpoints.hypermedia]] -=== Hypermedia for Actuator Web Endpoints -A "`discovery page`" is added with links to all the endpoints. -The "`discovery page`" is available on `/actuator` by default. - -To disable the "`discovery page`", add the following property to your application properties: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - endpoints: - web: - discovery: - enabled: false ----- - -When a custom management context path is configured, the "`discovery page`" automatically moves from `/actuator` to the root of the management context. -For example, if the management context path is `/management`, then the discovery page is available from `/management`. -When the management context path is set to `/`, the discovery page is disabled to prevent the possibility of a clash with other mappings. - - - -[[actuator.endpoints.cors]] -=== CORS Support -https://en.wikipedia.org/wiki/Cross-origin_resource_sharing[Cross-origin resource sharing] (CORS) is a https://www.w3.org/TR/cors/[W3C specification] that lets you specify in a flexible way what kind of cross-domain requests are authorized. -If you use Spring MVC or Spring WebFlux, Actuator's web endpoints can be configured to support such scenarios. - -CORS support is disabled by default and is only enabled once the configprop:management.endpoints.web.cors.allowed-origins[] property has been set. -The following configuration permits `GET` and `POST` calls from the `example.com` domain: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - endpoints: - web: - cors: - allowed-origins: "https://example.com" - allowed-methods: "GET,POST" ----- - -TIP: See {spring-boot-actuator-autoconfigure-module-code}/endpoint/web/CorsEndpointProperties.java[CorsEndpointProperties] for a complete list of options. - - - -[[actuator.endpoints.implementing-custom]] -=== Implementing Custom Endpoints -If you add a `@Bean` annotated with `@Endpoint`, any methods annotated with `@ReadOperation`, `@WriteOperation`, or `@DeleteOperation` are automatically exposed over JMX and, in a web application, over HTTP as well. -Endpoints can be exposed over HTTP using Jersey, Spring MVC, or Spring WebFlux. -If both Jersey and Spring MVC are available, Spring MVC will be used. - -The following example exposes a read operation that returns a custom object: - -[source,java,indent=0] ----- -include::{include-productionreadyfeatures}/endpoints/CustomEndpoint.java[tag=read] ----- - -You can also write technology-specific endpoints by using `@JmxEndpoint` or `@WebEndpoint`. -These endpoints are restricted to their respective technologies. -For example, `@WebEndpoint` is exposed only over HTTP and not over JMX. - -You can write technology-specific extensions by using `@EndpointWebExtension` and `@EndpointJmxExtension`. -These annotations let you provide technology-specific operations to augment an existing endpoint. - -Finally, if you need access to web-framework-specific functionality, you can implement Servlet or Spring `@Controller` and `@RestController` endpoints at the cost of them not being available over JMX or when using a different web framework. - - - -[[actuator.endpoints.implementing-custom.input]] -==== Receiving Input -Operations on an endpoint receive input via their parameters. -When exposed via the web, the values for these parameters are taken from the URL's query parameters and from the JSON request body. -When exposed via JMX, the parameters are mapped to the parameters of the MBean's operations. -Parameters are required by default. -They can be made optional by annotating them with either `@javax.annotation.Nullable` or `@org.springframework.lang.Nullable`. - -Each root property in the JSON request body can be mapped to a parameter of the endpoint. -Consider the following JSON request body: - -[source,json,indent=0] ----- - { - "name": "test", - "counter": 42 - } ----- - -This can be used to invoke a write operation that takes `String name` and `int counter` parameters, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-productionreadyfeatures}/endpoints/CustomEndpoint.java[tag=write] ----- - -TIP: Because endpoints are technology agnostic, only simple types can be specified in the method signature. -In particular declaring a single parameter with a `CustomData` type defining a `name` and `counter` properties is not supported. - -NOTE: To allow the input to be mapped to the operation method's parameters, Java code implementing an endpoint should be compiled with `-parameters`, and Kotlin code implementing an endpoint should be compiled with `-java-parameters`. -This will happen automatically if you are using Spring Boot's Gradle plugin or if you are using Maven and `spring-boot-starter-parent`. - - - -[[actuator.endpoints.implementing-custom.input.conversion]] -===== Input Type Conversion -The parameters passed to endpoint operation methods are, if necessary, automatically converted to the required type. -Before calling an operation method, the input received via JMX or an HTTP request is converted to the required types using an instance of `ApplicationConversionService` as well as any `Converter` or `GenericConverter` beans qualified with `@EndpointConverter`. - - - -[[actuator.endpoints.implementing-custom.web]] -==== Custom Web Endpoints -Operations on an `@Endpoint`, `@WebEndpoint`, or `@EndpointWebExtension` are automatically exposed over HTTP using Jersey, Spring MVC, or Spring WebFlux. -If both Jersey and Spring MVC are available, Spring MVC will be used. - - - -[[actuator.endpoints.implementing-custom.web.request-predicates]] -===== Web Endpoint Request Predicates -A request predicate is automatically generated for each operation on a web-exposed endpoint. - - - -[[actuator.endpoints.implementing-custom.web.path-predicates]] -===== Path -The path of the predicate is determined by the ID of the endpoint and the base path of web-exposed endpoints. -The default base path is `/actuator`. -For example, an endpoint with the ID `sessions` will use `/actuator/sessions` as its path in the predicate. - -The path can be further customized by annotating one or more parameters of the operation method with `@Selector`. -Such a parameter is added to the path predicate as a path variable. -The variable's value is passed into the operation method when the endpoint operation is invoked. -If you want to capture all remaining path elements, you can add `@Selector(Match=ALL_REMAINING)` to the last parameter and make it a type that is conversion compatible with a `String[]`. - - - -[[actuator.endpoints.implementing-custom.web.method-predicates]] -===== HTTP method -The HTTP method of the predicate is determined by the operation type, as shown in the following table: - -[cols="3, 1"] -|=== -| Operation | HTTP method - -| `@ReadOperation` -| `GET` - -| `@WriteOperation` -| `POST` - -| `@DeleteOperation` -| `DELETE` -|=== - - - -[[actuator.endpoints.implementing-custom.web.consumes-predicates]] -===== Consumes -For a `@WriteOperation` (HTTP `POST`) that uses the request body, the consumes clause of the predicate is `application/vnd.spring-boot.actuator.v2+json, application/json`. -For all other operations the consumes clause is empty. - - - -[[actuator.endpoints.implementing-custom.web.produces-predicates]] -===== Produces -The produces clause of the predicate can be determined by the `produces` attribute of the `@DeleteOperation`, `@ReadOperation`, and `@WriteOperation` annotations. -The attribute is optional. -If it is not used, the produces clause is determined automatically. - -If the operation method returns `void` or `Void` the produces clause is empty. -If the operation method returns a `org.springframework.core.io.Resource`, the produces clause is `application/octet-stream`. -For all other operations the produces clause is `application/vnd.spring-boot.actuator.v2+json, application/json`. - - - -[[actuator.endpoints.implementing-custom.web.response-status]] -===== Web Endpoint Response Status -The default response status for an endpoint operation depends on the operation type (read, write, or delete) and what, if anything, the operation returns. - -A `@ReadOperation` returns a value, the response status will be 200 (OK). -If it does not return a value, the response status will be 404 (Not Found). - -If a `@WriteOperation` or `@DeleteOperation` returns a value, the response status will be 200 (OK). -If it does not return a value the response status will be 204 (No Content). - -If an operation is invoked without a required parameter, or with a parameter that cannot be converted to the required type, the operation method will not be called and the response status will be 400 (Bad Request). - - - -[[actuator.endpoints.implementing-custom.web.range-requests]] -===== Web Endpoint Range Requests -An HTTP range request can be used to request part of an HTTP resource. -When using Spring MVC or Spring Web Flux, operations that return a `org.springframework.core.io.Resource` automatically support range requests. - -NOTE: Range requests are not supported when using Jersey. - - - -[[actuator.endpoints.implementing-custom.web.security]] -===== Web Endpoint Security -An operation on a web endpoint or a web-specific endpoint extension can receive the current `java.security.Principal` or `org.springframework.boot.actuate.endpoint.SecurityContext` as a method parameter. -The former is typically used in conjunction with `@Nullable` to provide different behavior for authenticated and unauthenticated users. -The latter is typically used to perform authorization checks using its `isUserInRole(String)` method. - - - -[[actuator.endpoints.implementing-custom.servlet]] -==== Servlet Endpoints -A `Servlet` can be exposed as an endpoint by implementing a class annotated with `@ServletEndpoint` that also implements `Supplier`. -Servlet endpoints provide deeper integration with the Servlet container but at the expense of portability. -They are intended to be used to expose an existing `Servlet` as an endpoint. -For new endpoints, the `@Endpoint` and `@WebEndpoint` annotations should be preferred whenever possible. - - - -[[actuator.endpoints.implementing-custom.controller]] -==== Controller Endpoints -`@ControllerEndpoint` and `@RestControllerEndpoint` can be used to implement an endpoint that is only exposed by Spring MVC or Spring WebFlux. -Methods are mapped using the standard annotations for Spring MVC and Spring WebFlux such as `@RequestMapping` and `@GetMapping`, with the endpoint's ID being used as a prefix for the path. -Controller endpoints provide deeper integration with Spring's web frameworks but at the expense of portability. -The `@Endpoint` and `@WebEndpoint` annotations should be preferred whenever possible. - - - -[[actuator.endpoints.health]] -=== Health Information -You can use health information to check the status of your running application. -It is often used by monitoring software to alert someone when a production system goes down. -The information exposed by the `health` endpoint depends on the configprop:management.endpoint.health.show-details[] and configprop:management.endpoint.health.show-components[] properties which can be configured with one of the following values: - -[cols="1, 3"] -|=== -| Name | Description - -| `never` -| Details are never shown. - -| `when-authorized` -| Details are only shown to authorized users. - Authorized roles can be configured using `management.endpoint.health.roles`. - -| `always` -| Details are shown to all users. -|=== - -The default value is `never`. -A user is considered to be authorized when they are in one or more of the endpoint's roles. -If the endpoint has no configured roles (the default) all authenticated users are considered to be authorized. -The roles can be configured using the configprop:management.endpoint.health.roles[] property. - -NOTE: If you have secured your application and wish to use `always`, your security configuration must permit access to the health endpoint for both authenticated and unauthenticated users. - -Health information is collected from the content of a {spring-boot-actuator-module-code}/health/HealthContributorRegistry.java[`HealthContributorRegistry`] (by default all {spring-boot-actuator-module-code}/health/HealthContributor.java[`HealthContributor`] instances defined in your `ApplicationContext`). -Spring Boot includes a number of auto-configured `HealthContributors` and you can also write your own. - -A `HealthContributor` can either be a `HealthIndicator` or a `CompositeHealthContributor`. -A `HealthIndicator` provides actual health information, including a `Status`. -A `CompositeHealthContributor` provides a composite of other `HealthContributors`. -Taken together, contributors form a tree structure to represent the overall system health. - -By default, the final system health is derived by a `StatusAggregator` which sorts the statuses from each `HealthIndicator` based on an ordered list of statuses. -The first status in the sorted list is used as the overall health status. -If no `HealthIndicator` returns a status that is known to the `StatusAggregator`, an `UNKNOWN` status is used. - -TIP: The `HealthContributorRegistry` can be used to register and unregister health indicators at runtime. - - - -[[actuator.endpoints.health.auto-configured-health-indicators]] -==== Auto-configured HealthIndicators -The following `HealthIndicators` are auto-configured by Spring Boot when appropriate. -You can also enable/disable selected indicators by configuring `management.health.key.enabled`, -with the `key` listed in the table below. - -[cols="2,4,6"] -|=== -| Key | Name | Description - -| `cassandra` -| {spring-boot-actuator-module-code}/cassandra/CassandraDriverHealthIndicator.java[`CassandraDriverHealthIndicator`] -| Checks that a Cassandra database is up. - -| `couchbase` -| {spring-boot-actuator-module-code}/couchbase/CouchbaseHealthIndicator.java[`CouchbaseHealthIndicator`] -| Checks that a Couchbase cluster is up. - -| `db` -| {spring-boot-actuator-module-code}/jdbc/DataSourceHealthIndicator.java[`DataSourceHealthIndicator`] -| Checks that a connection to `DataSource` can be obtained. - -| `diskspace` -| {spring-boot-actuator-module-code}/system/DiskSpaceHealthIndicator.java[`DiskSpaceHealthIndicator`] -| Checks for low disk space. - -| `elasticsearch` -| {spring-boot-actuator-module-code}/elasticsearch/ElasticsearchRestHealthIndicator.java[`ElasticsearchRestHealthIndicator`] -| Checks that an Elasticsearch cluster is up. - -| `hazelcast` -| {spring-boot-actuator-module-code}/hazelcast/HazelcastHealthIndicator.java[`HazelcastHealthIndicator`] -| Checks that a Hazelcast server is up. - -| `influxdb` -| {spring-boot-actuator-module-code}/influx/InfluxDbHealthIndicator.java[`InfluxDbHealthIndicator`] -| Checks that an InfluxDB server is up. - -| `jms` -| {spring-boot-actuator-module-code}/jms/JmsHealthIndicator.java[`JmsHealthIndicator`] -| Checks that a JMS broker is up. - -| `ldap` -| {spring-boot-actuator-module-code}/ldap/LdapHealthIndicator.java[`LdapHealthIndicator`] -| Checks that an LDAP server is up. - -| `mail` -| {spring-boot-actuator-module-code}/mail/MailHealthIndicator.java[`MailHealthIndicator`] -| Checks that a mail server is up. - -| `mongo` -| {spring-boot-actuator-module-code}/mongo/MongoHealthIndicator.java[`MongoHealthIndicator`] -| Checks that a Mongo database is up. - -| `neo4j` -| {spring-boot-actuator-module-code}/neo4j/Neo4jHealthIndicator.java[`Neo4jHealthIndicator`] -| Checks that a Neo4j database is up. - -| `ping` -| {spring-boot-actuator-module-code}/health/PingHealthIndicator.java[`PingHealthIndicator`] -| Always responds with `UP`. - -| `rabbit` -| {spring-boot-actuator-module-code}/amqp/RabbitHealthIndicator.java[`RabbitHealthIndicator`] -| Checks that a Rabbit server is up. - -| `redis` -| {spring-boot-actuator-module-code}/redis/RedisHealthIndicator.java[`RedisHealthIndicator`] -| Checks that a Redis server is up. - -| `solr` -| {spring-boot-actuator-module-code}/solr/SolrHealthIndicator.java[`SolrHealthIndicator`] -| Checks that a Solr server is up. -|=== - -TIP: You can disable them all by setting the configprop:management.health.defaults.enabled[] property. - -Additional `HealthIndicators` are available but not enabled by default: - -[cols="3,4,6"] -|=== -| Key | Name | Description - -| `livenessstate` -| {spring-boot-actuator-module-code}/availability/LivenessStateHealthIndicator.java[`LivenessStateHealthIndicator`] -| Exposes the "Liveness" application availability state. - -| `readinessstate` -| {spring-boot-actuator-module-code}/availability/ReadinessStateHealthIndicator.java[`ReadinessStateHealthIndicator`] -| Exposes the "Readiness" application availability state. -|=== - - - -[[actuator.endpoints.health.writing-custom-health-indicators]] -==== Writing Custom HealthIndicators -To provide custom health information, you can register Spring beans that implement the {spring-boot-actuator-module-code}/health/HealthIndicator.java[`HealthIndicator`] interface. -You need to provide an implementation of the `health()` method and return a `Health` response. -The `Health` response should include a status and can optionally include additional details to be displayed. -The following code shows a sample `HealthIndicator` implementation: - -[source,java,pending-extract=true,indent=0] ----- - import org.springframework.boot.actuate.health.Health; - import org.springframework.boot.actuate.health.HealthIndicator; - import org.springframework.stereotype.Component; - - @Component - public class MyHealthIndicator implements HealthIndicator { - - @Override - public Health health() { - int errorCode = check(); // perform some specific health check - if (errorCode != 0) { - return Health.down().withDetail("Error Code", errorCode).build(); - } - return Health.up().build(); - } - - } ----- - -NOTE: The identifier for a given `HealthIndicator` is the name of the bean without the `HealthIndicator` suffix, if it exists. -In the preceding example, the health information is available in an entry named `my`. - -In addition to Spring Boot's predefined {spring-boot-actuator-module-code}/health/Status.java[`Status`] types, it is also possible for `Health` to return a custom `Status` that represents a new system state. -In such cases, a custom implementation of the {spring-boot-actuator-module-code}/health/StatusAggregator.java[`StatusAggregator`] interface also needs to be provided, or the default implementation has to be configured by using the configprop:management.endpoint.health.status.order[] configuration property. - -For example, assume a new `Status` with code `FATAL` is being used in one of your `HealthIndicator` implementations. -To configure the severity order, add the following property to your application properties: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - endpoint: - health: - status: - order: "fatal,down,out-of-service,unknown,up" ----- - -The HTTP status code in the response reflects the overall health status. -By default, `OUT_OF_SERVICE` and `DOWN` map to 503. -Any unmapped health statuses, including `UP`, map to 200. -You might also want to register custom status mappings if you access the health endpoint over HTTP. -Configuring a custom mapping disables the defaults mappings for `DOWN` and `OUT_OF_SERVICE`. -If you want to retain the default mappings they must be configured explicitly alongside any custom mappings. -For example, the following property maps `FATAL` to 503 (service unavailable) and retains the default mappings for `DOWN` and `OUT_OF_SERVICE`: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - endpoint: - health: - status: - http-mapping: - down: 503 - fatal: 503 - out-of-service: 503 ----- - -TIP: If you need more control, you can define your own `HttpCodeStatusMapper` bean. - -The following table shows the default status mappings for the built-in statuses: - -[cols="1,3"] -|=== -| Status | Mapping - -| DOWN -| SERVICE_UNAVAILABLE (503) - -| OUT_OF_SERVICE -| SERVICE_UNAVAILABLE (503) - -| UP -| No mapping by default, so http status is 200 - -| UNKNOWN -| No mapping by default, so http status is 200 -|=== - - - -[[actuator.endpoints.health.reactive-health-indicators]] -==== Reactive Health Indicators -For reactive applications, such as those using Spring WebFlux, `ReactiveHealthContributor` provides a non-blocking contract for getting application health. -Similar to a traditional `HealthContributor`, health information is collected from the content of a {spring-boot-actuator-module-code}/health/ReactiveHealthContributorRegistry.java[`ReactiveHealthContributorRegistry`] (by default all {spring-boot-actuator-module-code}/health/HealthContributor.java[`HealthContributor`] and {spring-boot-actuator-module-code}/health/ReactiveHealthContributor.java[`ReactiveHealthContributor`] instances defined in your `ApplicationContext`). -Regular `HealthContributors` that do not check against a reactive API are executed on the elastic scheduler. - -TIP: In a reactive application, The `ReactiveHealthContributorRegistry` should be used to register and unregister health indicators at runtime. -If you need to register a regular `HealthContributor`, you should wrap it using `ReactiveHealthContributor#adapt`. - -To provide custom health information from a reactive API, you can register Spring beans that implement the {spring-boot-actuator-module-code}/health/ReactiveHealthIndicator.java[`ReactiveHealthIndicator`] interface. -The following code shows a sample `ReactiveHealthIndicator` implementation: - -[source,java,pending-extract=true,indent=0] ----- - @Component - public class MyReactiveHealthIndicator implements ReactiveHealthIndicator { - - @Override - public Mono health() { - return doHealthCheck() //perform some specific health check that returns a Mono - .onErrorResume(ex -> Mono.just(new Health.Builder().down(ex).build())); - } - - } ----- - -TIP: To handle the error automatically, consider extending from `AbstractReactiveHealthIndicator`. - - - -[[actuator.endpoints.health.auto-configured-reactive-health-indicators]] -==== Auto-configured ReactiveHealthIndicators -The following `ReactiveHealthIndicators` are auto-configured by Spring Boot when appropriate: - -[cols="2,4,6"] -|=== -| Key | Name | Description - -| `cassandra` -| {spring-boot-actuator-module-code}/cassandra/CassandraDriverReactiveHealthIndicator.java[`CassandraDriverReactiveHealthIndicator`] -| Checks that a Cassandra database is up. - -| `couchbase` -| {spring-boot-actuator-module-code}/couchbase/CouchbaseReactiveHealthIndicator.java[`CouchbaseReactiveHealthIndicator`] -| Checks that a Couchbase cluster is up. - -| `elasticsearch` -| {spring-boot-actuator-module-code}/elasticsearch/ElasticsearchReactiveHealthIndicator.java[`ElasticsearchReactiveHealthIndicator`] -| Checks that an Elasticsearch cluster is up. - -| `mongo` -| {spring-boot-actuator-module-code}/mongo/MongoReactiveHealthIndicator.java[`MongoReactiveHealthIndicator`] -| Checks that a Mongo database is up. - -| `neo4j` -| {spring-boot-actuator-module-code}/neo4j/Neo4jReactiveHealthIndicator.java[`Neo4jReactiveHealthIndicator`] -| Checks that a Neo4j database is up. - -| `redis` -| {spring-boot-actuator-module-code}/redis/RedisReactiveHealthIndicator.java[`RedisReactiveHealthIndicator`] -| Checks that a Redis server is up. -|=== - -TIP: If necessary, reactive indicators replace the regular ones. -Also, any `HealthIndicator` that is not handled explicitly is wrapped automatically. - - - -[[actuator.endpoints.health.groups]] -==== Health Groups -It's sometimes useful to organize health indicators into groups that can be used for different purposes. - -To create a health indicator group you can use the `management.endpoint.health.group.` property and specify a list of health indicator IDs to `include` or `exclude`. -For example, to create a group that includes only database indicators you can define the following: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - endpoint: - health: - group: - custom: - include: "db" ----- - -You can then check the result by hitting `http://localhost:8080/actuator/health/custom`. - -Similarly, to create a group that excludes the database indicators from the group and includes all the other indicators, you can define the following: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - endpoint: - health: - group: - custom: - exclude: "db" ----- - -By default groups will inherit the same `StatusAggregator` and `HttpCodeStatusMapper` settings as the system health, however, these can also be defined on a per-group basis. -It's also possible to override the `show-details` and `roles` properties if required: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - endpoint: - health: - group: - custom: - show-details: "when-authorized" - roles: "admin" - status: - order: "fatal,up" - http-mapping: - fatal: 500 - out-of-service: 500 ----- - -TIP: You can use `@Qualifier("groupname")` if you need to register custom `StatusAggregator` or `HttpCodeStatusMapper` beans for use with the group. - - - -[[actuator.endpoints.health.datasource]] -==== DataSource Health -The `DataSource` health indicator shows the health of both standard data source and routing data source beans. -The health of a routing data source includes the health of each of its target data sources. -In the health endpoint's response, each of a routing data source's targets is named using its routing key. -If you prefer not to include routing data sources in the indicator's output, set configprop:management.health.db.ignore-routing-data-sources[] to `true`. - - - -[[actuator.endpoints.kubernetes-probes]] -=== Kubernetes Probes -Applications deployed on Kubernetes can provide information about their internal state with https://kubernetes.io/docs/concepts/workloads/pods/pod-lifecycle/#container-probes[Container Probes]. -Depending on https://kubernetes.io/docs/tasks/configure-pod-container/configure-liveness-readiness-startup-probes/[your Kubernetes configuration], the kubelet will call those probes and react to the result. - -Spring Boot manages your <> out-of-the-box. -If deployed in a Kubernetes environment, actuator will gather the "Liveness" and "Readiness" information from the `ApplicationAvailability` interface and use that information in dedicated <>: `LivenessStateHealthIndicator` and `ReadinessStateHealthIndicator`. -These indicators will be shown on the global health endpoint (`"/actuator/health"`). -They will also be exposed as separate HTTP Probes using <>: `"/actuator/health/liveness"` and `"/actuator/health/readiness"`. - -You can then configure your Kubernetes infrastructure with the following endpoint information: - -[source,yml,indent=0] ----- -livenessProbe: - httpGet: - path: /actuator/health/liveness - port: - failureThreshold: ... - periodSeconds: ... - -readinessProbe: - httpGet: - path: /actuator/health/readiness - port: - failureThreshold: ... - periodSeconds: ... ----- - -NOTE: `` should be set to the port that the actuator endpoints are available on. -It could be the main web server port, or a separate management port if the `"management.server.port"` property has been set. - -These health groups are only enabled automatically if the application is <>. -You can enable them in any environment using the configprop:management.endpoint.health.probes.enabled[] configuration property. - -NOTE: If an application takes longer to start than the configured liveness period, Kubernetes mention the `"startupProbe"` as a possible solution. -The `"startupProbe"` is not necessarily needed here as the `"readinessProbe"` fails until all startup tasks are done, see <>. - -WARNING: If your Actuator endpoints are deployed on a separate management context, be aware that endpoints are then not using the same web infrastructure (port, connection pools, framework components) as the main application. -In this case, a probe check could be successful even if the main application does not work properly (for example, it cannot accept new connections). - - - -[[actuator.endpoints.kubernetes-probes.external-state]] -==== Checking External State with Kubernetes Probes -Actuator configures the "liveness" and "readiness" probes as Health Groups; this means that all the <> are available for them. -You can, for example, configure additional Health Indicators: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - endpoint: - health: - group: - readiness: - include: "readinessState,customCheck" ----- - -By default, Spring Boot does not add other Health Indicators to these groups. - -The "`liveness`" Probe should not depend on health checks for external systems. -If the <> is broken, Kubernetes will try to solve that problem by restarting the application instance. -This means that if an external system fails (e.g. a database, a Web API, an external cache), Kubernetes might restart all application instances and create cascading failures. - -As for the "`readiness`" Probe, the choice of checking external systems must be made carefully by the application developers, i.e. Spring Boot does not include any additional health checks in the readiness probe. -If the <> is unready, Kubernetes will not route traffic to that instance. -Some external systems might not be shared by application instances, in which case they could quite naturally be included in a readiness probe. -Other external systems might not be essential to the application (the application could have circuit breakers and fallbacks), in which case they definitely should not be included. -Unfortunately, an external system that is shared by all application instances is common, and you have to make a judgement call: include it in the readiness probe and expect that the application is taken out of service when the external service is down, or leave it out and deal with failures higher up the stack, e.g. using a circuit breaker in the caller. - -NOTE: If all instances of an application are unready, a Kubernetes Service with `type=ClusterIP` or `NodePort` will not accept any incoming connections. -There is no HTTP error response (503 etc.) since there is no connection. -A Service with `type=LoadBalancer` might or might not accept connections, depending on the provider. -A Service that has an explicit https://kubernetes.io/docs/concepts/services-networking/ingress/[Ingress] will also respond in a way that depends on the implementation - the ingress service itself will have to decide how to handle the "connection refused" from downstream. -HTTP 503 is quite likely in the case of both load balancer and ingress. - -Also, if an application is using Kubernetes https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale/[autoscaling] it may react differently to applications being taken out of the load-balancer, depending on its autoscaler configuration. - - - -[[actuator.endpoints.kubernetes-probes.lifecycle]] -==== Application Lifecycle and Probe States -An important aspect of the Kubernetes Probes support is its consistency with the application lifecycle. -There is a significant difference between the `AvailabilityState` which is the in-memory, internal state of the application -and the actual Probe which exposes that state: depending on the phase of application lifecycle, the Probe might not be available. - -Spring Boot publishes <>, -and Probes can listen to such events and expose the `AvailabilityState` information. - -The following tables show the `AvailabilityState` and the state of HTTP connectors at different stages. - -When a Spring Boot application starts: - -[cols="2,2,2,3,5"] -|=== -|Startup phase |LivenessState |ReadinessState |HTTP server |Notes - -|Starting -|`BROKEN` -|`REFUSING_TRAFFIC` -|Not started -|Kubernetes checks the "liveness" Probe and restarts the application if it takes too long. - -|Started -|`CORRECT` -|`REFUSING_TRAFFIC` -|Refuses requests -|The application context is refreshed. The application performs startup tasks and does not receive traffic yet. - -|Ready -|`CORRECT` -|`ACCEPTING_TRAFFIC` -|Accepts requests -|Startup tasks are finished. The application is receiving traffic. -|=== - -When a Spring Boot application shuts down: - -[cols="2,2,2,3,5"] -|=== -|Shutdown phase |Liveness State |Readiness State |HTTP server |Notes - -|Running -|`CORRECT` -|`ACCEPTING_TRAFFIC` -|Accepts requests -|Shutdown has been requested. - -|Graceful shutdown -|`CORRECT` -|`REFUSING_TRAFFIC` -|New requests are rejected -|If enabled, <>. - -|Shutdown complete -|N/A -|N/A -|Server is shut down -|The application context is closed and the application is shut down. -|=== - -TIP: Check out the <> for more information about Kubernetes deployment. - - - -[[actuator.endpoints.info]] -=== Application Information -Application information exposes various information collected from all {spring-boot-actuator-module-code}/info/InfoContributor.java[`InfoContributor`] beans defined in your `ApplicationContext`. -Spring Boot includes a number of auto-configured `InfoContributor` beans, and you can write your own. - - - -[[actuator.endpoints.info.auto-configured-info-contributors]] -==== Auto-configured InfoContributors -The following `InfoContributor` beans are auto-configured by Spring Boot, when appropriate: - -[cols="1,4"] -|=== -| Name | Description - -| {spring-boot-actuator-module-code}/info/EnvironmentInfoContributor.java[`EnvironmentInfoContributor`] -| Exposes any key from the `Environment` under the `info` key. - -| {spring-boot-actuator-module-code}/info/GitInfoContributor.java[`GitInfoContributor`] -| Exposes git information if a `git.properties` file is available. - -| {spring-boot-actuator-module-code}/info/BuildInfoContributor.java[`BuildInfoContributor`] -| Exposes build information if a `META-INF/build-info.properties` file is available. -|=== - -TIP: It is possible to disable them all by setting the configprop:management.info.defaults.enabled[] property. - - - -[[actuator.endpoints.info.custom-application-information]] -==== Custom Application Information -You can customize the data exposed by the `info` endpoint by setting `+info.*+` Spring properties. -All `Environment` properties under the `info` key are automatically exposed. -For example, you could add the following settings to your `application.properties` file: - -[source,yaml,indent=0,configprops,configblocks] ----- - info: - app: - encoding: "UTF-8" - java: - source: "11" - target: "11" ----- - -[TIP] -==== -Rather than hardcoding those values, you could also <>. - -Assuming you use Maven, you could rewrite the preceding example as follows: - -[source,yaml,indent=0,configprops,configblocks] ----- - info: - app: - encoding: "@project.build.sourceEncoding@" - java: - source: "@java.version@" - target: "@java.version@" ----- -==== - - - -[[actuator.endpoints.info.git-commit-information]] -==== Git Commit Information -Another useful feature of the `info` endpoint is its ability to publish information about the state of your `git` source code repository when the project was built. -If a `GitProperties` bean is available, the `info` endpoint can be used to expose these properties. - -TIP: A `GitProperties` bean is auto-configured if a `git.properties` file is available at the root of the classpath. -See "<>" for more details. - -By default, the endpoint exposes `git.branch`, `git.commit.id`, and `git.commit.time` properties, if present. -If you don't want any of these properties in the endpoint response, they need to be excluded from the `git.properties` file. -If you want to display the full git information (that is, the full content of `git.properties`), use the configprop:management.info.git.mode[] property, as follows: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - info: - git: - mode: "full" ----- - -To disable the git commit information from the `info` endpoint completely, set the configprop:management.info.git.enabled[] property to `false`, as follows: - -[source,properties,indent=0,configprops] ----- - management.info.git.enabled=false ----- - - - -[[actuator.endpoints.info.build-information]] -==== Build Information -If a `BuildProperties` bean is available, the `info` endpoint can also publish information about your build. -This happens if a `META-INF/build-info.properties` file is available in the classpath. - -TIP: The Maven and Gradle plugins can both generate that file. -See "<>" for more details. - - - -[[actuator.endpoints.info.writing-custom-info-contributors]] -==== Writing Custom InfoContributors -To provide custom application information, you can register Spring beans that implement the {spring-boot-actuator-module-code}/info/InfoContributor.java[`InfoContributor`] interface. - -The following example contributes an `example` entry with a single value: - -[source,java,pending-extract=true,indent=0] ----- - import java.util.Collections; - - import org.springframework.boot.actuate.info.Info; - import org.springframework.boot.actuate.info.InfoContributor; - import org.springframework.stereotype.Component; - - @Component - public class ExampleInfoContributor implements InfoContributor { - - @Override - public void contribute(Info.Builder builder) { - builder.withDetail("example", - Collections.singletonMap("key", "value")); - } - - } ----- - -If you reach the `info` endpoint, you should see a response that contains the following additional entry: - -[source,json,indent=0] ----- - { - "example": { - "key" : "value" - } - } ----- - - - -[[actuator.monitoring]] -== Monitoring and Management over HTTP -If you are developing a web application, Spring Boot Actuator auto-configures all enabled endpoints to be exposed over HTTP. -The default convention is to use the `id` of the endpoint with a prefix of `/actuator` as the URL path. -For example, `health` is exposed as `/actuator/health`. - -TIP: Actuator is supported natively with Spring MVC, Spring WebFlux, and Jersey. -If both Jersey and Spring MVC are available, Spring MVC will be used. - -NOTE: Jackson is a required dependency in order to get the correct JSON responses as documented in the API documentation ({spring-boot-actuator-restapi-docs}[HTML] or {spring-boot-actuator-restapi-pdfdocs}[PDF]). - - - -[[actuator.monitoring.customizing-management-server-context-path]] -=== Customizing the Management Endpoint Paths -Sometimes, it is useful to customize the prefix for the management endpoints. -For example, your application might already use `/actuator` for another purpose. -You can use the configprop:management.endpoints.web.base-path[] property to change the prefix for your management endpoint, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - endpoints: - web: - base-path: "/manage" ----- - -The preceding `application.properties` example changes the endpoint from `/actuator/\{id}` to `/manage/\{id}` (for example, `/manage/info`). - -NOTE: Unless the management port has been configured to <>, `management.endpoints.web.base-path` is relative to `server.servlet.context-path` (Servlet web applications) or `spring.webflux.base-path` (reactive web applications). -If `management.server.port` is configured, `management.endpoints.web.base-path` is relative to `management.server.base-path`. - -If you want to map endpoints to a different path, you can use the configprop:management.endpoints.web.path-mapping[] property. - -The following example remaps `/actuator/health` to `/healthcheck`: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - endpoints: - web: - base-path: "/" - path-mapping: - health: "healthcheck" ----- - - - -[[actuator.monitoring.customizing-management-server-port]] -=== Customizing the Management Server Port -Exposing management endpoints by using the default HTTP port is a sensible choice for cloud-based deployments. -If, however, your application runs inside your own data center, you may prefer to expose endpoints by using a different HTTP port. - -You can set the configprop:management.server.port[] property to change the HTTP port, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - server: - port: 8081 ----- - -NOTE: On Cloud Foundry, applications only receive requests on port 8080 for both HTTP and TCP routing, by default. -If you want to use a custom management port on Cloud Foundry, you will need to explicitly set up the application's routes to forward traffic to the custom port. - - - -[[actuator.monitoring.management-specific-ssl]] -=== Configuring Management-specific SSL -When configured to use a custom port, the management server can also be configured with its own SSL by using the various `management.server.ssl.*` properties. -For example, doing so lets a management server be available over HTTP while the main application uses HTTPS, as shown in the following property settings: - -[source,yaml,indent=0,configprops,configblocks] ----- - server: - port: 8443 - ssl: - enabled: true - key-store: "classpath:store.jks" - key-password: secret - management: - server: - port: 8080 - ssl: - enabled: false ----- - -Alternatively, both the main server and the management server can use SSL but with different key stores, as follows: - -[source,yaml,indent=0,configprops,configblocks] ----- - server: - port: 8443 - ssl: - enabled: true - key-store: "classpath:main.jks" - key-password: "secret" - management: - server: - port: 8080 - ssl: - enabled: true - key-store: "classpath:management.jks" - key-password: "secret" ----- - - - -[[actuator.monitoring.customizing-management-server-address]] -=== Customizing the Management Server Address -You can customize the address that the management endpoints are available on by setting the configprop:management.server.address[] property. -Doing so can be useful if you want to listen only on an internal or ops-facing network or to listen only for connections from `localhost`. - -NOTE: You can listen on a different address only when the port differs from the main server port. - -The following example `application.properties` does not allow remote management connections: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - server: - port: 8081 - address: "127.0.0.1" ----- - - - -[[actuator.monitoring.disabling-http-endpoints]] -=== Disabling HTTP Endpoints -If you do not want to expose endpoints over HTTP, you can set the management port to `-1`, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - server: - port: -1 ----- - -This can be achieved using the configprop:management.endpoints.web.exposure.exclude[] property as well, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - endpoints: - web: - exposure: - exclude: "*" ----- - - - -[[actuator.jmx]] -== Monitoring and Management over JMX -Java Management Extensions (JMX) provide a standard mechanism to monitor and manage applications. -By default, this feature is not enabled and can be turned on by setting the configuration property configprop:spring.jmx.enabled[] to `true`. -Spring Boot exposes management endpoints as JMX MBeans under the `org.springframework.boot` domain by default. -To Take full control over endpoints registration in the JMX domain, consider registering your own `EndpointObjectNameFactory` implementation. - - - -[[actuator.jmx.custom-mbean-names]] -=== Customizing MBean Names -The name of the MBean is usually generated from the `id` of the endpoint. -For example, the `health` endpoint is exposed as `org.springframework.boot:type=Endpoint,name=Health`. - -If your application contains more than one Spring `ApplicationContext`, you may find that names clash. -To solve this problem, you can set the configprop:spring.jmx.unique-names[] property to `true` so that MBean names are always unique. - -You can also customize the JMX domain under which endpoints are exposed. -The following settings show an example of doing so in `application.properties`: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - jmx: - unique-names: true - management: - endpoints: - jmx: - domain: "com.example.myapp" ----- - - - -[[actuator.jmx.disable-jmx-endpoints]] -=== Disabling JMX Endpoints -If you do not want to expose endpoints over JMX, you can set the configprop:management.endpoints.jmx.exposure.exclude[] property to `*`, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - endpoints: - jmx: - exposure: - exclude: "*" ----- - - - -[[actuator.jmx.jolokia]] -=== Using Jolokia for JMX over HTTP -Jolokia is a JMX-HTTP bridge that provides an alternative method of accessing JMX beans. -To use Jolokia, include a dependency to `org.jolokia:jolokia-core`. -For example, with Maven, you would add the following dependency: - -[source,xml,indent=0] ----- - - org.jolokia - jolokia-core - ----- - -The Jolokia endpoint can then be exposed by adding `jolokia` or `*` to the configprop:management.endpoints.web.exposure.include[] property. -You can then access it by using `/actuator/jolokia` on your management HTTP server. - -NOTE: The Jolokia endpoint exposes Jolokia's servlet as an actuator endpoint. -As a result, it is specific to servlet environments such as Spring MVC and Jersey. -The endpoint will not be available in a WebFlux application. - - - -[[actuator.jmx.jolokia.customizing]] -==== Customizing Jolokia -Jolokia has a number of settings that you would traditionally configure by setting servlet parameters. -With Spring Boot, you can use your `application.properties` file. -To do so, prefix the parameter with `management.endpoint.jolokia.config.`, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - endpoint: - jolokia: - config: - debug: true ----- - - - -[[actuator.jmx.jolokia.disabling]] -==== Disabling Jolokia -If you use Jolokia but do not want Spring Boot to configure it, set the configprop:management.endpoint.jolokia.enabled[] property to `false`, as follows: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - endpoint: - jolokia: - enabled: false ----- - - - -[[actuator.loggers]] -== Loggers -Spring Boot Actuator includes the ability to view and configure the log levels of your application at runtime. -You can view either the entire list or an individual logger's configuration, which is made up of both the explicitly configured logging level as well as the effective logging level given to it by the logging framework. -These levels can be one of: - -* `TRACE` -* `DEBUG` -* `INFO` -* `WARN` -* `ERROR` -* `FATAL` -* `OFF` -* `null` - -`null` indicates that there is no explicit configuration. - - - -[[actuator.loggers.configure]] -=== Configure a Logger -To configure a given logger, `POST` a partial entity to the resource's URI, as shown in the following example: - -[source,json,indent=0] ----- - { - "configuredLevel": "DEBUG" - } ----- - -TIP: To "`reset`" the specific level of the logger (and use the default configuration instead), you can pass a value of `null` as the `configuredLevel`. - - - -[[actuator.metrics]] -== Metrics -Spring Boot Actuator provides dependency management and auto-configuration for https://micrometer.io[Micrometer], an application metrics facade that supports {micrometer-docs}[numerous monitoring systems], including: - -- <> -- <> -- <> -- <> -- <> -- <> -- <> -- <> -- <> -- <> -- <> -- <> -- <> -- <> -- <> -- <> -- <> -- <> - -TIP: To learn more about Micrometer's capabilities, please refer to its https://micrometer.io/docs[reference documentation], in particular the {micrometer-concepts-docs}[concepts section]. - - - -[[actuator.metrics.getting-started]] -=== Getting started -Spring Boot auto-configures a composite `MeterRegistry` and adds a registry to the composite for each of the supported implementations that it finds on the classpath. -Having a dependency on `micrometer-registry-\{system}` in your runtime classpath is enough for Spring Boot to configure the registry. - -Most registries share common features. -For instance, you can disable a particular registry even if the Micrometer registry implementation is on the classpath. -For example, to disable Datadog: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - datadog: - enabled: false ----- - -You can also disable all registries unless stated otherwise by the registry-specific property, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - defaults: - enabled: false ----- - -Spring Boot will also add any auto-configured registries to the global static composite registry on the `Metrics` class unless you explicitly tell it not to: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - use-global-registry: false ----- - -You can register any number of `MeterRegistryCustomizer` beans to further configure the registry, such as applying common tags, before any meters are registered with the registry: - -[source,java,pending-extract=true,indent=0] ----- - @Bean - MeterRegistryCustomizer metricsCommonTags() { - return registry -> registry.config().commonTags("region", "us-east-1"); - } ----- - -You can apply customizations to particular registry implementations by being more specific about the generic type: - -[source,java,pending-extract=true,indent=0] ----- - @Bean - MeterRegistryCustomizer graphiteMetricsNamingConvention() { - return registry -> registry.config().namingConvention(MY_CUSTOM_CONVENTION); - } ----- - -Spring Boot also <> that you can control via configuration or dedicated annotation markers. - - - -[[actuator.metrics.export]] -=== Supported Monitoring Systems - - - -[[actuator.metrics.export.appoptics]] -==== AppOptics -By default, the AppOptics registry pushes metrics to `https://api.appoptics.com/v1/measurements` periodically. -To export metrics to SaaS {micrometer-registry-docs}/appOptics[AppOptics], your API token must be provided: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - appoptics: - api-token: "YOUR_TOKEN" ----- - - - -[[actuator.metrics.export.atlas]] -==== Atlas -By default, metrics are exported to {micrometer-registry-docs}/atlas[Atlas] running on your local machine. -The location of the https://github.com/Netflix/atlas[Atlas server] to use can be provided using: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - atlas: - uri: "https://atlas.example.com:7101/api/v1/publish" ----- - - - -[[actuator.metrics.export.datadog]] -==== Datadog -Datadog registry pushes metrics to https://www.datadoghq.com[datadoghq] periodically. -To export metrics to {micrometer-registry-docs}/datadog[Datadog], your API key must be provided: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - datadog: - api-key: "YOUR_KEY" ----- - -You can also change the interval at which metrics are sent to Datadog: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - datadog: - step: "30s" ----- - - - -[[actuator.metrics.export.dynatrace]] -==== Dynatrace -Dynatrace registry pushes metrics to the configured URI periodically. -To export metrics to {micrometer-registry-docs}/dynatrace[Dynatrace], your API token, device ID, and URI must be provided: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - dynatrace: - api-token: "YOUR_TOKEN" - device-id: "YOUR_DEVICE_ID" - uri: "YOUR_URI" ----- - -You can also change the interval at which metrics are sent to Dynatrace: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - dynatrace: - step: "30s" ----- - - - -[[actuator.metrics.export.elastic]] -==== Elastic -By default, metrics are exported to {micrometer-registry-docs}/elastic[Elastic] running on your local machine. -The location of the Elastic server to use can be provided using the following property: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - elastic: - host: "https://elastic.example.com:8086" ----- - - - -[[actuator.metrics.export.ganglia]] -==== Ganglia -By default, metrics are exported to {micrometer-registry-docs}/ganglia[Ganglia] running on your local machine. -The http://ganglia.sourceforge.net[Ganglia server] host and port to use can be provided using: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - ganglia: - host: "ganglia.example.com" - port: 9649 ----- - - - -[[actuator.metrics.export.graphite]] -==== Graphite -By default, metrics are exported to {micrometer-registry-docs}/graphite[Graphite] running on your local machine. -The https://graphiteapp.org[Graphite server] host and port to use can be provided using: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - graphite: - host: "graphite.example.com" - port: 9004 ----- - -Micrometer provides a default `HierarchicalNameMapper` that governs how a dimensional meter id is {micrometer-registry-docs}/graphite#_hierarchical_name_mapping[mapped to flat hierarchical names]. - -TIP: To take control over this behaviour, define your `GraphiteMeterRegistry` and supply your own `HierarchicalNameMapper`. -An auto-configured `GraphiteConfig` and `Clock` beans are provided unless you define your own: - -[source,java,pending-extract=true,indent=0] ----- - @Bean - public GraphiteMeterRegistry graphiteMeterRegistry(GraphiteConfig config, Clock clock) { - return new GraphiteMeterRegistry(config, clock, MY_HIERARCHICAL_MAPPER); - } ----- - - - -[[actuator.metrics.export.humio]] -==== Humio -By default, the Humio registry pushes metrics to https://cloud.humio.com periodically. -To export metrics to SaaS {micrometer-registry-docs}/humio[Humio], your API token must be provided: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - humio: - api-token: "YOUR_TOKEN" ----- - -You should also configure one or more tags to identify the data source to which metrics will be pushed: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - humio: - tags: - alpha: "a" - bravo: "b" ----- - - - -[[actuator.metrics.export.influx]] -==== Influx -By default, metrics are exported to an {micrometer-registry-docs}/influx[Influx] v1 instance running on your local machine with the default configuration. -To export metrics to InfluxDB v2, configure the `org`, `bucket`, and authentication `token` for writing metrics. -The location of the https://www.influxdata.com[Influx server] to use can be provided using: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - influx: - uri: "https://influx.example.com:8086" ----- - - - -[[actuator.metrics.export.jmx]] -==== JMX -Micrometer provides a hierarchical mapping to {micrometer-registry-docs}/jmx[JMX], primarily as a cheap and portable way to view metrics locally. -By default, metrics are exported to the `metrics` JMX domain. -The domain to use can be provided using: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - jmx: - domain: "com.example.app.metrics" ----- - -Micrometer provides a default `HierarchicalNameMapper` that governs how a dimensional meter id is {micrometer-registry-docs}/jmx#_hierarchical_name_mapping[mapped to flat hierarchical names]. - -TIP: To take control over this behaviour, define your `JmxMeterRegistry` and supply your own `HierarchicalNameMapper`. -An auto-configured `JmxConfig` and `Clock` beans are provided unless you define your own: - -[source,java,pending-extract=true,indent=0] ----- - @Bean - public JmxMeterRegistry jmxMeterRegistry(JmxConfig config, Clock clock) { - return new JmxMeterRegistry(config, clock, MY_HIERARCHICAL_MAPPER); - } ----- - - - -[[actuator.metrics.export.kairos]] -==== KairosDB -By default, metrics are exported to {micrometer-registry-docs}/kairos[KairosDB] running on your local machine. -The location of the https://kairosdb.github.io/[KairosDB server] to use can be provided using: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - kairos: - uri: "https://kairosdb.example.com:8080/api/v1/datapoints" ----- - - - -[[actuator.metrics.export.newrelic]] -==== New Relic -New Relic registry pushes metrics to {micrometer-registry-docs}/new-relic[New Relic] periodically. -To export metrics to https://newrelic.com[New Relic], your API key and account id must be provided: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - newrelic: - api-key: "YOUR_KEY" - account-id: "YOUR_ACCOUNT_ID" ----- - -You can also change the interval at which metrics are sent to New Relic: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - newrelic: - step: "30s" ----- - -By default, metrics are published via REST calls but it is also possible to use the Java Agent API if you have it on the classpath: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - newrelic: - client-provider-type: "insights-agent" ----- - -Finally, you can take full control by defining your own `NewRelicClientProvider` bean. - - - -[[actuator.metrics.export.prometheus]] -==== Prometheus -{micrometer-registry-docs}/prometheus[Prometheus] expects to scrape or poll individual app instances for metrics. -Spring Boot provides an actuator endpoint available at `/actuator/prometheus` to present a https://prometheus.io[Prometheus scrape] with the appropriate format. - -TIP: The endpoint is not available by default and must be exposed, see <> for more details. - -Here is an example `scrape_config` to add to `prometheus.yml`: - -[source,yaml,indent=0] ----- - scrape_configs: - - job_name: 'spring' - metrics_path: '/actuator/prometheus' - static_configs: - - targets: ['HOST:PORT'] ----- - -For ephemeral or batch jobs which may not exist long enough to be scraped, https://github.com/prometheus/pushgateway[Prometheus Pushgateway] support can be used to expose their metrics to Prometheus. -To enable Prometheus Pushgateway support, add the following dependency to your project: - -[source,xml,indent=0] ----- - - io.prometheus - simpleclient_pushgateway - ----- - -When the Prometheus Pushgateway dependency is present on the classpath and the configprop:management.metrics.export.prometheus.pushgateway.enabled[] property is set to `true`, a `PrometheusPushGatewayManager` bean is auto-configured. -This manages the pushing of metrics to a Prometheus Pushgateway. - -The `PrometheusPushGatewayManager` can be tuned using properties under `management.metrics.export.prometheus.pushgateway`. -For advanced configuration, you can also provide your own `PrometheusPushGatewayManager` bean. - - - -[[actuator.metrics.export.signalfx]] -==== SignalFx -SignalFx registry pushes metrics to {micrometer-registry-docs}/signalFx[SignalFx] periodically. -To export metrics to https://www.signalfx.com[SignalFx], your access token must be provided: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - signalfx: - access-token: "YOUR_ACCESS_TOKEN" ----- - -You can also change the interval at which metrics are sent to SignalFx: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - signalfx: - step: "30s" ----- - - - -[[actuator.metrics.export.simple]] -==== Simple -Micrometer ships with a simple, in-memory backend that is automatically used as a fallback if no other registry is configured. -This allows you to see what metrics are collected in the <>. - -The in-memory backend disables itself as soon as you're using any of the other available backend. -You can also disable it explicitly: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - simple: - enabled: false ----- - - - -[[actuator.metrics.export.stackdriver]] -==== Stackdriver -Stackdriver registry pushes metrics to https://cloud.google.com/stackdriver/[Stackdriver] periodically. -To export metrics to SaaS {micrometer-registry-docs}/stackdriver[Stackdriver], your Google Cloud project id must be provided: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - stackdriver: - project-id: "my-project" ----- - -You can also change the interval at which metrics are sent to Stackdriver: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - stackdriver: - step: "30s" ----- - - - -[[actuator.metrics.export.statsd]] -==== StatsD -The StatsD registry pushes metrics over UDP to a StatsD agent eagerly. -By default, metrics are exported to a {micrometer-registry-docs}/statsD[StatsD] agent running on your local machine. -The StatsD agent host, port, and protocol to use can be provided using: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - statsd: - host: "statsd.example.com" - port: 9125 - protocol: "udp" ----- - -You can also change the StatsD line protocol to use (default to Datadog): - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - statsd: - flavor: "etsy" ----- - - - -[[actuator.metrics.export.wavefront]] -==== Wavefront -Wavefront registry pushes metrics to {micrometer-registry-docs}/wavefront[Wavefront] periodically. -If you are exporting metrics to https://www.wavefront.com/[Wavefront] directly, your API token must be provided: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - wavefront: - api-token: "YOUR_API_TOKEN" ----- - -Alternatively, you may use a Wavefront sidecar or an internal proxy set up in your environment that forwards metrics data to the Wavefront API host: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - wavefront: - uri: "proxy://localhost:2878" ----- - -TIP: If publishing metrics to a Wavefront proxy (as described in https://docs.wavefront.com/proxies_installing.html[the documentation]), the host must be in the `proxy://HOST:PORT` format. - -You can also change the interval at which metrics are sent to Wavefront: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - export: - wavefront: - step: "30s" ----- - - - -[[actuator.metrics.supported]] -=== Supported Metrics and Meters -Spring Boot provides automatic meter registration for a wide variety of technologies. -In most situations, the out-of-the-box defaults will provide sensible metrics that can be published to any of the supported monioring systems. - - - -[[actuator.metrics.supported.jvm]] -==== JVM Metrics -Auto-configuration will enable JVM Metrics using core Micrometer classes. -JVM metrics are published under the `jvm.` meter name. - -The following JVM metrics are provided: - -* Various memory and buffer pool details -* Statistics related to garbage collection -* Threads utilization -* The Number of classes loaded/unloaded - - - -[[actuator.metrics.supported.system]] -==== System Metrics -Auto-configuration will enable system metrics using core Micrometer classes. -System metrics are published under the `system.` and `process.` meter names. - -The following system metrics are provided: - -* CPU metrics -* File descriptor metrics -* Uptime metrics (both the amount of time the application has been running as well as a fixed gauge of the absolute start time) - - - -[[actuator.metrics.supported.logger]] -==== Logger Metrics -Auto-configuration enables the event metrics for both Logback and Log4J2. -Details are published under the `log4j2.events.` or `logback.events.` meter names. - - - -[[actuator.metrics.supported.spring-mvc]] -==== Spring MVC Metrics -Auto-configuration enables the instrumentation of all requests handled by Spring MVC controllers and functional handlers. -By default, metrics are generated with the name, `http.server.requests`. -The name can be customized by setting the configprop:management.metrics.web.server.request.metric-name[] property. - -`@Timed` annotations are supported on `@Controller` classes and `@RequestMapping` methods (see <> for details). -If you don't want to record metrics for all Spring MVC requests, you can set configprop:management.metrics.web.server.request.autotime.enabled[] to `false` and exclusively use `@Timed` annotations instead. - -By default, Spring MVC related metrics are tagged with the following information: - -|=== -| Tag | Description - -| `exception` -| Simple class name of any exception that was thrown while handling the request. - -| `method` -| Request's method (for example, `GET` or `POST`) - -| `outcome` -| Request's outcome based on the status code of the response. - 1xx is `INFORMATIONAL`, 2xx is `SUCCESS`, 3xx is `REDIRECTION`, 4xx `CLIENT_ERROR`, and 5xx is `SERVER_ERROR` - -| `status` -| Response's HTTP status code (for example, `200` or `500`) - -| `uri` -| Request's URI template prior to variable substitution, if possible (for example, `/api/person/\{id}`) -|=== - -To add to the default tags, provide one or more ``@Bean``s that implement `WebMvcTagsContributor`. -To replace the default tags, provide a `@Bean` that implements `WebMvcTagsProvider`. - -TIP: In some cases, exceptions handled in Web controllers are not recorded as request metrics tags. -Applications can opt-in and record exceptions by <>. - - - -[[actuator.metrics.supported.spring-webflux]] -==== Spring WebFlux Metrics -Auto-configuration enables the instrumentation of all requests handled by Spring WebFlux controllers and functional handlers. -By default, metrics are generated with the name, `http.server.requests`. -The name can be customized by setting the configprop:management.metrics.web.server.request.metric-name[] property. - -`@Timed` annotations are supported on `@Controller` classes and `@RequestMapping` methods (see <> for details). -If you don't want to record metrics for all Spring WebFlux requests, you can set configprop:management.metrics.web.server.request.autotime.enabled[] to `false` and exclusively use `@Timed` annotations instead. - -By default, WebFlux related metrics are tagged with the following information: - -|=== -| Tag | Description - -| `exception` -| Simple class name of any exception that was thrown while handling the request. - -| `method` -| Request's method (for example, `GET` or `POST`) - -| `outcome` -| Request's outcome based on the status code of the response. - 1xx is `INFORMATIONAL`, 2xx is `SUCCESS`, 3xx is `REDIRECTION`, 4xx `CLIENT_ERROR`, and 5xx is `SERVER_ERROR` - -| `status` -| Response's HTTP status code (for example, `200` or `500`) - -| `uri` -| Request's URI template prior to variable substitution, if possible (for example, `/api/person/\{id}`) -|=== - -To add to the default tags, provide one or more ``@Bean``s that implement `WebFluxTagsContributor`. -To replace the default tags, provide a `@Bean` that implements `WebFluxTagsProvider`. - -TIP: In some cases, exceptions handled in controllers and handler functions are not recorded as request metrics tags. -Applications can opt-in and record exceptions by <>. - - - -[[actuator.metrics.supported.jersey]] -==== Jersey Server Metrics -Auto-configuration enables the instrumentation of all requests handled by the Jersey JAX-RS implementation whenever Micrometer's `micrometer-jersey2` module is on the classpath. -By default, metrics are generated with the name, `http.server.requests`. -The name can be customized by setting the configprop:management.metrics.web.server.request.metric-name[] property. - -`@Timed` annotations are supported on request-handling classes and methods (see <> for details). -If you don't want to record metrics for all Jersey requests, you can set configprop:management.metrics.web.server.request.autotime.enabled[] to `false` and exclusively use `@Timed` annotations instead. - -By default, Jersey server metrics are tagged with the following information: - -|=== -| Tag | Description - -| `exception` -| Simple class name of any exception that was thrown while handling the request. - -| `method` -| Request's method (for example, `GET` or `POST`) - -| `outcome` -| Request's outcome based on the status code of the response. - 1xx is `INFORMATIONAL`, 2xx is `SUCCESS`, 3xx is `REDIRECTION`, 4xx `CLIENT_ERROR`, and 5xx is `SERVER_ERROR` - -| `status` -| Response's HTTP status code (for example, `200` or `500`) - -| `uri` -| Request's URI template prior to variable substitution, if possible (for example, `/api/person/\{id}`) -|=== - -To customize the tags, provide a `@Bean` that implements `JerseyTagsProvider`. - - - -[[actuator.metrics.supported.http-clients]] -==== HTTP Client Metrics -Spring Boot Actuator manages the instrumentation of both `RestTemplate` and `WebClient`. -For that, you have to inject the auto-configured builder and use it to create instances: - -* `RestTemplateBuilder` for `RestTemplate` -* `WebClient.Builder` for `WebClient` - -It is also possible to apply manually the customizers responsible for this instrumentation, namely `MetricsRestTemplateCustomizer` and `MetricsWebClientCustomizer`. - -By default, metrics are generated with the name, `http.client.requests`. -The name can be customized by setting the configprop:management.metrics.web.client.request.metric-name[] property. - -By default, metrics generated by an instrumented client are tagged with the following information: - -|=== -| Tag | Description - -| `clientName` -| Host portion of the URI - -| `method` -| Request's method (for example, `GET` or `POST`) - -| `outcome` -| Request's outcome based on the status code of the response. - 1xx is `INFORMATIONAL`, 2xx is `SUCCESS`, 3xx is `REDIRECTION`, 4xx `CLIENT_ERROR`, and 5xx is `SERVER_ERROR`, `UNKNOWN` otherwise - -| `status` -| Response's HTTP status code if available (for example, `200` or `500`), or `IO_ERROR` in case of I/O issues, `CLIENT_ERROR` otherwise - -| `uri` -| Request's URI template prior to variable substitution, if possible (for example, `/api/person/\{id}`) -|=== - -To customize the tags, and depending on your choice of client, you can provide a `@Bean` that implements `RestTemplateExchangeTagsProvider` or `WebClientExchangeTagsProvider`. -There are convenience static functions in `RestTemplateExchangeTags` and `WebClientExchangeTags`. - - - -[[actuator.metrics.supported.tomcat]] -==== Tomcat Metrics -Auto-configuration will enable the instrumentation of Tomcat only when an `MBeanRegistry` is enabled. -By default, the `MBeanRegistry` is disabled, but you can enable it by setting configprop:server.tomcat.mbeanregistry.enabled[] to `true`. - -Tomcat metrics are published under the `tomcat.` meter name. - - - -[[actuator.metrics.supported.cache]] -==== Cache Metrics -Auto-configuration enables the instrumentation of all available ``Cache``s on startup with metrics prefixed with `cache`. -Cache instrumentation is standardized for a basic set of metrics. -Additional, cache-specific metrics are also available. - -The following cache libraries are supported: - -* Caffeine -* EhCache 2 -* Hazelcast -* Any compliant JCache (JSR-107) implementation -* Redis - -Metrics are tagged by the name of the cache and by the name of the `CacheManager` that is derived from the bean name. - -NOTE: Only caches that are configured on startup are bound to the registry. -For caches not defined in the cache’s configuration, e.g. caches created on-the-fly or programmatically after the startup phase, an explicit registration is required. -A `CacheMetricsRegistrar` bean is made available to make that process easier. - - - -[[actuator.metrics.supported.jdbc]] -==== DataSource Metrics -Auto-configuration enables the instrumentation of all available `DataSource` objects with metrics prefixed with `jdbc.connections`. -Data source instrumentation results in gauges representing the currently active, idle, maximum allowed, and minimum allowed connections in the pool. - -Metrics are also tagged by the name of the `DataSource` computed based on the bean name. - -TIP: By default, Spring Boot provides metadata for all supported data sources; you can add additional `DataSourcePoolMetadataProvider` beans if your favorite data source isn't supported out of the box. -See `DataSourcePoolMetadataProvidersConfiguration` for examples. - -Also, Hikari-specific metrics are exposed with a `hikaricp` prefix. -Each metric is tagged by the name of the Pool (can be controlled with `spring.datasource.name`). - - - -[[actuator.metrics.supported.hibernate]] -==== Hibernate Metrics -If `org.hibernate:hibernate-micrometer` is on the classpath, all available Hibernate `EntityManagerFactory` instances that have statistics enabled are instrumented with a metric named `hibernate`. - -Metrics are also tagged by the name of the `EntityManagerFactory` that is derived from the bean name. - -To enable statistics, the standard JPA property `hibernate.generate_statistics` must be set to `true`. -You can enable that on the auto-configured `EntityManagerFactory` as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - jpa: - properties: - "[hibernate.generate_statistics]": true ----- - - - -[[actuator.metrics.supported.spring-data-repository]] -==== Spring Data Repository Metrics -Auto-configuration enables the instrumentation of all Spring Data `Repository` method invocations. -By default, metrics are generated with the name, `spring.data.repository.invocations`. -The name can be customized by setting the configprop:management.metrics.data.repository.metric-name[] property. - -`@Timed` annotations are supported on `Repository` classes and methods (see <> for details). -If you don't want to record metrics for all `Repository` invocations, you can set configprop:management.metrics.data.repository.autotime.enabled[] to `false` and exclusively use `@Timed` annotations instead. - -By default, repository invocation related metrics are tagged with the following information: - -|=== -| Tag | Description - -| `repository` -| Simple class name of the source `Repository`. - -| `method` -| The name of the `Repository` method that was invoked. - -| `state` -| The result state (`SUCCESS`, `ERROR`, `CANCELED` or `RUNNING`). - -| `exception` -| Simple class name of any exception that was thrown from the invocation. -|=== - -To replace the default tags, provide a `@Bean` that implements `RepositoryTagsProvider`. - - - -[[actuator.metrics.supported.rabbitmq]] -==== RabbitMQ Metrics -Auto-configuration will enable the instrumentation of all available RabbitMQ connection factories with a metric named `rabbitmq`. - - - -[[actuator.metrics.supported.spring-integration]] -==== Spring Integration Metrics -Spring Integration provides {spring-integration-docs}system-management.html#micrometer-integration[Micrometer support] automatically whenever a `MeterRegistry` bean is available. -Metrics are published under the `spring.integration.` meter name. - - - -[[actuator.metrics.supported.kafka]] -==== Kafka Metrics -Auto-configuration will register a `MicrometerConsumerListener` and `MicrometerProducerListener` for the auto-configured consumer factory and producer factory respectively. -It will also register a `KafkaStreamsMicrometerListener` for `StreamsBuilderFactoryBean`. -For more details refer to {spring-kafka-docs}#micrometer-native[Micrometer Native Metrics] section of the Spring Kafka documentation. - - - -[[actuator.metrics.supported.mongodb]] -==== MongoDB Metrics - - - -[[actuator.metrics.supported.mongodb.command]] -===== Command Metrics -Auto-configuration will register a `MongoMetricsCommandListener` with the auto-configured `MongoClient`. - -A timer metric with the name `mongodb.driver.commands` is created for each command issued to the underlying MongoDB driver. -Each metric is tagged with the following information by default: -|=== -| Tag | Description - -| `command` -| Name of the command issued - -| `cluster.id` -| Identifier of the cluster the command was sent to - -| `server.address` -| Address of the server the command was sent to - -| `status` -| Outcome of the command - one of (`SUCCESS`, `FAILED`) -|=== - -To replace the default metric tags, define a `MongoCommandTagsProvider` bean, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-productionreadyfeatures}/metrics/mongo/SampleCommandTagsProviderConfiguration.java[] ----- - -To disable the auto-configured command metrics, set the following property: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - mongo: - command: - enabled: false ----- - - - -[[actuator.metrics.supported.mongodb.connection-pool]] -===== Connection Pool Metrics -Auto-configuration will register a `MongoMetricsConnectionPoolListener` with the auto-configured `MongoClient`. - -The following gauge metrics are created for the connection pool: - -* `mongodb.driver.pool.size` that reports the current size of the connection pool, including idle and and in-use members -* `mongodb.driver.pool.checkedout` that reports the count of connections that are currently in use -* `mongodb.driver.pool.waitqueuesize` that reports the current size of the wait queue for a connection from the pool - -Each metric is tagged with the following information by default: -|=== -| Tag | Description - -| `cluster.id` -| Identifier of the cluster the connection pool corresponds to - -| `server.address` -| Address of the server the connection pool corresponds to -|=== - -To replace the default metric tags, define a `MongoConnectionPoolTagsProvider` bean, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-productionreadyfeatures}/metrics/mongo/SampleConnectionPoolTagsProviderConfiguration.java[tag=*] ----- - -To disable the auto-configured connection pool metrics, set the following property: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - mongo: - connectionpool: - enabled: false ----- - - - -[[actuator.metrics.supported.timed-annotation]] -==== @Timed Annotation Support -The `@Timed` annotation from the `io.micrometer.core.annotation` package can be used with several of the supported technologies listed above. -If supported, the annotation can be used either at the class-level or the method-level. - -For example, the following code shows how the annotation can be used to instrument all request mappings in a `@RestController`: - -[source,java,pending-extract=true,indent=0] ----- - @RestController - @Timed - public class MyController { - - @GetMapping("/api/addresses") - public List listAddress() { ... } - - @GetMapping("/api/people") - public List listPeople() { ... } - - } ----- - -If you only want to instrument a single mapping, you can use the annotation on the method instead of the class: - -[source,java,pending-extract=true,indent=0] ----- - @RestController - public class MyController { - - @GetMapping("/api/addresses") - public List listAddress() { ... } - - @GetMapping("/api/people") - @Timed - public List listPeople() { ... } - - } ----- - -You can also combine class-level and method-level annotations if you want to change timing details for a specific method: - -[source,java,pending-extract=true,indent=0] ----- - @RestController - @Timed - public class MyController { - - @GetMapping("/api/addresses") - public List listPeople() { ... } - - @GetMapping("/api/people") - @Timed(extraTags = { "region", "us-east-1" }) - @Timed(value = "all.people", longTask = true) - public List listPeople() { ... } - - } ----- - -NOTE: A `@Timed` annotation with `longTask = true` will enable a long task timer for the method. -Long task timers require a separate metric name, and can be stacked with a short task timer. - - - -[[actuator.metrics.registering-custom]] -=== Registering Custom Metrics -To register custom metrics, inject `MeterRegistry` into your component, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-productionreadyfeatures}/metrics/MetricsMeterRegistryInjection.java[tag=*] ----- - -If your metrics depend on other beans, it is recommended that you use a `MeterBinder` to register them, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-productionreadyfeatures}/metrics/SampleMeterBinderConfiguration.java[tag=*] ----- - -Using a `MeterBinder` ensures that the correct dependency relationships are set up and that the bean is available when the metric's value is retrieved. -A `MeterBinder` implementation can also be useful if you find that you repeatedly instrument a suite of metrics across components or applications. - -NOTE: By default, metrics from all `MeterBinder` beans will be automatically bound to the Spring-managed `MeterRegistry`. - - - -[[actuator.metrics.customizing]] -=== Customizing Individual Metrics -If you need to apply customizations to specific `Meter` instances you can use the `io.micrometer.core.instrument.config.MeterFilter` interface. - -For example, if you want to rename the `mytag.region` tag to `mytag.area` for all meter IDs beginning with `com.example`, you can do the following: - -[source,java,indent=0] ----- -include::{include-productionreadyfeatures}/metrics/MetricsFilterConfiguration.java[tag=*] ----- - -NOTE: By default, all `MeterFilter` beans will be automatically bound to the Spring-managed `MeterRegistry`. -Make sure to register your metrics using the Spring-managed `MeterRegistry` and not any of the static methods on `Metrics`. -These use the global registry that is not Spring-managed. - - - -[[actuator.metrics.customizing.common-tags]] -==== Common Tags -Common tags are generally used for dimensional drill-down on the operating environment like host, instance, region, stack, etc. -Commons tags are applied to all meters and can be configured as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - tags: - region: "us-east-1" - stack: "prod" ----- - -The example above adds `region` and `stack` tags to all meters with a value of `us-east-1` and `prod` respectively. - -NOTE: The order of common tags is important if you are using Graphite. -As the order of common tags cannot be guaranteed using this approach, Graphite users are advised to define a custom `MeterFilter` instead. - - - -[[actuator.metrics.customizing.per-meter-properties]] -==== Per-meter Properties -In addition to `MeterFilter` beans, it's also possible to apply a limited set of customization on a per-meter basis using properties. -Per-meter customizations apply to any all meter IDs that start with the given name. -For example, the following will disable any meters that have an ID starting with `example.remote` - -[source,yaml,indent=0,configprops,configblocks] ----- - management: - metrics: - enable: - example: - remote: false ----- - -The following properties allow per-meter customization: - -.Per-meter customizations -|=== -| Property | Description - -| configprop:management.metrics.enable[] -| Whether to deny meters from emitting any metrics. - -| configprop:management.metrics.distribution.percentiles-histogram[] -| Whether to publish a histogram suitable for computing aggregable (across dimension) percentile approximations. - -| configprop:management.metrics.distribution.minimum-expected-value[], configprop:management.metrics.distribution.maximum-expected-value[] -| Publish less histogram buckets by clamping the range of expected values. - -| configprop:management.metrics.distribution.percentiles[] -| Publish percentile values computed in your application - -| configprop:management.metrics.distribution.slo[] -| Publish a cumulative histogram with buckets defined by your service-level objectives. -|=== - -For more details on concepts behind `percentiles-histogram`, `percentiles` and `slo` refer to the {micrometer-concepts-docs}#_histograms_and_percentiles["Histograms and percentiles" section] of the micrometer documentation. - - - -[[actuator.metrics.endpoint]] -=== Metrics Endpoint -Spring Boot provides a `metrics` endpoint that can be used diagnostically to examine the metrics collected by an application. -The endpoint is not available by default and must be exposed, see <> for more details. - -Navigating to `/actuator/metrics` displays a list of available meter names. -You can drill down to view information about a particular meter by providing its name as a selector, e.g. `/actuator/metrics/jvm.memory.max`. - -[TIP] -==== -The name you use here should match the name used in the code, not the name after it has been naming-convention normalized for a monitoring system it is shipped to. -In other words, if `jvm.memory.max` appears as `jvm_memory_max` in Prometheus because of its snake case naming convention, you should still use `jvm.memory.max` as the selector when inspecting the meter in the `metrics` endpoint. -==== - -You can also add any number of `tag=KEY:VALUE` query parameters to the end of the URL to dimensionally drill down on a meter, e.g. `/actuator/metrics/jvm.memory.max?tag=area:nonheap`. - -[TIP] -==== -The reported measurements are the _sum_ of the statistics of all meters matching the meter name and any tags that have been applied. -So in the example above, the returned "Value" statistic is the sum of the maximum memory footprints of "Code Cache", "Compressed Class Space", and "Metaspace" areas of the heap. -If you only wanted to see the maximum size for the "Metaspace", you could add an additional `tag=id:Metaspace`, i.e. `/actuator/metrics/jvm.memory.max?tag=area:nonheap&tag=id:Metaspace`. -==== - - - -[[actuator.auditing]] -== Auditing -Once Spring Security is in play, Spring Boot Actuator has a flexible audit framework that publishes events (by default, "`authentication success`", "`failure`" and "`access denied`" exceptions). -This feature can be very useful for reporting and for implementing a lock-out policy based on authentication failures. - -Auditing can be enabled by providing a bean of type `AuditEventRepository` in your application's configuration. -For convenience, Spring Boot offers an `InMemoryAuditEventRepository`. -`InMemoryAuditEventRepository` has limited capabilities and we recommend using it only for development environments. -For production environments, consider creating your own alternative `AuditEventRepository` implementation. - - - -[[actuator.auditing.custom]] -=== Custom Auditing -To customize published security events, you can provide your own implementations of `AbstractAuthenticationAuditListener` and `AbstractAuthorizationAuditListener`. - -You can also use the audit services for your own business events. -To do so, either inject the `AuditEventRepository` bean into your own components and use that directly or publish an `AuditApplicationEvent` with the Spring `ApplicationEventPublisher` (by implementing `ApplicationEventPublisherAware`). - - - -[[actuator.tracing]] -== HTTP Tracing -HTTP Tracing can be enabled by providing a bean of type `HttpTraceRepository` in your application's configuration. -For convenience, Spring Boot offers an `InMemoryHttpTraceRepository` that stores traces for the last 100 request-response exchanges, by default. -`InMemoryHttpTraceRepository` is limited compared to other tracing solutions and we recommend using it only for development environments. -For production environments, use of a production-ready tracing or observability solution, such as Zipkin or Spring Cloud Sleuth, is recommended. -Alternatively, create your own `HttpTraceRepository` that meets your needs. - -The `httptrace` endpoint can be used to obtain information about the request-response exchanges that are stored in the `HttpTraceRepository`. - - - -[[actuator.tracing.custom]] -=== Custom HTTP tracing -To customize the items that are included in each trace, use the configprop:management.trace.http.include[] configuration property. -For advanced customization, consider registering your own `HttpExchangeTracer` implementation. - - - -[[actuator.process-monitoring]] -== Process Monitoring -In the `spring-boot` module, you can find two classes to create files that are often useful for process monitoring: - -* `ApplicationPidFileWriter` creates a file containing the application PID (by default, in the application directory with a file name of `application.pid`). -* `WebServerPortFileWriter` creates a file (or files) containing the ports of the running web server (by default, in the application directory with a file name of `application.port`). - -By default, these writers are not activated, but you can enable: - -* <> -* <> - - - -[[actuator.process-monitoring.configuration]] -=== Extending Configuration -In the `META-INF/spring.factories` file, you can activate the listener(s) that writes a PID file, as shown in the following example: - -[indent=0] ----- - org.springframework.context.ApplicationListener=\ - org.springframework.boot.context.ApplicationPidFileWriter,\ - org.springframework.boot.web.context.WebServerPortFileWriter ----- - - - -[[actuator.process-monitoring.programmatically]] -=== Programmatically -You can also activate a listener by invoking the `SpringApplication.addListeners(...)` method and passing the appropriate `Writer` object. -This method also lets you customize the file name and path in the `Writer` constructor. - - - -[[actuator.cloud-foundry]] -== Cloud Foundry Support -Spring Boot's actuator module includes additional support that is activated when you deploy to a compatible Cloud Foundry instance. -The `/cloudfoundryapplication` path provides an alternative secured route to all `@Endpoint` beans. - -The extended support lets Cloud Foundry management UIs (such as the web application that you can use to view deployed applications) be augmented with Spring Boot actuator information. -For example, an application status page may include full health information instead of the typical "`running`" or "`stopped`" status. - -NOTE: The `/cloudfoundryapplication` path is not directly accessible to regular users. -In order to use the endpoint, a valid UAA token must be passed with the request. - - - -[[actuator.cloud-foundry.disable]] -=== Disabling Extended Cloud Foundry Actuator Support -If you want to fully disable the `/cloudfoundryapplication` endpoints, you can add the following setting to your `application.properties` file: - - -.application.properties -[source,yaml,indent=0,configprops,configblocks] ----- - management: - cloudfoundry: - enabled: false ----- - - - -[[actuator.cloud-foundry.ssl]] -=== Cloud Foundry Self-signed Certificates -By default, the security verification for `/cloudfoundryapplication` endpoints makes SSL calls to various Cloud Foundry services. -If your Cloud Foundry UAA or Cloud Controller services use self-signed certificates, you need to set the following property: - -.application.properties -[source,yaml,indent=0,configprops,configblocks] ----- - management: - cloudfoundry: - skip-ssl-validation: true ----- - - - -[[actuator.cloud-foundry.custom-context-path]] -=== Custom Context Path -If the server's context-path has been configured to anything other than `/`, the Cloud Foundry endpoints will not be available at the root of the application. -For example, if `server.servlet.context-path=/app`, Cloud Foundry endpoints will be available at `/app/cloudfoundryapplication/*`. - -If you expect the Cloud Foundry endpoints to always be available at `/cloudfoundryapplication/*`, regardless of the server's context-path, you will need to explicitly configure that in your application. -The configuration will differ depending on the web server in use. -For Tomcat, the following configuration can be added: - -[source,java,indent=0] ----- -include::{include-productionreadyfeatures}/cloudfoundry/CloudFoundryCustomContextPathConfiguration.java[tag=*] ----- - - - -[[actuator.whats-next]] -== What to Read Next -You might want to read about graphing tools such as https://graphiteapp.org[Graphite]. - -Otherwise, you can continue on, to read about <> or jump ahead for some in-depth information about Spring Boot's _<>_. +include::actuator/whats-next.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/auditing.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/auditing.adoc new file mode 100644 index 0000000000..2a18952ed1 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/auditing.adoc @@ -0,0 +1,18 @@ +[[actuator.auditing]] +== Auditing +Once Spring Security is in play, Spring Boot Actuator has a flexible audit framework that publishes events (by default, "`authentication success`", "`failure`" and "`access denied`" exceptions). +This feature can be very useful for reporting and for implementing a lock-out policy based on authentication failures. + +Auditing can be enabled by providing a bean of type `AuditEventRepository` in your application's configuration. +For convenience, Spring Boot offers an `InMemoryAuditEventRepository`. +`InMemoryAuditEventRepository` has limited capabilities and we recommend using it only for development environments. +For production environments, consider creating your own alternative `AuditEventRepository` implementation. + + + +[[actuator.auditing.custom]] +=== Custom Auditing +To customize published security events, you can provide your own implementations of `AbstractAuthenticationAuditListener` and `AbstractAuthorizationAuditListener`. + +You can also use the audit services for your own business events. +To do so, either inject the `AuditEventRepository` bean into your own components and use that directly or publish an `AuditApplicationEvent` with the Spring `ApplicationEventPublisher` (by implementing `ApplicationEventPublisherAware`). diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/cloud-foundry.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/cloud-foundry.adoc new file mode 100644 index 0000000000..d4028b1ce9 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/cloud-foundry.adoc @@ -0,0 +1,56 @@ +[[actuator.cloud-foundry]] +== Cloud Foundry Support +Spring Boot's actuator module includes additional support that is activated when you deploy to a compatible Cloud Foundry instance. +The `/cloudfoundryapplication` path provides an alternative secured route to all `@Endpoint` beans. + +The extended support lets Cloud Foundry management UIs (such as the web application that you can use to view deployed applications) be augmented with Spring Boot actuator information. +For example, an application status page may include full health information instead of the typical "`running`" or "`stopped`" status. + +NOTE: The `/cloudfoundryapplication` path is not directly accessible to regular users. +In order to use the endpoint, a valid UAA token must be passed with the request. + + + +[[actuator.cloud-foundry.disable]] +=== Disabling Extended Cloud Foundry Actuator Support +If you want to fully disable the `/cloudfoundryapplication` endpoints, you can add the following setting to your `application.properties` file: + + +.application.properties +[source,yaml,indent=0,configprops,configblocks] +---- + management: + cloudfoundry: + enabled: false +---- + + + +[[actuator.cloud-foundry.ssl]] +=== Cloud Foundry Self-signed Certificates +By default, the security verification for `/cloudfoundryapplication` endpoints makes SSL calls to various Cloud Foundry services. +If your Cloud Foundry UAA or Cloud Controller services use self-signed certificates, you need to set the following property: + +.application.properties +[source,yaml,indent=0,configprops,configblocks] +---- + management: + cloudfoundry: + skip-ssl-validation: true +---- + + + +[[actuator.cloud-foundry.custom-context-path]] +=== Custom Context Path +If the server's context-path has been configured to anything other than `/`, the Cloud Foundry endpoints will not be available at the root of the application. +For example, if `server.servlet.context-path=/app`, Cloud Foundry endpoints will be available at `/app/cloudfoundryapplication/*`. + +If you expect the Cloud Foundry endpoints to always be available at `/cloudfoundryapplication/*`, regardless of the server's context-path, you will need to explicitly configure that in your application. +The configuration will differ depending on the web server in use. +For Tomcat, the following configuration can be added: + +[source,java,indent=0] +---- +include::{include-productionreadyfeatures}/cloudfoundry/CloudFoundryCustomContextPathConfiguration.java[tag=*] +---- diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/enabling.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/enabling.adoc new file mode 100644 index 0000000000..f8162750f7 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/enabling.adoc @@ -0,0 +1,31 @@ +[[actuator.enabling]] +== Enabling Production-ready Features +The {spring-boot-code}/spring-boot-project/spring-boot-actuator[`spring-boot-actuator`] module provides all of Spring Boot's production-ready features. +The recommended way to enable the features is to add a dependency on the `spring-boot-starter-actuator` '`Starter`'. + +.Definition of Actuator +**** +An actuator is a manufacturing term that refers to a mechanical device for moving or controlling something. +Actuators can generate a large amount of motion from a small change. +**** + +To add the actuator to a Maven based project, add the following '`Starter`' dependency: + +[source,xml,indent=0] +---- + + + org.springframework.boot + spring-boot-starter-actuator + + +---- + +For Gradle, use the following declaration: + +[source,groovy,indent=0] +---- + dependencies { + implementation 'org.springframework.boot:spring-boot-starter-actuator' + } +---- diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/endpoints.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/endpoints.adoc new file mode 100644 index 0000000000..9cd28a92c1 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/endpoints.adoc @@ -0,0 +1,1250 @@ +[[actuator.endpoints]] +== Endpoints +Actuator endpoints let you monitor and interact with your application. +Spring Boot includes a number of built-in endpoints and lets you add your own. +For example, the `health` endpoint provides basic application health information. + +Each individual endpoint can be <> and <>. +An endpoint is considered to be available when it is both enabled and exposed. +The built-in endpoints will only be auto-configured when they are available. +Most applications choose exposure via HTTP, where the ID of the endpoint along with a prefix of `/actuator` is mapped to a URL. +For example, by default, the `health` endpoint is mapped to `/actuator/health`. + +TIP: To learn more about the Actuator's endpoints and their request and response formats, please refer to the separate API documentation ({spring-boot-actuator-restapi-docs}[HTML] or {spring-boot-actuator-restapi-pdfdocs}[PDF]). + +The following technology-agnostic endpoints are available: + +[cols="2,5"] +|=== +| ID | Description + +| `auditevents` +| Exposes audit events information for the current application. + Requires an `AuditEventRepository` bean. + +| `beans` +| Displays a complete list of all the Spring beans in your application. + +| `caches` +| Exposes available caches. + +| `conditions` +| Shows the conditions that were evaluated on configuration and auto-configuration classes and the reasons why they did or did not match. + +| `configprops` +| Displays a collated list of all `@ConfigurationProperties`. + +| `env` +| Exposes properties from Spring's `ConfigurableEnvironment`. + +| `flyway` +| Shows any Flyway database migrations that have been applied. + Requires one or more `Flyway` beans. + +| `health` +| Shows application health information. + +| `httptrace` +| Displays HTTP trace information (by default, the last 100 HTTP request-response exchanges). + Requires an `HttpTraceRepository` bean. + +| `info` +| Displays arbitrary application info. + +| `integrationgraph` +| Shows the Spring Integration graph. + Requires a dependency on `spring-integration-core`. + +| `loggers` +| Shows and modifies the configuration of loggers in the application. + +| `liquibase` +| Shows any Liquibase database migrations that have been applied. + Requires one or more `Liquibase` beans. + +| `metrics` +| Shows '`metrics`' information for the current application. + +| `mappings` +| Displays a collated list of all `@RequestMapping` paths. + +|`quartz` +|Shows information about Quartz Scheduler jobs. + +| `scheduledtasks` +| Displays the scheduled tasks in your application. + +| `sessions` +| Allows retrieval and deletion of user sessions from a Spring Session-backed session store. + Requires a Servlet-based web application using Spring Session. + +| `shutdown` +| Lets the application be gracefully shutdown. + Disabled by default. + +| `startup` +| Shows the <> collected by the `ApplicationStartup`. + Requires the `SpringApplication` to be configured with a `BufferingApplicationStartup`. + +| `threaddump` +| Performs a thread dump. +|=== + +If your application is a web application (Spring MVC, Spring WebFlux, or Jersey), you can use the following additional endpoints: + +[cols="2,5"] +|=== +| ID | Description + +| `heapdump` +| Returns an `hprof` heap dump file. + +| `jolokia` +| Exposes JMX beans over HTTP (when Jolokia is on the classpath, not available for WebFlux). + Requires a dependency on `jolokia-core`. + +| `logfile` +| Returns the contents of the logfile (if `logging.file.name` or `logging.file.path` properties have been set). + Supports the use of the HTTP `Range` header to retrieve part of the log file's content. + +| `prometheus` +| Exposes metrics in a format that can be scraped by a Prometheus server. + Requires a dependency on `micrometer-registry-prometheus`. +|=== + + + +[[actuator.endpoints.enabling]] +=== Enabling Endpoints +By default, all endpoints except for `shutdown` are enabled. +To configure the enablement of an endpoint, use its `management.endpoint..enabled` property. +The following example enables the `shutdown` endpoint: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + endpoint: + shutdown: + enabled: true +---- + +If you prefer endpoint enablement to be opt-in rather than opt-out, set the configprop:management.endpoints.enabled-by-default[] property to `false` and use individual endpoint `enabled` properties to opt back in. +The following example enables the `info` endpoint and disables all other endpoints: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + endpoints: + enabled-by-default: false + endpoint: + info: + enabled: true +---- + +NOTE: Disabled endpoints are removed entirely from the application context. +If you want to change only the technologies over which an endpoint is exposed, use the <> instead. + + + +[[actuator.endpoints.exposing]] +=== Exposing Endpoints +Since Endpoints may contain sensitive information, careful consideration should be given about when to expose them. +The following table shows the default exposure for the built-in endpoints: + +[cols="1,1,1"] +|=== +| ID | JMX | Web + +| `auditevents` +| Yes +| No + +| `beans` +| Yes +| No + +| `caches` +| Yes +| No + +| `conditions` +| Yes +| No + +| `configprops` +| Yes +| No + +| `env` +| Yes +| No + +| `flyway` +| Yes +| No + +| `health` +| Yes +| Yes + +| `heapdump` +| N/A +| No + +| `httptrace` +| Yes +| No + +| `info` +| Yes +| Yes + +| `integrationgraph` +| Yes +| No + +| `jolokia` +| N/A +| No + +| `logfile` +| N/A +| No + +| `loggers` +| Yes +| No + +| `liquibase` +| Yes +| No + +| `metrics` +| Yes +| No + +| `mappings` +| Yes +| No + +| `prometheus` +| N/A +| No + +| `quartz` +| Yes +| No + +| `scheduledtasks` +| Yes +| No + +| `sessions` +| Yes +| No + +| `shutdown` +| Yes +| No + +| `startup` +| Yes +| No + +| `threaddump` +| Yes +| No +|=== + +To change which endpoints are exposed, use the following technology-specific `include` and `exclude` properties: + +[cols="3,1"] +|=== +| Property | Default + +| configprop:management.endpoints.jmx.exposure.exclude[] +| + +| configprop:management.endpoints.jmx.exposure.include[] +| `*` + +| configprop:management.endpoints.web.exposure.exclude[] +| + +| configprop:management.endpoints.web.exposure.include[] +| `info, health` +|=== + +The `include` property lists the IDs of the endpoints that are exposed. +The `exclude` property lists the IDs of the endpoints that should not be exposed. +The `exclude` property takes precedence over the `include` property. +Both `include` and `exclude` properties can be configured with a list of endpoint IDs. + +For example, to stop exposing all endpoints over JMX and only expose the `health` and `info` endpoints, use the following property: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + endpoints: + jmx: + exposure: + include: "health,info" +---- + +`*` can be used to select all endpoints. +For example, to expose everything over HTTP except the `env` and `beans` endpoints, use the following properties: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + endpoints: + web: + exposure: + include: "*" + exclude: "env,beans" +---- + +NOTE: `*` has a special meaning in YAML, so be sure to add quotes if you want to include (or exclude) all endpoints. + +NOTE: If your application is exposed publicly, we strongly recommend that you also <>. + +TIP: If you want to implement your own strategy for when endpoints are exposed, you can register an `EndpointFilter` bean. + + + +[[actuator.endpoints.security]] +=== Securing HTTP Endpoints +You should take care to secure HTTP endpoints in the same way that you would any other sensitive URL. +If Spring Security is present, endpoints are secured by default using Spring Security’s content-negotiation strategy. +If you wish to configure custom security for HTTP endpoints, for example, only allow users with a certain role to access them, Spring Boot provides some convenient `RequestMatcher` objects that can be used in combination with Spring Security. + +A typical Spring Security configuration might look something like the following example: + +[source,java,pending-extract=true,indent=0] +---- + @Bean + public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception { + http.requestMatcher(EndpointRequest.toAnyEndpoint()).authorizeRequests((requests) -> + requests.anyRequest().hasRole("ENDPOINT_ADMIN")); + http.httpBasic(); + return http.build(); + } +---- + +The preceding example uses `EndpointRequest.toAnyEndpoint()` to match a request to any endpoint and then ensures that all have the `ENDPOINT_ADMIN` role. +Several other matcher methods are also available on `EndpointRequest`. +See the API documentation ({spring-boot-actuator-restapi-docs}[HTML] or {spring-boot-actuator-restapi-pdfdocs}[PDF]) for details. + +If you deploy applications behind a firewall, you may prefer that all your actuator endpoints can be accessed without requiring authentication. +You can do so by changing the configprop:management.endpoints.web.exposure.include[] property, as follows: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + endpoints: + web: + exposure: + include: "*" +---- + +Additionally, if Spring Security is present, you would need to add custom security configuration that allows unauthenticated access to the endpoints as shown in the following example: + +[source,java,pending-extract=true,indent=0] +---- + @Bean + public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception { + http.requestMatcher(EndpointRequest.toAnyEndpoint()).authorizeRequests((requests) -> + requests.anyRequest().permitAll()); + return http.build(); + } +---- + +NOTE: In both the examples above, the configuration applies only to the actuator endpoints. +Since Spring Boot's security configuration backs off completely in the presence of any `SecurityFilterChain` bean, you will need to configure an additional `SecurityFilterChain` bean with rules that apply to the rest of the application. + + + +[[actuator.endpoints.caching]] +=== Configuring Endpoints +Endpoints automatically cache responses to read operations that do not take any parameters. +To configure the amount of time for which an endpoint will cache a response, use its `cache.time-to-live` property. +The following example sets the time-to-live of the `beans` endpoint's cache to 10 seconds: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + endpoint: + beans: + cache: + time-to-live: "10s" +---- + +NOTE: The prefix `management.endpoint.` is used to uniquely identify the endpoint that is being configured. + + + +[[actuator.endpoints.hypermedia]] +=== Hypermedia for Actuator Web Endpoints +A "`discovery page`" is added with links to all the endpoints. +The "`discovery page`" is available on `/actuator` by default. + +To disable the "`discovery page`", add the following property to your application properties: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + endpoints: + web: + discovery: + enabled: false +---- + +When a custom management context path is configured, the "`discovery page`" automatically moves from `/actuator` to the root of the management context. +For example, if the management context path is `/management`, then the discovery page is available from `/management`. +When the management context path is set to `/`, the discovery page is disabled to prevent the possibility of a clash with other mappings. + + + +[[actuator.endpoints.cors]] +=== CORS Support +https://en.wikipedia.org/wiki/Cross-origin_resource_sharing[Cross-origin resource sharing] (CORS) is a https://www.w3.org/TR/cors/[W3C specification] that lets you specify in a flexible way what kind of cross-domain requests are authorized. +If you use Spring MVC or Spring WebFlux, Actuator's web endpoints can be configured to support such scenarios. + +CORS support is disabled by default and is only enabled once the configprop:management.endpoints.web.cors.allowed-origins[] property has been set. +The following configuration permits `GET` and `POST` calls from the `example.com` domain: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + endpoints: + web: + cors: + allowed-origins: "https://example.com" + allowed-methods: "GET,POST" +---- + +TIP: See {spring-boot-actuator-autoconfigure-module-code}/endpoint/web/CorsEndpointProperties.java[CorsEndpointProperties] for a complete list of options. + + + +[[actuator.endpoints.implementing-custom]] +=== Implementing Custom Endpoints +If you add a `@Bean` annotated with `@Endpoint`, any methods annotated with `@ReadOperation`, `@WriteOperation`, or `@DeleteOperation` are automatically exposed over JMX and, in a web application, over HTTP as well. +Endpoints can be exposed over HTTP using Jersey, Spring MVC, or Spring WebFlux. +If both Jersey and Spring MVC are available, Spring MVC will be used. + +The following example exposes a read operation that returns a custom object: + +[source,java,indent=0] +---- +include::{include-productionreadyfeatures}/endpoints/CustomEndpoint.java[tag=read] +---- + +You can also write technology-specific endpoints by using `@JmxEndpoint` or `@WebEndpoint`. +These endpoints are restricted to their respective technologies. +For example, `@WebEndpoint` is exposed only over HTTP and not over JMX. + +You can write technology-specific extensions by using `@EndpointWebExtension` and `@EndpointJmxExtension`. +These annotations let you provide technology-specific operations to augment an existing endpoint. + +Finally, if you need access to web-framework-specific functionality, you can implement Servlet or Spring `@Controller` and `@RestController` endpoints at the cost of them not being available over JMX or when using a different web framework. + + + +[[actuator.endpoints.implementing-custom.input]] +==== Receiving Input +Operations on an endpoint receive input via their parameters. +When exposed via the web, the values for these parameters are taken from the URL's query parameters and from the JSON request body. +When exposed via JMX, the parameters are mapped to the parameters of the MBean's operations. +Parameters are required by default. +They can be made optional by annotating them with either `@javax.annotation.Nullable` or `@org.springframework.lang.Nullable`. + +Each root property in the JSON request body can be mapped to a parameter of the endpoint. +Consider the following JSON request body: + +[source,json,indent=0] +---- + { + "name": "test", + "counter": 42 + } +---- + +This can be used to invoke a write operation that takes `String name` and `int counter` parameters, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-productionreadyfeatures}/endpoints/CustomEndpoint.java[tag=write] +---- + +TIP: Because endpoints are technology agnostic, only simple types can be specified in the method signature. +In particular declaring a single parameter with a `CustomData` type defining a `name` and `counter` properties is not supported. + +NOTE: To allow the input to be mapped to the operation method's parameters, Java code implementing an endpoint should be compiled with `-parameters`, and Kotlin code implementing an endpoint should be compiled with `-java-parameters`. +This will happen automatically if you are using Spring Boot's Gradle plugin or if you are using Maven and `spring-boot-starter-parent`. + + + +[[actuator.endpoints.implementing-custom.input.conversion]] +===== Input Type Conversion +The parameters passed to endpoint operation methods are, if necessary, automatically converted to the required type. +Before calling an operation method, the input received via JMX or an HTTP request is converted to the required types using an instance of `ApplicationConversionService` as well as any `Converter` or `GenericConverter` beans qualified with `@EndpointConverter`. + + + +[[actuator.endpoints.implementing-custom.web]] +==== Custom Web Endpoints +Operations on an `@Endpoint`, `@WebEndpoint`, or `@EndpointWebExtension` are automatically exposed over HTTP using Jersey, Spring MVC, or Spring WebFlux. +If both Jersey and Spring MVC are available, Spring MVC will be used. + + + +[[actuator.endpoints.implementing-custom.web.request-predicates]] +===== Web Endpoint Request Predicates +A request predicate is automatically generated for each operation on a web-exposed endpoint. + + + +[[actuator.endpoints.implementing-custom.web.path-predicates]] +===== Path +The path of the predicate is determined by the ID of the endpoint and the base path of web-exposed endpoints. +The default base path is `/actuator`. +For example, an endpoint with the ID `sessions` will use `/actuator/sessions` as its path in the predicate. + +The path can be further customized by annotating one or more parameters of the operation method with `@Selector`. +Such a parameter is added to the path predicate as a path variable. +The variable's value is passed into the operation method when the endpoint operation is invoked. +If you want to capture all remaining path elements, you can add `@Selector(Match=ALL_REMAINING)` to the last parameter and make it a type that is conversion compatible with a `String[]`. + + + +[[actuator.endpoints.implementing-custom.web.method-predicates]] +===== HTTP method +The HTTP method of the predicate is determined by the operation type, as shown in the following table: + +[cols="3, 1"] +|=== +| Operation | HTTP method + +| `@ReadOperation` +| `GET` + +| `@WriteOperation` +| `POST` + +| `@DeleteOperation` +| `DELETE` +|=== + + + +[[actuator.endpoints.implementing-custom.web.consumes-predicates]] +===== Consumes +For a `@WriteOperation` (HTTP `POST`) that uses the request body, the consumes clause of the predicate is `application/vnd.spring-boot.actuator.v2+json, application/json`. +For all other operations the consumes clause is empty. + + + +[[actuator.endpoints.implementing-custom.web.produces-predicates]] +===== Produces +The produces clause of the predicate can be determined by the `produces` attribute of the `@DeleteOperation`, `@ReadOperation`, and `@WriteOperation` annotations. +The attribute is optional. +If it is not used, the produces clause is determined automatically. + +If the operation method returns `void` or `Void` the produces clause is empty. +If the operation method returns a `org.springframework.core.io.Resource`, the produces clause is `application/octet-stream`. +For all other operations the produces clause is `application/vnd.spring-boot.actuator.v2+json, application/json`. + + + +[[actuator.endpoints.implementing-custom.web.response-status]] +===== Web Endpoint Response Status +The default response status for an endpoint operation depends on the operation type (read, write, or delete) and what, if anything, the operation returns. + +A `@ReadOperation` returns a value, the response status will be 200 (OK). +If it does not return a value, the response status will be 404 (Not Found). + +If a `@WriteOperation` or `@DeleteOperation` returns a value, the response status will be 200 (OK). +If it does not return a value the response status will be 204 (No Content). + +If an operation is invoked without a required parameter, or with a parameter that cannot be converted to the required type, the operation method will not be called and the response status will be 400 (Bad Request). + + + +[[actuator.endpoints.implementing-custom.web.range-requests]] +===== Web Endpoint Range Requests +An HTTP range request can be used to request part of an HTTP resource. +When using Spring MVC or Spring Web Flux, operations that return a `org.springframework.core.io.Resource` automatically support range requests. + +NOTE: Range requests are not supported when using Jersey. + + + +[[actuator.endpoints.implementing-custom.web.security]] +===== Web Endpoint Security +An operation on a web endpoint or a web-specific endpoint extension can receive the current `java.security.Principal` or `org.springframework.boot.actuate.endpoint.SecurityContext` as a method parameter. +The former is typically used in conjunction with `@Nullable` to provide different behavior for authenticated and unauthenticated users. +The latter is typically used to perform authorization checks using its `isUserInRole(String)` method. + + + +[[actuator.endpoints.implementing-custom.servlet]] +==== Servlet Endpoints +A `Servlet` can be exposed as an endpoint by implementing a class annotated with `@ServletEndpoint` that also implements `Supplier`. +Servlet endpoints provide deeper integration with the Servlet container but at the expense of portability. +They are intended to be used to expose an existing `Servlet` as an endpoint. +For new endpoints, the `@Endpoint` and `@WebEndpoint` annotations should be preferred whenever possible. + + + +[[actuator.endpoints.implementing-custom.controller]] +==== Controller Endpoints +`@ControllerEndpoint` and `@RestControllerEndpoint` can be used to implement an endpoint that is only exposed by Spring MVC or Spring WebFlux. +Methods are mapped using the standard annotations for Spring MVC and Spring WebFlux such as `@RequestMapping` and `@GetMapping`, with the endpoint's ID being used as a prefix for the path. +Controller endpoints provide deeper integration with Spring's web frameworks but at the expense of portability. +The `@Endpoint` and `@WebEndpoint` annotations should be preferred whenever possible. + + + +[[actuator.endpoints.health]] +=== Health Information +You can use health information to check the status of your running application. +It is often used by monitoring software to alert someone when a production system goes down. +The information exposed by the `health` endpoint depends on the configprop:management.endpoint.health.show-details[] and configprop:management.endpoint.health.show-components[] properties which can be configured with one of the following values: + +[cols="1, 3"] +|=== +| Name | Description + +| `never` +| Details are never shown. + +| `when-authorized` +| Details are only shown to authorized users. + Authorized roles can be configured using `management.endpoint.health.roles`. + +| `always` +| Details are shown to all users. +|=== + +The default value is `never`. +A user is considered to be authorized when they are in one or more of the endpoint's roles. +If the endpoint has no configured roles (the default) all authenticated users are considered to be authorized. +The roles can be configured using the configprop:management.endpoint.health.roles[] property. + +NOTE: If you have secured your application and wish to use `always`, your security configuration must permit access to the health endpoint for both authenticated and unauthenticated users. + +Health information is collected from the content of a {spring-boot-actuator-module-code}/health/HealthContributorRegistry.java[`HealthContributorRegistry`] (by default all {spring-boot-actuator-module-code}/health/HealthContributor.java[`HealthContributor`] instances defined in your `ApplicationContext`). +Spring Boot includes a number of auto-configured `HealthContributors` and you can also write your own. + +A `HealthContributor` can either be a `HealthIndicator` or a `CompositeHealthContributor`. +A `HealthIndicator` provides actual health information, including a `Status`. +A `CompositeHealthContributor` provides a composite of other `HealthContributors`. +Taken together, contributors form a tree structure to represent the overall system health. + +By default, the final system health is derived by a `StatusAggregator` which sorts the statuses from each `HealthIndicator` based on an ordered list of statuses. +The first status in the sorted list is used as the overall health status. +If no `HealthIndicator` returns a status that is known to the `StatusAggregator`, an `UNKNOWN` status is used. + +TIP: The `HealthContributorRegistry` can be used to register and unregister health indicators at runtime. + + + +[[actuator.endpoints.health.auto-configured-health-indicators]] +==== Auto-configured HealthIndicators +The following `HealthIndicators` are auto-configured by Spring Boot when appropriate. +You can also enable/disable selected indicators by configuring `management.health.key.enabled`, +with the `key` listed in the table below. + +[cols="2,4,6"] +|=== +| Key | Name | Description + +| `cassandra` +| {spring-boot-actuator-module-code}/cassandra/CassandraDriverHealthIndicator.java[`CassandraDriverHealthIndicator`] +| Checks that a Cassandra database is up. + +| `couchbase` +| {spring-boot-actuator-module-code}/couchbase/CouchbaseHealthIndicator.java[`CouchbaseHealthIndicator`] +| Checks that a Couchbase cluster is up. + +| `db` +| {spring-boot-actuator-module-code}/jdbc/DataSourceHealthIndicator.java[`DataSourceHealthIndicator`] +| Checks that a connection to `DataSource` can be obtained. + +| `diskspace` +| {spring-boot-actuator-module-code}/system/DiskSpaceHealthIndicator.java[`DiskSpaceHealthIndicator`] +| Checks for low disk space. + +| `elasticsearch` +| {spring-boot-actuator-module-code}/elasticsearch/ElasticsearchRestHealthIndicator.java[`ElasticsearchRestHealthIndicator`] +| Checks that an Elasticsearch cluster is up. + +| `hazelcast` +| {spring-boot-actuator-module-code}/hazelcast/HazelcastHealthIndicator.java[`HazelcastHealthIndicator`] +| Checks that a Hazelcast server is up. + +| `influxdb` +| {spring-boot-actuator-module-code}/influx/InfluxDbHealthIndicator.java[`InfluxDbHealthIndicator`] +| Checks that an InfluxDB server is up. + +| `jms` +| {spring-boot-actuator-module-code}/jms/JmsHealthIndicator.java[`JmsHealthIndicator`] +| Checks that a JMS broker is up. + +| `ldap` +| {spring-boot-actuator-module-code}/ldap/LdapHealthIndicator.java[`LdapHealthIndicator`] +| Checks that an LDAP server is up. + +| `mail` +| {spring-boot-actuator-module-code}/mail/MailHealthIndicator.java[`MailHealthIndicator`] +| Checks that a mail server is up. + +| `mongo` +| {spring-boot-actuator-module-code}/mongo/MongoHealthIndicator.java[`MongoHealthIndicator`] +| Checks that a Mongo database is up. + +| `neo4j` +| {spring-boot-actuator-module-code}/neo4j/Neo4jHealthIndicator.java[`Neo4jHealthIndicator`] +| Checks that a Neo4j database is up. + +| `ping` +| {spring-boot-actuator-module-code}/health/PingHealthIndicator.java[`PingHealthIndicator`] +| Always responds with `UP`. + +| `rabbit` +| {spring-boot-actuator-module-code}/amqp/RabbitHealthIndicator.java[`RabbitHealthIndicator`] +| Checks that a Rabbit server is up. + +| `redis` +| {spring-boot-actuator-module-code}/redis/RedisHealthIndicator.java[`RedisHealthIndicator`] +| Checks that a Redis server is up. + +| `solr` +| {spring-boot-actuator-module-code}/solr/SolrHealthIndicator.java[`SolrHealthIndicator`] +| Checks that a Solr server is up. +|=== + +TIP: You can disable them all by setting the configprop:management.health.defaults.enabled[] property. + +Additional `HealthIndicators` are available but not enabled by default: + +[cols="3,4,6"] +|=== +| Key | Name | Description + +| `livenessstate` +| {spring-boot-actuator-module-code}/availability/LivenessStateHealthIndicator.java[`LivenessStateHealthIndicator`] +| Exposes the "Liveness" application availability state. + +| `readinessstate` +| {spring-boot-actuator-module-code}/availability/ReadinessStateHealthIndicator.java[`ReadinessStateHealthIndicator`] +| Exposes the "Readiness" application availability state. +|=== + + + +[[actuator.endpoints.health.writing-custom-health-indicators]] +==== Writing Custom HealthIndicators +To provide custom health information, you can register Spring beans that implement the {spring-boot-actuator-module-code}/health/HealthIndicator.java[`HealthIndicator`] interface. +You need to provide an implementation of the `health()` method and return a `Health` response. +The `Health` response should include a status and can optionally include additional details to be displayed. +The following code shows a sample `HealthIndicator` implementation: + +[source,java,pending-extract=true,indent=0] +---- + import org.springframework.boot.actuate.health.Health; + import org.springframework.boot.actuate.health.HealthIndicator; + import org.springframework.stereotype.Component; + + @Component + public class MyHealthIndicator implements HealthIndicator { + + @Override + public Health health() { + int errorCode = check(); // perform some specific health check + if (errorCode != 0) { + return Health.down().withDetail("Error Code", errorCode).build(); + } + return Health.up().build(); + } + + } +---- + +NOTE: The identifier for a given `HealthIndicator` is the name of the bean without the `HealthIndicator` suffix, if it exists. +In the preceding example, the health information is available in an entry named `my`. + +In addition to Spring Boot's predefined {spring-boot-actuator-module-code}/health/Status.java[`Status`] types, it is also possible for `Health` to return a custom `Status` that represents a new system state. +In such cases, a custom implementation of the {spring-boot-actuator-module-code}/health/StatusAggregator.java[`StatusAggregator`] interface also needs to be provided, or the default implementation has to be configured by using the configprop:management.endpoint.health.status.order[] configuration property. + +For example, assume a new `Status` with code `FATAL` is being used in one of your `HealthIndicator` implementations. +To configure the severity order, add the following property to your application properties: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + endpoint: + health: + status: + order: "fatal,down,out-of-service,unknown,up" +---- + +The HTTP status code in the response reflects the overall health status. +By default, `OUT_OF_SERVICE` and `DOWN` map to 503. +Any unmapped health statuses, including `UP`, map to 200. +You might also want to register custom status mappings if you access the health endpoint over HTTP. +Configuring a custom mapping disables the defaults mappings for `DOWN` and `OUT_OF_SERVICE`. +If you want to retain the default mappings they must be configured explicitly alongside any custom mappings. +For example, the following property maps `FATAL` to 503 (service unavailable) and retains the default mappings for `DOWN` and `OUT_OF_SERVICE`: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + endpoint: + health: + status: + http-mapping: + down: 503 + fatal: 503 + out-of-service: 503 +---- + +TIP: If you need more control, you can define your own `HttpCodeStatusMapper` bean. + +The following table shows the default status mappings for the built-in statuses: + +[cols="1,3"] +|=== +| Status | Mapping + +| DOWN +| SERVICE_UNAVAILABLE (503) + +| OUT_OF_SERVICE +| SERVICE_UNAVAILABLE (503) + +| UP +| No mapping by default, so http status is 200 + +| UNKNOWN +| No mapping by default, so http status is 200 +|=== + + + +[[actuator.endpoints.health.reactive-health-indicators]] +==== Reactive Health Indicators +For reactive applications, such as those using Spring WebFlux, `ReactiveHealthContributor` provides a non-blocking contract for getting application health. +Similar to a traditional `HealthContributor`, health information is collected from the content of a {spring-boot-actuator-module-code}/health/ReactiveHealthContributorRegistry.java[`ReactiveHealthContributorRegistry`] (by default all {spring-boot-actuator-module-code}/health/HealthContributor.java[`HealthContributor`] and {spring-boot-actuator-module-code}/health/ReactiveHealthContributor.java[`ReactiveHealthContributor`] instances defined in your `ApplicationContext`). +Regular `HealthContributors` that do not check against a reactive API are executed on the elastic scheduler. + +TIP: In a reactive application, The `ReactiveHealthContributorRegistry` should be used to register and unregister health indicators at runtime. +If you need to register a regular `HealthContributor`, you should wrap it using `ReactiveHealthContributor#adapt`. + +To provide custom health information from a reactive API, you can register Spring beans that implement the {spring-boot-actuator-module-code}/health/ReactiveHealthIndicator.java[`ReactiveHealthIndicator`] interface. +The following code shows a sample `ReactiveHealthIndicator` implementation: + +[source,java,pending-extract=true,indent=0] +---- + @Component + public class MyReactiveHealthIndicator implements ReactiveHealthIndicator { + + @Override + public Mono health() { + return doHealthCheck() //perform some specific health check that returns a Mono + .onErrorResume(ex -> Mono.just(new Health.Builder().down(ex).build())); + } + + } +---- + +TIP: To handle the error automatically, consider extending from `AbstractReactiveHealthIndicator`. + + + +[[actuator.endpoints.health.auto-configured-reactive-health-indicators]] +==== Auto-configured ReactiveHealthIndicators +The following `ReactiveHealthIndicators` are auto-configured by Spring Boot when appropriate: + +[cols="2,4,6"] +|=== +| Key | Name | Description + +| `cassandra` +| {spring-boot-actuator-module-code}/cassandra/CassandraDriverReactiveHealthIndicator.java[`CassandraDriverReactiveHealthIndicator`] +| Checks that a Cassandra database is up. + +| `couchbase` +| {spring-boot-actuator-module-code}/couchbase/CouchbaseReactiveHealthIndicator.java[`CouchbaseReactiveHealthIndicator`] +| Checks that a Couchbase cluster is up. + +| `elasticsearch` +| {spring-boot-actuator-module-code}/elasticsearch/ElasticsearchReactiveHealthIndicator.java[`ElasticsearchReactiveHealthIndicator`] +| Checks that an Elasticsearch cluster is up. + +| `mongo` +| {spring-boot-actuator-module-code}/mongo/MongoReactiveHealthIndicator.java[`MongoReactiveHealthIndicator`] +| Checks that a Mongo database is up. + +| `neo4j` +| {spring-boot-actuator-module-code}/neo4j/Neo4jReactiveHealthIndicator.java[`Neo4jReactiveHealthIndicator`] +| Checks that a Neo4j database is up. + +| `redis` +| {spring-boot-actuator-module-code}/redis/RedisReactiveHealthIndicator.java[`RedisReactiveHealthIndicator`] +| Checks that a Redis server is up. +|=== + +TIP: If necessary, reactive indicators replace the regular ones. +Also, any `HealthIndicator` that is not handled explicitly is wrapped automatically. + + + +[[actuator.endpoints.health.groups]] +==== Health Groups +It's sometimes useful to organize health indicators into groups that can be used for different purposes. + +To create a health indicator group you can use the `management.endpoint.health.group.` property and specify a list of health indicator IDs to `include` or `exclude`. +For example, to create a group that includes only database indicators you can define the following: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + endpoint: + health: + group: + custom: + include: "db" +---- + +You can then check the result by hitting `http://localhost:8080/actuator/health/custom`. + +Similarly, to create a group that excludes the database indicators from the group and includes all the other indicators, you can define the following: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + endpoint: + health: + group: + custom: + exclude: "db" +---- + +By default groups will inherit the same `StatusAggregator` and `HttpCodeStatusMapper` settings as the system health, however, these can also be defined on a per-group basis. +It's also possible to override the `show-details` and `roles` properties if required: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + endpoint: + health: + group: + custom: + show-details: "when-authorized" + roles: "admin" + status: + order: "fatal,up" + http-mapping: + fatal: 500 + out-of-service: 500 +---- + +TIP: You can use `@Qualifier("groupname")` if you need to register custom `StatusAggregator` or `HttpCodeStatusMapper` beans for use with the group. + + + +[[actuator.endpoints.health.datasource]] +==== DataSource Health +The `DataSource` health indicator shows the health of both standard data source and routing data source beans. +The health of a routing data source includes the health of each of its target data sources. +In the health endpoint's response, each of a routing data source's targets is named using its routing key. +If you prefer not to include routing data sources in the indicator's output, set configprop:management.health.db.ignore-routing-data-sources[] to `true`. + + + +[[actuator.endpoints.kubernetes-probes]] +=== Kubernetes Probes +Applications deployed on Kubernetes can provide information about their internal state with https://kubernetes.io/docs/concepts/workloads/pods/pod-lifecycle/#container-probes[Container Probes]. +Depending on https://kubernetes.io/docs/tasks/configure-pod-container/configure-liveness-readiness-startup-probes/[your Kubernetes configuration], the kubelet will call those probes and react to the result. + +Spring Boot manages your <> out-of-the-box. +If deployed in a Kubernetes environment, actuator will gather the "Liveness" and "Readiness" information from the `ApplicationAvailability` interface and use that information in dedicated <>: `LivenessStateHealthIndicator` and `ReadinessStateHealthIndicator`. +These indicators will be shown on the global health endpoint (`"/actuator/health"`). +They will also be exposed as separate HTTP Probes using <>: `"/actuator/health/liveness"` and `"/actuator/health/readiness"`. + +You can then configure your Kubernetes infrastructure with the following endpoint information: + +[source,yml,indent=0] +---- +livenessProbe: + httpGet: + path: /actuator/health/liveness + port: + failureThreshold: ... + periodSeconds: ... + +readinessProbe: + httpGet: + path: /actuator/health/readiness + port: + failureThreshold: ... + periodSeconds: ... +---- + +NOTE: `` should be set to the port that the actuator endpoints are available on. +It could be the main web server port, or a separate management port if the `"management.server.port"` property has been set. + +These health groups are only enabled automatically if the application is <>. +You can enable them in any environment using the configprop:management.endpoint.health.probes.enabled[] configuration property. + +NOTE: If an application takes longer to start than the configured liveness period, Kubernetes mention the `"startupProbe"` as a possible solution. +The `"startupProbe"` is not necessarily needed here as the `"readinessProbe"` fails until all startup tasks are done, see <>. + +WARNING: If your Actuator endpoints are deployed on a separate management context, be aware that endpoints are then not using the same web infrastructure (port, connection pools, framework components) as the main application. +In this case, a probe check could be successful even if the main application does not work properly (for example, it cannot accept new connections). + + + +[[actuator.endpoints.kubernetes-probes.external-state]] +==== Checking External State with Kubernetes Probes +Actuator configures the "liveness" and "readiness" probes as Health Groups; this means that all the <> are available for them. +You can, for example, configure additional Health Indicators: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + endpoint: + health: + group: + readiness: + include: "readinessState,customCheck" +---- + +By default, Spring Boot does not add other Health Indicators to these groups. + +The "`liveness`" Probe should not depend on health checks for external systems. +If the <> is broken, Kubernetes will try to solve that problem by restarting the application instance. +This means that if an external system fails (e.g. a database, a Web API, an external cache), Kubernetes might restart all application instances and create cascading failures. + +As for the "`readiness`" Probe, the choice of checking external systems must be made carefully by the application developers, i.e. Spring Boot does not include any additional health checks in the readiness probe. +If the <> is unready, Kubernetes will not route traffic to that instance. +Some external systems might not be shared by application instances, in which case they could quite naturally be included in a readiness probe. +Other external systems might not be essential to the application (the application could have circuit breakers and fallbacks), in which case they definitely should not be included. +Unfortunately, an external system that is shared by all application instances is common, and you have to make a judgement call: include it in the readiness probe and expect that the application is taken out of service when the external service is down, or leave it out and deal with failures higher up the stack, e.g. using a circuit breaker in the caller. + +NOTE: If all instances of an application are unready, a Kubernetes Service with `type=ClusterIP` or `NodePort` will not accept any incoming connections. +There is no HTTP error response (503 etc.) since there is no connection. +A Service with `type=LoadBalancer` might or might not accept connections, depending on the provider. +A Service that has an explicit https://kubernetes.io/docs/concepts/services-networking/ingress/[Ingress] will also respond in a way that depends on the implementation - the ingress service itself will have to decide how to handle the "connection refused" from downstream. +HTTP 503 is quite likely in the case of both load balancer and ingress. + +Also, if an application is using Kubernetes https://kubernetes.io/docs/tasks/run-application/horizontal-pod-autoscale/[autoscaling] it may react differently to applications being taken out of the load-balancer, depending on its autoscaler configuration. + + + +[[actuator.endpoints.kubernetes-probes.lifecycle]] +==== Application Lifecycle and Probe States +An important aspect of the Kubernetes Probes support is its consistency with the application lifecycle. +There is a significant difference between the `AvailabilityState` which is the in-memory, internal state of the application +and the actual Probe which exposes that state: depending on the phase of application lifecycle, the Probe might not be available. + +Spring Boot publishes <>, +and Probes can listen to such events and expose the `AvailabilityState` information. + +The following tables show the `AvailabilityState` and the state of HTTP connectors at different stages. + +When a Spring Boot application starts: + +[cols="2,2,2,3,5"] +|=== +|Startup phase |LivenessState |ReadinessState |HTTP server |Notes + +|Starting +|`BROKEN` +|`REFUSING_TRAFFIC` +|Not started +|Kubernetes checks the "liveness" Probe and restarts the application if it takes too long. + +|Started +|`CORRECT` +|`REFUSING_TRAFFIC` +|Refuses requests +|The application context is refreshed. The application performs startup tasks and does not receive traffic yet. + +|Ready +|`CORRECT` +|`ACCEPTING_TRAFFIC` +|Accepts requests +|Startup tasks are finished. The application is receiving traffic. +|=== + +When a Spring Boot application shuts down: + +[cols="2,2,2,3,5"] +|=== +|Shutdown phase |Liveness State |Readiness State |HTTP server |Notes + +|Running +|`CORRECT` +|`ACCEPTING_TRAFFIC` +|Accepts requests +|Shutdown has been requested. + +|Graceful shutdown +|`CORRECT` +|`REFUSING_TRAFFIC` +|New requests are rejected +|If enabled, <>. + +|Shutdown complete +|N/A +|N/A +|Server is shut down +|The application context is closed and the application is shut down. +|=== + +TIP: Check out the <> for more information about Kubernetes deployment. + + + +[[actuator.endpoints.info]] +=== Application Information +Application information exposes various information collected from all {spring-boot-actuator-module-code}/info/InfoContributor.java[`InfoContributor`] beans defined in your `ApplicationContext`. +Spring Boot includes a number of auto-configured `InfoContributor` beans, and you can write your own. + + + +[[actuator.endpoints.info.auto-configured-info-contributors]] +==== Auto-configured InfoContributors +The following `InfoContributor` beans are auto-configured by Spring Boot, when appropriate: + +[cols="1,4"] +|=== +| Name | Description + +| {spring-boot-actuator-module-code}/info/EnvironmentInfoContributor.java[`EnvironmentInfoContributor`] +| Exposes any key from the `Environment` under the `info` key. + +| {spring-boot-actuator-module-code}/info/GitInfoContributor.java[`GitInfoContributor`] +| Exposes git information if a `git.properties` file is available. + +| {spring-boot-actuator-module-code}/info/BuildInfoContributor.java[`BuildInfoContributor`] +| Exposes build information if a `META-INF/build-info.properties` file is available. +|=== + +TIP: It is possible to disable them all by setting the configprop:management.info.defaults.enabled[] property. + + + +[[actuator.endpoints.info.custom-application-information]] +==== Custom Application Information +You can customize the data exposed by the `info` endpoint by setting `+info.*+` Spring properties. +All `Environment` properties under the `info` key are automatically exposed. +For example, you could add the following settings to your `application.properties` file: + +[source,yaml,indent=0,configprops,configblocks] +---- + info: + app: + encoding: "UTF-8" + java: + source: "11" + target: "11" +---- + +[TIP] +==== +Rather than hardcoding those values, you could also <>. + +Assuming you use Maven, you could rewrite the preceding example as follows: + +[source,yaml,indent=0,configprops,configblocks] +---- + info: + app: + encoding: "@project.build.sourceEncoding@" + java: + source: "@java.version@" + target: "@java.version@" +---- +==== + + + +[[actuator.endpoints.info.git-commit-information]] +==== Git Commit Information +Another useful feature of the `info` endpoint is its ability to publish information about the state of your `git` source code repository when the project was built. +If a `GitProperties` bean is available, the `info` endpoint can be used to expose these properties. + +TIP: A `GitProperties` bean is auto-configured if a `git.properties` file is available at the root of the classpath. +See "<>" for more details. + +By default, the endpoint exposes `git.branch`, `git.commit.id`, and `git.commit.time` properties, if present. +If you don't want any of these properties in the endpoint response, they need to be excluded from the `git.properties` file. +If you want to display the full git information (that is, the full content of `git.properties`), use the configprop:management.info.git.mode[] property, as follows: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + info: + git: + mode: "full" +---- + +To disable the git commit information from the `info` endpoint completely, set the configprop:management.info.git.enabled[] property to `false`, as follows: + +[source,properties,indent=0,configprops] +---- + management.info.git.enabled=false +---- + + + +[[actuator.endpoints.info.build-information]] +==== Build Information +If a `BuildProperties` bean is available, the `info` endpoint can also publish information about your build. +This happens if a `META-INF/build-info.properties` file is available in the classpath. + +TIP: The Maven and Gradle plugins can both generate that file. +See "<>" for more details. + + + +[[actuator.endpoints.info.writing-custom-info-contributors]] +==== Writing Custom InfoContributors +To provide custom application information, you can register Spring beans that implement the {spring-boot-actuator-module-code}/info/InfoContributor.java[`InfoContributor`] interface. + +The following example contributes an `example` entry with a single value: + +[source,java,pending-extract=true,indent=0] +---- + import java.util.Collections; + + import org.springframework.boot.actuate.info.Info; + import org.springframework.boot.actuate.info.InfoContributor; + import org.springframework.stereotype.Component; + + @Component + public class ExampleInfoContributor implements InfoContributor { + + @Override + public void contribute(Info.Builder builder) { + builder.withDetail("example", + Collections.singletonMap("key", "value")); + } + + } +---- + +If you reach the `info` endpoint, you should see a response that contains the following additional entry: + +[source,json,indent=0] +---- + { + "example": { + "key" : "value" + } + } +---- diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/jmx.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/jmx.adoc new file mode 100644 index 0000000000..bc36fc6714 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/jmx.adoc @@ -0,0 +1,99 @@ +[[actuator.jmx]] +== Monitoring and Management over JMX +Java Management Extensions (JMX) provide a standard mechanism to monitor and manage applications. +By default, this feature is not enabled and can be turned on by setting the configuration property configprop:spring.jmx.enabled[] to `true`. +Spring Boot exposes management endpoints as JMX MBeans under the `org.springframework.boot` domain by default. +To Take full control over endpoints registration in the JMX domain, consider registering your own `EndpointObjectNameFactory` implementation. + + + +[[actuator.jmx.custom-mbean-names]] +=== Customizing MBean Names +The name of the MBean is usually generated from the `id` of the endpoint. +For example, the `health` endpoint is exposed as `org.springframework.boot:type=Endpoint,name=Health`. + +If your application contains more than one Spring `ApplicationContext`, you may find that names clash. +To solve this problem, you can set the configprop:spring.jmx.unique-names[] property to `true` so that MBean names are always unique. + +You can also customize the JMX domain under which endpoints are exposed. +The following settings show an example of doing so in `application.properties`: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + jmx: + unique-names: true + management: + endpoints: + jmx: + domain: "com.example.myapp" +---- + + + +[[actuator.jmx.disable-jmx-endpoints]] +=== Disabling JMX Endpoints +If you do not want to expose endpoints over JMX, you can set the configprop:management.endpoints.jmx.exposure.exclude[] property to `*`, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + endpoints: + jmx: + exposure: + exclude: "*" +---- + + + +[[actuator.jmx.jolokia]] +=== Using Jolokia for JMX over HTTP +Jolokia is a JMX-HTTP bridge that provides an alternative method of accessing JMX beans. +To use Jolokia, include a dependency to `org.jolokia:jolokia-core`. +For example, with Maven, you would add the following dependency: + +[source,xml,indent=0] +---- + + org.jolokia + jolokia-core + +---- + +The Jolokia endpoint can then be exposed by adding `jolokia` or `*` to the configprop:management.endpoints.web.exposure.include[] property. +You can then access it by using `/actuator/jolokia` on your management HTTP server. + +NOTE: The Jolokia endpoint exposes Jolokia's servlet as an actuator endpoint. +As a result, it is specific to servlet environments such as Spring MVC and Jersey. +The endpoint will not be available in a WebFlux application. + + + +[[actuator.jmx.jolokia.customizing]] +==== Customizing Jolokia +Jolokia has a number of settings that you would traditionally configure by setting servlet parameters. +With Spring Boot, you can use your `application.properties` file. +To do so, prefix the parameter with `management.endpoint.jolokia.config.`, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + endpoint: + jolokia: + config: + debug: true +---- + + + +[[actuator.jmx.jolokia.disabling]] +==== Disabling Jolokia +If you use Jolokia but do not want Spring Boot to configure it, set the configprop:management.endpoint.jolokia.enabled[] property to `false`, as follows: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + endpoint: + jolokia: + enabled: false +---- diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/loggers.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/loggers.adoc new file mode 100644 index 0000000000..74e320c669 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/loggers.adoc @@ -0,0 +1,31 @@ +[[actuator.loggers]] +== Loggers +Spring Boot Actuator includes the ability to view and configure the log levels of your application at runtime. +You can view either the entire list or an individual logger's configuration, which is made up of both the explicitly configured logging level as well as the effective logging level given to it by the logging framework. +These levels can be one of: + +* `TRACE` +* `DEBUG` +* `INFO` +* `WARN` +* `ERROR` +* `FATAL` +* `OFF` +* `null` + +`null` indicates that there is no explicit configuration. + + + +[[actuator.loggers.configure]] +=== Configure a Logger +To configure a given logger, `POST` a partial entity to the resource's URI, as shown in the following example: + +[source,json,indent=0] +---- + { + "configuredLevel": "DEBUG" + } +---- + +TIP: To "`reset`" the specific level of the logger (and use the default configuration instead), you can pass a value of `null` as the `configuredLevel`. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/metrics.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/metrics.adoc new file mode 100644 index 0000000000..2a8128e9d8 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/metrics.adoc @@ -0,0 +1,1144 @@ +[[actuator.metrics]] +== Metrics +Spring Boot Actuator provides dependency management and auto-configuration for https://micrometer.io[Micrometer], an application metrics facade that supports {micrometer-docs}[numerous monitoring systems], including: + +- <> +- <> +- <> +- <> +- <> +- <> +- <> +- <> +- <> +- <> +- <> +- <> +- <> +- <> +- <> +- <> +- <> +- <> + +TIP: To learn more about Micrometer's capabilities, please refer to its https://micrometer.io/docs[reference documentation], in particular the {micrometer-concepts-docs}[concepts section]. + + + +[[actuator.metrics.getting-started]] +=== Getting started +Spring Boot auto-configures a composite `MeterRegistry` and adds a registry to the composite for each of the supported implementations that it finds on the classpath. +Having a dependency on `micrometer-registry-\{system}` in your runtime classpath is enough for Spring Boot to configure the registry. + +Most registries share common features. +For instance, you can disable a particular registry even if the Micrometer registry implementation is on the classpath. +For example, to disable Datadog: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + datadog: + enabled: false +---- + +You can also disable all registries unless stated otherwise by the registry-specific property, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + defaults: + enabled: false +---- + +Spring Boot will also add any auto-configured registries to the global static composite registry on the `Metrics` class unless you explicitly tell it not to: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + use-global-registry: false +---- + +You can register any number of `MeterRegistryCustomizer` beans to further configure the registry, such as applying common tags, before any meters are registered with the registry: + +[source,java,pending-extract=true,indent=0] +---- + @Bean + MeterRegistryCustomizer metricsCommonTags() { + return registry -> registry.config().commonTags("region", "us-east-1"); + } +---- + +You can apply customizations to particular registry implementations by being more specific about the generic type: + +[source,java,pending-extract=true,indent=0] +---- + @Bean + MeterRegistryCustomizer graphiteMetricsNamingConvention() { + return registry -> registry.config().namingConvention(MY_CUSTOM_CONVENTION); + } +---- + +Spring Boot also <> that you can control via configuration or dedicated annotation markers. + + + +[[actuator.metrics.export]] +=== Supported Monitoring Systems + + + +[[actuator.metrics.export.appoptics]] +==== AppOptics +By default, the AppOptics registry pushes metrics to `https://api.appoptics.com/v1/measurements` periodically. +To export metrics to SaaS {micrometer-registry-docs}/appOptics[AppOptics], your API token must be provided: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + appoptics: + api-token: "YOUR_TOKEN" +---- + + + +[[actuator.metrics.export.atlas]] +==== Atlas +By default, metrics are exported to {micrometer-registry-docs}/atlas[Atlas] running on your local machine. +The location of the https://github.com/Netflix/atlas[Atlas server] to use can be provided using: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + atlas: + uri: "https://atlas.example.com:7101/api/v1/publish" +---- + + + +[[actuator.metrics.export.datadog]] +==== Datadog +Datadog registry pushes metrics to https://www.datadoghq.com[datadoghq] periodically. +To export metrics to {micrometer-registry-docs}/datadog[Datadog], your API key must be provided: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + datadog: + api-key: "YOUR_KEY" +---- + +You can also change the interval at which metrics are sent to Datadog: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + datadog: + step: "30s" +---- + + + +[[actuator.metrics.export.dynatrace]] +==== Dynatrace +Dynatrace registry pushes metrics to the configured URI periodically. +To export metrics to {micrometer-registry-docs}/dynatrace[Dynatrace], your API token, device ID, and URI must be provided: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + dynatrace: + api-token: "YOUR_TOKEN" + device-id: "YOUR_DEVICE_ID" + uri: "YOUR_URI" +---- + +You can also change the interval at which metrics are sent to Dynatrace: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + dynatrace: + step: "30s" +---- + + + +[[actuator.metrics.export.elastic]] +==== Elastic +By default, metrics are exported to {micrometer-registry-docs}/elastic[Elastic] running on your local machine. +The location of the Elastic server to use can be provided using the following property: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + elastic: + host: "https://elastic.example.com:8086" +---- + + + +[[actuator.metrics.export.ganglia]] +==== Ganglia +By default, metrics are exported to {micrometer-registry-docs}/ganglia[Ganglia] running on your local machine. +The http://ganglia.sourceforge.net[Ganglia server] host and port to use can be provided using: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + ganglia: + host: "ganglia.example.com" + port: 9649 +---- + + + +[[actuator.metrics.export.graphite]] +==== Graphite +By default, metrics are exported to {micrometer-registry-docs}/graphite[Graphite] running on your local machine. +The https://graphiteapp.org[Graphite server] host and port to use can be provided using: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + graphite: + host: "graphite.example.com" + port: 9004 +---- + +Micrometer provides a default `HierarchicalNameMapper` that governs how a dimensional meter id is {micrometer-registry-docs}/graphite#_hierarchical_name_mapping[mapped to flat hierarchical names]. + +TIP: To take control over this behaviour, define your `GraphiteMeterRegistry` and supply your own `HierarchicalNameMapper`. +An auto-configured `GraphiteConfig` and `Clock` beans are provided unless you define your own: + +[source,java,pending-extract=true,indent=0] +---- + @Bean + public GraphiteMeterRegistry graphiteMeterRegistry(GraphiteConfig config, Clock clock) { + return new GraphiteMeterRegistry(config, clock, MY_HIERARCHICAL_MAPPER); + } +---- + + + +[[actuator.metrics.export.humio]] +==== Humio +By default, the Humio registry pushes metrics to https://cloud.humio.com periodically. +To export metrics to SaaS {micrometer-registry-docs}/humio[Humio], your API token must be provided: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + humio: + api-token: "YOUR_TOKEN" +---- + +You should also configure one or more tags to identify the data source to which metrics will be pushed: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + humio: + tags: + alpha: "a" + bravo: "b" +---- + + + +[[actuator.metrics.export.influx]] +==== Influx +By default, metrics are exported to an {micrometer-registry-docs}/influx[Influx] v1 instance running on your local machine with the default configuration. +To export metrics to InfluxDB v2, configure the `org`, `bucket`, and authentication `token` for writing metrics. +The location of the https://www.influxdata.com[Influx server] to use can be provided using: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + influx: + uri: "https://influx.example.com:8086" +---- + + + +[[actuator.metrics.export.jmx]] +==== JMX +Micrometer provides a hierarchical mapping to {micrometer-registry-docs}/jmx[JMX], primarily as a cheap and portable way to view metrics locally. +By default, metrics are exported to the `metrics` JMX domain. +The domain to use can be provided using: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + jmx: + domain: "com.example.app.metrics" +---- + +Micrometer provides a default `HierarchicalNameMapper` that governs how a dimensional meter id is {micrometer-registry-docs}/jmx#_hierarchical_name_mapping[mapped to flat hierarchical names]. + +TIP: To take control over this behaviour, define your `JmxMeterRegistry` and supply your own `HierarchicalNameMapper`. +An auto-configured `JmxConfig` and `Clock` beans are provided unless you define your own: + +[source,java,pending-extract=true,indent=0] +---- + @Bean + public JmxMeterRegistry jmxMeterRegistry(JmxConfig config, Clock clock) { + return new JmxMeterRegistry(config, clock, MY_HIERARCHICAL_MAPPER); + } +---- + + + +[[actuator.metrics.export.kairos]] +==== KairosDB +By default, metrics are exported to {micrometer-registry-docs}/kairos[KairosDB] running on your local machine. +The location of the https://kairosdb.github.io/[KairosDB server] to use can be provided using: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + kairos: + uri: "https://kairosdb.example.com:8080/api/v1/datapoints" +---- + + + +[[actuator.metrics.export.newrelic]] +==== New Relic +New Relic registry pushes metrics to {micrometer-registry-docs}/new-relic[New Relic] periodically. +To export metrics to https://newrelic.com[New Relic], your API key and account id must be provided: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + newrelic: + api-key: "YOUR_KEY" + account-id: "YOUR_ACCOUNT_ID" +---- + +You can also change the interval at which metrics are sent to New Relic: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + newrelic: + step: "30s" +---- + +By default, metrics are published via REST calls but it is also possible to use the Java Agent API if you have it on the classpath: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + newrelic: + client-provider-type: "insights-agent" +---- + +Finally, you can take full control by defining your own `NewRelicClientProvider` bean. + + + +[[actuator.metrics.export.prometheus]] +==== Prometheus +{micrometer-registry-docs}/prometheus[Prometheus] expects to scrape or poll individual app instances for metrics. +Spring Boot provides an actuator endpoint available at `/actuator/prometheus` to present a https://prometheus.io[Prometheus scrape] with the appropriate format. + +TIP: The endpoint is not available by default and must be exposed, see <> for more details. + +Here is an example `scrape_config` to add to `prometheus.yml`: + +[source,yaml,indent=0] +---- + scrape_configs: + - job_name: 'spring' + metrics_path: '/actuator/prometheus' + static_configs: + - targets: ['HOST:PORT'] +---- + +For ephemeral or batch jobs which may not exist long enough to be scraped, https://github.com/prometheus/pushgateway[Prometheus Pushgateway] support can be used to expose their metrics to Prometheus. +To enable Prometheus Pushgateway support, add the following dependency to your project: + +[source,xml,indent=0] +---- + + io.prometheus + simpleclient_pushgateway + +---- + +When the Prometheus Pushgateway dependency is present on the classpath and the configprop:management.metrics.export.prometheus.pushgateway.enabled[] property is set to `true`, a `PrometheusPushGatewayManager` bean is auto-configured. +This manages the pushing of metrics to a Prometheus Pushgateway. + +The `PrometheusPushGatewayManager` can be tuned using properties under `management.metrics.export.prometheus.pushgateway`. +For advanced configuration, you can also provide your own `PrometheusPushGatewayManager` bean. + + + +[[actuator.metrics.export.signalfx]] +==== SignalFx +SignalFx registry pushes metrics to {micrometer-registry-docs}/signalFx[SignalFx] periodically. +To export metrics to https://www.signalfx.com[SignalFx], your access token must be provided: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + signalfx: + access-token: "YOUR_ACCESS_TOKEN" +---- + +You can also change the interval at which metrics are sent to SignalFx: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + signalfx: + step: "30s" +---- + + + +[[actuator.metrics.export.simple]] +==== Simple +Micrometer ships with a simple, in-memory backend that is automatically used as a fallback if no other registry is configured. +This allows you to see what metrics are collected in the <>. + +The in-memory backend disables itself as soon as you're using any of the other available backend. +You can also disable it explicitly: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + simple: + enabled: false +---- + + + +[[actuator.metrics.export.stackdriver]] +==== Stackdriver +Stackdriver registry pushes metrics to https://cloud.google.com/stackdriver/[Stackdriver] periodically. +To export metrics to SaaS {micrometer-registry-docs}/stackdriver[Stackdriver], your Google Cloud project id must be provided: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + stackdriver: + project-id: "my-project" +---- + +You can also change the interval at which metrics are sent to Stackdriver: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + stackdriver: + step: "30s" +---- + + + +[[actuator.metrics.export.statsd]] +==== StatsD +The StatsD registry pushes metrics over UDP to a StatsD agent eagerly. +By default, metrics are exported to a {micrometer-registry-docs}/statsD[StatsD] agent running on your local machine. +The StatsD agent host, port, and protocol to use can be provided using: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + statsd: + host: "statsd.example.com" + port: 9125 + protocol: "udp" +---- + +You can also change the StatsD line protocol to use (default to Datadog): + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + statsd: + flavor: "etsy" +---- + + + +[[actuator.metrics.export.wavefront]] +==== Wavefront +Wavefront registry pushes metrics to {micrometer-registry-docs}/wavefront[Wavefront] periodically. +If you are exporting metrics to https://www.wavefront.com/[Wavefront] directly, your API token must be provided: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + wavefront: + api-token: "YOUR_API_TOKEN" +---- + +Alternatively, you may use a Wavefront sidecar or an internal proxy set up in your environment that forwards metrics data to the Wavefront API host: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + wavefront: + uri: "proxy://localhost:2878" +---- + +TIP: If publishing metrics to a Wavefront proxy (as described in https://docs.wavefront.com/proxies_installing.html[the documentation]), the host must be in the `proxy://HOST:PORT` format. + +You can also change the interval at which metrics are sent to Wavefront: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + export: + wavefront: + step: "30s" +---- + + + +[[actuator.metrics.supported]] +=== Supported Metrics and Meters +Spring Boot provides automatic meter registration for a wide variety of technologies. +In most situations, the out-of-the-box defaults will provide sensible metrics that can be published to any of the supported monioring systems. + + + +[[actuator.metrics.supported.jvm]] +==== JVM Metrics +Auto-configuration will enable JVM Metrics using core Micrometer classes. +JVM metrics are published under the `jvm.` meter name. + +The following JVM metrics are provided: + +* Various memory and buffer pool details +* Statistics related to garbage collection +* Threads utilization +* The Number of classes loaded/unloaded + + + +[[actuator.metrics.supported.system]] +==== System Metrics +Auto-configuration will enable system metrics using core Micrometer classes. +System metrics are published under the `system.` and `process.` meter names. + +The following system metrics are provided: + +* CPU metrics +* File descriptor metrics +* Uptime metrics (both the amount of time the application has been running as well as a fixed gauge of the absolute start time) + + + +[[actuator.metrics.supported.logger]] +==== Logger Metrics +Auto-configuration enables the event metrics for both Logback and Log4J2. +Details are published under the `log4j2.events.` or `logback.events.` meter names. + + + +[[actuator.metrics.supported.spring-mvc]] +==== Spring MVC Metrics +Auto-configuration enables the instrumentation of all requests handled by Spring MVC controllers and functional handlers. +By default, metrics are generated with the name, `http.server.requests`. +The name can be customized by setting the configprop:management.metrics.web.server.request.metric-name[] property. + +`@Timed` annotations are supported on `@Controller` classes and `@RequestMapping` methods (see <> for details). +If you don't want to record metrics for all Spring MVC requests, you can set configprop:management.metrics.web.server.request.autotime.enabled[] to `false` and exclusively use `@Timed` annotations instead. + +By default, Spring MVC related metrics are tagged with the following information: + +|=== +| Tag | Description + +| `exception` +| Simple class name of any exception that was thrown while handling the request. + +| `method` +| Request's method (for example, `GET` or `POST`) + +| `outcome` +| Request's outcome based on the status code of the response. + 1xx is `INFORMATIONAL`, 2xx is `SUCCESS`, 3xx is `REDIRECTION`, 4xx `CLIENT_ERROR`, and 5xx is `SERVER_ERROR` + +| `status` +| Response's HTTP status code (for example, `200` or `500`) + +| `uri` +| Request's URI template prior to variable substitution, if possible (for example, `/api/person/\{id}`) +|=== + +To add to the default tags, provide one or more ``@Bean``s that implement `WebMvcTagsContributor`. +To replace the default tags, provide a `@Bean` that implements `WebMvcTagsProvider`. + +TIP: In some cases, exceptions handled in Web controllers are not recorded as request metrics tags. +Applications can opt-in and record exceptions by <>. + + + +[[actuator.metrics.supported.spring-webflux]] +==== Spring WebFlux Metrics +Auto-configuration enables the instrumentation of all requests handled by Spring WebFlux controllers and functional handlers. +By default, metrics are generated with the name, `http.server.requests`. +The name can be customized by setting the configprop:management.metrics.web.server.request.metric-name[] property. + +`@Timed` annotations are supported on `@Controller` classes and `@RequestMapping` methods (see <> for details). +If you don't want to record metrics for all Spring WebFlux requests, you can set configprop:management.metrics.web.server.request.autotime.enabled[] to `false` and exclusively use `@Timed` annotations instead. + +By default, WebFlux related metrics are tagged with the following information: + +|=== +| Tag | Description + +| `exception` +| Simple class name of any exception that was thrown while handling the request. + +| `method` +| Request's method (for example, `GET` or `POST`) + +| `outcome` +| Request's outcome based on the status code of the response. + 1xx is `INFORMATIONAL`, 2xx is `SUCCESS`, 3xx is `REDIRECTION`, 4xx `CLIENT_ERROR`, and 5xx is `SERVER_ERROR` + +| `status` +| Response's HTTP status code (for example, `200` or `500`) + +| `uri` +| Request's URI template prior to variable substitution, if possible (for example, `/api/person/\{id}`) +|=== + +To add to the default tags, provide one or more ``@Bean``s that implement `WebFluxTagsContributor`. +To replace the default tags, provide a `@Bean` that implements `WebFluxTagsProvider`. + +TIP: In some cases, exceptions handled in controllers and handler functions are not recorded as request metrics tags. +Applications can opt-in and record exceptions by <>. + + + +[[actuator.metrics.supported.jersey]] +==== Jersey Server Metrics +Auto-configuration enables the instrumentation of all requests handled by the Jersey JAX-RS implementation whenever Micrometer's `micrometer-jersey2` module is on the classpath. +By default, metrics are generated with the name, `http.server.requests`. +The name can be customized by setting the configprop:management.metrics.web.server.request.metric-name[] property. + +`@Timed` annotations are supported on request-handling classes and methods (see <> for details). +If you don't want to record metrics for all Jersey requests, you can set configprop:management.metrics.web.server.request.autotime.enabled[] to `false` and exclusively use `@Timed` annotations instead. + +By default, Jersey server metrics are tagged with the following information: + +|=== +| Tag | Description + +| `exception` +| Simple class name of any exception that was thrown while handling the request. + +| `method` +| Request's method (for example, `GET` or `POST`) + +| `outcome` +| Request's outcome based on the status code of the response. + 1xx is `INFORMATIONAL`, 2xx is `SUCCESS`, 3xx is `REDIRECTION`, 4xx `CLIENT_ERROR`, and 5xx is `SERVER_ERROR` + +| `status` +| Response's HTTP status code (for example, `200` or `500`) + +| `uri` +| Request's URI template prior to variable substitution, if possible (for example, `/api/person/\{id}`) +|=== + +To customize the tags, provide a `@Bean` that implements `JerseyTagsProvider`. + + + +[[actuator.metrics.supported.http-clients]] +==== HTTP Client Metrics +Spring Boot Actuator manages the instrumentation of both `RestTemplate` and `WebClient`. +For that, you have to inject the auto-configured builder and use it to create instances: + +* `RestTemplateBuilder` for `RestTemplate` +* `WebClient.Builder` for `WebClient` + +It is also possible to apply manually the customizers responsible for this instrumentation, namely `MetricsRestTemplateCustomizer` and `MetricsWebClientCustomizer`. + +By default, metrics are generated with the name, `http.client.requests`. +The name can be customized by setting the configprop:management.metrics.web.client.request.metric-name[] property. + +By default, metrics generated by an instrumented client are tagged with the following information: + +|=== +| Tag | Description + +| `clientName` +| Host portion of the URI + +| `method` +| Request's method (for example, `GET` or `POST`) + +| `outcome` +| Request's outcome based on the status code of the response. + 1xx is `INFORMATIONAL`, 2xx is `SUCCESS`, 3xx is `REDIRECTION`, 4xx `CLIENT_ERROR`, and 5xx is `SERVER_ERROR`, `UNKNOWN` otherwise + +| `status` +| Response's HTTP status code if available (for example, `200` or `500`), or `IO_ERROR` in case of I/O issues, `CLIENT_ERROR` otherwise + +| `uri` +| Request's URI template prior to variable substitution, if possible (for example, `/api/person/\{id}`) +|=== + +To customize the tags, and depending on your choice of client, you can provide a `@Bean` that implements `RestTemplateExchangeTagsProvider` or `WebClientExchangeTagsProvider`. +There are convenience static functions in `RestTemplateExchangeTags` and `WebClientExchangeTags`. + + + +[[actuator.metrics.supported.tomcat]] +==== Tomcat Metrics +Auto-configuration will enable the instrumentation of Tomcat only when an `MBeanRegistry` is enabled. +By default, the `MBeanRegistry` is disabled, but you can enable it by setting configprop:server.tomcat.mbeanregistry.enabled[] to `true`. + +Tomcat metrics are published under the `tomcat.` meter name. + + + +[[actuator.metrics.supported.cache]] +==== Cache Metrics +Auto-configuration enables the instrumentation of all available ``Cache``s on startup with metrics prefixed with `cache`. +Cache instrumentation is standardized for a basic set of metrics. +Additional, cache-specific metrics are also available. + +The following cache libraries are supported: + +* Caffeine +* EhCache 2 +* Hazelcast +* Any compliant JCache (JSR-107) implementation +* Redis + +Metrics are tagged by the name of the cache and by the name of the `CacheManager` that is derived from the bean name. + +NOTE: Only caches that are configured on startup are bound to the registry. +For caches not defined in the cache’s configuration, e.g. caches created on-the-fly or programmatically after the startup phase, an explicit registration is required. +A `CacheMetricsRegistrar` bean is made available to make that process easier. + + + +[[actuator.metrics.supported.jdbc]] +==== DataSource Metrics +Auto-configuration enables the instrumentation of all available `DataSource` objects with metrics prefixed with `jdbc.connections`. +Data source instrumentation results in gauges representing the currently active, idle, maximum allowed, and minimum allowed connections in the pool. + +Metrics are also tagged by the name of the `DataSource` computed based on the bean name. + +TIP: By default, Spring Boot provides metadata for all supported data sources; you can add additional `DataSourcePoolMetadataProvider` beans if your favorite data source isn't supported out of the box. +See `DataSourcePoolMetadataProvidersConfiguration` for examples. + +Also, Hikari-specific metrics are exposed with a `hikaricp` prefix. +Each metric is tagged by the name of the Pool (can be controlled with `spring.datasource.name`). + + + +[[actuator.metrics.supported.hibernate]] +==== Hibernate Metrics +If `org.hibernate:hibernate-micrometer` is on the classpath, all available Hibernate `EntityManagerFactory` instances that have statistics enabled are instrumented with a metric named `hibernate`. + +Metrics are also tagged by the name of the `EntityManagerFactory` that is derived from the bean name. + +To enable statistics, the standard JPA property `hibernate.generate_statistics` must be set to `true`. +You can enable that on the auto-configured `EntityManagerFactory` as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + jpa: + properties: + "[hibernate.generate_statistics]": true +---- + + + +[[actuator.metrics.supported.spring-data-repository]] +==== Spring Data Repository Metrics +Auto-configuration enables the instrumentation of all Spring Data `Repository` method invocations. +By default, metrics are generated with the name, `spring.data.repository.invocations`. +The name can be customized by setting the configprop:management.metrics.data.repository.metric-name[] property. + +`@Timed` annotations are supported on `Repository` classes and methods (see <> for details). +If you don't want to record metrics for all `Repository` invocations, you can set configprop:management.metrics.data.repository.autotime.enabled[] to `false` and exclusively use `@Timed` annotations instead. + +By default, repository invocation related metrics are tagged with the following information: + +|=== +| Tag | Description + +| `repository` +| Simple class name of the source `Repository`. + +| `method` +| The name of the `Repository` method that was invoked. + +| `state` +| The result state (`SUCCESS`, `ERROR`, `CANCELED` or `RUNNING`). + +| `exception` +| Simple class name of any exception that was thrown from the invocation. +|=== + +To replace the default tags, provide a `@Bean` that implements `RepositoryTagsProvider`. + + + +[[actuator.metrics.supported.rabbitmq]] +==== RabbitMQ Metrics +Auto-configuration will enable the instrumentation of all available RabbitMQ connection factories with a metric named `rabbitmq`. + + + +[[actuator.metrics.supported.spring-integration]] +==== Spring Integration Metrics +Spring Integration provides {spring-integration-docs}system-management.html#micrometer-integration[Micrometer support] automatically whenever a `MeterRegistry` bean is available. +Metrics are published under the `spring.integration.` meter name. + + + +[[actuator.metrics.supported.kafka]] +==== Kafka Metrics +Auto-configuration will register a `MicrometerConsumerListener` and `MicrometerProducerListener` for the auto-configured consumer factory and producer factory respectively. +It will also register a `KafkaStreamsMicrometerListener` for `StreamsBuilderFactoryBean`. +For more details refer to {spring-kafka-docs}#micrometer-native[Micrometer Native Metrics] section of the Spring Kafka documentation. + + + +[[actuator.metrics.supported.mongodb]] +==== MongoDB Metrics + + + +[[actuator.metrics.supported.mongodb.command]] +===== Command Metrics +Auto-configuration will register a `MongoMetricsCommandListener` with the auto-configured `MongoClient`. + +A timer metric with the name `mongodb.driver.commands` is created for each command issued to the underlying MongoDB driver. +Each metric is tagged with the following information by default: +|=== +| Tag | Description + +| `command` +| Name of the command issued + +| `cluster.id` +| Identifier of the cluster the command was sent to + +| `server.address` +| Address of the server the command was sent to + +| `status` +| Outcome of the command - one of (`SUCCESS`, `FAILED`) +|=== + +To replace the default metric tags, define a `MongoCommandTagsProvider` bean, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-productionreadyfeatures}/metrics/mongo/SampleCommandTagsProviderConfiguration.java[] +---- + +To disable the auto-configured command metrics, set the following property: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + mongo: + command: + enabled: false +---- + + + +[[actuator.metrics.supported.mongodb.connection-pool]] +===== Connection Pool Metrics +Auto-configuration will register a `MongoMetricsConnectionPoolListener` with the auto-configured `MongoClient`. + +The following gauge metrics are created for the connection pool: + +* `mongodb.driver.pool.size` that reports the current size of the connection pool, including idle and and in-use members +* `mongodb.driver.pool.checkedout` that reports the count of connections that are currently in use +* `mongodb.driver.pool.waitqueuesize` that reports the current size of the wait queue for a connection from the pool + +Each metric is tagged with the following information by default: +|=== +| Tag | Description + +| `cluster.id` +| Identifier of the cluster the connection pool corresponds to + +| `server.address` +| Address of the server the connection pool corresponds to +|=== + +To replace the default metric tags, define a `MongoConnectionPoolTagsProvider` bean, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-productionreadyfeatures}/metrics/mongo/SampleConnectionPoolTagsProviderConfiguration.java[tag=*] +---- + +To disable the auto-configured connection pool metrics, set the following property: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + mongo: + connectionpool: + enabled: false +---- + + + +[[actuator.metrics.supported.timed-annotation]] +==== @Timed Annotation Support +The `@Timed` annotation from the `io.micrometer.core.annotation` package can be used with several of the supported technologies listed above. +If supported, the annotation can be used either at the class-level or the method-level. + +For example, the following code shows how the annotation can be used to instrument all request mappings in a `@RestController`: + +[source,java,pending-extract=true,indent=0] +---- + @RestController + @Timed + public class MyController { + + @GetMapping("/api/addresses") + public List listAddress() { ... } + + @GetMapping("/api/people") + public List listPeople() { ... } + + } +---- + +If you only want to instrument a single mapping, you can use the annotation on the method instead of the class: + +[source,java,pending-extract=true,indent=0] +---- + @RestController + public class MyController { + + @GetMapping("/api/addresses") + public List listAddress() { ... } + + @GetMapping("/api/people") + @Timed + public List listPeople() { ... } + + } +---- + +You can also combine class-level and method-level annotations if you want to change timing details for a specific method: + +[source,java,pending-extract=true,indent=0] +---- + @RestController + @Timed + public class MyController { + + @GetMapping("/api/addresses") + public List listPeople() { ... } + + @GetMapping("/api/people") + @Timed(extraTags = { "region", "us-east-1" }) + @Timed(value = "all.people", longTask = true) + public List listPeople() { ... } + + } +---- + +NOTE: A `@Timed` annotation with `longTask = true` will enable a long task timer for the method. +Long task timers require a separate metric name, and can be stacked with a short task timer. + + + +[[actuator.metrics.registering-custom]] +=== Registering Custom Metrics +To register custom metrics, inject `MeterRegistry` into your component, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-productionreadyfeatures}/metrics/MetricsMeterRegistryInjection.java[tag=*] +---- + +If your metrics depend on other beans, it is recommended that you use a `MeterBinder` to register them, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-productionreadyfeatures}/metrics/SampleMeterBinderConfiguration.java[tag=*] +---- + +Using a `MeterBinder` ensures that the correct dependency relationships are set up and that the bean is available when the metric's value is retrieved. +A `MeterBinder` implementation can also be useful if you find that you repeatedly instrument a suite of metrics across components or applications. + +NOTE: By default, metrics from all `MeterBinder` beans will be automatically bound to the Spring-managed `MeterRegistry`. + + + +[[actuator.metrics.customizing]] +=== Customizing Individual Metrics +If you need to apply customizations to specific `Meter` instances you can use the `io.micrometer.core.instrument.config.MeterFilter` interface. + +For example, if you want to rename the `mytag.region` tag to `mytag.area` for all meter IDs beginning with `com.example`, you can do the following: + +[source,java,indent=0] +---- +include::{include-productionreadyfeatures}/metrics/MetricsFilterConfiguration.java[tag=*] +---- + +NOTE: By default, all `MeterFilter` beans will be automatically bound to the Spring-managed `MeterRegistry`. +Make sure to register your metrics using the Spring-managed `MeterRegistry` and not any of the static methods on `Metrics`. +These use the global registry that is not Spring-managed. + + + +[[actuator.metrics.customizing.common-tags]] +==== Common Tags +Common tags are generally used for dimensional drill-down on the operating environment like host, instance, region, stack, etc. +Commons tags are applied to all meters and can be configured as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + tags: + region: "us-east-1" + stack: "prod" +---- + +The example above adds `region` and `stack` tags to all meters with a value of `us-east-1` and `prod` respectively. + +NOTE: The order of common tags is important if you are using Graphite. +As the order of common tags cannot be guaranteed using this approach, Graphite users are advised to define a custom `MeterFilter` instead. + + + +[[actuator.metrics.customizing.per-meter-properties]] +==== Per-meter Properties +In addition to `MeterFilter` beans, it's also possible to apply a limited set of customization on a per-meter basis using properties. +Per-meter customizations apply to any all meter IDs that start with the given name. +For example, the following will disable any meters that have an ID starting with `example.remote` + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + metrics: + enable: + example: + remote: false +---- + +The following properties allow per-meter customization: + +.Per-meter customizations +|=== +| Property | Description + +| configprop:management.metrics.enable[] +| Whether to deny meters from emitting any metrics. + +| configprop:management.metrics.distribution.percentiles-histogram[] +| Whether to publish a histogram suitable for computing aggregable (across dimension) percentile approximations. + +| configprop:management.metrics.distribution.minimum-expected-value[], configprop:management.metrics.distribution.maximum-expected-value[] +| Publish less histogram buckets by clamping the range of expected values. + +| configprop:management.metrics.distribution.percentiles[] +| Publish percentile values computed in your application + +| configprop:management.metrics.distribution.slo[] +| Publish a cumulative histogram with buckets defined by your service-level objectives. +|=== + +For more details on concepts behind `percentiles-histogram`, `percentiles` and `slo` refer to the {micrometer-concepts-docs}#_histograms_and_percentiles["Histograms and percentiles" section] of the micrometer documentation. + + + +[[actuator.metrics.endpoint]] +=== Metrics Endpoint +Spring Boot provides a `metrics` endpoint that can be used diagnostically to examine the metrics collected by an application. +The endpoint is not available by default and must be exposed, see <> for more details. + +Navigating to `/actuator/metrics` displays a list of available meter names. +You can drill down to view information about a particular meter by providing its name as a selector, e.g. `/actuator/metrics/jvm.memory.max`. + +[TIP] +==== +The name you use here should match the name used in the code, not the name after it has been naming-convention normalized for a monitoring system it is shipped to. +In other words, if `jvm.memory.max` appears as `jvm_memory_max` in Prometheus because of its snake case naming convention, you should still use `jvm.memory.max` as the selector when inspecting the meter in the `metrics` endpoint. +==== + +You can also add any number of `tag=KEY:VALUE` query parameters to the end of the URL to dimensionally drill down on a meter, e.g. `/actuator/metrics/jvm.memory.max?tag=area:nonheap`. + +[TIP] +==== +The reported measurements are the _sum_ of the statistics of all meters matching the meter name and any tags that have been applied. +So in the example above, the returned "Value" statistic is the sum of the maximum memory footprints of "Code Cache", "Compressed Class Space", and "Metaspace" areas of the heap. +If you only wanted to see the maximum size for the "Metaspace", you could add an additional `tag=id:Metaspace`, i.e. `/actuator/metrics/jvm.memory.max?tag=area:nonheap&tag=id:Metaspace`. +==== diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/monitoring.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/monitoring.adoc new file mode 100644 index 0000000000..b93fcf75ea --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/monitoring.adoc @@ -0,0 +1,148 @@ +[[actuator.monitoring]] +== Monitoring and Management over HTTP +If you are developing a web application, Spring Boot Actuator auto-configures all enabled endpoints to be exposed over HTTP. +The default convention is to use the `id` of the endpoint with a prefix of `/actuator` as the URL path. +For example, `health` is exposed as `/actuator/health`. + +TIP: Actuator is supported natively with Spring MVC, Spring WebFlux, and Jersey. +If both Jersey and Spring MVC are available, Spring MVC will be used. + +NOTE: Jackson is a required dependency in order to get the correct JSON responses as documented in the API documentation ({spring-boot-actuator-restapi-docs}[HTML] or {spring-boot-actuator-restapi-pdfdocs}[PDF]). + + + +[[actuator.monitoring.customizing-management-server-context-path]] +=== Customizing the Management Endpoint Paths +Sometimes, it is useful to customize the prefix for the management endpoints. +For example, your application might already use `/actuator` for another purpose. +You can use the configprop:management.endpoints.web.base-path[] property to change the prefix for your management endpoint, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + endpoints: + web: + base-path: "/manage" +---- + +The preceding `application.properties` example changes the endpoint from `/actuator/\{id}` to `/manage/\{id}` (for example, `/manage/info`). + +NOTE: Unless the management port has been configured to <>, `management.endpoints.web.base-path` is relative to `server.servlet.context-path` (Servlet web applications) or `spring.webflux.base-path` (reactive web applications). +If `management.server.port` is configured, `management.endpoints.web.base-path` is relative to `management.server.base-path`. + +If you want to map endpoints to a different path, you can use the configprop:management.endpoints.web.path-mapping[] property. + +The following example remaps `/actuator/health` to `/healthcheck`: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + endpoints: + web: + base-path: "/" + path-mapping: + health: "healthcheck" +---- + + + +[[actuator.monitoring.customizing-management-server-port]] +=== Customizing the Management Server Port +Exposing management endpoints by using the default HTTP port is a sensible choice for cloud-based deployments. +If, however, your application runs inside your own data center, you may prefer to expose endpoints by using a different HTTP port. + +You can set the configprop:management.server.port[] property to change the HTTP port, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + server: + port: 8081 +---- + +NOTE: On Cloud Foundry, applications only receive requests on port 8080 for both HTTP and TCP routing, by default. +If you want to use a custom management port on Cloud Foundry, you will need to explicitly set up the application's routes to forward traffic to the custom port. + + + +[[actuator.monitoring.management-specific-ssl]] +=== Configuring Management-specific SSL +When configured to use a custom port, the management server can also be configured with its own SSL by using the various `management.server.ssl.*` properties. +For example, doing so lets a management server be available over HTTP while the main application uses HTTPS, as shown in the following property settings: + +[source,yaml,indent=0,configprops,configblocks] +---- + server: + port: 8443 + ssl: + enabled: true + key-store: "classpath:store.jks" + key-password: secret + management: + server: + port: 8080 + ssl: + enabled: false +---- + +Alternatively, both the main server and the management server can use SSL but with different key stores, as follows: + +[source,yaml,indent=0,configprops,configblocks] +---- + server: + port: 8443 + ssl: + enabled: true + key-store: "classpath:main.jks" + key-password: "secret" + management: + server: + port: 8080 + ssl: + enabled: true + key-store: "classpath:management.jks" + key-password: "secret" +---- + + + +[[actuator.monitoring.customizing-management-server-address]] +=== Customizing the Management Server Address +You can customize the address that the management endpoints are available on by setting the configprop:management.server.address[] property. +Doing so can be useful if you want to listen only on an internal or ops-facing network or to listen only for connections from `localhost`. + +NOTE: You can listen on a different address only when the port differs from the main server port. + +The following example `application.properties` does not allow remote management connections: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + server: + port: 8081 + address: "127.0.0.1" +---- + + + +[[actuator.monitoring.disabling-http-endpoints]] +=== Disabling HTTP Endpoints +If you do not want to expose endpoints over HTTP, you can set the management port to `-1`, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + server: + port: -1 +---- + +This can be achieved using the configprop:management.endpoints.web.exposure.exclude[] property as well, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + management: + endpoints: + web: + exposure: + exclude: "*" +---- diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/process-monitoring.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/process-monitoring.adoc new file mode 100644 index 0000000000..365d3c1853 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/process-monitoring.adoc @@ -0,0 +1,31 @@ +[[actuator.process-monitoring]] +== Process Monitoring +In the `spring-boot` module, you can find two classes to create files that are often useful for process monitoring: + +* `ApplicationPidFileWriter` creates a file containing the application PID (by default, in the application directory with a file name of `application.pid`). +* `WebServerPortFileWriter` creates a file (or files) containing the ports of the running web server (by default, in the application directory with a file name of `application.port`). + +By default, these writers are not activated, but you can enable: + +* <> +* <> + + + +[[actuator.process-monitoring.configuration]] +=== Extending Configuration +In the `META-INF/spring.factories` file, you can activate the listener(s) that writes a PID file, as shown in the following example: + +[indent=0] +---- + org.springframework.context.ApplicationListener=\ + org.springframework.boot.context.ApplicationPidFileWriter,\ + org.springframework.boot.web.context.WebServerPortFileWriter +---- + + + +[[actuator.process-monitoring.programmatically]] +=== Programmatically +You can also activate a listener by invoking the `SpringApplication.addListeners(...)` method and passing the appropriate `Writer` object. +This method also lets you customize the file name and path in the `Writer` constructor. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/tracing.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/tracing.adoc new file mode 100644 index 0000000000..df0adbbdd9 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/tracing.adoc @@ -0,0 +1,16 @@ +[[actuator.tracing]] +== HTTP Tracing +HTTP Tracing can be enabled by providing a bean of type `HttpTraceRepository` in your application's configuration. +For convenience, Spring Boot offers an `InMemoryHttpTraceRepository` that stores traces for the last 100 request-response exchanges, by default. +`InMemoryHttpTraceRepository` is limited compared to other tracing solutions and we recommend using it only for development environments. +For production environments, use of a production-ready tracing or observability solution, such as Zipkin or Spring Cloud Sleuth, is recommended. +Alternatively, create your own `HttpTraceRepository` that meets your needs. + +The `httptrace` endpoint can be used to obtain information about the request-response exchanges that are stored in the `HttpTraceRepository`. + + + +[[actuator.tracing.custom]] +=== Custom HTTP tracing +To customize the items that are included in each trace, use the configprop:management.trace.http.include[] configuration property. +For advanced customization, consider registering your own `HttpExchangeTracer` implementation. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/whats-next.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/whats-next.adoc new file mode 100644 index 0000000000..652c0d147a --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/whats-next.adoc @@ -0,0 +1,5 @@ +[[actuator.whats-next]] +== What to Read Next +You might want to read about graphing tools such as https://graphiteapp.org[Graphite]. + +Otherwise, you can continue on, to read about <> or jump ahead for some in-depth information about Spring Boot's _<>_. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/anchor-rewrite.properties b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/anchor-rewrite.properties index 31ebe7363b..d5d39f2e53 100644 --- a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/anchor-rewrite.properties +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/anchor-rewrite.properties @@ -173,7 +173,7 @@ getting-started.first-application.executable-jar # 2 == What to Read Next getting-started-whats-next=\ -getting-started.whats=next +getting-started.whats-next @@ -2856,252 +2856,252 @@ howto.testcontainers # (appendix-application-properties.adoc) # 1 = Common Application properties common-application-properties=\ -appendix.common-application-properties +application-properties # 2 == Core Properties [[core-properties]] common-application-properties-core=\ -appendix.common-application-properties.core +application-properties.core # 2 == Cache Properties [[cache-properties]] common-application-properties-cache=\ -appendix.common-application-properties.cache +application-properties.cache # 2 == Mail Properties [[mail-properties]] common-application-properties-mail=\ -appendix.common-application-properties.mail +application-properties.mail # 2 == JSON Properties [[json-properties]] common-application-properties-json=\ -appendix.common-application-properties.json +application-properties.json # 2 == Data Properties [[data-properties]] common-application-properties-data=\ -appendix.common-application-properties.data +application-properties.data # 2 == Transaction Properties [[transaction-properties]] common-application-properties-transaction=\ -appendix.common-application-properties.transaction +application-properties.transaction # 2 == Data Migration Properties [[data-migration-properties]] common-application-properties-data-migration=\ -appendix.common-application-properties.data-migration +application-properties.data-migration # 2 == Integration Properties [[integration-properties]] common-application-properties-integration=\ -appendix.common-application-properties.integration +application-properties.integration # 2 == Web Properties [[web-properties]] common-application-properties-web=\ -appendix.common-application-properties.web +application-properties.web # 2 == Templating Properties [[templating-properties]] common-application-properties-templating=\ -appendix.common-application-properties.templating +application-properties.templating # 2 == Server Properties [[server-properties]] common-application-properties-server=\ -appendix.common-application-properties.server +application-properties.server # 2 == Security Properties [[security-properties]] common-application-properties-security=\ -appendix.common-application-properties.security +application-properties.security # 2 == RSocket Properties [[rsocket-properties]] common-application-properties-rsocket=\ -appendix.common-application-properties.rsocket +application-properties.rsocket # 2 == Actuator Properties [[actuator-properties]] common-application-properties-actuator=\ -appendix.common-application-properties.actuator +application-properties.actuator # 2 == Devtools Properties [[devtools-properties]] common-application-properties-devtools=\ -appendix.common-application-properties.devtools +application-properties.devtools # 2 == Testing Properties [[testing-properties]] common-application-properties-testing=\ -appendix.common-application-properties.testing +application-properties.testing # (configuration-metadata.adoc) # 1 = Configuration Metadata configuration-metadata=\ -appendix.configuration-metadata +configuration-metadata # 2 == Metadata Format configuration-metadata-format=\ -appendix.configuration-metadata.format +configuration-metadata.format # 3 === Group Attributes configuration-metadata-group-attributes=\ -appendix.configuration-metadata.format.group +configuration-metadata.format.group # 3 === Property Attributes configuration-metadata-property-attributes=\ -appendix.configuration-metadata.format.property +configuration-metadata.format.property # 3 === Hint Attributes configuration-metadata-hints-attributes=\ -appendix.configuration-metadata.format.hints +configuration-metadata.format.hints # 3 === Repeated Metadata Items configuration-metadata-repeated-items=\ -appendix.configuration-metadata.format.repeated-items +configuration-metadata.format.repeated-items # 2 == Providing Manual Hints configuration-metadata-providing-manual-hints=\ -appendix.configuration-metadata.manual-hints +configuration-metadata.manual-hints # 3 === Value Hint configuration-metadata-providing-manual-hints-value-hint=\ -appendix.configuration-metadata.manual-hints.value-hint +configuration-metadata.manual-hints.value-hint # 3 === Value Providers configuration-metadata-providing-manual-hints-value-providers=\ -appendix.configuration-metadata.manual-hints.value-providers +configuration-metadata.manual-hints.value-providers # 4 ==== Any configuration-metadata-providing-manual-hints-any=\ -appendix.configuration-metadata.manual-hints.value-providers.any +configuration-metadata.manual-hints.value-providers.any # 4 ==== Class Reference configuration-metadata-providing-manual-hints-class-reference=\ -appendix.configuration-metadata.manual-hints.value-providers.class-reference +configuration-metadata.manual-hints.value-providers.class-reference # 4 ==== Handle As configuration-metadata-providing-manual-hints-handle-as=\ -appendix.configuration-metadata.manual-hints.value-providers.handle-as +configuration-metadata.manual-hints.value-providers.handle-as # 4 ==== Logger Name configuration-metadata-providing-manual-hints-logger-name=\ -appendix.configuration-metadata.manual-hints.value-providers.logger-name +configuration-metadata.manual-hints.value-providers.logger-name # 4 ==== Spring Bean Reference configuration-metadata-providing-manual-hints-spring-bean-reference=\ -appendix.configuration-metadata.manual-hints.value-providers.spring-bean-reference +configuration-metadata.manual-hints.value-providers.spring-bean-reference # 4 ==== Spring Profile Name configuration-metadata-providing-manual-hints-spring-profile-name=\ -appendix.configuration-metadata.manual-hints.value-providers.spring-profile-name +configuration-metadata.manual-hints.value-providers.spring-profile-name # 2 == Generating Your Own Metadata by Using the Annotation Processor configuration-metadata-annotation-processor=\ -appendix.configuration-metadata.annotation-processor +configuration-metadata.annotation-processor # 3 === Configuring the Annotation Processor configuration-metadata-annotation-processor-setup=\ -appendix.configuration-metadata.annotation-processor.configuring +configuration-metadata.annotation-processor.configuring # 3 === Automatic Metadata Generation configuration-metadata-annotation-processor-metadata-generation=\ -appendix.configuration-metadata.annotation-processor.automatic-metadata-generation +configuration-metadata.annotation-processor.automatic-metadata-generation # 4 ==== Nested Properties configuration-metadata-annotation-processor-metadata-generation-nested=\ -appendix.configuration-metadata.annotation-processor.automatic-metadata-generation.nested-properties +configuration-metadata.annotation-processor.automatic-metadata-generation.nested-properties # 3 === Adding Additional Metadata configuration-metadata-additional-metadata=\ -appendix.configuration-metadata.annotation-processor.adding-additional-metadata +configuration-metadata.annotation-processor.adding-additional-metadata # (auto-configuration-classes.adoc) # 1 = Auto-configuration Classes auto-configuration-classes=\ -appendix.auto-configuration-classes +auto-configuration-classes # 2 == spring-boot-autoconfigure auto-configuration-classes-from-autoconfigure-module=\ -appendix.auto-configuration-classes.core +auto-configuration-classes.core # 2 == spring-boot-actuator-autoconfigure auto-configuration-classes-from-actuator=\ -appendix.auto-configuration-classes.actuator +auto-configuration-classes.actuator # (test-auto-configuration.adoc) # 1 = Test Auto-configuration Annotations test-auto-configuration=\ -appendix.test-auto-configuration +test-auto-configuration # 2 == Test Slices test-auto-configuration-slices=\ -appendix.test-auto-configuration.slices +test-auto-configuration.slices # (executable-jar.adoc) # 1 = The Executable Jar Format executable-jar=\ -appendix.executable-jar +executable-jar # 2 == Nested JARs executable-jar-nested-jars=\ -appendix.executable-jar.nested-jars +executable-jar.nested-jars # 3 === The Executable Jar File Structure executable-jar-jar-file-structure=\ -appendix.executable-jar.nested-jars.jar-structure +executable-jar.nested-jars.jar-structure # 3 === The Executable War File Structure executable-jar-war-file-structure=\ -appendix.executable-jar.nested-jars.war-structure +executable-jar.nested-jars.war-structure # 3 === Index Files executable-jar-war-index-files=\ -appendix.executable-jar.nested-jars.index-files +executable-jar.nested-jars.index-files # 3 === Classpath Index executable-jar-war-index-files-classpath=\ -appendix.executable-jar.nested-jars.classpath-index +executable-jar.nested-jars.classpath-index # 3 === Layer Index executable-jar-war-index-files-layers=\ -appendix.executable-jar.nested-jars.layer-index +executable-jar.nested-jars.layer-index # 2 == Spring Boot's "`JarFile`" Class executable-jar-jarfile=\ -appendix.executable-jar.jarfile-class +executable-jar.jarfile-class # 3 === Compatibility with the Standard Java "`JarFile`" executable-jar-jarfile-compatibility=\ -appendix.executable-jar.jarfile-class.compatibilty +executable-jar.jarfile-class.compatibilty # 2 == Launching Executable Jars executable-jar-launching=\ -appendix.executable-jar.launching +executable-jar.launching # 3 === Launcher Manifest executable-jar-launcher-manifest=\ -appendix.executable-jar.launching.manifest +executable-jar.launching.manifest # 2 == PropertiesLauncher Features executable-jar-property-launcher-features=\ -appendix.executable-jar.property-launcher +executable-jar.property-launcher # 2 == Executable Jar Restrictions executable-jar-restrictions=\ -appendix.executable-jar.restrictions +executable-jar.restrictions # 2 == Alternative Single Jar Solutions executable-jar-alternatives=\ -appendix.executable-jar.alternatives +executable-jar.alternatives # (dependency-versions.adoc) # 1 = Dependency versions dependency-versions=\ -appendix.dependency-versions +dependency-versions # 2 == Managed Dependency Coordinates dependency-versions-coordinates=\ -appendix.dependency-versions.coordinates +dependency-versions.coordinates # 2 == Version Properties dependency-versions-properties=\ -appendix.dependency-versions.properties +dependency-versions.properties diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties.adoc new file mode 100644 index 0000000000..7a9710ecf9 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties.adoc @@ -0,0 +1,48 @@ +[appendix] +[[application-properties]] += Common Application properties +include::attributes.adoc[] + + + +Various properties can be specified inside your `application.properties` file, inside your `application.yml` file, or as command line switches. +This appendix provides a list of common Spring Boot properties and references to the underlying classes that consume them. + +TIP: Spring Boot provides various conversion mechanism with advanced value formatting, make sure to review <>. + +NOTE: Property contributions can come from additional jar files on your classpath, so you should not consider this an exhaustive list. +Also, you can define your own properties. + + + +include::application-properties/core.adoc[] + +include::application-properties/cache.adoc[] + +include::application-properties/mail.adoc[] + +include::application-properties/json.adoc[] + +include::application-properties/data.adoc[] + +include::application-properties/transaction.adoc[] + +include::application-properties/data-migration.adoc[] + +include::application-properties/integration.adoc[] + +include::application-properties/web.adoc[] + +include::application-properties/templating.adoc[] + +include::application-properties/server.adoc[] + +include::application-properties/security.adoc[] + +include::application-properties/rsocket.adoc[] + +include::application-properties/actuator.adoc[] + +include::application-properties/devtools.adoc[] + +include::application-properties/testing.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/actuator.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/actuator.adoc new file mode 100644 index 0000000000..3839fe3fde --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/actuator.adoc @@ -0,0 +1,3 @@ +[[application-properties.actuator]] +== Actuator Properties [[actuator-properties]] +include::documented-application-properties/actuator.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/cache.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/cache.adoc new file mode 100644 index 0000000000..b7b94177a3 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/cache.adoc @@ -0,0 +1,3 @@ +[[application-properties.cache]] +== Cache Properties [[cache-properties]] +include::documented-application-properties/cache.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/core.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/core.adoc new file mode 100644 index 0000000000..53e5caef77 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/core.adoc @@ -0,0 +1,3 @@ +[[application-properties.core]] +== Core Properties [[core-properties]] +include::documented-application-properties/core.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/data-migration.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/data-migration.adoc new file mode 100644 index 0000000000..892b5b41e1 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/data-migration.adoc @@ -0,0 +1,3 @@ +[[application-properties.data-migration]] +== Data Migration Properties [[data-migration-properties]] +include::documented-application-properties/data-migration.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/data.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/data.adoc new file mode 100644 index 0000000000..ce85689133 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/data.adoc @@ -0,0 +1,3 @@ +[[application-properties.data]] +== Data Properties [[data-properties]] +include::documented-application-properties/data.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/devtools.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/devtools.adoc new file mode 100644 index 0000000000..4a6966aeb9 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/devtools.adoc @@ -0,0 +1,3 @@ +[[application-properties.devtools]] +== Devtools Properties [[devtools-properties]] +include::documented-application-properties/devtools.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/integration.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/integration.adoc new file mode 100644 index 0000000000..409416e23c --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/integration.adoc @@ -0,0 +1,3 @@ +[[application-properties.integration]] +== Integration Properties [[integration-properties]] +include::documented-application-properties/integration.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/json.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/json.adoc new file mode 100644 index 0000000000..5ae84a1874 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/json.adoc @@ -0,0 +1,3 @@ +[[application-properties.json]] +== JSON Properties [[json-properties]] +include::documented-application-properties/json.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/mail.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/mail.adoc new file mode 100644 index 0000000000..8c93a6d828 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/mail.adoc @@ -0,0 +1,3 @@ +[[application-properties.mail]] +== Mail Properties [[mail-properties]] +include::documented-application-properties/mail.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/rsocket.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/rsocket.adoc new file mode 100644 index 0000000000..4c83b0bd26 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/rsocket.adoc @@ -0,0 +1,3 @@ +[[application-properties.rsocket]] +== RSocket Properties [[rsocket-properties]] +include::documented-application-properties/rsocket.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/security.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/security.adoc new file mode 100644 index 0000000000..8d20e4e49b --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/security.adoc @@ -0,0 +1,3 @@ +[[application-properties.security]] +== Security Properties [[security-properties]] +include::documented-application-properties/security.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/server.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/server.adoc new file mode 100644 index 0000000000..0302e18819 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/server.adoc @@ -0,0 +1,3 @@ +[[application-properties.server]] +== Server Properties [[server-properties]] +include::documented-application-properties/server.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/templating.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/templating.adoc new file mode 100644 index 0000000000..cc6fdea198 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/templating.adoc @@ -0,0 +1,3 @@ +[[application-properties.templating]] +== Templating Properties [[templating-properties]] +include::documented-application-properties/templating.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/testing.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/testing.adoc new file mode 100644 index 0000000000..bb5b918f97 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/testing.adoc @@ -0,0 +1,3 @@ +[[application-properties.testing]] +== Testing Properties [[testing-properties]] +include::documented-application-properties/testing.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/transaction.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/transaction.adoc new file mode 100644 index 0000000000..7c5cb71348 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/transaction.adoc @@ -0,0 +1,3 @@ +[[application-properties.transaction]] +== Transaction Properties [[transaction-properties]] +include::documented-application-properties/transaction.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/web.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/web.adoc new file mode 100644 index 0000000000..f9567ca2c4 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/application-properties/web.adoc @@ -0,0 +1,3 @@ +[[application-properties.web]] +== Web Properties [[web-properties]] +include::documented-application-properties/web.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/attributes.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/attributes.adoc index 82665fb8c1..c6bf2e4609 100644 --- a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/attributes.adoc +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/attributes.adoc @@ -10,21 +10,17 @@ :hide-uri-scheme: :docinfo: shared,private :chomp: tags formatters headers packages - :spring-boot-artifactory-repo: snapshot :github-tag: main :spring-boot-version: current - :github-repo: spring-projects/spring-boot :github-raw: https://raw.githubusercontent.com/{github-repo}/{github-tag} :github-issues: https://github.com/{github-repo}/issues/ :github-wiki: https://github.com/{github-repo}/wiki - -:include: ../main/java/org/springframework/boot/docs +:include: ../../main/java/org/springframework/boot/docs :include-springbootfeatures: {include}/springbootfeatures :include-productionreadyfeatures: {include}/productionreadyfeatures :include-howto: {include}/howto - :spring-boot-code: https://github.com/{github-repo}/tree/{github-tag} :spring-boot-api: https://docs.spring.io/spring-boot/docs/{spring-boot-version}/api :spring-boot-docs: https://docs.spring.io/spring-boot/docs/{spring-boot-version}/reference @@ -38,7 +34,6 @@ :spring-boot-gradle-plugin-docs: https://docs.spring.io/spring-boot/docs/{spring-boot-version}/gradle-plugin/reference/htmlsingle/ :spring-boot-gradle-plugin-pdfdocs: https://docs.spring.io/spring-boot/docs/{spring-boot-version}/gradle-plugin/reference/pdf/spring-boot-gradle-plugin-reference.pdf :spring-boot-gradle-plugin-api: https://docs.spring.io/spring-boot/docs/{spring-boot-version}/gradle-plugin/api/ - :spring-boot-module-code: {spring-boot-code}/spring-boot-project/spring-boot/src/main/java/org/springframework/boot :spring-boot-module-api: {spring-boot-api}/org/springframework/boot :spring-boot-autoconfigure-module-code: {spring-boot-code}/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure @@ -55,7 +50,6 @@ :spring-boot-test-module-api: {spring-boot-api}/org/springframework/boot/test :spring-boot-test-autoconfigure-module-code: {spring-boot-code}/spring-boot-project/spring-boot-test-autoconfigure/src/main/java/org/springframework/boot/test/autoconfigure :spring-boot-test-autoconfigure-module-api: {spring-boot-api}/org/springframework/boot/test/autoconfigure - :spring-amqp-api: https://docs.spring.io/spring-amqp/docs/{spring-amqp-version}/api/org/springframework/amqp :spring-batch: https://spring.io/projects/spring-batch :spring-batch-api: https://docs.spring.io/spring-batch/docs/{spring-batch-version}/api/org/springframework/batch @@ -94,7 +88,6 @@ :spring-security-oauth2-docs: https://projects.spring.io/spring-security-oauth/docs/oauth2.html :spring-session: https://spring.io/projects/spring-session :spring-webservices-docs: https://docs.spring.io/spring-ws/docs/{spring-webservices-version}/reference/ - :ant-docs: https://ant.apache.org/manual :dependency-management-plugin-code: https://github.com/spring-gradle-plugins/dependency-management-plugin :gradle-docs: https://docs.gradle.org/current/userguide diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/auto-configuration-classes.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/auto-configuration-classes.adoc index 2be9668ad8..c0d586a076 100644 --- a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/auto-configuration-classes.adoc +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/auto-configuration-classes.adoc @@ -1,24 +1,16 @@ [appendix] -[[appendix.auto-configuration-classes]] +[[auto-configuration-classes]] = Auto-configuration Classes include::attributes.adoc[] + + This appendix contains details of all of the auto-configuration classes provided by Spring Boot, with links to documentation and source code. Remember to also look at the conditions report in your application for more details of which features are switched on. (To do so, start the app with `--debug` or `-Ddebug` or, in an Actuator application, use the `conditions` endpoint). -[[appendix.auto-configuration-classes.core]] -== spring-boot-autoconfigure -The following auto-configuration classes are from the `spring-boot-autoconfigure` module: +include::auto-configuration-classes/core.adoc[] -include::auto-configuration-classes/spring-boot-autoconfigure.adoc[] - - - -[[appendix.auto-configuration-classes.actuator]] -== spring-boot-actuator-autoconfigure -The following auto-configuration classes are from the `spring-boot-actuator-autoconfigure` module: - -include::auto-configuration-classes/spring-boot-actuator-autoconfigure.adoc[] +include::auto-configuration-classes/actuator.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/auto-configuration-classes/actuator.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/auto-configuration-classes/actuator.adoc new file mode 100644 index 0000000000..4403ec3da3 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/auto-configuration-classes/actuator.adoc @@ -0,0 +1,5 @@ +[[auto-configuration-classes.actuator]] +== spring-boot-actuator-autoconfigure +The following auto-configuration classes are from the `spring-boot-actuator-autoconfigure` module: + +include::documented-auto-configuration-classes/spring-boot-actuator-autoconfigure.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/auto-configuration-classes/core.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/auto-configuration-classes/core.adoc new file mode 100644 index 0000000000..eb9c201c88 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/auto-configuration-classes/core.adoc @@ -0,0 +1,5 @@ +[[auto-configuration-classes.core]] +== spring-boot-autoconfigure +The following auto-configuration classes are from the `spring-boot-autoconfigure` module: + +include::documented-auto-configuration-classes/spring-boot-autoconfigure.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/build-tool-plugins.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/build-tool-plugins.adoc index b2ffec82a3..1fff3b6bf0 100644 --- a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/build-tool-plugins.adoc +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/build-tool-plugins.adoc @@ -2,244 +2,21 @@ = Build Tool Plugins include::attributes.adoc[] + + Spring Boot provides build tool plugins for Maven and Gradle. The plugins offer a variety of features, including the packaging of executable jars. This section provides more details on both plugins as well as some help should you need to extend an unsupported build system. -If you are just getting started, you might want to read "`<>`" from the "`<>`" section first. +If you are just getting started, you might want to read "`<>`" from the "`<>`" section first. -[[build-tool-plugins.maven]] -== Spring Boot Maven Plugin -The Spring Boot Maven Plugin provides Spring Boot support in Maven, letting you package executable jar or war archives and run an application "`in-place`". -To use it, you must use Maven 3.2 (or later). +include::build-tool-plugins/maven.adoc[] -Please refer to the plugin's documentation to learn more: +include::build-tool-plugins/gradle.adoc[] -* Reference ({spring-boot-maven-plugin-docs}[HTML] and {spring-boot-maven-plugin-pdfdocs}[PDF]) -* {spring-boot-maven-plugin-api}[API] +include::build-tool-plugins/antlib.adoc[] +include::build-tool-plugins/other-build-systems.adoc[] - -[[build-tool-plugins.gradle]] -== Spring Boot Gradle Plugin -The Spring Boot Gradle Plugin provides Spring Boot support in Gradle, letting you package executable jar or war archives, run Spring Boot applications, and use the dependency management provided by `spring-boot-dependencies`. -It requires Gradle 6.8 or 7.x. -Please refer to the plugin's documentation to learn more: - -* Reference ({spring-boot-gradle-plugin-docs}[HTML] and {spring-boot-gradle-plugin-pdfdocs}[PDF]) -* {spring-boot-gradle-plugin-api}[API] - - - -[[build-tool-plugins.antlib]] -== Spring Boot AntLib Module -The Spring Boot AntLib module provides basic Spring Boot support for Apache Ant. -You can use the module to create executable jars. -To use the module, you need to declare an additional `spring-boot` namespace in your `build.xml`, as shown in the following example: - -[source,xml,indent=0] ----- - - ... - ----- - -You need to remember to start Ant using the `-lib` option, as shown in the following example: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - $ ant -lib ----- - -TIP: The "`Using Spring Boot`" section includes a more complete example of <>. - - - -[[build-tool-plugins.antlib.tasks]] -=== Spring Boot Ant Tasks -Once the `spring-boot-antlib` namespace has been declared, the following additional tasks are available: - -* <> -* <> - - - -[[build-tool-plugins.antlib.tasks.exejar]] -==== Using the "`exejar`" Task -You can use the `exejar` task to create a Spring Boot executable jar. -The following attributes are supported by the task: - -[cols="1,2,2"] -|==== -| Attribute | Description | Required - -| `destfile` -| The destination jar file to create -| Yes - -| `classes` -| The root directory of Java class files -| Yes - -| `start-class` -| The main application class to run -| No _(the default is the first class found that declares a `main` method)_ -|==== - -The following nested elements can be used with the task: - -[cols="1,4"] -|==== -| Element | Description - -| `resources` -| One or more {ant-docs}/Types/resources.html#collection[Resource Collections] describing a set of {ant-docs}/Types/resources.html[Resources] that should be added to the content of the created +jar+ file. - -| `lib` -| One or more {ant-docs}/Types/resources.html#collection[Resource Collections] that should be added to the set of jar libraries that make up the runtime dependency classpath of the application. -|==== - - - -[[build-tool-plugins.antlib.tasks.examples]] -==== Examples -This section shows two examples of Ant tasks. - -.Specify +start-class+ -[source,xml,indent=0] ----- - - - - - - - - ----- - -.Detect +start-class+ -[source,xml,indent=0] ----- - - - - - ----- - - - -[[build-tool-plugins.antlib.findmainclass]] -=== Using the "`findmainclass`" Task -The `findmainclass` task is used internally by `exejar` to locate a class declaring a `main`. -If necessary, you can also use this task directly in your build. -The following attributes are supported: - -[cols="1,2,2"] -|==== -| Attribute | Description | Required - -| `classesroot` -| The root directory of Java class files -| Yes _(unless `mainclass` is specified)_ - -| `mainclass` -| Can be used to short-circuit the `main` class search -| No - -| `property` -| The Ant property that should be set with the result -| No _(result will be logged if unspecified)_ -|==== - - - -[[build-tool-plugins.antlib.findmainclass.examples]] -==== Examples -This section contains three examples of using `findmainclass`. - -.Find and log -[source,xml,indent=0] ----- - ----- - -.Find and set -[source,xml,indent=0] ----- - ----- - -.Override and set -[source,xml,indent=0] ----- - ----- - - - -[[build-tool-plugins.other-build-systems]] -== Supporting Other Build Systems -If you want to use a build tool other than Maven, Gradle, or Ant, you likely need to develop your own plugin. -Executable jars need to follow a specific format and certain entries need to be written in an uncompressed form (see the "`<>`" section in the appendix for details). - -The Spring Boot Maven and Gradle plugins both make use of `spring-boot-loader-tools` to actually generate jars. -If you need to, you may use this library directly. - - - -[[build-tool-plugins.other-build-systems.repackaging-archives]] -=== Repackaging Archives -To repackage an existing archive so that it becomes a self-contained executable archive, use `org.springframework.boot.loader.tools.Repackager`. -The `Repackager` class takes a single constructor argument that refers to an existing jar or war archive. -Use one of the two available `repackage()` methods to either replace the original file or write to a new destination. -Various settings can also be configured on the repackager before it is run. - - - -[[build-tool-plugins.other-build-systems.nested-libraries]] -=== Nested Libraries -When repackaging an archive, you can include references to dependency files by using the `org.springframework.boot.loader.tools.Libraries` interface. -We do not provide any concrete implementations of `Libraries` here as they are usually build-system-specific. - -If your archive already includes libraries, you can use `Libraries.NONE`. - - - -[[build-tool-plugins.other-build-systems.finding-main-class]] -=== Finding a Main Class -If you do not use `Repackager.setMainClass()` to specify a main class, the repackager uses https://asm.ow2.io/[ASM] to read class files and tries to find a suitable class with a `public static void main(String[] args)` method. -An exception is thrown if more than one candidate is found. - - - -[[build-tool-plugins.other-build-systems.example-repackage-implementation]] -=== Example Repackage Implementation -The following example shows a typical repackage implementation: - -[source,java,pending-extract=true,indent=0] ----- - Repackager repackager = new Repackager(sourceJarFile); - repackager.setBackupSource(false); - repackager.repackage(new Libraries() { - @Override - public void doWithLibraries(LibraryCallback callback) throws IOException { - // Build system specific implementation, callback for each dependency - // callback.library(new Library(nestedFile, LibraryScope.COMPILE)); - } - }); ----- - - - -[[build-tool-plugins.whats-next]] -== What to Read Next -If you are interested in how the build tool plugins work, you can look at the {spring-boot-code}/spring-boot-project/spring-boot-tools[`spring-boot-tools`] module on GitHub. -More technical details of the executable jar format are covered in <>. - -If you have specific build-related questions, you can check out the "`<>`" guides. +include::build-tool-plugins/whats-next.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/build-tool-plugins/antlib.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/build-tool-plugins/antlib.adoc new file mode 100644 index 0000000000..2187652855 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/build-tool-plugins/antlib.adoc @@ -0,0 +1,148 @@ +[[build-tool-plugins.antlib]] +== Spring Boot AntLib Module +The Spring Boot AntLib module provides basic Spring Boot support for Apache Ant. +You can use the module to create executable jars. +To use the module, you need to declare an additional `spring-boot` namespace in your `build.xml`, as shown in the following example: + +[source,xml,indent=0] +---- + + ... + +---- + +You need to remember to start Ant using the `-lib` option, as shown in the following example: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + $ ant -lib +---- + +TIP: The "`Using Spring Boot`" section includes a more complete example of <>. + + + +[[build-tool-plugins.antlib.tasks]] +=== Spring Boot Ant Tasks +Once the `spring-boot-antlib` namespace has been declared, the following additional tasks are available: + +* <> +* <> + + + +[[build-tool-plugins.antlib.tasks.exejar]] +==== Using the "`exejar`" Task +You can use the `exejar` task to create a Spring Boot executable jar. +The following attributes are supported by the task: + +[cols="1,2,2"] +|==== +| Attribute | Description | Required + +| `destfile` +| The destination jar file to create +| Yes + +| `classes` +| The root directory of Java class files +| Yes + +| `start-class` +| The main application class to run +| No _(the default is the first class found that declares a `main` method)_ +|==== + +The following nested elements can be used with the task: + +[cols="1,4"] +|==== +| Element | Description + +| `resources` +| One or more {ant-docs}/Types/resources.html#collection[Resource Collections] describing a set of {ant-docs}/Types/resources.html[Resources] that should be added to the content of the created +jar+ file. + +| `lib` +| One or more {ant-docs}/Types/resources.html#collection[Resource Collections] that should be added to the set of jar libraries that make up the runtime dependency classpath of the application. +|==== + + + +[[build-tool-plugins.antlib.tasks.examples]] +==== Examples +This section shows two examples of Ant tasks. + +.Specify +start-class+ +[source,xml,indent=0] +---- + + + + + + + + +---- + +.Detect +start-class+ +[source,xml,indent=0] +---- + + + + + +---- + + + +[[build-tool-plugins.antlib.findmainclass]] +=== Using the "`findmainclass`" Task +The `findmainclass` task is used internally by `exejar` to locate a class declaring a `main`. +If necessary, you can also use this task directly in your build. +The following attributes are supported: + +[cols="1,2,2"] +|==== +| Attribute | Description | Required + +| `classesroot` +| The root directory of Java class files +| Yes _(unless `mainclass` is specified)_ + +| `mainclass` +| Can be used to short-circuit the `main` class search +| No + +| `property` +| The Ant property that should be set with the result +| No _(result will be logged if unspecified)_ +|==== + + + +[[build-tool-plugins.antlib.findmainclass.examples]] +==== Examples +This section contains three examples of using `findmainclass`. + +.Find and log +[source,xml,indent=0] +---- + +---- + +.Find and set +[source,xml,indent=0] +---- + +---- + +.Override and set +[source,xml,indent=0] +---- + +---- diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/build-tool-plugins/gradle.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/build-tool-plugins/gradle.adoc new file mode 100644 index 0000000000..4d9065c13b --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/build-tool-plugins/gradle.adoc @@ -0,0 +1,8 @@ +[[build-tool-plugins.gradle]] +== Spring Boot Gradle Plugin +The Spring Boot Gradle Plugin provides Spring Boot support in Gradle, letting you package executable jar or war archives, run Spring Boot applications, and use the dependency management provided by `spring-boot-dependencies`. +It requires Gradle 6.8 or 7.x. +Please refer to the plugin's documentation to learn more: + +* Reference ({spring-boot-gradle-plugin-docs}[HTML] and {spring-boot-gradle-plugin-pdfdocs}[PDF]) +* {spring-boot-gradle-plugin-api}[API] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/build-tool-plugins/maven.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/build-tool-plugins/maven.adoc new file mode 100644 index 0000000000..452f039101 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/build-tool-plugins/maven.adoc @@ -0,0 +1,9 @@ +[[build-tool-plugins.maven]] +== Spring Boot Maven Plugin +The Spring Boot Maven Plugin provides Spring Boot support in Maven, letting you package executable jar or war archives and run an application "`in-place`". +To use it, you must use Maven 3.2 (or later). + +Please refer to the plugin's documentation to learn more: + +* Reference ({spring-boot-maven-plugin-docs}[HTML] and {spring-boot-maven-plugin-pdfdocs}[PDF]) +* {spring-boot-maven-plugin-api}[API] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/build-tool-plugins/other-build-systems.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/build-tool-plugins/other-build-systems.adoc new file mode 100644 index 0000000000..30295b63d1 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/build-tool-plugins/other-build-systems.adoc @@ -0,0 +1,51 @@ +[[build-tool-plugins.other-build-systems]] +== Supporting Other Build Systems +If you want to use a build tool other than Maven, Gradle, or Ant, you likely need to develop your own plugin. +Executable jars need to follow a specific format and certain entries need to be written in an uncompressed form (see the "`<>`" section in the appendix for details). + +The Spring Boot Maven and Gradle plugins both make use of `spring-boot-loader-tools` to actually generate jars. +If you need to, you may use this library directly. + + + +[[build-tool-plugins.other-build-systems.repackaging-archives]] +=== Repackaging Archives +To repackage an existing archive so that it becomes a self-contained executable archive, use `org.springframework.boot.loader.tools.Repackager`. +The `Repackager` class takes a single constructor argument that refers to an existing jar or war archive. +Use one of the two available `repackage()` methods to either replace the original file or write to a new destination. +Various settings can also be configured on the repackager before it is run. + + + +[[build-tool-plugins.other-build-systems.nested-libraries]] +=== Nested Libraries +When repackaging an archive, you can include references to dependency files by using the `org.springframework.boot.loader.tools.Libraries` interface. +We do not provide any concrete implementations of `Libraries` here as they are usually build-system-specific. + +If your archive already includes libraries, you can use `Libraries.NONE`. + + + +[[build-tool-plugins.other-build-systems.finding-main-class]] +=== Finding a Main Class +If you do not use `Repackager.setMainClass()` to specify a main class, the repackager uses https://asm.ow2.io/[ASM] to read class files and tries to find a suitable class with a `public static void main(String[] args)` method. +An exception is thrown if more than one candidate is found. + + + +[[build-tool-plugins.other-build-systems.example-repackage-implementation]] +=== Example Repackage Implementation +The following example shows a typical repackage implementation: + +[source,java,pending-extract=true,indent=0] +---- + Repackager repackager = new Repackager(sourceJarFile); + repackager.setBackupSource(false); + repackager.repackage(new Libraries() { + @Override + public void doWithLibraries(LibraryCallback callback) throws IOException { + // Build system specific implementation, callback for each dependency + // callback.library(new Library(nestedFile, LibraryScope.COMPILE)); + } + }); +---- diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/build-tool-plugins/whats-next.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/build-tool-plugins/whats-next.adoc new file mode 100644 index 0000000000..ed22fc2e9c --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/build-tool-plugins/whats-next.adoc @@ -0,0 +1,6 @@ +[[build-tool-plugins.whats-next]] +== What to Read Next +If you are interested in how the build tool plugins work, you can look at the {spring-boot-code}/spring-boot-project/spring-boot-tools[`spring-boot-tools`] module on GitHub. +More technical details of the executable jar format are covered in <>. + +If you have specific build-related questions, you can check out the "`<>`" guides. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/cli.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/cli.adoc index 61b3a7c638..e573303d9c 100644 --- a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/cli.adoc +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/cli.adoc @@ -2,434 +2,19 @@ = Spring Boot CLI include::attributes.adoc[] + The Spring Boot CLI is a command line tool that you can use if you want to quickly develop a Spring application. It lets you run Groovy scripts, which means that you have a familiar Java-like syntax without so much boilerplate code. You can also bootstrap a new project or write your own command for it. -[[cli.installation]] -== Installing the CLI -The Spring Boot CLI (Command-Line Interface) can be installed manually by using SDKMAN! (the SDK Manager) or by using Homebrew or MacPorts if you are an OSX user. -See _<>_ in the "`Getting started`" section for comprehensive installation instructions. +include::cli/installation.adoc[] +include::cli/using-the-cli.adoc[] +include::cli/groovy-beans-dsl.adoc[] -[[cli.using-the-cli]] -== Using the CLI -Once you have installed the CLI, you can run it by typing `spring` and pressing Enter at the command line. -If you run `spring` without any arguments, a help screen is displayed, as follows: +include::cli/maven-setting.adoc[] -[indent=0,subs="verbatim,quotes,attributes"] ----- - $ spring - usage: spring [--help] [--version] - [] - - Available commands are: - - run [options] [--] [args] - Run a spring groovy script - - _... more command help is shown here_ ----- - -You can type `spring help` to get more details about any of the supported commands, as shown in the following example: - -[indent=0] ----- - $ spring help run - spring run - Run a spring groovy script - - usage: spring run [options] [--] [args] - - Option Description - ------ ----------- - --autoconfigure [Boolean] Add autoconfigure compiler - transformations (default: true) - --classpath, -cp Additional classpath entries - --no-guess-dependencies Do not attempt to guess dependencies - --no-guess-imports Do not attempt to guess imports - -q, --quiet Quiet logging - -v, --verbose Verbose logging of dependency - resolution - --watch Watch the specified file for changes ----- - -The `version` command provides a quick way to check which version of Spring Boot you are using, as follows: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - $ spring version - Spring CLI v{spring-boot-version} ----- - - - -[[cli.using-the-cli.run]] -=== Running Applications with the CLI -You can compile and run Groovy source code by using the `run` command. -The Spring Boot CLI is completely self-contained, so you do not need any external Groovy installation. - -The following example shows a "`hello world`" web application written in Groovy: - -.hello.groovy -[source,groovy,indent=0,subs="verbatim,quotes,attributes"] ----- - @RestController - class WebApplication { - - @RequestMapping("/") - String home() { - "Hello World!" - } - - } ----- - -To compile and run the application, type the following command: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - $ spring run hello.groovy ----- - -To pass command-line arguments to the application, use `--` to separate the commands from the "`spring`" command arguments, as shown in the following example: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - $ spring run hello.groovy -- --server.port=9000 ----- - -To set JVM command line arguments, you can use the `JAVA_OPTS` environment variable, as shown in the following example: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - $ JAVA_OPTS=-Xmx1024m spring run hello.groovy ----- - -NOTE: When setting `JAVA_OPTS` on Microsoft Windows, make sure to quote the entire instruction, such as `set "JAVA_OPTS=-Xms256m -Xmx2048m"`. -Doing so ensures the values are properly passed to the process. - - - -[[cli.using-the-cli.run.deduced-grab-annotations]] -==== Deduced "`grab`" Dependencies -Standard Groovy includes a `@Grab` annotation, which lets you declare dependencies on third-party libraries. -This useful technique lets Groovy download jars in the same way as Maven or Gradle would but without requiring you to use a build tool. - -Spring Boot extends this technique further and tries to deduce which libraries to "`grab`" based on your code. -For example, since the `WebApplication` code shown previously uses `@RestController` annotations, Spring Boot grabs "Tomcat" and "Spring MVC". - -The following items are used as "`grab hints`": - -|=== -| Items | Grabs - -| `JdbcTemplate`, `NamedParameterJdbcTemplate`, `DataSource` -| JDBC Application. - -| `@EnableJms` -| JMS Application. - -| `@EnableCaching` -| Caching abstraction. - -| `@Test` -| JUnit. - -| `@EnableRabbit` -| RabbitMQ. - -| extends `Specification` -| Spock test. - -| `@EnableBatchProcessing` -| Spring Batch. - -| `@MessageEndpoint` `@EnableIntegration` -| Spring Integration. - -| `@Controller` `@RestController` `@EnableWebMvc` -| Spring MVC + Embedded Tomcat. - -| `@EnableWebSecurity` -| Spring Security. - -| `@EnableTransactionManagement` -| Spring Transaction Management. -|=== - -TIP: See subclasses of {spring-boot-cli-module-code}/compiler/CompilerAutoConfiguration.java[`CompilerAutoConfiguration`] in the Spring Boot CLI source code to understand exactly how customizations are applied. - - - -[[cli.using-the-cli.run.deduced-grab-coordinates]] -==== Deduced "`grab`" Coordinates -Spring Boot extends Groovy's standard `@Grab` support by letting you specify a dependency without a group or version (for example, `@Grab('freemarker')`). -Doing so consults Spring Boot's default dependency metadata to deduce the artifact's group and version. - -NOTE: The default metadata is tied to the version of the CLI that you use. -It changes only when you move to a new version of the CLI, putting you in control of when the versions of your dependencies may change. -A table showing the dependencies and their versions that are included in the default metadata can be found in the <>. - - - -[[cli.using-the-cli.run.default-import-statements]] -==== Default Import Statements -To help reduce the size of your Groovy code, several `import` statements are automatically included. -Notice how the preceding example refers to `@Component`, `@RestController`, and `@RequestMapping` without needing to use fully-qualified names or `import` statements. - -TIP: Many Spring annotations work without using `import` statements. -Try running your application to see what fails before adding imports. - - - -[[cli.using-the-cli.run.automatic-main-method]] -==== Automatic Main Method -Unlike the equivalent Java application, you do not need to include a `public static void main(String[] args)` method with your `Groovy` scripts. -A `SpringApplication` is automatically created, with your compiled code acting as the `source`. - - - -[[cli.using-the-cli.run.custom-dependency-management]] -==== Custom Dependency Management -By default, the CLI uses the dependency management declared in `spring-boot-dependencies` when resolving `@Grab` dependencies. -Additional dependency management, which overrides the default dependency management, can be configured by using the `@DependencyManagementBom` annotation. -The annotation's value should specify the coordinates (`groupId:artifactId:version`) of one or more Maven BOMs. - -For example, consider the following declaration: - -[source,groovy,indent=0] ----- - @DependencyManagementBom("com.example.custom-bom:1.0.0") ----- - -The preceding declaration picks up `custom-bom-1.0.0.pom` in a Maven repository under `com/example/custom-versions/1.0.0/`. - -When you specify multiple BOMs, they are applied in the order in which you declare them, as shown in the following example: - -[source,java,pending-extract=true,indent=0] ----- - @DependencyManagementBom(["com.example.custom-bom:1.0.0", - "com.example.another-bom:1.0.0"]) ----- - -The preceding example indicates that the dependency management in `another-bom` overrides the dependency management in `custom-bom`. - -You can use `@DependencyManagementBom` anywhere that you can use `@Grab`. -However, to ensure consistent ordering of the dependency management, you can use `@DependencyManagementBom` at most once in your application. - - - -[[cli.using-the-cli.multiple-source-files]] -=== Applications with Multiple Source Files -You can use "`shell globbing`" with all commands that accept file input. -Doing so lets you use multiple files from a single directory, as shown in the following example: - -[indent=0] ----- - $ spring run *.groovy ----- - - - -[[cli.using-the-cli.packaging]] -=== Packaging Your Application -You can use the `jar` command to package your application into a self-contained executable jar file, as shown in the following example: - -[indent=0] ----- - $ spring jar my-app.jar *.groovy ----- - -The resulting jar contains the classes produced by compiling the application and all of the application's dependencies so that it can then be run by using `java -jar`. -The jar file also contains entries from the application's classpath. -You can add and remove explicit paths to the jar by using `--include` and `--exclude`. -Both are comma-separated, and both accept prefixes, in the form of "`+`" and "`-`", to signify that they should be removed from the defaults. -The default includes are as follows: - -[indent=0] ----- - public/**, resources/**, static/**, templates/**, META-INF/**, * ----- - -The default excludes are as follows: - -[indent=0] ----- - .*, repository/**, build/**, target/**, **/*.jar, **/*.groovy ----- - -Type `spring help jar` on the command line for more information. - - - -[[cli.using-the-cli.initialize-new-project]] -=== Initialize a New Project -The `init` command lets you create a new project by using https://start.spring.io without leaving the shell, as shown in the following example: - -[indent=0] ----- - $ spring init --dependencies=web,data-jpa my-project - Using service at https://start.spring.io - Project extracted to '/Users/developer/example/my-project' ----- - -The preceding example creates a `my-project` directory with a Maven-based project that uses `spring-boot-starter-web` and `spring-boot-starter-data-jpa`. -You can list the capabilities of the service by using the `--list` flag, as shown in the following example: - -[indent=0] ----- - $ spring init --list - ======================================= - Capabilities of https://start.spring.io - ======================================= - - Available dependencies: - ----------------------- - actuator - Actuator: Production ready features to help you monitor and manage your application - ... - web - Web: Support for full-stack web development, including Tomcat and spring-webmvc - websocket - Websocket: Support for WebSocket development - ws - WS: Support for Spring Web Services - - Available project types: - ------------------------ - gradle-build - Gradle Config [format:build, build:gradle] - gradle-project - Gradle Project [format:project, build:gradle] - maven-build - Maven POM [format:build, build:maven] - maven-project - Maven Project [format:project, build:maven] (default) - - ... ----- - -The `init` command supports many options. -See the `help` output for more details. -For instance, the following command creates a Gradle project that uses Java 8 and `war` packaging: - -[indent=0] ----- - $ spring init --build=gradle --java-version=1.8 --dependencies=websocket --packaging=war sample-app.zip - Using service at https://start.spring.io - Content saved to 'sample-app.zip' ----- - - - -[[cli.using-the-cli.embedded-shell]] -=== Using the Embedded Shell -Spring Boot includes command-line completion scripts for the BASH and zsh shells. -If you do not use either of these shells (perhaps you are a Windows user), you can use the `shell` command to launch an integrated shell, as shown in the following example: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - $ spring shell - *Spring Boot* (v{spring-boot-version}) - Hit TAB to complete. Type \'help' and hit RETURN for help, and \'exit' to quit. ----- - -From inside the embedded shell, you can run other commands directly: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - $ version - Spring CLI v{spring-boot-version} ----- - -The embedded shell supports ANSI color output as well as `tab` completion. -If you need to run a native command, you can use the `!` prefix. -To exit the embedded shell, press `ctrl-c`. - - - -[[cli.using-the-cli.extensions]] -=== Adding Extensions to the CLI -You can add extensions to the CLI by using the `install` command. -The command takes one or more sets of artifact coordinates in the format `group:artifact:version`, as shown in the following example: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - $ spring install com.example:spring-boot-cli-extension:1.0.0.RELEASE ----- - -In addition to installing the artifacts identified by the coordinates you supply, all of the artifacts' dependencies are also installed. - -To uninstall a dependency, use the `uninstall` command. -As with the `install` command, it takes one or more sets of artifact coordinates in the format of `group:artifact:version`, as shown in the following example: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - $ spring uninstall com.example:spring-boot-cli-extension:1.0.0.RELEASE ----- - -It uninstalls the artifacts identified by the coordinates you supply and their dependencies. - -To uninstall all additional dependencies, you can use the `--all` option, as shown in the following example: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - $ spring uninstall --all ----- - - - -[[cli.groovy-beans-dsl]] -== Developing Applications with the Groovy Beans DSL -Spring Framework 4.0 has native support for a `beans{}` "`DSL`" (borrowed from https://grails.org/[Grails]), and you can embed bean definitions in your Groovy application scripts by using the same format. -This is sometimes a good way to include external features like middleware declarations, as shown in the following example: - -[source,groovy,indent=0] ----- - @Configuration(proxyBeanMethods = false) - class Application implements CommandLineRunner { - - @Autowired - SharedService service - - @Override - void run(String... args) { - println service.message - } - - } - - import my.company.SharedService - - beans { - service(SharedService) { - message = "Hello World" - } - } ----- - -You can mix class declarations with `beans{}` in the same file as long as they stay at the top level, or, if you prefer, you can put the beans DSL in a separate file. - - - -[[cli.maven-setting]] -== Configuring the CLI with settings.xml -The Spring Boot CLI uses Aether, Maven's dependency resolution engine, to resolve dependencies. -The CLI makes use of the Maven configuration found in `~/.m2/settings.xml` to configure Aether. -The following configuration settings are honored by the CLI: - -* Offline -* Mirrors -* Servers -* Proxies -* Profiles -** Activation -** Repositories -* Active profiles - -See https://maven.apache.org/settings.html[Maven's settings documentation] for further information. - - - -[[cli.whats-next]] -== What to Read Next -There are some {spring-boot-code}/spring-boot-project/spring-boot-cli/samples[sample groovy scripts] available from the GitHub repository that you can use to try out the Spring Boot CLI. -There is also extensive Javadoc throughout the {spring-boot-cli-module-code}[source code]. - -If you find that you reach the limit of the CLI tool, you probably want to look at converting your application to a full Gradle or Maven built "`Groovy project`". -The next section covers Spring Boot's "<>", which you can use with Gradle or Maven. +include::cli/whats-next.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/cli/groovy-beans-dsl.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/cli/groovy-beans-dsl.adoc new file mode 100644 index 0000000000..336aa513b6 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/cli/groovy-beans-dsl.adoc @@ -0,0 +1,30 @@ +[[cli.groovy-beans-dsl]] +== Developing Applications with the Groovy Beans DSL +Spring Framework 4.0 has native support for a `beans{}` "`DSL`" (borrowed from https://grails.org/[Grails]), and you can embed bean definitions in your Groovy application scripts by using the same format. +This is sometimes a good way to include external features like middleware declarations, as shown in the following example: + +[source,groovy,indent=0] +---- + @Configuration(proxyBeanMethods = false) + class Application implements CommandLineRunner { + + @Autowired + SharedService service + + @Override + void run(String... args) { + println service.message + } + + } + + import my.company.SharedService + + beans { + service(SharedService) { + message = "Hello World" + } + } +---- + +You can mix class declarations with `beans{}` in the same file as long as they stay at the top level, or, if you prefer, you can put the beans DSL in a separate file. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/cli/installation.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/cli/installation.adoc new file mode 100644 index 0000000000..e4c1cdd9b1 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/cli/installation.adoc @@ -0,0 +1,4 @@ +[[cli.installation]] +== Installing the CLI +The Spring Boot CLI (Command-Line Interface) can be installed manually by using SDKMAN! (the SDK Manager) or by using Homebrew or MacPorts if you are an OSX user. +See _<>_ in the "`Getting started`" section for comprehensive installation instructions. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/cli/maven-setting.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/cli/maven-setting.adoc new file mode 100644 index 0000000000..7ff6423802 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/cli/maven-setting.adoc @@ -0,0 +1,16 @@ +[[cli.maven-setting]] +== Configuring the CLI with settings.xml +The Spring Boot CLI uses Aether, Maven's dependency resolution engine, to resolve dependencies. +The CLI makes use of the Maven configuration found in `~/.m2/settings.xml` to configure Aether. +The following configuration settings are honored by the CLI: + +* Offline +* Mirrors +* Servers +* Proxies +* Profiles +** Activation +** Repositories +* Active profiles + +See https://maven.apache.org/settings.html[Maven's settings documentation] for further information. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/cli/using-the-cli.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/cli/using-the-cli.adoc new file mode 100644 index 0000000000..ce26dd28e2 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/cli/using-the-cli.adoc @@ -0,0 +1,356 @@ +[[cli.using-the-cli]] +== Using the CLI +Once you have installed the CLI, you can run it by typing `spring` and pressing Enter at the command line. +If you run `spring` without any arguments, a help screen is displayed, as follows: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + $ spring + usage: spring [--help] [--version] + [] + + Available commands are: + + run [options] [--] [args] + Run a spring groovy script + + _... more command help is shown here_ +---- + +You can type `spring help` to get more details about any of the supported commands, as shown in the following example: + +[indent=0] +---- + $ spring help run + spring run - Run a spring groovy script + + usage: spring run [options] [--] [args] + + Option Description + ------ ----------- + --autoconfigure [Boolean] Add autoconfigure compiler + transformations (default: true) + --classpath, -cp Additional classpath entries + --no-guess-dependencies Do not attempt to guess dependencies + --no-guess-imports Do not attempt to guess imports + -q, --quiet Quiet logging + -v, --verbose Verbose logging of dependency + resolution + --watch Watch the specified file for changes +---- + +The `version` command provides a quick way to check which version of Spring Boot you are using, as follows: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + $ spring version + Spring CLI v{spring-boot-version} +---- + + + +[[cli.using-the-cli.run]] +=== Running Applications with the CLI +You can compile and run Groovy source code by using the `run` command. +The Spring Boot CLI is completely self-contained, so you do not need any external Groovy installation. + +The following example shows a "`hello world`" web application written in Groovy: + +.hello.groovy +[source,groovy,indent=0,subs="verbatim,quotes,attributes"] +---- + @RestController + class WebApplication { + + @RequestMapping("/") + String home() { + "Hello World!" + } + + } +---- + +To compile and run the application, type the following command: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + $ spring run hello.groovy +---- + +To pass command-line arguments to the application, use `--` to separate the commands from the "`spring`" command arguments, as shown in the following example: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + $ spring run hello.groovy -- --server.port=9000 +---- + +To set JVM command line arguments, you can use the `JAVA_OPTS` environment variable, as shown in the following example: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + $ JAVA_OPTS=-Xmx1024m spring run hello.groovy +---- + +NOTE: When setting `JAVA_OPTS` on Microsoft Windows, make sure to quote the entire instruction, such as `set "JAVA_OPTS=-Xms256m -Xmx2048m"`. +Doing so ensures the values are properly passed to the process. + + + +[[cli.using-the-cli.run.deduced-grab-annotations]] +==== Deduced "`grab`" Dependencies +Standard Groovy includes a `@Grab` annotation, which lets you declare dependencies on third-party libraries. +This useful technique lets Groovy download jars in the same way as Maven or Gradle would but without requiring you to use a build tool. + +Spring Boot extends this technique further and tries to deduce which libraries to "`grab`" based on your code. +For example, since the `WebApplication` code shown previously uses `@RestController` annotations, Spring Boot grabs "Tomcat" and "Spring MVC". + +The following items are used as "`grab hints`": + +|=== +| Items | Grabs + +| `JdbcTemplate`, `NamedParameterJdbcTemplate`, `DataSource` +| JDBC Application. + +| `@EnableJms` +| JMS Application. + +| `@EnableCaching` +| Caching abstraction. + +| `@Test` +| JUnit. + +| `@EnableRabbit` +| RabbitMQ. + +| extends `Specification` +| Spock test. + +| `@EnableBatchProcessing` +| Spring Batch. + +| `@MessageEndpoint` `@EnableIntegration` +| Spring Integration. + +| `@Controller` `@RestController` `@EnableWebMvc` +| Spring MVC + Embedded Tomcat. + +| `@EnableWebSecurity` +| Spring Security. + +| `@EnableTransactionManagement` +| Spring Transaction Management. +|=== + +TIP: See subclasses of {spring-boot-cli-module-code}/compiler/CompilerAutoConfiguration.java[`CompilerAutoConfiguration`] in the Spring Boot CLI source code to understand exactly how customizations are applied. + + + +[[cli.using-the-cli.run.deduced-grab-coordinates]] +==== Deduced "`grab`" Coordinates +Spring Boot extends Groovy's standard `@Grab` support by letting you specify a dependency without a group or version (for example, `@Grab('freemarker')`). +Doing so consults Spring Boot's default dependency metadata to deduce the artifact's group and version. + +NOTE: The default metadata is tied to the version of the CLI that you use. +It changes only when you move to a new version of the CLI, putting you in control of when the versions of your dependencies may change. +A table showing the dependencies and their versions that are included in the default metadata can be found in the <>. + + + +[[cli.using-the-cli.run.default-import-statements]] +==== Default Import Statements +To help reduce the size of your Groovy code, several `import` statements are automatically included. +Notice how the preceding example refers to `@Component`, `@RestController`, and `@RequestMapping` without needing to use fully-qualified names or `import` statements. + +TIP: Many Spring annotations work without using `import` statements. +Try running your application to see what fails before adding imports. + + + +[[cli.using-the-cli.run.automatic-main-method]] +==== Automatic Main Method +Unlike the equivalent Java application, you do not need to include a `public static void main(String[] args)` method with your `Groovy` scripts. +A `SpringApplication` is automatically created, with your compiled code acting as the `source`. + + + +[[cli.using-the-cli.run.custom-dependency-management]] +==== Custom Dependency Management +By default, the CLI uses the dependency management declared in `spring-boot-dependencies` when resolving `@Grab` dependencies. +Additional dependency management, which overrides the default dependency management, can be configured by using the `@DependencyManagementBom` annotation. +The annotation's value should specify the coordinates (`groupId:artifactId:version`) of one or more Maven BOMs. + +For example, consider the following declaration: + +[source,groovy,indent=0] +---- + @DependencyManagementBom("com.example.custom-bom:1.0.0") +---- + +The preceding declaration picks up `custom-bom-1.0.0.pom` in a Maven repository under `com/example/custom-versions/1.0.0/`. + +When you specify multiple BOMs, they are applied in the order in which you declare them, as shown in the following example: + +[source,java,pending-extract=true,indent=0] +---- + @DependencyManagementBom(["com.example.custom-bom:1.0.0", + "com.example.another-bom:1.0.0"]) +---- + +The preceding example indicates that the dependency management in `another-bom` overrides the dependency management in `custom-bom`. + +You can use `@DependencyManagementBom` anywhere that you can use `@Grab`. +However, to ensure consistent ordering of the dependency management, you can use `@DependencyManagementBom` at most once in your application. + + + +[[cli.using-the-cli.multiple-source-files]] +=== Applications with Multiple Source Files +You can use "`shell globbing`" with all commands that accept file input. +Doing so lets you use multiple files from a single directory, as shown in the following example: + +[indent=0] +---- + $ spring run *.groovy +---- + + + +[[cli.using-the-cli.packaging]] +=== Packaging Your Application +You can use the `jar` command to package your application into a self-contained executable jar file, as shown in the following example: + +[indent=0] +---- + $ spring jar my-app.jar *.groovy +---- + +The resulting jar contains the classes produced by compiling the application and all of the application's dependencies so that it can then be run by using `java -jar`. +The jar file also contains entries from the application's classpath. +You can add and remove explicit paths to the jar by using `--include` and `--exclude`. +Both are comma-separated, and both accept prefixes, in the form of "`+`" and "`-`", to signify that they should be removed from the defaults. +The default includes are as follows: + +[indent=0] +---- + public/**, resources/**, static/**, templates/**, META-INF/**, * +---- + +The default excludes are as follows: + +[indent=0] +---- + .*, repository/**, build/**, target/**, **/*.jar, **/*.groovy +---- + +Type `spring help jar` on the command line for more information. + + + +[[cli.using-the-cli.initialize-new-project]] +=== Initialize a New Project +The `init` command lets you create a new project by using https://start.spring.io without leaving the shell, as shown in the following example: + +[indent=0] +---- + $ spring init --dependencies=web,data-jpa my-project + Using service at https://start.spring.io + Project extracted to '/Users/developer/example/my-project' +---- + +The preceding example creates a `my-project` directory with a Maven-based project that uses `spring-boot-starter-web` and `spring-boot-starter-data-jpa`. +You can list the capabilities of the service by using the `--list` flag, as shown in the following example: + +[indent=0] +---- + $ spring init --list + ======================================= + Capabilities of https://start.spring.io + ======================================= + + Available dependencies: + ----------------------- + actuator - Actuator: Production ready features to help you monitor and manage your application + ... + web - Web: Support for full-stack web development, including Tomcat and spring-webmvc + websocket - Websocket: Support for WebSocket development + ws - WS: Support for Spring Web Services + + Available project types: + ------------------------ + gradle-build - Gradle Config [format:build, build:gradle] + gradle-project - Gradle Project [format:project, build:gradle] + maven-build - Maven POM [format:build, build:maven] + maven-project - Maven Project [format:project, build:maven] (default) + + ... +---- + +The `init` command supports many options. +See the `help` output for more details. +For instance, the following command creates a Gradle project that uses Java 8 and `war` packaging: + +[indent=0] +---- + $ spring init --build=gradle --java-version=1.8 --dependencies=websocket --packaging=war sample-app.zip + Using service at https://start.spring.io + Content saved to 'sample-app.zip' +---- + + + +[[cli.using-the-cli.embedded-shell]] +=== Using the Embedded Shell +Spring Boot includes command-line completion scripts for the BASH and zsh shells. +If you do not use either of these shells (perhaps you are a Windows user), you can use the `shell` command to launch an integrated shell, as shown in the following example: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + $ spring shell + *Spring Boot* (v{spring-boot-version}) + Hit TAB to complete. Type \'help' and hit RETURN for help, and \'exit' to quit. +---- + +From inside the embedded shell, you can run other commands directly: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + $ version + Spring CLI v{spring-boot-version} +---- + +The embedded shell supports ANSI color output as well as `tab` completion. +If you need to run a native command, you can use the `!` prefix. +To exit the embedded shell, press `ctrl-c`. + + + +[[cli.using-the-cli.extensions]] +=== Adding Extensions to the CLI +You can add extensions to the CLI by using the `install` command. +The command takes one or more sets of artifact coordinates in the format `group:artifact:version`, as shown in the following example: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + $ spring install com.example:spring-boot-cli-extension:1.0.0.RELEASE +---- + +In addition to installing the artifacts identified by the coordinates you supply, all of the artifacts' dependencies are also installed. + +To uninstall a dependency, use the `uninstall` command. +As with the `install` command, it takes one or more sets of artifact coordinates in the format of `group:artifact:version`, as shown in the following example: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + $ spring uninstall com.example:spring-boot-cli-extension:1.0.0.RELEASE +---- + +It uninstalls the artifacts identified by the coordinates you supply and their dependencies. + +To uninstall all additional dependencies, you can use the `--all` option, as shown in the following example: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + $ spring uninstall --all +---- diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/cli/whats-next.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/cli/whats-next.adoc new file mode 100644 index 0000000000..f3d05acbfe --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/cli/whats-next.adoc @@ -0,0 +1,7 @@ +[[cli.whats-next]] +== What to Read Next +There are some {spring-boot-code}/spring-boot-project/spring-boot-cli/samples[sample groovy scripts] available from the GitHub repository that you can use to try out the Spring Boot CLI. +There is also extensive Javadoc throughout the {spring-boot-cli-module-code}[source code]. + +If you find that you reach the limit of the CLI tool, you probably want to look at converting your application to a full Gradle or Maven built "`Groovy project`". +The next section covers Spring Boot's "<>", which you can use with Gradle or Maven. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/common-application-properties.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/common-application-properties.adoc deleted file mode 100644 index ea6fa49ea3..0000000000 --- a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/common-application-properties.adoc +++ /dev/null @@ -1,109 +0,0 @@ -:numbered!: -[appendix] -[[appendix.common-application-properties]] -= Common Application properties -include::attributes.adoc[] - -Various properties can be specified inside your `application.properties` file, inside your `application.yml` file, or as command line switches. -This appendix provides a list of common Spring Boot properties and references to the underlying classes that consume them. - -TIP: Spring Boot provides various conversion mechanism with advanced value formatting, make sure to review <>. - -NOTE: Property contributions can come from additional jar files on your classpath, so you should not consider this an exhaustive list. -Also, you can define your own properties. - - - -[[appendix.common-application-properties.core]] -== Core Properties [[core-properties]] -include::config-docs/core.adoc[] - - - -[[appendix.common-application-properties.cache]] -== Cache Properties [[cache-properties]] -include::config-docs/cache.adoc[] - - - -[[appendix.common-application-properties.mail]] -== Mail Properties [[mail-properties]] -include::config-docs/mail.adoc[] - - - -[[appendix.common-application-properties.json]] -== JSON Properties [[json-properties]] -include::config-docs/json.adoc[] - - - -[[appendix.common-application-properties.data]] -== Data Properties [[data-properties]] -include::config-docs/data.adoc[] - - - -[[appendix.common-application-properties.transaction]] -== Transaction Properties [[transaction-properties]] -include::config-docs/transaction.adoc[] - - - -[[appendix.common-application-properties.data-migration]] -== Data Migration Properties [[data-migration-properties]] -include::config-docs/data-migration.adoc[] - - - -[[appendix.common-application-properties.integration]] -== Integration Properties [[integration-properties]] -include::config-docs/integration.adoc[] - - - -[[appendix.common-application-properties.web]] -== Web Properties [[web-properties]] -include::config-docs/web.adoc[] - - - -[[appendix.common-application-properties.templating]] -== Templating Properties [[templating-properties]] -include::config-docs/templating.adoc[] - - - -[[appendix.common-application-properties.server]] -== Server Properties [[server-properties]] -include::config-docs/server.adoc[] - - - -[[appendix.common-application-properties.security]] -== Security Properties [[security-properties]] -include::config-docs/security.adoc[] - - - -[[appendix.common-application-properties.rsocket]] -== RSocket Properties [[rsocket-properties]] -include::config-docs/rsocket.adoc[] - - - -[[appendix.common-application-properties.actuator]] -== Actuator Properties [[actuator-properties]] -include::config-docs/actuator.adoc[] - - - -[[appendix.common-application-properties.devtools]] -== Devtools Properties [[devtools-properties]] -include::config-docs/devtools.adoc[] - - - -[[appendix.common-application-properties.testing]] -== Testing Properties [[testing-properties]] -include::config-docs/testing.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/configuration-metadata.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/configuration-metadata.adoc index e8587fb892..a2346feb67 100644 --- a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/configuration-metadata.adoc +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/configuration-metadata.adoc @@ -1,902 +1,20 @@ [appendix] -[[appendix.configuration-metadata]] +[[configuration-metadata]] = Configuration Metadata include::attributes.adoc[] + + Spring Boot jars include metadata files that provide details of all supported configuration properties. The files are designed to let IDE developers offer contextual help and "`code completion`" as users are working with `application.properties` or `application.yml` files. The majority of the metadata file is generated automatically at compile time by processing all items annotated with `@ConfigurationProperties`. -However, it is possible to <> for corner cases or more advanced use cases. +However, it is possible to <> for corner cases or more advanced use cases. -[[appendix.configuration-metadata.format]] -== Metadata Format -Configuration metadata files are located inside jars under `META-INF/spring-configuration-metadata.json`. -They use a JSON format with items categorized under either "`groups`" or "`properties`" and additional values hints categorized under "hints", as shown in the following example: +include::configuration-metadata/format.adoc[] -[source,json,indent=0] ----- - {"groups": [ - { - "name": "server", - "type": "org.springframework.boot.autoconfigure.web.ServerProperties", - "sourceType": "org.springframework.boot.autoconfigure.web.ServerProperties" - }, - { - "name": "spring.jpa.hibernate", - "type": "org.springframework.boot.autoconfigure.orm.jpa.JpaProperties$Hibernate", - "sourceType": "org.springframework.boot.autoconfigure.orm.jpa.JpaProperties", - "sourceMethod": "getHibernate()" - } - ... - ],"properties": [ - { - "name": "server.port", - "type": "java.lang.Integer", - "sourceType": "org.springframework.boot.autoconfigure.web.ServerProperties" - }, - { - "name": "server.address", - "type": "java.net.InetAddress", - "sourceType": "org.springframework.boot.autoconfigure.web.ServerProperties" - }, - { - "name": "spring.jpa.hibernate.ddl-auto", - "type": "java.lang.String", - "description": "DDL mode. This is actually a shortcut for the \"hibernate.hbm2ddl.auto\" property.", - "sourceType": "org.springframework.boot.autoconfigure.orm.jpa.JpaProperties$Hibernate" - } - ... - ],"hints": [ - { - "name": "spring.jpa.hibernate.ddl-auto", - "values": [ - { - "value": "none", - "description": "Disable DDL handling." - }, - { - "value": "validate", - "description": "Validate the schema, make no changes to the database." - }, - { - "value": "update", - "description": "Update the schema if necessary." - }, - { - "value": "create", - "description": "Create the schema and destroy previous data." - }, - { - "value": "create-drop", - "description": "Create and then destroy the schema at the end of the session." - } - ] - } - ]} ----- +include::configuration-metadata/manual-hints.adoc[] -Each "`property`" is a configuration item that the user specifies with a given value. -For example, `server.port` and `server.address` might be specified in `application.properties`, as follows: - -[source,properties,indent=0,configprops] ----- - server.port=9090 - server.address=127.0.0.1 ----- - -The "`groups`" are higher level items that do not themselves specify a value but instead provide a contextual grouping for properties. -For example, the `server.port` and `server.address` properties are part of the `server` group. - -NOTE: It is not required that every "`property`" has a "`group`". -Some properties might exist in their own right. - -Finally, "`hints`" are additional information used to assist the user in configuring a given property. -For example, when a developer is configuring the configprop:spring.jpa.hibernate.ddl-auto[] property, a tool can use the hints to offer some auto-completion help for the `none`, `validate`, `update`, `create`, and `create-drop` values. - - - -[[appendix.configuration-metadata.format.group]] -=== Group Attributes -The JSON object contained in the `groups` array can contain the attributes shown in the following table: - -[cols="1,1,4"] -|=== -| Name | Type | Purpose - -| `name` -| String -| The full name of the group. - This attribute is mandatory. - -| `type` -| String -| The class name of the data type of the group. - For example, if the group were based on a class annotated with `@ConfigurationProperties`, the attribute would contain the fully qualified name of that class. - If it were based on a `@Bean` method, it would be the return type of that method. - If the type is not known, the attribute may be omitted. - -| `description` -| String -| A short description of the group that can be displayed to users. - If no description is available, it may be omitted. - It is recommended that descriptions be short paragraphs, with the first line providing a concise summary. - The last line in the description should end with a period (`.`). - -| `sourceType` -| String -| The class name of the source that contributed this group. - For example, if the group were based on a `@Bean` method annotated with `@ConfigurationProperties`, this attribute would contain the fully qualified name of the `@Configuration` class that contains the method. - If the source type is not known, the attribute may be omitted. - -| `sourceMethod` -| String -| The full name of the method (include parenthesis and argument types) that contributed this group (for example, the name of a `@ConfigurationProperties` annotated `@Bean` method). - If the source method is not known, it may be omitted. -|=== - - - -[[appendix.configuration-metadata.format.property]] -=== Property Attributes -The JSON object contained in the `properties` array can contain the attributes described in the following table: - -[cols="1,1,4"] -|=== -| Name | Type | Purpose - -| `name` -| String -| The full name of the property. - Names are in lower-case period-separated form (for example, `server.address`). - This attribute is mandatory. - -| `type` -| String -| The full signature of the data type of the property (for example, `java.lang.String`) but also a full generic type (such as `java.util.Map`). - You can use this attribute to guide the user as to the types of values that they can enter. - For consistency, the type of a primitive is specified by using its wrapper counterpart (for example, `boolean` becomes `java.lang.Boolean`). - Note that this class may be a complex type that gets converted from a `String` as values are bound. - If the type is not known, it may be omitted. - -| `description` -| String -| A short description of the property that can be displayed to users. - If no description is available, it may be omitted. - It is recommended that descriptions be short paragraphs, with the first line providing a concise summary. - The last line in the description should end with a period (`.`). - -| `sourceType` -| String -| The class name of the source that contributed this property. - For example, if the property were from a class annotated with `@ConfigurationProperties`, this attribute would contain the fully qualified name of that class. - If the source type is unknown, it may be omitted. - -| `defaultValue` -| Object -| The default value, which is used if the property is not specified. - If the type of the property is an array, it can be an array of value(s). - If the default value is unknown, it may be omitted. - -| `deprecation` -| Deprecation -| Specify whether the property is deprecated. - If the field is not deprecated or if that information is not known, it may be omitted. - The next table offers more detail about the `deprecation` attribute. -|=== - -The JSON object contained in the `deprecation` attribute of each `properties` element can contain the following attributes: - -[cols="1,1,4"] -|=== -| Name | Type | Purpose - -| `level` -| String -| The level of deprecation, which can be either `warning` (the default) or `error`. - When a property has a `warning` deprecation level, it should still be bound in the environment. - However, when it has an `error` deprecation level, the property is no longer managed and is not bound. - -| `reason` -| String -| A short description of the reason why the property was deprecated. - If no reason is available, it may be omitted. - It is recommended that descriptions be short paragraphs, with the first line providing a concise summary. - The last line in the description should end with a period (`.`). - -| `replacement` -| String -| The full name of the property that _replaces_ this deprecated property. - If there is no replacement for this property, it may be omitted. -|=== - -NOTE: Prior to Spring Boot 1.3, a single `deprecated` boolean attribute can be used instead of the `deprecation` element. -This is still supported in a deprecated fashion and should no longer be used. -If no reason and replacement are available, an empty `deprecation` object should be set. - -Deprecation can also be specified declaratively in code by adding the `@DeprecatedConfigurationProperty` annotation to the getter exposing the deprecated property. -For instance, assume that the `app.acme.target` property was confusing and was renamed to `app.acme.name`. -The following example shows how to handle that situation: - -[source,java,pending-extract=true,indent=0] ----- - @ConfigurationProperties("app.acme") - public class AcmeProperties { - - private String name; - - public String getName() { ... } - - public void setName(String name) { ... } - - @DeprecatedConfigurationProperty(replacement = "app.acme.name") - @Deprecated - public String getTarget() { - return getName(); - } - - @Deprecated - public void setTarget(String target) { - setName(target); - } - } ----- - -NOTE: There is no way to set a `level`. -`warning` is always assumed, since code is still handling the property. - -The preceding code makes sure that the deprecated property still works (delegating to the `name` property behind the scenes). -Once the `getTarget` and `setTarget` methods can be removed from your public API, the automatic deprecation hint in the metadata goes away as well. -If you want to keep a hint, adding manual metadata with an `error` deprecation level ensures that users are still informed about that property. -Doing so is particularly useful when a `replacement` is provided. - - - -[[appendix.configuration-metadata.format.hints]] -=== Hint Attributes -The JSON object contained in the `hints` array can contain the attributes shown in the following table: - -[cols="1,1,4"] -|=== -| Name | Type | Purpose - -| `name` -| String -| The full name of the property to which this hint refers. - Names are in lower-case period-separated form (such as `spring.mvc.servlet.path`). - If the property refers to a map (such as `system.contexts`), the hint either applies to the _keys_ of the map (`system.contexts.keys`) or the _values_ (`system.contexts.values`) of the map. - This attribute is mandatory. - -| `values` -| ValueHint[] -| A list of valid values as defined by the `ValueHint` object (described in the next table). - Each entry defines the value and may have a description. - -| `providers` -| ValueProvider[] -| A list of providers as defined by the `ValueProvider` object (described later in this document). - Each entry defines the name of the provider and its parameters, if any. -|=== - -The JSON object contained in the `values` attribute of each `hint` element can contain the attributes described in the following table: - -[cols="1,1,4"] -|=== -| Name | Type | Purpose - -| `value` -| Object -| A valid value for the element to which the hint refers. - If the type of the property is an array, it can also be an array of value(s). - This attribute is mandatory. - -| `description` -| String -| A short description of the value that can be displayed to users. - If no description is available, it may be omitted. - It is recommended that descriptions be short paragraphs, with the first line providing a concise summary. - The last line in the description should end with a period (`.`). -|=== - -The JSON object contained in the `providers` attribute of each `hint` element can contain the attributes described in the following table: - -[cols="1,1,4"] -|=== -|Name | Type |Purpose - -| `name` -| String -| The name of the provider to use to offer additional content assistance for the element to which the hint refers. - -| `parameters` -| JSON object -| Any additional parameter that the provider supports (check the documentation of the provider for more details). -|=== - - - -[[appendix.configuration-metadata.format.repeated-items]] -=== Repeated Metadata Items -Objects with the same "`property`" and "`group`" name can appear multiple times within a metadata file. -For example, you could bind two separate classes to the same prefix, with each having potentially overlapping property names. -While the same names appearing in the metadata multiple times should not be common, consumers of metadata should take care to ensure that they support it. - - - -[[appendix.configuration-metadata.manual-hints]] -== Providing Manual Hints -To improve the user experience and further assist the user in configuring a given property, you can provide additional metadata that: - -* Describes the list of potential values for a property. -* Associates a provider, to attach a well defined semantic to a property, so that a tool can discover the list of potential values based on the project's context. - - - -[[appendix.configuration-metadata.manual-hints.value-hint]] -=== Value Hint -The `name` attribute of each hint refers to the `name` of a property. -In the <>, we provide five values for the `spring.jpa.hibernate.ddl-auto` property: `none`, `validate`, `update`, `create`, and `create-drop`. -Each value may have a description as well. - -If your property is of type `Map`, you can provide hints for both the keys and the values (but not for the map itself). -The special `.keys` and `.values` suffixes must refer to the keys and the values, respectively. - -Assume a `sample.contexts` maps magic `String` values to an integer, as shown in the following example: - -[source,java,pending-extract=true,indent=0] ----- - @ConfigurationProperties("sample") - public class SampleProperties { - - private Map contexts; - // getters and setters - } ----- - -The magic values are (in this example) are `sample1` and `sample2`. -In order to offer additional content assistance for the keys, you could add the following JSON to <>: - -[source,json,indent=0] ----- - {"hints": [ - { - "name": "sample.contexts.keys", - "values": [ - { - "value": "sample1" - }, - { - "value": "sample2" - } - ] - } - ]} ----- - -TIP: We recommend that you use an `Enum` for those two values instead. -If your IDE supports it, this is by far the most effective approach to auto-completion. - - - -[[appendix.configuration-metadata.manual-hints.value-providers]] -=== Value Providers -Providers are a powerful way to attach semantics to a property. -In this section, we define the official providers that you can use for your own hints. -However, your favorite IDE may implement some of these or none of them. -Also, it could eventually provide its own. - -NOTE: As this is a new feature, IDE vendors must catch up with how it works. -Adoption times naturally vary. - -The following table summarizes the list of supported providers: - -[cols="2,4"] -|=== -| Name | Description - -| `any` -| Permits any additional value to be provided. - -| `class-reference` -| Auto-completes the classes available in the project. - Usually constrained by a base class that is specified by the `target` parameter. - -| `handle-as` -| Handles the property as if it were defined by the type defined by the mandatory `target` parameter. - -| `logger-name` -| Auto-completes valid logger names and <>. - Typically, package and class names available in the current project can be auto-completed as well as defined groups. - -| `spring-bean-reference` -| Auto-completes the available bean names in the current project. - Usually constrained by a base class that is specified by the `target` parameter. - -| `spring-profile-name` -| Auto-completes the available Spring profile names in the project. -|=== - -TIP: Only one provider can be active for a given property, but you can specify several providers if they can all manage the property _in some way_. -Make sure to place the most powerful provider first, as the IDE must use the first one in the JSON section that it can handle. -If no provider for a given property is supported, no special content assistance is provided, either. - - - -[[appendix.configuration-metadata.manual-hints.value-providers.any]] -==== Any -The special **any** provider value permits any additional values to be provided. -Regular value validation based on the property type should be applied if this is supported. - -This provider is typically used if you have a list of values and any extra values should still be considered as valid. - -The following example offers `on` and `off` as auto-completion values for `system.state`: - -[source,json,indent=0] ----- - {"hints": [ - { - "name": "system.state", - "values": [ - { - "value": "on" - }, - { - "value": "off" - } - ], - "providers": [ - { - "name": "any" - } - ] - } - ]} ----- - -Note that, in the preceding example, any other value is also allowed. - - - -[[appendix.configuration-metadata.manual-hints.value-providers.class-reference]] -==== Class Reference -The **class-reference** provider auto-completes classes available in the project. -This provider supports the following parameters: - -[cols="1,1,2,4"] -|=== -| Parameter | Type | Default value | Description - -| `target` -| `String` (`Class`) -| _none_ -| The fully qualified name of the class that should be assignable to the chosen value. - Typically used to filter out-non candidate classes. - Note that this information can be provided by the type itself by exposing a class with the appropriate upper bound. - -| `concrete` -| `boolean` -| true -| Specify whether only concrete classes are to be considered as valid candidates. -|=== - - -The following metadata snippet corresponds to the standard `server.servlet.jsp.class-name` property that defines the `JspServlet` class name to use: - -[source,json,indent=0] ----- - {"hints": [ - { - "name": "server.servlet.jsp.class-name", - "providers": [ - { - "name": "class-reference", - "parameters": { - "target": "javax.servlet.http.HttpServlet" - } - } - ] - } - ]} ----- - - - -[[appendix.configuration-metadata.manual-hints.value-providers.handle-as]] -==== Handle As -The **handle-as** provider lets you substitute the type of the property to a more high-level type. -This typically happens when the property has a `java.lang.String` type, because you do not want your configuration classes to rely on classes that may not be on the classpath. -This provider supports the following parameters: - -[cols="1,1,2,4"] -|=== -| Parameter | Type | Default value | Description - -| **`target`** -| `String` (`Class`) -| _none_ -| The fully qualified name of the type to consider for the property. - This parameter is mandatory. -|=== - -The following types can be used: - -* Any `java.lang.Enum`: Lists the possible values for the property. - (We recommend defining the property with the `Enum` type, as no further hint should be required for the IDE to auto-complete the values) -* `java.nio.charset.Charset`: Supports auto-completion of charset/encoding values (such as `UTF-8`) -* `java.util.Locale`: auto-completion of locales (such as `en_US`) -* `org.springframework.util.MimeType`: Supports auto-completion of content type values (such as `text/plain`) -* `org.springframework.core.io.Resource`: Supports auto-completion of Spring’s Resource abstraction to refer to a file on the filesystem or on the classpath (such as `classpath:/sample.properties`) - -TIP: If multiple values can be provided, use a `Collection` or _Array_ type to teach the IDE about it. - -The following metadata snippet corresponds to the standard `spring.liquibase.change-log` property that defines the path to the changelog to use. -It is actually used internally as a `org.springframework.core.io.Resource` but cannot be exposed as such, because we need to keep the original String value to pass it to the Liquibase API. - -[source,json,indent=0] ----- - {"hints": [ - { - "name": "spring.liquibase.change-log", - "providers": [ - { - "name": "handle-as", - "parameters": { - "target": "org.springframework.core.io.Resource" - } - } - ] - } - ]} ----- - - - -[[appendix.configuration-metadata.manual-hints.value-providers.logger-name]] -==== Logger Name -The **logger-name** provider auto-completes valid logger names and <>. -Typically, package and class names available in the current project can be auto-completed. -If groups are enabled (default) and if a custom logger group is identified in the configuration, auto-completion for it should be provided. -Specific frameworks may have extra magic logger names that can be supported as well. - -This provider supports the following parameters: - -[cols="1,1,2,4"] -|=== -| Parameter | Type | Default value | Description - -| `group` -| `boolean` -| `true` -| Specify whether known groups should be considered. -|=== - -Since a logger name can be any arbitrary name, this provider should allow any value but could highlight valid package and class names that are not available in the project's classpath. - -The following metadata snippet corresponds to the standard `logging.level` property. -Keys are _logger names_, and values correspond to the standard log levels or any custom level. -As Spring Boot defines a few logger groups out-of-the-box, dedicated value hints have been added for those. - -[source,json,indent=0] ----- - {"hints": [ - { - "name": "logging.level.keys", - "values": [ - { - "value": "root", - "description": "Root logger used to assign the default logging level." - }, - { - "value": "sql", - "description": "SQL logging group including Hibernate SQL logger." - }, - { - "value": "web", - "description": "Web logging group including codecs." - } - ], - "providers": [ - { - "name": "logger-name" - } - ] - }, - { - "name": "logging.level.values", - "values": [ - { - "value": "trace" - }, - { - "value": "debug" - }, - { - "value": "info" - }, - { - "value": "warn" - }, - { - "value": "error" - }, - { - "value": "fatal" - }, - { - "value": "off" - } - - ], - "providers": [ - { - "name": "any" - } - ] - } - ]} ----- - - - -[[appendix.configuration-metadata.manual-hints.value-providers.spring-bean-reference]] -==== Spring Bean Reference -The **spring-bean-reference** provider auto-completes the beans that are defined in the configuration of the current project. -This provider supports the following parameters: - -[cols="1,1,2,4"] -|=== -| Parameter | Type | Default value | Description - -| `target` -| `String` (`Class`) -| _none_ -| The fully qualified name of the bean class that should be assignable to the candidate. - Typically used to filter out non-candidate beans. -|=== - -The following metadata snippet corresponds to the standard `spring.jmx.server` property that defines the name of the `MBeanServer` bean to use: - -[source,json,indent=0] ----- - {"hints": [ - { - "name": "spring.jmx.server", - "providers": [ - { - "name": "spring-bean-reference", - "parameters": { - "target": "javax.management.MBeanServer" - } - } - ] - } - ]} ----- - -NOTE: The binder is not aware of the metadata. -If you provide that hint, you still need to transform the bean name into an actual Bean reference using by the `ApplicationContext`. - - - -[[appendix.configuration-metadata.manual-hints.value-providers.spring-profile-name]] -==== Spring Profile Name -The **spring-profile-name** provider auto-completes the Spring profiles that are defined in the configuration of the current project. - -The following metadata snippet corresponds to the standard `spring.profiles.active` property that defines the name of the Spring profile(s) to enable: - -[source,json,indent=0] ----- - {"hints": [ - { - "name": "spring.profiles.active", - "providers": [ - { - "name": "spring-profile-name" - } - ] - } - ]} ----- - - - -[[appendix.configuration-metadata.annotation-processor]] -== Generating Your Own Metadata by Using the Annotation Processor -You can easily generate your own configuration metadata file from items annotated with `@ConfigurationProperties` by using the `spring-boot-configuration-processor` jar. -The jar includes a Java annotation processor which is invoked as your project is compiled. - - - -[[appendix.configuration-metadata.annotation-processor.configuring]] -=== Configuring the Annotation Processor -To use the processor, include a dependency on `spring-boot-configuration-processor`. - -With Maven the dependency should be declared as optional, as shown in the following example: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - org.springframework.boot - spring-boot-configuration-processor - true - ----- - -With Gradle, the dependency should be declared in the `annotationProcessor` configuration, as shown in the following example: - -[source,groovy,indent=0,subs="verbatim,quotes,attributes"] ----- - dependencies { - annotationProcessor "org.springframework.boot:spring-boot-configuration-processor" - } ----- - -If you are using an `additional-spring-configuration-metadata.json` file, the `compileJava` task should be configured to depend on the `processResources` task, as shown in the following example: - -[source,groovy,indent=0,subs="verbatim,quotes,attributes"] ----- - compileJava.inputs.files(processResources) ----- - -This dependency ensures that the additional metadata is available when the annotation processor runs during compilation. - -[NOTE] -==== -If you are using AspectJ in your project, you need to make sure that the annotation processor runs only once. -There are several ways to do this. -With Maven, you can configure the `maven-apt-plugin` explicitly and add the dependency to the annotation processor only there. -You could also let the AspectJ plugin run all the processing and disable annotation processing in the `maven-compiler-plugin` configuration, as follows: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - org.apache.maven.plugins - maven-compiler-plugin - - none - - ----- -==== - - - -[[appendix.configuration-metadata.annotation-processor.automatic-metadata-generation]] -=== Automatic Metadata Generation -The processor picks up both classes and methods that are annotated with `@ConfigurationProperties`. - -If the class is also annotated with `@ConstructorBinding`, a single constructor is expected and one property is created per constructor parameter. -Otherwise, properties are discovered through the presence of standard getters and setters with special handling for collection and map types (that is detected even if only a getter is present). -The annotation processor also supports the use of the `@Data`, `@Getter`, and `@Setter` lombok annotations. - -Consider the following example: - -[source,java,pending-extract=true,indent=0,subs="verbatim,attributes"] ----- - @ConfigurationProperties(prefix="server") - public class ServerProperties { - - /** - * Name of the server. - */ - private String name; - - /** - * IP address to listen to. - */ - private String ip = "127.0.0.1"; - - /** - * Port to listener to. - */ - private int port = 9797; - - // ... getter and setters - - } ----- - -This exposes three properties where `server.name` has no default and `server.ip` and `server.port` defaults to `"127.0.0.1"` and `9797` respectively. -The Javadoc on fields is used to populate the `description` attribute. For instance, the description of `server.ip` is "IP address to listen to.". - -NOTE: You should only use plain text with `@ConfigurationProperties` field Javadoc, since they are not processed before being added to the JSON. - -The annotation processor applies a number of heuristics to extract the default value from the source model. -Default values have to be provided statically. In particular, do not refer to a constant defined in another class. -Also, the annotation processor cannot auto-detect default values for ``Enum``s and ``Collections``s. - -For cases where the default value could not be detected, <> should be provided. -Consider the following example: - -[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] ----- - @ConfigurationProperties(prefix = "acme.messaging") - public class MessagingProperties { - - private List addresses = new ArrayList<>(Arrays.asList("a", "b")); - - private ContainerType containerType = ContainerType.SIMPLE; - - // ... getter and setters - - public enum ContainerType { - - SIMPLE, - DIRECT - - } - - } ----- - -In order to document default values for properties in the class above, you could add the following content to <>: - -[source,json,indent=0] ----- - {"properties": [ - { - "name": "acme.messaging.addresses", - "defaultValue": ["a", "b"] - }, - { - "name": "acme.messaging.container-type", - "defaultValue": "simple" - } - ]} ----- - -NOTE: Only the `name` of the property is required to document additional metadata for existing properties. - - - -[[appendix.configuration-metadata.annotation-processor.automatic-metadata-generation.nested-properties]] -==== Nested Properties -The annotation processor automatically considers inner classes as nested properties. -Rather than documenting the `ip` and `port` at the root of the namespace, we could create a sub-namespace for it. -Consider the updated example: - -[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] ----- - @ConfigurationProperties(prefix="server") - public class ServerProperties { - - private String name; - - private Host host; - - // ... getter and setters - - public static class Host { - - private String ip; - - private int port; - - // ... getter and setters - - } - - } ----- - -The preceding example produces metadata information for `server.name`, `server.host.ip`, and `server.host.port` properties. -You can use the `@NestedConfigurationProperty` annotation on a field to indicate that a regular (non-inner) class should be treated as if it were nested. - -TIP: This has no effect on collections and maps, as those types are automatically identified, and a single metadata property is generated for each of them. - - - -[[appendix.configuration-metadata.annotation-processor.adding-additional-metadata]] -=== Adding Additional Metadata -Spring Boot's configuration file handling is quite flexible, and it is often the case that properties may exist that are not bound to a `@ConfigurationProperties` bean. -You may also need to tune some attributes of an existing key. -To support such cases and let you provide custom "hints", the annotation processor automatically merges items from `META-INF/additional-spring-configuration-metadata.json` into the main metadata file. - -If you refer to a property that has been detected automatically, the description, default value, and deprecation information are overridden, if specified. -If the manual property declaration is not identified in the current module, it is added as a new property. - -The format of the `additional-spring-configuration-metadata.json` file is exactly the same as the regular `spring-configuration-metadata.json`. -The additional properties file is optional. -If you do not have any additional properties, do not add the file. +include::configuration-metadata/annotation-processor.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/configuration-metadata/annotation-processor.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/configuration-metadata/annotation-processor.adoc new file mode 100644 index 0000000000..993275a71f --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/configuration-metadata/annotation-processor.adoc @@ -0,0 +1,198 @@ +[[configuration-metadata.annotation-processor]] +== Generating Your Own Metadata by Using the Annotation Processor +You can easily generate your own configuration metadata file from items annotated with `@ConfigurationProperties` by using the `spring-boot-configuration-processor` jar. +The jar includes a Java annotation processor which is invoked as your project is compiled. + + + +[[configuration-metadata.annotation-processor.configuring]] +=== Configuring the Annotation Processor +To use the processor, include a dependency on `spring-boot-configuration-processor`. + +With Maven the dependency should be declared as optional, as shown in the following example: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + org.springframework.boot + spring-boot-configuration-processor + true + +---- + +With Gradle, the dependency should be declared in the `annotationProcessor` configuration, as shown in the following example: + +[source,groovy,indent=0,subs="verbatim,quotes,attributes"] +---- + dependencies { + annotationProcessor "org.springframework.boot:spring-boot-configuration-processor" + } +---- + +If you are using an `additional-spring-configuration-metadata.json` file, the `compileJava` task should be configured to depend on the `processResources` task, as shown in the following example: + +[source,groovy,indent=0,subs="verbatim,quotes,attributes"] +---- + compileJava.inputs.files(processResources) +---- + +This dependency ensures that the additional metadata is available when the annotation processor runs during compilation. + +[NOTE] +==== +If you are using AspectJ in your project, you need to make sure that the annotation processor runs only once. +There are several ways to do this. +With Maven, you can configure the `maven-apt-plugin` explicitly and add the dependency to the annotation processor only there. +You could also let the AspectJ plugin run all the processing and disable annotation processing in the `maven-compiler-plugin` configuration, as follows: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + org.apache.maven.plugins + maven-compiler-plugin + + none + + +---- +==== + + + +[[configuration-metadata.annotation-processor.automatic-metadata-generation]] +=== Automatic Metadata Generation +The processor picks up both classes and methods that are annotated with `@ConfigurationProperties`. + +If the class is also annotated with `@ConstructorBinding`, a single constructor is expected and one property is created per constructor parameter. +Otherwise, properties are discovered through the presence of standard getters and setters with special handling for collection and map types (that is detected even if only a getter is present). +The annotation processor also supports the use of the `@Data`, `@Getter`, and `@Setter` lombok annotations. + +Consider the following example: + +[source,java,pending-extract=true,indent=0,subs="verbatim,attributes"] +---- + @ConfigurationProperties(prefix="server") + public class ServerProperties { + + /** + * Name of the server. + */ + private String name; + + /** + * IP address to listen to. + */ + private String ip = "127.0.0.1"; + + /** + * Port to listener to. + */ + private int port = 9797; + + // ... getter and setters + + } +---- + +This exposes three properties where `server.name` has no default and `server.ip` and `server.port` defaults to `"127.0.0.1"` and `9797` respectively. +The Javadoc on fields is used to populate the `description` attribute. For instance, the description of `server.ip` is "IP address to listen to.". + +NOTE: You should only use plain text with `@ConfigurationProperties` field Javadoc, since they are not processed before being added to the JSON. + +The annotation processor applies a number of heuristics to extract the default value from the source model. +Default values have to be provided statically. In particular, do not refer to a constant defined in another class. +Also, the annotation processor cannot auto-detect default values for ``Enum``s and ``Collections``s. + +For cases where the default value could not be detected, <> should be provided. +Consider the following example: + +[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] +---- + @ConfigurationProperties(prefix = "acme.messaging") + public class MessagingProperties { + + private List addresses = new ArrayList<>(Arrays.asList("a", "b")); + + private ContainerType containerType = ContainerType.SIMPLE; + + // ... getter and setters + + public enum ContainerType { + + SIMPLE, + DIRECT + + } + + } +---- + +In order to document default values for properties in the class above, you could add the following content to <>: + +[source,json,indent=0] +---- + {"properties": [ + { + "name": "acme.messaging.addresses", + "defaultValue": ["a", "b"] + }, + { + "name": "acme.messaging.container-type", + "defaultValue": "simple" + } + ]} +---- + +NOTE: Only the `name` of the property is required to document additional metadata for existing properties. + + + +[[configuration-metadata.annotation-processor.automatic-metadata-generation.nested-properties]] +==== Nested Properties +The annotation processor automatically considers inner classes as nested properties. +Rather than documenting the `ip` and `port` at the root of the namespace, we could create a sub-namespace for it. +Consider the updated example: + +[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] +---- + @ConfigurationProperties(prefix="server") + public class ServerProperties { + + private String name; + + private Host host; + + // ... getter and setters + + public static class Host { + + private String ip; + + private int port; + + // ... getter and setters + + } + + } +---- + +The preceding example produces metadata information for `server.name`, `server.host.ip`, and `server.host.port` properties. +You can use the `@NestedConfigurationProperty` annotation on a field to indicate that a regular (non-inner) class should be treated as if it were nested. + +TIP: This has no effect on collections and maps, as those types are automatically identified, and a single metadata property is generated for each of them. + + + +[[configuration-metadata.annotation-processor.adding-additional-metadata]] +=== Adding Additional Metadata +Spring Boot's configuration file handling is quite flexible, and it is often the case that properties may exist that are not bound to a `@ConfigurationProperties` bean. +You may also need to tune some attributes of an existing key. +To support such cases and let you provide custom "hints", the annotation processor automatically merges items from `META-INF/additional-spring-configuration-metadata.json` into the main metadata file. + +If you refer to a property that has been detected automatically, the description, default value, and deprecation information are overridden, if specified. +If the manual property declaration is not identified in the current module, it is added as a new property. + +The format of the `additional-spring-configuration-metadata.json` file is exactly the same as the regular `spring-configuration-metadata.json`. +The additional properties file is optional. +If you do not have any additional properties, do not add the file. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/configuration-metadata/format.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/configuration-metadata/format.adoc new file mode 100644 index 0000000000..84f5c3efc7 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/configuration-metadata/format.adoc @@ -0,0 +1,311 @@ +[[configuration-metadata.format]] +== Metadata Format +Configuration metadata files are located inside jars under `META-INF/spring-configuration-metadata.json`. +They use a JSON format with items categorized under either "`groups`" or "`properties`" and additional values hints categorized under "hints", as shown in the following example: + +[source,json,indent=0] +---- + {"groups": [ + { + "name": "server", + "type": "org.springframework.boot.autoconfigure.web.ServerProperties", + "sourceType": "org.springframework.boot.autoconfigure.web.ServerProperties" + }, + { + "name": "spring.jpa.hibernate", + "type": "org.springframework.boot.autoconfigure.orm.jpa.JpaProperties$Hibernate", + "sourceType": "org.springframework.boot.autoconfigure.orm.jpa.JpaProperties", + "sourceMethod": "getHibernate()" + } + ... + ],"properties": [ + { + "name": "server.port", + "type": "java.lang.Integer", + "sourceType": "org.springframework.boot.autoconfigure.web.ServerProperties" + }, + { + "name": "server.address", + "type": "java.net.InetAddress", + "sourceType": "org.springframework.boot.autoconfigure.web.ServerProperties" + }, + { + "name": "spring.jpa.hibernate.ddl-auto", + "type": "java.lang.String", + "description": "DDL mode. This is actually a shortcut for the \"hibernate.hbm2ddl.auto\" property.", + "sourceType": "org.springframework.boot.autoconfigure.orm.jpa.JpaProperties$Hibernate" + } + ... + ],"hints": [ + { + "name": "spring.jpa.hibernate.ddl-auto", + "values": [ + { + "value": "none", + "description": "Disable DDL handling." + }, + { + "value": "validate", + "description": "Validate the schema, make no changes to the database." + }, + { + "value": "update", + "description": "Update the schema if necessary." + }, + { + "value": "create", + "description": "Create the schema and destroy previous data." + }, + { + "value": "create-drop", + "description": "Create and then destroy the schema at the end of the session." + } + ] + } + ]} +---- + +Each "`property`" is a configuration item that the user specifies with a given value. +For example, `server.port` and `server.address` might be specified in `application.properties`, as follows: + +[source,properties,indent=0,configprops] +---- + server.port=9090 + server.address=127.0.0.1 +---- + +The "`groups`" are higher level items that do not themselves specify a value but instead provide a contextual grouping for properties. +For example, the `server.port` and `server.address` properties are part of the `server` group. + +NOTE: It is not required that every "`property`" has a "`group`". +Some properties might exist in their own right. + +Finally, "`hints`" are additional information used to assist the user in configuring a given property. +For example, when a developer is configuring the configprop:spring.jpa.hibernate.ddl-auto[] property, a tool can use the hints to offer some auto-completion help for the `none`, `validate`, `update`, `create`, and `create-drop` values. + + + +[[configuration-metadata.format.group]] +=== Group Attributes +The JSON object contained in the `groups` array can contain the attributes shown in the following table: + +[cols="1,1,4"] +|=== +| Name | Type | Purpose + +| `name` +| String +| The full name of the group. + This attribute is mandatory. + +| `type` +| String +| The class name of the data type of the group. + For example, if the group were based on a class annotated with `@ConfigurationProperties`, the attribute would contain the fully qualified name of that class. + If it were based on a `@Bean` method, it would be the return type of that method. + If the type is not known, the attribute may be omitted. + +| `description` +| String +| A short description of the group that can be displayed to users. + If no description is available, it may be omitted. + It is recommended that descriptions be short paragraphs, with the first line providing a concise summary. + The last line in the description should end with a period (`.`). + +| `sourceType` +| String +| The class name of the source that contributed this group. + For example, if the group were based on a `@Bean` method annotated with `@ConfigurationProperties`, this attribute would contain the fully qualified name of the `@Configuration` class that contains the method. + If the source type is not known, the attribute may be omitted. + +| `sourceMethod` +| String +| The full name of the method (include parenthesis and argument types) that contributed this group (for example, the name of a `@ConfigurationProperties` annotated `@Bean` method). + If the source method is not known, it may be omitted. +|=== + + + +[[configuration-metadata.format.property]] +=== Property Attributes +The JSON object contained in the `properties` array can contain the attributes described in the following table: + +[cols="1,1,4"] +|=== +| Name | Type | Purpose + +| `name` +| String +| The full name of the property. + Names are in lower-case period-separated form (for example, `server.address`). + This attribute is mandatory. + +| `type` +| String +| The full signature of the data type of the property (for example, `java.lang.String`) but also a full generic type (such as `java.util.Map`). + You can use this attribute to guide the user as to the types of values that they can enter. + For consistency, the type of a primitive is specified by using its wrapper counterpart (for example, `boolean` becomes `java.lang.Boolean`). + Note that this class may be a complex type that gets converted from a `String` as values are bound. + If the type is not known, it may be omitted. + +| `description` +| String +| A short description of the property that can be displayed to users. + If no description is available, it may be omitted. + It is recommended that descriptions be short paragraphs, with the first line providing a concise summary. + The last line in the description should end with a period (`.`). + +| `sourceType` +| String +| The class name of the source that contributed this property. + For example, if the property were from a class annotated with `@ConfigurationProperties`, this attribute would contain the fully qualified name of that class. + If the source type is unknown, it may be omitted. + +| `defaultValue` +| Object +| The default value, which is used if the property is not specified. + If the type of the property is an array, it can be an array of value(s). + If the default value is unknown, it may be omitted. + +| `deprecation` +| Deprecation +| Specify whether the property is deprecated. + If the field is not deprecated or if that information is not known, it may be omitted. + The next table offers more detail about the `deprecation` attribute. +|=== + +The JSON object contained in the `deprecation` attribute of each `properties` element can contain the following attributes: + +[cols="1,1,4"] +|=== +| Name | Type | Purpose + +| `level` +| String +| The level of deprecation, which can be either `warning` (the default) or `error`. + When a property has a `warning` deprecation level, it should still be bound in the environment. + However, when it has an `error` deprecation level, the property is no longer managed and is not bound. + +| `reason` +| String +| A short description of the reason why the property was deprecated. + If no reason is available, it may be omitted. + It is recommended that descriptions be short paragraphs, with the first line providing a concise summary. + The last line in the description should end with a period (`.`). + +| `replacement` +| String +| The full name of the property that _replaces_ this deprecated property. + If there is no replacement for this property, it may be omitted. +|=== + +NOTE: Prior to Spring Boot 1.3, a single `deprecated` boolean attribute can be used instead of the `deprecation` element. +This is still supported in a deprecated fashion and should no longer be used. +If no reason and replacement are available, an empty `deprecation` object should be set. + +Deprecation can also be specified declaratively in code by adding the `@DeprecatedConfigurationProperty` annotation to the getter exposing the deprecated property. +For instance, assume that the `app.acme.target` property was confusing and was renamed to `app.acme.name`. +The following example shows how to handle that situation: + +[source,java,pending-extract=true,indent=0] +---- + @ConfigurationProperties("app.acme") + public class AcmeProperties { + + private String name; + + public String getName() { ... } + + public void setName(String name) { ... } + + @DeprecatedConfigurationProperty(replacement = "app.acme.name") + @Deprecated + public String getTarget() { + return getName(); + } + + @Deprecated + public void setTarget(String target) { + setName(target); + } + } +---- + +NOTE: There is no way to set a `level`. +`warning` is always assumed, since code is still handling the property. + +The preceding code makes sure that the deprecated property still works (delegating to the `name` property behind the scenes). +Once the `getTarget` and `setTarget` methods can be removed from your public API, the automatic deprecation hint in the metadata goes away as well. +If you want to keep a hint, adding manual metadata with an `error` deprecation level ensures that users are still informed about that property. +Doing so is particularly useful when a `replacement` is provided. + + + +[[configuration-metadata.format.hints]] +=== Hint Attributes +The JSON object contained in the `hints` array can contain the attributes shown in the following table: + +[cols="1,1,4"] +|=== +| Name | Type | Purpose + +| `name` +| String +| The full name of the property to which this hint refers. + Names are in lower-case period-separated form (such as `spring.mvc.servlet.path`). + If the property refers to a map (such as `system.contexts`), the hint either applies to the _keys_ of the map (`system.contexts.keys`) or the _values_ (`system.contexts.values`) of the map. + This attribute is mandatory. + +| `values` +| ValueHint[] +| A list of valid values as defined by the `ValueHint` object (described in the next table). + Each entry defines the value and may have a description. + +| `providers` +| ValueProvider[] +| A list of providers as defined by the `ValueProvider` object (described later in this document). + Each entry defines the name of the provider and its parameters, if any. +|=== + +The JSON object contained in the `values` attribute of each `hint` element can contain the attributes described in the following table: + +[cols="1,1,4"] +|=== +| Name | Type | Purpose + +| `value` +| Object +| A valid value for the element to which the hint refers. + If the type of the property is an array, it can also be an array of value(s). + This attribute is mandatory. + +| `description` +| String +| A short description of the value that can be displayed to users. + If no description is available, it may be omitted. + It is recommended that descriptions be short paragraphs, with the first line providing a concise summary. + The last line in the description should end with a period (`.`). +|=== + +The JSON object contained in the `providers` attribute of each `hint` element can contain the attributes described in the following table: + +[cols="1,1,4"] +|=== +|Name | Type |Purpose + +| `name` +| String +| The name of the provider to use to offer additional content assistance for the element to which the hint refers. + +| `parameters` +| JSON object +| Any additional parameter that the provider supports (check the documentation of the provider for more details). +|=== + + + +[[configuration-metadata.format.repeated-items]] +=== Repeated Metadata Items +Objects with the same "`property`" and "`group`" name can appear multiple times within a metadata file. +For example, you could bind two separate classes to the same prefix, with each having potentially overlapping property names. +While the same names appearing in the metadata multiple times should not be common, consumers of metadata should take care to ensure that they support it. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/configuration-metadata/manual-hints.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/configuration-metadata/manual-hints.adoc new file mode 100644 index 0000000000..7ad151578a --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/configuration-metadata/manual-hints.adoc @@ -0,0 +1,374 @@ +[[configuration-metadata.manual-hints]] +== Providing Manual Hints +To improve the user experience and further assist the user in configuring a given property, you can provide additional metadata that: + +* Describes the list of potential values for a property. +* Associates a provider, to attach a well defined semantic to a property, so that a tool can discover the list of potential values based on the project's context. + + + +[[configuration-metadata.manual-hints.value-hint]] +=== Value Hint +The `name` attribute of each hint refers to the `name` of a property. +In the <>, we provide five values for the `spring.jpa.hibernate.ddl-auto` property: `none`, `validate`, `update`, `create`, and `create-drop`. +Each value may have a description as well. + +If your property is of type `Map`, you can provide hints for both the keys and the values (but not for the map itself). +The special `.keys` and `.values` suffixes must refer to the keys and the values, respectively. + +Assume a `sample.contexts` maps magic `String` values to an integer, as shown in the following example: + +[source,java,pending-extract=true,indent=0] +---- + @ConfigurationProperties("sample") + public class SampleProperties { + + private Map contexts; + // getters and setters + } +---- + +The magic values are (in this example) are `sample1` and `sample2`. +In order to offer additional content assistance for the keys, you could add the following JSON to <>: + +[source,json,indent=0] +---- + {"hints": [ + { + "name": "sample.contexts.keys", + "values": [ + { + "value": "sample1" + }, + { + "value": "sample2" + } + ] + } + ]} +---- + +TIP: We recommend that you use an `Enum` for those two values instead. +If your IDE supports it, this is by far the most effective approach to auto-completion. + + + +[[configuration-metadata.manual-hints.value-providers]] +=== Value Providers +Providers are a powerful way to attach semantics to a property. +In this section, we define the official providers that you can use for your own hints. +However, your favorite IDE may implement some of these or none of them. +Also, it could eventually provide its own. + +NOTE: As this is a new feature, IDE vendors must catch up with how it works. +Adoption times naturally vary. + +The following table summarizes the list of supported providers: + +[cols="2,4"] +|=== +| Name | Description + +| `any` +| Permits any additional value to be provided. + +| `class-reference` +| Auto-completes the classes available in the project. + Usually constrained by a base class that is specified by the `target` parameter. + +| `handle-as` +| Handles the property as if it were defined by the type defined by the mandatory `target` parameter. + +| `logger-name` +| Auto-completes valid logger names and <>. + Typically, package and class names available in the current project can be auto-completed as well as defined groups. + +| `spring-bean-reference` +| Auto-completes the available bean names in the current project. + Usually constrained by a base class that is specified by the `target` parameter. + +| `spring-profile-name` +| Auto-completes the available Spring profile names in the project. +|=== + +TIP: Only one provider can be active for a given property, but you can specify several providers if they can all manage the property _in some way_. +Make sure to place the most powerful provider first, as the IDE must use the first one in the JSON section that it can handle. +If no provider for a given property is supported, no special content assistance is provided, either. + + + +[[configuration-metadata.manual-hints.value-providers.any]] +==== Any +The special **any** provider value permits any additional values to be provided. +Regular value validation based on the property type should be applied if this is supported. + +This provider is typically used if you have a list of values and any extra values should still be considered as valid. + +The following example offers `on` and `off` as auto-completion values for `system.state`: + +[source,json,indent=0] +---- + {"hints": [ + { + "name": "system.state", + "values": [ + { + "value": "on" + }, + { + "value": "off" + } + ], + "providers": [ + { + "name": "any" + } + ] + } + ]} +---- + +Note that, in the preceding example, any other value is also allowed. + + + +[[configuration-metadata.manual-hints.value-providers.class-reference]] +==== Class Reference +The **class-reference** provider auto-completes classes available in the project. +This provider supports the following parameters: + +[cols="1,1,2,4"] +|=== +| Parameter | Type | Default value | Description + +| `target` +| `String` (`Class`) +| _none_ +| The fully qualified name of the class that should be assignable to the chosen value. + Typically used to filter out-non candidate classes. + Note that this information can be provided by the type itself by exposing a class with the appropriate upper bound. + +| `concrete` +| `boolean` +| true +| Specify whether only concrete classes are to be considered as valid candidates. +|=== + + +The following metadata snippet corresponds to the standard `server.servlet.jsp.class-name` property that defines the `JspServlet` class name to use: + +[source,json,indent=0] +---- + {"hints": [ + { + "name": "server.servlet.jsp.class-name", + "providers": [ + { + "name": "class-reference", + "parameters": { + "target": "javax.servlet.http.HttpServlet" + } + } + ] + } + ]} +---- + + + +[[configuration-metadata.manual-hints.value-providers.handle-as]] +==== Handle As +The **handle-as** provider lets you substitute the type of the property to a more high-level type. +This typically happens when the property has a `java.lang.String` type, because you do not want your configuration classes to rely on classes that may not be on the classpath. +This provider supports the following parameters: + +[cols="1,1,2,4"] +|=== +| Parameter | Type | Default value | Description + +| **`target`** +| `String` (`Class`) +| _none_ +| The fully qualified name of the type to consider for the property. + This parameter is mandatory. +|=== + +The following types can be used: + +* Any `java.lang.Enum`: Lists the possible values for the property. + (We recommend defining the property with the `Enum` type, as no further hint should be required for the IDE to auto-complete the values) +* `java.nio.charset.Charset`: Supports auto-completion of charset/encoding values (such as `UTF-8`) +* `java.util.Locale`: auto-completion of locales (such as `en_US`) +* `org.springframework.util.MimeType`: Supports auto-completion of content type values (such as `text/plain`) +* `org.springframework.core.io.Resource`: Supports auto-completion of Spring’s Resource abstraction to refer to a file on the filesystem or on the classpath (such as `classpath:/sample.properties`) + +TIP: If multiple values can be provided, use a `Collection` or _Array_ type to teach the IDE about it. + +The following metadata snippet corresponds to the standard `spring.liquibase.change-log` property that defines the path to the changelog to use. +It is actually used internally as a `org.springframework.core.io.Resource` but cannot be exposed as such, because we need to keep the original String value to pass it to the Liquibase API. + +[source,json,indent=0] +---- + {"hints": [ + { + "name": "spring.liquibase.change-log", + "providers": [ + { + "name": "handle-as", + "parameters": { + "target": "org.springframework.core.io.Resource" + } + } + ] + } + ]} +---- + + + +[[configuration-metadata.manual-hints.value-providers.logger-name]] +==== Logger Name +The **logger-name** provider auto-completes valid logger names and <>. +Typically, package and class names available in the current project can be auto-completed. +If groups are enabled (default) and if a custom logger group is identified in the configuration, auto-completion for it should be provided. +Specific frameworks may have extra magic logger names that can be supported as well. + +This provider supports the following parameters: + +[cols="1,1,2,4"] +|=== +| Parameter | Type | Default value | Description + +| `group` +| `boolean` +| `true` +| Specify whether known groups should be considered. +|=== + +Since a logger name can be any arbitrary name, this provider should allow any value but could highlight valid package and class names that are not available in the project's classpath. + +The following metadata snippet corresponds to the standard `logging.level` property. +Keys are _logger names_, and values correspond to the standard log levels or any custom level. +As Spring Boot defines a few logger groups out-of-the-box, dedicated value hints have been added for those. + +[source,json,indent=0] +---- + {"hints": [ + { + "name": "logging.level.keys", + "values": [ + { + "value": "root", + "description": "Root logger used to assign the default logging level." + }, + { + "value": "sql", + "description": "SQL logging group including Hibernate SQL logger." + }, + { + "value": "web", + "description": "Web logging group including codecs." + } + ], + "providers": [ + { + "name": "logger-name" + } + ] + }, + { + "name": "logging.level.values", + "values": [ + { + "value": "trace" + }, + { + "value": "debug" + }, + { + "value": "info" + }, + { + "value": "warn" + }, + { + "value": "error" + }, + { + "value": "fatal" + }, + { + "value": "off" + } + + ], + "providers": [ + { + "name": "any" + } + ] + } + ]} +---- + + + +[[configuration-metadata.manual-hints.value-providers.spring-bean-reference]] +==== Spring Bean Reference +The **spring-bean-reference** provider auto-completes the beans that are defined in the configuration of the current project. +This provider supports the following parameters: + +[cols="1,1,2,4"] +|=== +| Parameter | Type | Default value | Description + +| `target` +| `String` (`Class`) +| _none_ +| The fully qualified name of the bean class that should be assignable to the candidate. + Typically used to filter out non-candidate beans. +|=== + +The following metadata snippet corresponds to the standard `spring.jmx.server` property that defines the name of the `MBeanServer` bean to use: + +[source,json,indent=0] +---- + {"hints": [ + { + "name": "spring.jmx.server", + "providers": [ + { + "name": "spring-bean-reference", + "parameters": { + "target": "javax.management.MBeanServer" + } + } + ] + } + ]} +---- + +NOTE: The binder is not aware of the metadata. +If you provide that hint, you still need to transform the bean name into an actual Bean reference using by the `ApplicationContext`. + + + +[[configuration-metadata.manual-hints.value-providers.spring-profile-name]] +==== Spring Profile Name +The **spring-profile-name** provider auto-completes the Spring profiles that are defined in the configuration of the current project. + +The following metadata snippet corresponds to the standard `spring.profiles.active` property that defines the name of the Spring profile(s) to enable: + +[source,json,indent=0] +---- + {"hints": [ + { + "name": "spring.profiles.active", + "providers": [ + { + "name": "spring-profile-name" + } + ] + } + ]} +---- diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/dependency-versions.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/dependency-versions.adoc index 05f5a20bf4..8e33b0b0e7 100644 --- a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/dependency-versions.adoc +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/dependency-versions.adoc @@ -1,27 +1,14 @@ [appendix] -[[appendix.dependency-versions]] -= Dependency versions +[[dependency-versions]] += Dependency Versions include::attributes.adoc[] + + This appendix provides details of the dependencies that are managed by Spring Boot. -[[appendix.dependency-versions.coordinates]] -== Managed Dependency Coordinates +include::dependency-versions/coordinates.adoc[] -The following table provides details of all of the dependency versions that are provided by Spring Boot in its CLI (Command Line Interface), Maven dependency management, and Gradle plugin. -When you declare a dependency on one of these artifacts without declaring a version, the version listed in the table is used. - -include::generated-dependency-versions.adoc[] - - - -[[appendix.dependency-versions.properties]] -== Version Properties - -The following table provides all properties that can be used to override the versions managed by Spring Boot. -Browse the {spring-boot-code}/spring-boot-project/spring-boot-dependencies/build.gradle[`spring-boot-dependencies` build.gradle] for a complete list of dependencies. -You can learn how to customize these versions in your application in the <>. - -include::generated-version-properties.adoc[] +include::dependency-versions/properties.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/dependency-versions/coordinates.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/dependency-versions/coordinates.adoc new file mode 100644 index 0000000000..981831b262 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/dependency-versions/coordinates.adoc @@ -0,0 +1,7 @@ +[[dependency-versions.coordinates]] +== Managed Dependency Coordinates + +The following table provides details of all of the dependency versions that are provided by Spring Boot in its CLI (Command Line Interface), Maven dependency management, and Gradle plugin. +When you declare a dependency on one of these artifacts without declaring a version, the version listed in the table is used. + +include::documented-coordinates.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/dependency-versions/properties.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/dependency-versions/properties.adoc new file mode 100644 index 0000000000..a2bdfa141d --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/dependency-versions/properties.adoc @@ -0,0 +1,8 @@ +[[dependency-versions.properties]] +== Version Properties + +The following table provides all properties that can be used to override the versions managed by Spring Boot. +Browse the {spring-boot-code}/spring-boot-project/spring-boot-dependencies/build.gradle[`spring-boot-dependencies` build.gradle] for a complete list of dependencies. +You can learn how to customize these versions in your application in the <>. + +include::documented-properties.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/deployment.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/deployment.adoc index eef88b99cb..c390eb5846 100644 --- a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/deployment.adoc +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/deployment.adoc @@ -2,6 +2,8 @@ = Deploying Spring Boot Applications include::attributes.adoc[] + + Spring Boot's flexible packaging options provide a great deal of choice when it comes to deploying your application. You can deploy Spring Boot applications to a variety of cloud platforms, to container images (such as Docker), or to virtual/real machines. @@ -9,851 +11,10 @@ This section covers some of the more common deployment scenarios. -[[deployment.containers]] -== Deploying to Containers -If you are running your application from a container, you can use an executable jar, but it is also often an advantage to explode it and run it in a different way. -Certain PaaS implementations may also choose to unpack archives before they run. -For example, Cloud Foundry operates this way. -One way to run an unpacked archive is by starting the appropriate launcher, as follows: +include::deployment/containers.adoc[] -[indent=0] ----- - $ jar -xf myapp.jar - $ java org.springframework.boot.loader.JarLauncher ----- +include::deployment/cloud.adoc[] -This is actually slightly faster on startup (depending on the size of the jar) than running from an unexploded archive. -At runtime you shouldn't expect any differences. +include::deployment/installing.adoc[] -Once you have unpacked the jar file, you can also get an extra boost to startup time by running the app with its "natural" main method instead of the `JarLauncher`. For example: - -[indent=0] ----- - $ jar -xf myapp.jar - $ java -cp BOOT-INF/classes:BOOT-INF/lib/* com.example.MyApplication ----- - -NOTE: Using the `JarLauncher` over the application's main method has the added benefit of a predictable classpath order. -The jar contains a `classpath.idx` file which is used by the `JarLauncher` when constructing the classpath. - -More efficient container images can also be created by <> for your dependencies and application classes and resources (which normally change more frequently). - - - -[[deployment.cloud]] -== Deploying to the Cloud -Spring Boot's executable jars are ready-made for most popular cloud PaaS (Platform-as-a-Service) providers. -These providers tend to require that you "`bring your own container`". -They manage application processes (not Java applications specifically), so they need an intermediary layer that adapts _your_ application to the _cloud's_ notion of a running process. - -Two popular cloud providers, Heroku and Cloud Foundry, employ a "`buildpack`" approach. -The buildpack wraps your deployed code in whatever is needed to _start_ your application. -It might be a JDK and a call to `java`, an embedded web server, or a full-fledged application server. -A buildpack is pluggable, but ideally you should be able to get by with as few customizations to it as possible. -This reduces the footprint of functionality that is not under your control. -It minimizes divergence between development and production environments. - -Ideally, your application, like a Spring Boot executable jar, has everything that it needs to run packaged within it. - -In this section, we look at what it takes to get the <> in the "`Getting Started`" section up and running in the Cloud. - - - -[[deployment.cloud.cloud-foundry]] -=== Cloud Foundry -Cloud Foundry provides default buildpacks that come into play if no other buildpack is specified. -The Cloud Foundry https://github.com/cloudfoundry/java-buildpack[Java buildpack] has excellent support for Spring applications, including Spring Boot. -You can deploy stand-alone executable jar applications as well as traditional `.war` packaged applications. - -Once you have built your application (by using, for example, `mvn clean package`) and have https://docs.cloudfoundry.org/cf-cli/install-go-cli.html[installed the `cf` command line tool], deploy your application by using the `cf push` command, substituting the path to your compiled `.jar`. -Be sure to have https://docs.cloudfoundry.org/cf-cli/getting-started.html#login[logged in with your `cf` command line client] before pushing an application. -The following line shows using the `cf push` command to deploy an application: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - $ cf push acloudyspringtime -p target/demo-0.0.1-SNAPSHOT.jar ----- - -NOTE: In the preceding example, we substitute `acloudyspringtime` for whatever value you give `cf` as the name of your application. - -See the https://docs.cloudfoundry.org/cf-cli/getting-started.html#push[`cf push` documentation] for more options. -If there is a Cloud Foundry https://docs.cloudfoundry.org/devguide/deploy-apps/manifest.html[`manifest.yml`] file present in the same directory, it is considered. - -At this point, `cf` starts uploading your application, producing output similar to the following example: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - Uploading acloudyspringtime... *OK* - Preparing to start acloudyspringtime... *OK* - -----> Downloaded app package (*8.9M*) - -----> Java Buildpack Version: v3.12 (offline) | https://github.com/cloudfoundry/java-buildpack.git#6f25b7e - -----> Downloading Open Jdk JRE 1.8.0_121 from https://java-buildpack.cloudfoundry.org/openjdk/trusty/x86_64/openjdk-1.8.0_121.tar.gz (found in cache) - Expanding Open Jdk JRE to .java-buildpack/open_jdk_jre (1.6s) - -----> Downloading Open JDK Like Memory Calculator 2.0.2_RELEASE from https://java-buildpack.cloudfoundry.org/memory-calculator/trusty/x86_64/memory-calculator-2.0.2_RELEASE.tar.gz (found in cache) - Memory Settings: -Xss349K -Xmx681574K -XX:MaxMetaspaceSize=104857K -Xms681574K -XX:MetaspaceSize=104857K - -----> Downloading Container Certificate Trust Store 1.0.0_RELEASE from https://java-buildpack.cloudfoundry.org/container-certificate-trust-store/container-certificate-trust-store-1.0.0_RELEASE.jar (found in cache) - Adding certificates to .java-buildpack/container_certificate_trust_store/truststore.jks (0.6s) - -----> Downloading Spring Auto Reconfiguration 1.10.0_RELEASE from https://java-buildpack.cloudfoundry.org/auto-reconfiguration/auto-reconfiguration-1.10.0_RELEASE.jar (found in cache) - Checking status of app 'acloudyspringtime'... - 0 of 1 instances running (1 starting) - ... - 0 of 1 instances running (1 starting) - ... - 0 of 1 instances running (1 starting) - ... - 1 of 1 instances running (1 running) - - App started ----- - -Congratulations! The application is now live! - -Once your application is live, you can verify the status of the deployed application by using the `cf apps` command, as shown in the following example: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - $ cf apps - Getting applications in ... - OK - - name requested state instances memory disk urls - ... - acloudyspringtime started 1/1 512M 1G acloudyspringtime.cfapps.io - ... ----- - -Once Cloud Foundry acknowledges that your application has been deployed, you should be able to find the application at the URI given. -In the preceding example, you could find it at `\https://acloudyspringtime.cfapps.io/`. - - - -[[deployment.cloud.cloud-foundry.binding-to-services]] -==== Binding to Services -By default, metadata about the running application as well as service connection information is exposed to the application as environment variables (for example: `$VCAP_SERVICES`). -This architecture decision is due to Cloud Foundry's polyglot (any language and platform can be supported as a buildpack) nature. -Process-scoped environment variables are language agnostic. - -Environment variables do not always make for the easiest API, so Spring Boot automatically extracts them and flattens the data into properties that can be accessed through Spring's `Environment` abstraction, as shown in the following example: - -[source,java,pending-extract=true,indent=0] ----- - @Component - class MyBean implements EnvironmentAware { - - private String instanceId; - - @Override - public void setEnvironment(Environment environment) { - this.instanceId = environment.getProperty("vcap.application.instance_id"); - } - - // ... - - } ----- - -All Cloud Foundry properties are prefixed with `vcap`. -You can use `vcap` properties to access application information (such as the public URL of the application) and service information (such as database credentials). -See the {spring-boot-module-api}/cloud/CloudFoundryVcapEnvironmentPostProcessor.html['`CloudFoundryVcapEnvironmentPostProcessor`'] Javadoc for complete details. - -TIP: The https://github.com/pivotal-cf/java-cfenv/[Java CFEnv] project is a better fit for tasks such as configuring a DataSource. - - - -[[deployment.cloud.kubernetes]] -=== Kubernetes -Spring Boot auto-detects Kubernetes deployment environments by checking the environment for `"*_SERVICE_HOST"` and `"*_SERVICE_PORT"` variables. -You can override this detection with the configprop:spring.main.cloud-platform[] configuration property. - -Spring Boot helps you to <> and export it with <>. - - - -[[deployment.cloud.kubernetes.container-lifecycle]] -==== Kubernetes Container Lifecycle -When Kubernetes deletes an application instance, the shutdown process involves several subsystems concurrently: shutdown hooks, unregistering the service, removing the instance from the load-balancer... -Because this shutdown processing happens in parallel (and due to the nature of distributed systems), there is a window during which traffic can be routed to a pod that has also begun its shutdown processing. - -You can configure a sleep execution in a preStop handler to avoid requests being routed to a pod that has already begun shutting down. -This sleep should be long enough for new requests to stop being routed to the pod and its duration will vary from deployment to deployment. -The preStop handler can be configured via the PodSpec in the pod's configuration file as follows: - -[source,yml,indent=0] ----- -spec: - containers: - - name: example-container - image: example-image - lifecycle: - preStop: - exec: - command: ["sh", "-c", "sleep 10"] ----- - -Once the pre-stop hook has completed, SIGTERM will be sent to the container and <> will begin, allowing any remaining in-flight requests to complete. - - - -[[deployment.cloud.heroku]] -=== Heroku -Heroku is another popular PaaS platform. -To customize Heroku builds, you provide a `Procfile`, which provides the incantation required to deploy an application. -Heroku assigns a `port` for the Java application to use and then ensures that routing to the external URI works. - -You must configure your application to listen on the correct port. -The following example shows the `Procfile` for our starter REST application: - -[indent=0] ----- - web: java -Dserver.port=$PORT -jar target/demo-0.0.1-SNAPSHOT.jar ----- - -Spring Boot makes `-D` arguments available as properties accessible from a Spring `Environment` instance. -The `server.port` configuration property is fed to the embedded Tomcat, Jetty, or Undertow instance, which then uses the port when it starts up. -The `$PORT` environment variable is assigned to us by the Heroku PaaS. - -This should be everything you need. -The most common deployment workflow for Heroku deployments is to `git push` the code to production, as shown in the following example: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - $ git push heroku main - - Initializing repository, *done*. - Counting objects: 95, *done*. - Delta compression using up to 8 threads. - Compressing objects: 100% (78/78), *done*. - Writing objects: 100% (95/95), 8.66 MiB | 606.00 KiB/s, *done*. - Total 95 (delta 31), reused 0 (delta 0) - - -----> Java app detected - -----> Installing OpenJDK 1.8... *done* - -----> Installing Maven 3.3.1... *done* - -----> Installing settings.xml... *done* - -----> Executing: mvn -B -DskipTests=true clean install - - [INFO] Scanning for projects... - Downloading: https://repo.spring.io/... - Downloaded: https://repo.spring.io/... (818 B at 1.8 KB/sec) - .... - Downloaded: https://s3pository.heroku.com/jvm/... (152 KB at 595.3 KB/sec) - [INFO] Installing /tmp/build_0c35a5d2-a067-4abc-a232-14b1fb7a8229/target/... - [INFO] Installing /tmp/build_0c35a5d2-a067-4abc-a232-14b1fb7a8229/pom.xml ... - [INFO] ------------------------------------------------------------------------ - [INFO] *BUILD SUCCESS* - [INFO] ------------------------------------------------------------------------ - [INFO] Total time: 59.358s - [INFO] Finished at: Fri Mar 07 07:28:25 UTC 2014 - [INFO] Final Memory: 20M/493M - [INFO] ------------------------------------------------------------------------ - - -----> Discovering process types - Procfile declares types -> *web* - - -----> Compressing... *done*, 70.4MB - -----> Launching... *done*, v6 - https://agile-sierra-1405.herokuapp.com/ *deployed to Heroku* - - To git@heroku.com:agile-sierra-1405.git - * [new branch] main -> main ----- - -Your application should now be up and running on Heroku. -For more details, refer to https://devcenter.heroku.com/articles/deploying-spring-boot-apps-to-heroku[Deploying Spring Boot Applications to Heroku]. - - - -[[deployment.cloud.openshift]] -=== OpenShift -https://www.openshift.com/[OpenShift] has many resources describing how to deploy Spring Boot applications, including: - -* https://blog.openshift.com/using-openshift-enterprise-grade-spring-boot-deployments/[Using the S2I builder] -* https://access.redhat.com/documentation/en-us/reference_architectures/2017/html-single/spring_boot_microservices_on_red_hat_openshift_container_platform_3/[Architecture guide] -* https://blog.openshift.com/using-spring-boot-on-openshift/[Running as a traditional web application on Wildfly] -* https://blog.openshift.com/openshift-commons-briefing-96-cloud-native-applications-spring-rhoar/[OpenShift Commons Briefing] - - - -[[deployment.cloud.aws]] -=== Amazon Web Services (AWS) -Amazon Web Services offers multiple ways to install Spring Boot-based applications, either as traditional web applications (war) or as executable jar files with an embedded web server. -The options include: - -* AWS Elastic Beanstalk -* AWS Code Deploy -* AWS OPS Works -* AWS Cloud Formation -* AWS Container Registry - -Each has different features and pricing models. -In this document, we describe to approach using AWS Elastic Beanstalk. - - - -[[deployment.cloud.aws.beanstalk]] -==== AWS Elastic Beanstalk -As described in the official https://docs.aws.amazon.com/elasticbeanstalk/latest/dg/create_deploy_Java.html[Elastic Beanstalk Java guide], there are two main options to deploy a Java application. -You can either use the "`Tomcat Platform`" or the "`Java SE platform`". - - - -[[deployment.cloud.aws.beanstalk.tomcat-platform]] -===== Using the Tomcat Platform -This option applies to Spring Boot projects that produce a war file. -No special configuration is required. -You need only follow the official guide. - - - -[[deployment.cloud.aws.beanstalk.java-se-platform]] -===== Using the Java SE Platform -This option applies to Spring Boot projects that produce a jar file and run an embedded web container. -Elastic Beanstalk environments run an nginx instance on port 80 to proxy the actual application, running on port 5000. -To configure it, add the following line to your `application.properties` file: - -[indent=0] ----- - server.port=5000 ----- - - -[TIP] -.Upload binaries instead of sources -==== -By default, Elastic Beanstalk uploads sources and compiles them in AWS. -However, it is best to upload the binaries instead. -To do so, add lines similar to the following to your `.elasticbeanstalk/config.yml` file: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - deploy: - artifact: target/demo-0.0.1-SNAPSHOT.jar ----- -==== - -[TIP] -.Reduce costs by setting the environment type -==== -By default an Elastic Beanstalk environment is load balanced. -The load balancer has a significant cost. -To avoid that cost, set the environment type to "`Single instance`", as described in https://docs.aws.amazon.com/elasticbeanstalk/latest/dg/environments-create-wizard.html#environments-create-wizard-capacity[the Amazon documentation]. -You can also create single instance environments by using the CLI and the following command: - -[indent=0] ----- - eb create -s ----- -==== - - - -[[deployment.cloud.aws.summary]] -==== Summary -This is one of the easiest ways to get to AWS, but there are more things to cover, such as how to integrate Elastic Beanstalk into any CI / CD tool, use the Elastic Beanstalk Maven plugin instead of the CLI, and others. -There is a https://exampledriven.wordpress.com/2017/01/09/spring-boot-aws-elastic-beanstalk-example/[blog post] covering these topics more in detail. - - - -[[deployment.cloud.boxfuse]] -=== Boxfuse and Amazon Web Services -https://boxfuse.com/[Boxfuse] works by turning your Spring Boot executable jar or war into a minimal VM image that can be deployed unchanged either on VirtualBox or on AWS. -Boxfuse comes with deep integration for Spring Boot and uses the information from your Spring Boot configuration file to automatically configure ports and health check URLs. -Boxfuse leverages this information both for the images it produces as well as for all the resources it provisions (instances, security groups, elastic load balancers, and so on). - -Once you have created a https://console.boxfuse.com[Boxfuse account], connected it to your AWS account, installed the latest version of the Boxfuse Client, and ensured that the application has been built by Maven or Gradle (by using, for example, `mvn clean package`), you can deploy your Spring Boot application to AWS with a command similar to the following: - -[indent=0] ----- - $ boxfuse run myapp-1.0.jar -env=prod ----- - -See the https://boxfuse.com/docs/commandline/run.html[`boxfuse run` documentation] for more options. -If there is a https://boxfuse.com/docs/commandline/#configuration[`boxfuse.conf`] file present in the current directory, it is considered. - -TIP: By default, Boxfuse activates a Spring profile named `boxfuse` on startup. -If your executable jar or war contains an https://boxfuse.com/docs/payloads/springboot.html#configuration[`application-boxfuse.properties`] file, Boxfuse bases its configuration on the properties it contains. - -At this point, `boxfuse` creates an image for your application, uploads it, and configures and starts the necessary resources on AWS, resulting in output similar to the following example: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - Fusing Image for myapp-1.0.jar ... - Image fused in 00:06.838s (53937 K) -> axelfontaine/myapp:1.0 - Creating axelfontaine/myapp ... - Pushing axelfontaine/myapp:1.0 ... - Verifying axelfontaine/myapp:1.0 ... - Creating Elastic IP ... - Mapping myapp-axelfontaine.boxfuse.io to 52.28.233.167 ... - Waiting for AWS to create an AMI for axelfontaine/myapp:1.0 in eu-central-1 (this may take up to 50 seconds) ... - AMI created in 00:23.557s -> ami-d23f38cf - Creating security group boxfuse-sg_axelfontaine/myapp:1.0 ... - Launching t2.micro instance of axelfontaine/myapp:1.0 (ami-d23f38cf) in eu-central-1 ... - Instance launched in 00:30.306s -> i-92ef9f53 - Waiting for AWS to boot Instance i-92ef9f53 and Payload to start at https://52.28.235.61/ ... - Payload started in 00:29.266s -> https://52.28.235.61/ - Remapping Elastic IP 52.28.233.167 to i-92ef9f53 ... - Waiting 15s for AWS to complete Elastic IP Zero Downtime transition ... - Deployment completed successfully. axelfontaine/myapp:1.0 is up and running at https://myapp-axelfontaine.boxfuse.io/ ----- - -Your application should now be up and running on AWS. - -See the blog post on https://boxfuse.com/blog/spring-boot-ec2.html[deploying Spring Boot apps on EC2] as well as the https://boxfuse.com/docs/payloads/springboot.html[documentation for the Boxfuse Spring Boot integration] to get started with a Maven build to run the app. - - - -[[deployment.cloud.google]] -=== Google Cloud -Google Cloud has several options that can be used to launch Spring Boot applications. -The easiest to get started with is probably App Engine, but you could also find ways to run Spring Boot in a container with Container Engine or on a virtual machine with Compute Engine. - -To run in App Engine, you can create a project in the UI first, which sets up a unique identifier for you and also sets up HTTP routes. -Add a Java app to the project and leave it empty and then use the https://cloud.google.com/sdk/install[Google Cloud SDK] to push your Spring Boot app into that slot from the command line or CI build. - -App Engine Standard requires you to use WAR packaging. -Follow https://github.com/GoogleCloudPlatform/java-docs-samples/tree/master/appengine-java8/springboot-helloworld/README.md[these steps] to deploy App Engine Standard application to Google Cloud. - -Alternatively, App Engine Flex requires you to create an `app.yaml` file to describe the resources your app requires. -Normally, you put this file in `src/main/appengine`, and it should resemble the following file: - -[source,yaml,indent=0] ----- - service: default - - runtime: java - env: flex - - runtime_config: - jdk: openjdk8 - - handlers: - - url: /.* - script: this field is required, but ignored - - manual_scaling: - instances: 1 - - health_check: - enable_health_check: False - - env_variables: - ENCRYPT_KEY: your_encryption_key_here ----- - -You can deploy the app (for example, with a Maven plugin) by adding the project ID to the build configuration, as shown in the following example: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - com.google.cloud.tools - appengine-maven-plugin - 1.3.0 - - myproject - - ----- - -Then deploy with `mvn appengine:deploy` (if you need to authenticate first, the build fails). - - - -[[deployment.installing]] -== Installing Spring Boot Applications -In addition to running Spring Boot applications by using `java -jar`, it is also possible to make fully executable applications for Unix systems. -A fully executable jar can be executed like any other executable binary or it can be <>. -This helps when installing and managing Spring Boot applications in common production environments. - -CAUTION: Fully executable jars work by embedding an extra script at the front of the file. -Currently, some tools do not accept this format, so you may not always be able to use this technique. -For example, `jar -xf` may silently fail to extract a jar or war that has been made fully executable. -It is recommended that you make your jar or war fully executable only if you intend to execute it directly, rather than running it with `java -jar` or deploying it to a servlet container. - -CAUTION: A zip64-format jar file cannot be made fully executable. -Attempting to do so will result in a jar file that is reported as corrupt when executed directly or with `java -jar`. -A standard-format jar file that contains one or more zip64-format nested jars can be fully executable. - -To create a '`fully executable`' jar with Maven, use the following plugin configuration: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - org.springframework.boot - spring-boot-maven-plugin - - true - - ----- - -The following example shows the equivalent Gradle configuration: - -[source,groovy,indent=0,subs="verbatim,quotes,attributes"] ----- - bootJar { - launchScript() - } ----- - -You can then run your application by typing `./my-application.jar` (where `my-application` is the name of your artifact). -The directory containing the jar is used as your application's working directory. - - - -[[deployment.installing.supported-operating-systems]] -=== Supported Operating Systems -The default script supports most Linux distributions and is tested on CentOS and Ubuntu. -Other platforms, such as OS X and FreeBSD, require the use of a custom `embeddedLaunchScript`. - - - -[[deployment.installing.nix-services]] -=== Unix/Linux Services -Spring Boot application can be easily started as Unix/Linux services by using either `init.d` or `systemd`. - - - -[[deployment.installing.nix-services.init-d]] -==== Installation as an init.d Service (System V) -If you configured Spring Boot's Maven or Gradle plugin to generate a <>, and you do not use a custom `embeddedLaunchScript`, your application can be used as an `init.d` service. -To do so, symlink the jar to `init.d` to support the standard `start`, `stop`, `restart`, and `status` commands. - -The script supports the following features: - -* Starts the services as the user that owns the jar file -* Tracks the application's PID by using `/var/run//.pid` -* Writes console logs to `/var/log/.log` - -Assuming that you have a Spring Boot application installed in `/var/myapp`, to install a Spring Boot application as an `init.d` service, create a symlink, as follows: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - $ sudo ln -s /var/myapp/myapp.jar /etc/init.d/myapp ----- - -Once installed, you can start and stop the service in the usual way. -For example, on a Debian-based system, you could start it with the following command: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - $ service myapp start ----- - -TIP: If your application fails to start, check the log file written to `/var/log/.log` for errors. - -You can also flag the application to start automatically by using your standard operating system tools. -For example, on Debian, you could use the following command: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - $ update-rc.d myapp defaults ----- - - - -[[deployment.installing.nix-services.init-d.securing]] -===== Securing an init.d Service -NOTE: The following is a set of guidelines on how to secure a Spring Boot application that runs as an init.d service. -It is not intended to be an exhaustive list of everything that should be done to harden an application and the environment in which it runs. - -When executed as root, as is the case when root is being used to start an init.d service, the default executable script runs the application as the user specified in the `RUN_AS_USER` environment variable. -When the environment variable is not set, the user who owns the jar file is used instead. -You should never run a Spring Boot application as `root`, so `RUN_AS_USER` should never be root and your application's jar file should never be owned by root. -Instead, create a specific user to run your application and set the `RUN_AS_USER` environment variable or use `chown` to make it the owner of the jar file, as shown in the following example: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - $ chown bootapp:bootapp your-app.jar ----- - -In this case, the default executable script runs the application as the `bootapp` user. - -TIP: To reduce the chances of the application's user account being compromised, you should consider preventing it from using a login shell. -For example, you can set the account's shell to `/usr/sbin/nologin`. - -You should also take steps to prevent the modification of your application's jar file. -Firstly, configure its permissions so that it cannot be written and can only be read or executed by its owner, as shown in the following example: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - $ chmod 500 your-app.jar ----- - -Second, you should also take steps to limit the damage if your application or the account that's running it is compromised. -If an attacker does gain access, they could make the jar file writable and change its contents. -One way to protect against this is to make it immutable by using `chattr`, as shown in the following example: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - $ sudo chattr +i your-app.jar ----- - -This will prevent any user, including root, from modifying the jar. - -If root is used to control the application's service and you <> to customize its startup, the `.conf` file is read and evaluated by the root user. -It should be secured accordingly. -Use `chmod` so that the file can only be read by the owner and use `chown` to make root the owner, as shown in the following example: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - $ chmod 400 your-app.conf - $ sudo chown root:root your-app.conf ----- - - - -[[deployment.installing.nix-services.system-d]] -==== Installation as a systemd Service -`systemd` is the successor of the System V init system and is now being used by many modern Linux distributions. -Although you can continue to use `init.d` scripts with `systemd`, it is also possible to launch Spring Boot applications by using `systemd` '`service`' scripts. - -Assuming that you have a Spring Boot application installed in `/var/myapp`, to install a Spring Boot application as a `systemd` service, create a script named `myapp.service` and place it in `/etc/systemd/system` directory. -The following script offers an example: - -[indent=0] ----- - [Unit] - Description=myapp - After=syslog.target - - [Service] - User=myapp - ExecStart=/var/myapp/myapp.jar - SuccessExitStatus=143 - - [Install] - WantedBy=multi-user.target ----- - -IMPORTANT: Remember to change the `Description`, `User`, and `ExecStart` fields for your application. - -NOTE: The `ExecStart` field does not declare the script action command, which means that the `run` command is used by default. - -Note that, unlike when running as an `init.d` service, the user that runs the application, the PID file, and the console log file are managed by `systemd` itself and therefore must be configured by using appropriate fields in the '`service`' script. -Consult the https://www.freedesktop.org/software/systemd/man/systemd.service.html[service unit configuration man page] for more details. - -To flag the application to start automatically on system boot, use the following command: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - $ systemctl enable myapp.service ----- - -Refer to `man systemctl` for more details. - - - -[[deployment.installing.nix-services.script-customization]] -==== Customizing the Startup Script -The default embedded startup script written by the Maven or Gradle plugin can be customized in a number of ways. -For most people, using the default script along with a few customizations is usually enough. -If you find you cannot customize something that you need to, use the `embeddedLaunchScript` option to write your own file entirely. - - - -[[deployment.installing.nix-services.script-customization.when-written]] -===== Customizing the Start Script When It Is Written -It often makes sense to customize elements of the start script as it is written into the jar file. -For example, init.d scripts can provide a "`description`". -Since you know the description up front (and it need not change), you may as well provide it when the jar is generated. - -To customize written elements, use the `embeddedLaunchScriptProperties` option of the Spring Boot Maven plugin or the {spring-boot-gradle-plugin-docs}#packaging-executable-configuring-launch-script[`properties` property of the Spring Boot Gradle plugin's `launchScript`]. - -The following property substitutions are supported with the default script: - -[cols="1,3,3,3"] -|=== -| Name | Description | Gradle default | Maven default - -| `mode` -| The script mode. -| `auto` -| `auto` - -| `initInfoProvides` -| The `Provides` section of "`INIT INFO`" -| `${task.baseName}` -| `${project.artifactId}` - -| `initInfoRequiredStart` -| `Required-Start` section of "`INIT INFO`". -| `$remote_fs $syslog $network` -| `$remote_fs $syslog $network` - -| `initInfoRequiredStop` -| `Required-Stop` section of "`INIT INFO`". -| `$remote_fs $syslog $network` -| `$remote_fs $syslog $network` - -| `initInfoDefaultStart` -| `Default-Start` section of "`INIT INFO`". -| `2 3 4 5` -| `2 3 4 5` - -| `initInfoDefaultStop` -| `Default-Stop` section of "`INIT INFO`". -| `0 1 6` -| `0 1 6` - -| `initInfoShortDescription` -| `Short-Description` section of "`INIT INFO`". -| Single-line version of `${project.description}` (falling back to `${task.baseName}`) -| `${project.name}` - -| `initInfoDescription` -| `Description` section of "`INIT INFO`". -| `${project.description}` (falling back to `${task.baseName}`) -| `${project.description}` (falling back to `${project.name}`) - -| `initInfoChkconfig` -| `chkconfig` section of "`INIT INFO`" -| `2345 99 01` -| `2345 99 01` - -| `confFolder` -| The default value for `CONF_FOLDER` -| Folder containing the jar -| Folder containing the jar - -| `inlinedConfScript` -| Reference to a file script that should be inlined in the default launch script. - This can be used to set environmental variables such as `JAVA_OPTS` before any external config files are loaded -| -| - -| `logFolder` -| Default value for `LOG_FOLDER`. - Only valid for an `init.d` service -| -| - -| `logFilename` -| Default value for `LOG_FILENAME`. - Only valid for an `init.d` service -| -| - -| `pidFolder` -| Default value for `PID_FOLDER`. - Only valid for an `init.d` service -| -| - -| `pidFilename` -| Default value for the name of the PID file in `PID_FOLDER`. - Only valid for an `init.d` service -| -| - -| `useStartStopDaemon` -| Whether the `start-stop-daemon` command, when it's available, should be used to control the process -| `true` -| `true` - -| `stopWaitTime` -| Default value for `STOP_WAIT_TIME` in seconds. - Only valid for an `init.d` service -| 60 -| 60 -|=== - - - -[[deployment.installing.nix-services.script-customization.when-running]] -===== Customizing a Script When It Runs -For items of the script that need to be customized _after_ the jar has been written, you can use environment variables or a <>. - -The following environment properties are supported with the default script: - -[cols="1,6"] -|=== -| Variable | Description - -| `MODE` -| The "`mode`" of operation. - The default depends on the way the jar was built but is usually `auto` (meaning it tries to guess if it is an init script by checking if it is a symlink in a directory called `init.d`). - You can explicitly set it to `service` so that the `stop\|start\|status\|restart` commands work or to `run` if you want to run the script in the foreground. - -| `RUN_AS_USER` -| The user that will be used to run the application. - When not set, the user that owns the jar file will be used. - -| `USE_START_STOP_DAEMON` -| Whether the `start-stop-daemon` command, when it's available, should be used to control the process. - Defaults to `true`. - -| `PID_FOLDER` -| The root name of the pid folder (`/var/run` by default). - -| `LOG_FOLDER` -| The name of the folder in which to put log files (`/var/log` by default). - -| `CONF_FOLDER` -| The name of the folder from which to read .conf files (same folder as jar-file by default). - -| `LOG_FILENAME` -| The name of the log file in the `LOG_FOLDER` (`.log` by default). - -| `APP_NAME` -| The name of the app. - If the jar is run from a symlink, the script guesses the app name. - If it is not a symlink or you want to explicitly set the app name, this can be useful. - -| `RUN_ARGS` -| The arguments to pass to the program (the Spring Boot app). - -| `JAVA_HOME` -| The location of the `java` executable is discovered by using the `PATH` by default, but you can set it explicitly if there is an executable file at `$JAVA_HOME/bin/java`. - -| `JAVA_OPTS` -| Options that are passed to the JVM when it is launched. - -| `JARFILE` -| The explicit location of the jar file, in case the script is being used to launch a jar that it is not actually embedded. - -| `DEBUG` -| If not empty, sets the `-x` flag on the shell process, allowing you to see the logic in the script. - -| `STOP_WAIT_TIME` -| The time in seconds to wait when stopping the application before forcing a shutdown (`60` by default). -|=== - -NOTE: The `PID_FOLDER`, `LOG_FOLDER`, and `LOG_FILENAME` variables are only valid for an `init.d` service. -For `systemd`, the equivalent customizations are made by using the '`service`' script. -See the https://www.freedesktop.org/software/systemd/man/systemd.service.html[service unit configuration man page] for more details. - - - -[[deployment-script-customization-conf-file]] -With the exception of `JARFILE` and `APP_NAME`, the settings listed in the preceding section can be configured by using a `.conf` file. -The file is expected to be next to the jar file and have the same name but suffixed with `.conf` rather than `.jar`. -For example, a jar named `/var/myapp/myapp.jar` uses the configuration file named `/var/myapp/myapp.conf`, as shown in the following example: - -.myapp.conf -[indent=0,subs="verbatim,quotes,attributes"] ----- - JAVA_OPTS=-Xmx1024M - LOG_FOLDER=/custom/log/folder ----- - -TIP: If you do not like having the config file next to the jar file, you can set a `CONF_FOLDER` environment variable to customize the location of the config file. - -To learn about securing this file appropriately, see <>. - - - -[[deployment.installing.windows-services]] -=== Microsoft Windows Services -A Spring Boot application can be started as a Windows service by using https://github.com/kohsuke/winsw[`winsw`]. - -A (https://github.com/snicoll/spring-boot-daemon[separately maintained sample]) describes step-by-step how you can create a Windows service for your Spring Boot application. - - - -[[deployment.whats-next]] -== What to Read Next -Check out the https://www.cloudfoundry.org/[Cloud Foundry], https://www.heroku.com/[Heroku], https://www.openshift.com[OpenShift], and https://boxfuse.com[Boxfuse] web sites for more information about the kinds of features that a PaaS can offer. -These are just four of the most popular Java PaaS providers. -Since Spring Boot is so amenable to cloud-based deployment, you can freely consider other providers as well. - -The next section goes on to cover the _<>_, or you can jump ahead to read about _<>_. +include::deployment/whats-next.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/deployment/cloud.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/deployment/cloud.adoc new file mode 100644 index 0000000000..f9e2fe3964 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/deployment/cloud.adoc @@ -0,0 +1,415 @@ +[[deployment.cloud]] +== Deploying to the Cloud +Spring Boot's executable jars are ready-made for most popular cloud PaaS (Platform-as-a-Service) providers. +These providers tend to require that you "`bring your own container`". +They manage application processes (not Java applications specifically), so they need an intermediary layer that adapts _your_ application to the _cloud's_ notion of a running process. + +Two popular cloud providers, Heroku and Cloud Foundry, employ a "`buildpack`" approach. +The buildpack wraps your deployed code in whatever is needed to _start_ your application. +It might be a JDK and a call to `java`, an embedded web server, or a full-fledged application server. +A buildpack is pluggable, but ideally you should be able to get by with as few customizations to it as possible. +This reduces the footprint of functionality that is not under your control. +It minimizes divergence between development and production environments. + +Ideally, your application, like a Spring Boot executable jar, has everything that it needs to run packaged within it. + +In this section, we look at what it takes to get the <> in the "`Getting Started`" section up and running in the Cloud. + + + +[[deployment.cloud.cloud-foundry]] +=== Cloud Foundry +Cloud Foundry provides default buildpacks that come into play if no other buildpack is specified. +The Cloud Foundry https://github.com/cloudfoundry/java-buildpack[Java buildpack] has excellent support for Spring applications, including Spring Boot. +You can deploy stand-alone executable jar applications as well as traditional `.war` packaged applications. + +Once you have built your application (by using, for example, `mvn clean package`) and have https://docs.cloudfoundry.org/cf-cli/install-go-cli.html[installed the `cf` command line tool], deploy your application by using the `cf push` command, substituting the path to your compiled `.jar`. +Be sure to have https://docs.cloudfoundry.org/cf-cli/getting-started.html#login[logged in with your `cf` command line client] before pushing an application. +The following line shows using the `cf push` command to deploy an application: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + $ cf push acloudyspringtime -p target/demo-0.0.1-SNAPSHOT.jar +---- + +NOTE: In the preceding example, we substitute `acloudyspringtime` for whatever value you give `cf` as the name of your application. + +See the https://docs.cloudfoundry.org/cf-cli/getting-started.html#push[`cf push` documentation] for more options. +If there is a Cloud Foundry https://docs.cloudfoundry.org/devguide/deploy-apps/manifest.html[`manifest.yml`] file present in the same directory, it is considered. + +At this point, `cf` starts uploading your application, producing output similar to the following example: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + Uploading acloudyspringtime... *OK* + Preparing to start acloudyspringtime... *OK* + -----> Downloaded app package (*8.9M*) + -----> Java Buildpack Version: v3.12 (offline) | https://github.com/cloudfoundry/java-buildpack.git#6f25b7e + -----> Downloading Open Jdk JRE 1.8.0_121 from https://java-buildpack.cloudfoundry.org/openjdk/trusty/x86_64/openjdk-1.8.0_121.tar.gz (found in cache) + Expanding Open Jdk JRE to .java-buildpack/open_jdk_jre (1.6s) + -----> Downloading Open JDK Like Memory Calculator 2.0.2_RELEASE from https://java-buildpack.cloudfoundry.org/memory-calculator/trusty/x86_64/memory-calculator-2.0.2_RELEASE.tar.gz (found in cache) + Memory Settings: -Xss349K -Xmx681574K -XX:MaxMetaspaceSize=104857K -Xms681574K -XX:MetaspaceSize=104857K + -----> Downloading Container Certificate Trust Store 1.0.0_RELEASE from https://java-buildpack.cloudfoundry.org/container-certificate-trust-store/container-certificate-trust-store-1.0.0_RELEASE.jar (found in cache) + Adding certificates to .java-buildpack/container_certificate_trust_store/truststore.jks (0.6s) + -----> Downloading Spring Auto Reconfiguration 1.10.0_RELEASE from https://java-buildpack.cloudfoundry.org/auto-reconfiguration/auto-reconfiguration-1.10.0_RELEASE.jar (found in cache) + Checking status of app 'acloudyspringtime'... + 0 of 1 instances running (1 starting) + ... + 0 of 1 instances running (1 starting) + ... + 0 of 1 instances running (1 starting) + ... + 1 of 1 instances running (1 running) + + App started +---- + +Congratulations! The application is now live! + +Once your application is live, you can verify the status of the deployed application by using the `cf apps` command, as shown in the following example: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + $ cf apps + Getting applications in ... + OK + + name requested state instances memory disk urls + ... + acloudyspringtime started 1/1 512M 1G acloudyspringtime.cfapps.io + ... +---- + +Once Cloud Foundry acknowledges that your application has been deployed, you should be able to find the application at the URI given. +In the preceding example, you could find it at `\https://acloudyspringtime.cfapps.io/`. + + + +[[deployment.cloud.cloud-foundry.binding-to-services]] +==== Binding to Services +By default, metadata about the running application as well as service connection information is exposed to the application as environment variables (for example: `$VCAP_SERVICES`). +This architecture decision is due to Cloud Foundry's polyglot (any language and platform can be supported as a buildpack) nature. +Process-scoped environment variables are language agnostic. + +Environment variables do not always make for the easiest API, so Spring Boot automatically extracts them and flattens the data into properties that can be accessed through Spring's `Environment` abstraction, as shown in the following example: + +[source,java,pending-extract=true,indent=0] +---- + @Component + class MyBean implements EnvironmentAware { + + private String instanceId; + + @Override + public void setEnvironment(Environment environment) { + this.instanceId = environment.getProperty("vcap.application.instance_id"); + } + + // ... + + } +---- + +All Cloud Foundry properties are prefixed with `vcap`. +You can use `vcap` properties to access application information (such as the public URL of the application) and service information (such as database credentials). +See the {spring-boot-module-api}/cloud/CloudFoundryVcapEnvironmentPostProcessor.html['`CloudFoundryVcapEnvironmentPostProcessor`'] Javadoc for complete details. + +TIP: The https://github.com/pivotal-cf/java-cfenv/[Java CFEnv] project is a better fit for tasks such as configuring a DataSource. + + + +[[deployment.cloud.kubernetes]] +=== Kubernetes +Spring Boot auto-detects Kubernetes deployment environments by checking the environment for `"*_SERVICE_HOST"` and `"*_SERVICE_PORT"` variables. +You can override this detection with the configprop:spring.main.cloud-platform[] configuration property. + +Spring Boot helps you to <> and export it with <>. + + + +[[deployment.cloud.kubernetes.container-lifecycle]] +==== Kubernetes Container Lifecycle +When Kubernetes deletes an application instance, the shutdown process involves several subsystems concurrently: shutdown hooks, unregistering the service, removing the instance from the load-balancer... +Because this shutdown processing happens in parallel (and due to the nature of distributed systems), there is a window during which traffic can be routed to a pod that has also begun its shutdown processing. + +You can configure a sleep execution in a preStop handler to avoid requests being routed to a pod that has already begun shutting down. +This sleep should be long enough for new requests to stop being routed to the pod and its duration will vary from deployment to deployment. +The preStop handler can be configured via the PodSpec in the pod's configuration file as follows: + +[source,yml,indent=0] +---- +spec: + containers: + - name: example-container + image: example-image + lifecycle: + preStop: + exec: + command: ["sh", "-c", "sleep 10"] +---- + +Once the pre-stop hook has completed, SIGTERM will be sent to the container and <> will begin, allowing any remaining in-flight requests to complete. + + + +[[deployment.cloud.heroku]] +=== Heroku +Heroku is another popular PaaS platform. +To customize Heroku builds, you provide a `Procfile`, which provides the incantation required to deploy an application. +Heroku assigns a `port` for the Java application to use and then ensures that routing to the external URI works. + +You must configure your application to listen on the correct port. +The following example shows the `Procfile` for our starter REST application: + +[indent=0] +---- + web: java -Dserver.port=$PORT -jar target/demo-0.0.1-SNAPSHOT.jar +---- + +Spring Boot makes `-D` arguments available as properties accessible from a Spring `Environment` instance. +The `server.port` configuration property is fed to the embedded Tomcat, Jetty, or Undertow instance, which then uses the port when it starts up. +The `$PORT` environment variable is assigned to us by the Heroku PaaS. + +This should be everything you need. +The most common deployment workflow for Heroku deployments is to `git push` the code to production, as shown in the following example: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + $ git push heroku main + + Initializing repository, *done*. + Counting objects: 95, *done*. + Delta compression using up to 8 threads. + Compressing objects: 100% (78/78), *done*. + Writing objects: 100% (95/95), 8.66 MiB | 606.00 KiB/s, *done*. + Total 95 (delta 31), reused 0 (delta 0) + + -----> Java app detected + -----> Installing OpenJDK 1.8... *done* + -----> Installing Maven 3.3.1... *done* + -----> Installing settings.xml... *done* + -----> Executing: mvn -B -DskipTests=true clean install + + [INFO] Scanning for projects... + Downloading: https://repo.spring.io/... + Downloaded: https://repo.spring.io/... (818 B at 1.8 KB/sec) + .... + Downloaded: https://s3pository.heroku.com/jvm/... (152 KB at 595.3 KB/sec) + [INFO] Installing /tmp/build_0c35a5d2-a067-4abc-a232-14b1fb7a8229/target/... + [INFO] Installing /tmp/build_0c35a5d2-a067-4abc-a232-14b1fb7a8229/pom.xml ... + [INFO] ------------------------------------------------------------------------ + [INFO] *BUILD SUCCESS* + [INFO] ------------------------------------------------------------------------ + [INFO] Total time: 59.358s + [INFO] Finished at: Fri Mar 07 07:28:25 UTC 2014 + [INFO] Final Memory: 20M/493M + [INFO] ------------------------------------------------------------------------ + + -----> Discovering process types + Procfile declares types -> *web* + + -----> Compressing... *done*, 70.4MB + -----> Launching... *done*, v6 + https://agile-sierra-1405.herokuapp.com/ *deployed to Heroku* + + To git@heroku.com:agile-sierra-1405.git + * [new branch] main -> main +---- + +Your application should now be up and running on Heroku. +For more details, refer to https://devcenter.heroku.com/articles/deploying-spring-boot-apps-to-heroku[Deploying Spring Boot Applications to Heroku]. + + + +[[deployment.cloud.openshift]] +=== OpenShift +https://www.openshift.com/[OpenShift] has many resources describing how to deploy Spring Boot applications, including: + +* https://blog.openshift.com/using-openshift-enterprise-grade-spring-boot-deployments/[Using the S2I builder] +* https://access.redhat.com/documentation/en-us/reference_architectures/2017/html-single/spring_boot_microservices_on_red_hat_openshift_container_platform_3/[Architecture guide] +* https://blog.openshift.com/using-spring-boot-on-openshift/[Running as a traditional web application on Wildfly] +* https://blog.openshift.com/openshift-commons-briefing-96-cloud-native-applications-spring-rhoar/[OpenShift Commons Briefing] + + + +[[deployment.cloud.aws]] +=== Amazon Web Services (AWS) +Amazon Web Services offers multiple ways to install Spring Boot-based applications, either as traditional web applications (war) or as executable jar files with an embedded web server. +The options include: + +* AWS Elastic Beanstalk +* AWS Code Deploy +* AWS OPS Works +* AWS Cloud Formation +* AWS Container Registry + +Each has different features and pricing models. +In this document, we describe to approach using AWS Elastic Beanstalk. + + + +[[deployment.cloud.aws.beanstalk]] +==== AWS Elastic Beanstalk +As described in the official https://docs.aws.amazon.com/elasticbeanstalk/latest/dg/create_deploy_Java.html[Elastic Beanstalk Java guide], there are two main options to deploy a Java application. +You can either use the "`Tomcat Platform`" or the "`Java SE platform`". + + + +[[deployment.cloud.aws.beanstalk.tomcat-platform]] +===== Using the Tomcat Platform +This option applies to Spring Boot projects that produce a war file. +No special configuration is required. +You need only follow the official guide. + + + +[[deployment.cloud.aws.beanstalk.java-se-platform]] +===== Using the Java SE Platform +This option applies to Spring Boot projects that produce a jar file and run an embedded web container. +Elastic Beanstalk environments run an nginx instance on port 80 to proxy the actual application, running on port 5000. +To configure it, add the following line to your `application.properties` file: + +[indent=0] +---- + server.port=5000 +---- + + +[TIP] +.Upload binaries instead of sources +==== +By default, Elastic Beanstalk uploads sources and compiles them in AWS. +However, it is best to upload the binaries instead. +To do so, add lines similar to the following to your `.elasticbeanstalk/config.yml` file: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + deploy: + artifact: target/demo-0.0.1-SNAPSHOT.jar +---- +==== + +[TIP] +.Reduce costs by setting the environment type +==== +By default an Elastic Beanstalk environment is load balanced. +The load balancer has a significant cost. +To avoid that cost, set the environment type to "`Single instance`", as described in https://docs.aws.amazon.com/elasticbeanstalk/latest/dg/environments-create-wizard.html#environments-create-wizard-capacity[the Amazon documentation]. +You can also create single instance environments by using the CLI and the following command: + +[indent=0] +---- + eb create -s +---- +==== + + + +[[deployment.cloud.aws.summary]] +==== Summary +This is one of the easiest ways to get to AWS, but there are more things to cover, such as how to integrate Elastic Beanstalk into any CI / CD tool, use the Elastic Beanstalk Maven plugin instead of the CLI, and others. +There is a https://exampledriven.wordpress.com/2017/01/09/spring-boot-aws-elastic-beanstalk-example/[blog post] covering these topics more in detail. + + + +[[deployment.cloud.boxfuse]] +=== Boxfuse and Amazon Web Services +https://boxfuse.com/[Boxfuse] works by turning your Spring Boot executable jar or war into a minimal VM image that can be deployed unchanged either on VirtualBox or on AWS. +Boxfuse comes with deep integration for Spring Boot and uses the information from your Spring Boot configuration file to automatically configure ports and health check URLs. +Boxfuse leverages this information both for the images it produces as well as for all the resources it provisions (instances, security groups, elastic load balancers, and so on). + +Once you have created a https://console.boxfuse.com[Boxfuse account], connected it to your AWS account, installed the latest version of the Boxfuse Client, and ensured that the application has been built by Maven or Gradle (by using, for example, `mvn clean package`), you can deploy your Spring Boot application to AWS with a command similar to the following: + +[indent=0] +---- + $ boxfuse run myapp-1.0.jar -env=prod +---- + +See the https://boxfuse.com/docs/commandline/run.html[`boxfuse run` documentation] for more options. +If there is a https://boxfuse.com/docs/commandline/#configuration[`boxfuse.conf`] file present in the current directory, it is considered. + +TIP: By default, Boxfuse activates a Spring profile named `boxfuse` on startup. +If your executable jar or war contains an https://boxfuse.com/docs/payloads/springboot.html#configuration[`application-boxfuse.properties`] file, Boxfuse bases its configuration on the properties it contains. + +At this point, `boxfuse` creates an image for your application, uploads it, and configures and starts the necessary resources on AWS, resulting in output similar to the following example: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + Fusing Image for myapp-1.0.jar ... + Image fused in 00:06.838s (53937 K) -> axelfontaine/myapp:1.0 + Creating axelfontaine/myapp ... + Pushing axelfontaine/myapp:1.0 ... + Verifying axelfontaine/myapp:1.0 ... + Creating Elastic IP ... + Mapping myapp-axelfontaine.boxfuse.io to 52.28.233.167 ... + Waiting for AWS to create an AMI for axelfontaine/myapp:1.0 in eu-central-1 (this may take up to 50 seconds) ... + AMI created in 00:23.557s -> ami-d23f38cf + Creating security group boxfuse-sg_axelfontaine/myapp:1.0 ... + Launching t2.micro instance of axelfontaine/myapp:1.0 (ami-d23f38cf) in eu-central-1 ... + Instance launched in 00:30.306s -> i-92ef9f53 + Waiting for AWS to boot Instance i-92ef9f53 and Payload to start at https://52.28.235.61/ ... + Payload started in 00:29.266s -> https://52.28.235.61/ + Remapping Elastic IP 52.28.233.167 to i-92ef9f53 ... + Waiting 15s for AWS to complete Elastic IP Zero Downtime transition ... + Deployment completed successfully. axelfontaine/myapp:1.0 is up and running at https://myapp-axelfontaine.boxfuse.io/ +---- + +Your application should now be up and running on AWS. + +See the blog post on https://boxfuse.com/blog/spring-boot-ec2.html[deploying Spring Boot apps on EC2] as well as the https://boxfuse.com/docs/payloads/springboot.html[documentation for the Boxfuse Spring Boot integration] to get started with a Maven build to run the app. + + + +[[deployment.cloud.google]] +=== Google Cloud +Google Cloud has several options that can be used to launch Spring Boot applications. +The easiest to get started with is probably App Engine, but you could also find ways to run Spring Boot in a container with Container Engine or on a virtual machine with Compute Engine. + +To run in App Engine, you can create a project in the UI first, which sets up a unique identifier for you and also sets up HTTP routes. +Add a Java app to the project and leave it empty and then use the https://cloud.google.com/sdk/install[Google Cloud SDK] to push your Spring Boot app into that slot from the command line or CI build. + +App Engine Standard requires you to use WAR packaging. +Follow https://github.com/GoogleCloudPlatform/java-docs-samples/tree/master/appengine-java8/springboot-helloworld/README.md[these steps] to deploy App Engine Standard application to Google Cloud. + +Alternatively, App Engine Flex requires you to create an `app.yaml` file to describe the resources your app requires. +Normally, you put this file in `src/main/appengine`, and it should resemble the following file: + +[source,yaml,indent=0] +---- + service: default + + runtime: java + env: flex + + runtime_config: + jdk: openjdk8 + + handlers: + - url: /.* + script: this field is required, but ignored + + manual_scaling: + instances: 1 + + health_check: + enable_health_check: False + + env_variables: + ENCRYPT_KEY: your_encryption_key_here +---- + +You can deploy the app (for example, with a Maven plugin) by adding the project ID to the build configuration, as shown in the following example: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + com.google.cloud.tools + appengine-maven-plugin + 1.3.0 + + myproject + + +---- + +Then deploy with `mvn appengine:deploy` (if you need to authenticate first, the build fails). diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/deployment/containers.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/deployment/containers.adoc new file mode 100644 index 0000000000..be1979f124 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/deployment/containers.adoc @@ -0,0 +1,28 @@ +[[deployment.containers]] +== Deploying to Containers +If you are running your application from a container, you can use an executable jar, but it is also often an advantage to explode it and run it in a different way. +Certain PaaS implementations may also choose to unpack archives before they run. +For example, Cloud Foundry operates this way. +One way to run an unpacked archive is by starting the appropriate launcher, as follows: + +[indent=0] +---- + $ jar -xf myapp.jar + $ java org.springframework.boot.loader.JarLauncher +---- + +This is actually slightly faster on startup (depending on the size of the jar) than running from an unexploded archive. +At runtime you shouldn't expect any differences. + +Once you have unpacked the jar file, you can also get an extra boost to startup time by running the app with its "natural" main method instead of the `JarLauncher`. For example: + +[indent=0] +---- + $ jar -xf myapp.jar + $ java -cp BOOT-INF/classes:BOOT-INF/lib/* com.example.MyApplication +---- + +NOTE: Using the `JarLauncher` over the application's main method has the added benefit of a predictable classpath order. +The jar contains a `classpath.idx` file which is used by the `JarLauncher` when constructing the classpath. + +More efficient container images can also be created by <> for your dependencies and application classes and resources (which normally change more frequently). diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/deployment/installing.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/deployment/installing.adoc new file mode 100644 index 0000000000..96fd61360c --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/deployment/installing.adoc @@ -0,0 +1,389 @@ +[[deployment.installing]] +== Installing Spring Boot Applications +In addition to running Spring Boot applications by using `java -jar`, it is also possible to make fully executable applications for Unix systems. +A fully executable jar can be executed like any other executable binary or it can be <>. +This helps when installing and managing Spring Boot applications in common production environments. + +CAUTION: Fully executable jars work by embedding an extra script at the front of the file. +Currently, some tools do not accept this format, so you may not always be able to use this technique. +For example, `jar -xf` may silently fail to extract a jar or war that has been made fully executable. +It is recommended that you make your jar or war fully executable only if you intend to execute it directly, rather than running it with `java -jar` or deploying it to a servlet container. + +CAUTION: A zip64-format jar file cannot be made fully executable. +Attempting to do so will result in a jar file that is reported as corrupt when executed directly or with `java -jar`. +A standard-format jar file that contains one or more zip64-format nested jars can be fully executable. + +To create a '`fully executable`' jar with Maven, use the following plugin configuration: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + org.springframework.boot + spring-boot-maven-plugin + + true + + +---- + +The following example shows the equivalent Gradle configuration: + +[source,groovy,indent=0,subs="verbatim,quotes,attributes"] +---- + bootJar { + launchScript() + } +---- + +You can then run your application by typing `./my-application.jar` (where `my-application` is the name of your artifact). +The directory containing the jar is used as your application's working directory. + + + +[[deployment.installing.supported-operating-systems]] +=== Supported Operating Systems +The default script supports most Linux distributions and is tested on CentOS and Ubuntu. +Other platforms, such as OS X and FreeBSD, require the use of a custom `embeddedLaunchScript`. + + + +[[deployment.installing.nix-services]] +=== Unix/Linux Services +Spring Boot application can be easily started as Unix/Linux services by using either `init.d` or `systemd`. + + + +[[deployment.installing.nix-services.init-d]] +==== Installation as an init.d Service (System V) +If you configured Spring Boot's Maven or Gradle plugin to generate a <>, and you do not use a custom `embeddedLaunchScript`, your application can be used as an `init.d` service. +To do so, symlink the jar to `init.d` to support the standard `start`, `stop`, `restart`, and `status` commands. + +The script supports the following features: + +* Starts the services as the user that owns the jar file +* Tracks the application's PID by using `/var/run//.pid` +* Writes console logs to `/var/log/.log` + +Assuming that you have a Spring Boot application installed in `/var/myapp`, to install a Spring Boot application as an `init.d` service, create a symlink, as follows: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + $ sudo ln -s /var/myapp/myapp.jar /etc/init.d/myapp +---- + +Once installed, you can start and stop the service in the usual way. +For example, on a Debian-based system, you could start it with the following command: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + $ service myapp start +---- + +TIP: If your application fails to start, check the log file written to `/var/log/.log` for errors. + +You can also flag the application to start automatically by using your standard operating system tools. +For example, on Debian, you could use the following command: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + $ update-rc.d myapp defaults +---- + + + +[[deployment.installing.nix-services.init-d.securing]] +===== Securing an init.d Service +NOTE: The following is a set of guidelines on how to secure a Spring Boot application that runs as an init.d service. +It is not intended to be an exhaustive list of everything that should be done to harden an application and the environment in which it runs. + +When executed as root, as is the case when root is being used to start an init.d service, the default executable script runs the application as the user specified in the `RUN_AS_USER` environment variable. +When the environment variable is not set, the user who owns the jar file is used instead. +You should never run a Spring Boot application as `root`, so `RUN_AS_USER` should never be root and your application's jar file should never be owned by root. +Instead, create a specific user to run your application and set the `RUN_AS_USER` environment variable or use `chown` to make it the owner of the jar file, as shown in the following example: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + $ chown bootapp:bootapp your-app.jar +---- + +In this case, the default executable script runs the application as the `bootapp` user. + +TIP: To reduce the chances of the application's user account being compromised, you should consider preventing it from using a login shell. +For example, you can set the account's shell to `/usr/sbin/nologin`. + +You should also take steps to prevent the modification of your application's jar file. +Firstly, configure its permissions so that it cannot be written and can only be read or executed by its owner, as shown in the following example: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + $ chmod 500 your-app.jar +---- + +Second, you should also take steps to limit the damage if your application or the account that's running it is compromised. +If an attacker does gain access, they could make the jar file writable and change its contents. +One way to protect against this is to make it immutable by using `chattr`, as shown in the following example: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + $ sudo chattr +i your-app.jar +---- + +This will prevent any user, including root, from modifying the jar. + +If root is used to control the application's service and you <> to customize its startup, the `.conf` file is read and evaluated by the root user. +It should be secured accordingly. +Use `chmod` so that the file can only be read by the owner and use `chown` to make root the owner, as shown in the following example: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + $ chmod 400 your-app.conf + $ sudo chown root:root your-app.conf +---- + + + +[[deployment.installing.nix-services.system-d]] +==== Installation as a systemd Service +`systemd` is the successor of the System V init system and is now being used by many modern Linux distributions. +Although you can continue to use `init.d` scripts with `systemd`, it is also possible to launch Spring Boot applications by using `systemd` '`service`' scripts. + +Assuming that you have a Spring Boot application installed in `/var/myapp`, to install a Spring Boot application as a `systemd` service, create a script named `myapp.service` and place it in `/etc/systemd/system` directory. +The following script offers an example: + +[indent=0] +---- + [Unit] + Description=myapp + After=syslog.target + + [Service] + User=myapp + ExecStart=/var/myapp/myapp.jar + SuccessExitStatus=143 + + [Install] + WantedBy=multi-user.target +---- + +IMPORTANT: Remember to change the `Description`, `User`, and `ExecStart` fields for your application. + +NOTE: The `ExecStart` field does not declare the script action command, which means that the `run` command is used by default. + +Note that, unlike when running as an `init.d` service, the user that runs the application, the PID file, and the console log file are managed by `systemd` itself and therefore must be configured by using appropriate fields in the '`service`' script. +Consult the https://www.freedesktop.org/software/systemd/man/systemd.service.html[service unit configuration man page] for more details. + +To flag the application to start automatically on system boot, use the following command: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + $ systemctl enable myapp.service +---- + +Refer to `man systemctl` for more details. + + + +[[deployment.installing.nix-services.script-customization]] +==== Customizing the Startup Script +The default embedded startup script written by the Maven or Gradle plugin can be customized in a number of ways. +For most people, using the default script along with a few customizations is usually enough. +If you find you cannot customize something that you need to, use the `embeddedLaunchScript` option to write your own file entirely. + + + +[[deployment.installing.nix-services.script-customization.when-written]] +===== Customizing the Start Script When It Is Written +It often makes sense to customize elements of the start script as it is written into the jar file. +For example, init.d scripts can provide a "`description`". +Since you know the description up front (and it need not change), you may as well provide it when the jar is generated. + +To customize written elements, use the `embeddedLaunchScriptProperties` option of the Spring Boot Maven plugin or the {spring-boot-gradle-plugin-docs}#packaging-executable-configuring-launch-script[`properties` property of the Spring Boot Gradle plugin's `launchScript`]. + +The following property substitutions are supported with the default script: + +[cols="1,3,3,3"] +|=== +| Name | Description | Gradle default | Maven default + +| `mode` +| The script mode. +| `auto` +| `auto` + +| `initInfoProvides` +| The `Provides` section of "`INIT INFO`" +| `${task.baseName}` +| `${project.artifactId}` + +| `initInfoRequiredStart` +| `Required-Start` section of "`INIT INFO`". +| `$remote_fs $syslog $network` +| `$remote_fs $syslog $network` + +| `initInfoRequiredStop` +| `Required-Stop` section of "`INIT INFO`". +| `$remote_fs $syslog $network` +| `$remote_fs $syslog $network` + +| `initInfoDefaultStart` +| `Default-Start` section of "`INIT INFO`". +| `2 3 4 5` +| `2 3 4 5` + +| `initInfoDefaultStop` +| `Default-Stop` section of "`INIT INFO`". +| `0 1 6` +| `0 1 6` + +| `initInfoShortDescription` +| `Short-Description` section of "`INIT INFO`". +| Single-line version of `${project.description}` (falling back to `${task.baseName}`) +| `${project.name}` + +| `initInfoDescription` +| `Description` section of "`INIT INFO`". +| `${project.description}` (falling back to `${task.baseName}`) +| `${project.description}` (falling back to `${project.name}`) + +| `initInfoChkconfig` +| `chkconfig` section of "`INIT INFO`" +| `2345 99 01` +| `2345 99 01` + +| `confFolder` +| The default value for `CONF_FOLDER` +| Folder containing the jar +| Folder containing the jar + +| `inlinedConfScript` +| Reference to a file script that should be inlined in the default launch script. + This can be used to set environmental variables such as `JAVA_OPTS` before any external config files are loaded +| +| + +| `logFolder` +| Default value for `LOG_FOLDER`. + Only valid for an `init.d` service +| +| + +| `logFilename` +| Default value for `LOG_FILENAME`. + Only valid for an `init.d` service +| +| + +| `pidFolder` +| Default value for `PID_FOLDER`. + Only valid for an `init.d` service +| +| + +| `pidFilename` +| Default value for the name of the PID file in `PID_FOLDER`. + Only valid for an `init.d` service +| +| + +| `useStartStopDaemon` +| Whether the `start-stop-daemon` command, when it's available, should be used to control the process +| `true` +| `true` + +| `stopWaitTime` +| Default value for `STOP_WAIT_TIME` in seconds. + Only valid for an `init.d` service +| 60 +| 60 +|=== + + + +[[deployment.installing.nix-services.script-customization.when-running]] +===== Customizing a Script When It Runs +For items of the script that need to be customized _after_ the jar has been written, you can use environment variables or a <>. + +The following environment properties are supported with the default script: + +[cols="1,6"] +|=== +| Variable | Description + +| `MODE` +| The "`mode`" of operation. + The default depends on the way the jar was built but is usually `auto` (meaning it tries to guess if it is an init script by checking if it is a symlink in a directory called `init.d`). + You can explicitly set it to `service` so that the `stop\|start\|status\|restart` commands work or to `run` if you want to run the script in the foreground. + +| `RUN_AS_USER` +| The user that will be used to run the application. + When not set, the user that owns the jar file will be used. + +| `USE_START_STOP_DAEMON` +| Whether the `start-stop-daemon` command, when it's available, should be used to control the process. + Defaults to `true`. + +| `PID_FOLDER` +| The root name of the pid folder (`/var/run` by default). + +| `LOG_FOLDER` +| The name of the folder in which to put log files (`/var/log` by default). + +| `CONF_FOLDER` +| The name of the folder from which to read .conf files (same folder as jar-file by default). + +| `LOG_FILENAME` +| The name of the log file in the `LOG_FOLDER` (`.log` by default). + +| `APP_NAME` +| The name of the app. + If the jar is run from a symlink, the script guesses the app name. + If it is not a symlink or you want to explicitly set the app name, this can be useful. + +| `RUN_ARGS` +| The arguments to pass to the program (the Spring Boot app). + +| `JAVA_HOME` +| The location of the `java` executable is discovered by using the `PATH` by default, but you can set it explicitly if there is an executable file at `$JAVA_HOME/bin/java`. + +| `JAVA_OPTS` +| Options that are passed to the JVM when it is launched. + +| `JARFILE` +| The explicit location of the jar file, in case the script is being used to launch a jar that it is not actually embedded. + +| `DEBUG` +| If not empty, sets the `-x` flag on the shell process, allowing you to see the logic in the script. + +| `STOP_WAIT_TIME` +| The time in seconds to wait when stopping the application before forcing a shutdown (`60` by default). +|=== + +NOTE: The `PID_FOLDER`, `LOG_FOLDER`, and `LOG_FILENAME` variables are only valid for an `init.d` service. +For `systemd`, the equivalent customizations are made by using the '`service`' script. +See the https://www.freedesktop.org/software/systemd/man/systemd.service.html[service unit configuration man page] for more details. + + + +[[deployment.installing.nix-services.script-customization.when-running.conf-file]] +With the exception of `JARFILE` and `APP_NAME`, the settings listed in the preceding section can be configured by using a `.conf` file. +The file is expected to be next to the jar file and have the same name but suffixed with `.conf` rather than `.jar`. +For example, a jar named `/var/myapp/myapp.jar` uses the configuration file named `/var/myapp/myapp.conf`, as shown in the following example: + +.myapp.conf +[indent=0,subs="verbatim,quotes,attributes"] +---- + JAVA_OPTS=-Xmx1024M + LOG_FOLDER=/custom/log/folder +---- + +TIP: If you do not like having the config file next to the jar file, you can set a `CONF_FOLDER` environment variable to customize the location of the config file. + +To learn about securing this file appropriately, see <>. + + + +[[deployment.installing.windows-services]] +=== Microsoft Windows Services +A Spring Boot application can be started as a Windows service by using https://github.com/kohsuke/winsw[`winsw`]. + +A (https://github.com/snicoll/spring-boot-daemon[separately maintained sample]) describes step-by-step how you can create a Windows service for your Spring Boot application. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/deployment/whats-next.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/deployment/whats-next.adoc new file mode 100644 index 0000000000..f755bb5664 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/deployment/whats-next.adoc @@ -0,0 +1,7 @@ +[[deployment.whats-next]] +== What to Read Next +Check out the https://www.cloudfoundry.org/[Cloud Foundry], https://www.heroku.com/[Heroku], https://www.openshift.com[OpenShift], and https://boxfuse.com[Boxfuse] web sites for more information about the kinds of features that a PaaS can offer. +These are just four of the most popular Java PaaS providers. +Since Spring Boot is so amenable to cloud-based deployment, you can freely consider other providers as well. + +The next section goes on to cover the _<>_, or you can jump ahead to read about _<>_. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation.adoc index aea797e667..bce98f62d0 100644 --- a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation.adoc +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation.adoc @@ -1,107 +1,30 @@ +include::attributes.adoc[] + + + [[documentation]] = Spring Boot Documentation include::attributes.adoc[] + + This section provides a brief overview of Spring Boot reference documentation. It serves as a map for the rest of the document. -[[documentation.about]] -== About the Documentation -The Spring Boot reference guide is available as: +include::documentation/about.adoc[] -* {spring-boot-docs}/html/[Multi-page HTML] -* {spring-boot-docs}/htmlsingle/[Single page HTML] -* {spring-boot-docs}/pdf/spring-boot-reference.pdf[PDF] +include::documentation/getting-help.adoc[] -The latest copy is available at {spring-boot-current-docs}. +include::documentation/upgrading.adoc[] -Copies of this document may be made for your own use and for distribution to others, provided that you do not charge any fee for such copies and further provided that each copy contains this Copyright Notice, whether distributed in print or electronically. +include::documentation/first-steps.adoc[] +include::documentation/using.adoc[] +include::documentation/features.adoc[] -[[documentation.getting-help]] -== Getting Help -If you have trouble with Spring Boot, we would like to help. +include::documentation/actuator.adoc[] -* Try the <>. - They provide solutions to the most common questions. -* Learn the Spring basics. - Spring Boot builds on many other Spring projects. - Check the https://spring.io[spring.io] web-site for a wealth of reference documentation. - If you are starting out with Spring, try one of the https://spring.io/guides[guides]. -* Ask a question. - We monitor https://stackoverflow.com[stackoverflow.com] for questions tagged with https://stackoverflow.com/tags/spring-boot[`spring-boot`]. -* Report bugs with Spring Boot at https://github.com/spring-projects/spring-boot/issues. - -NOTE: All of Spring Boot is open source, including the documentation. -If you find problems with the docs or if you want to improve them, please {spring-boot-code}[get involved]. - - - -[[documentation.upgrading]] -== Upgrading From an Earlier Version -Instructions for how to upgrade from earlier versions of Spring Boot are provided on the project {github-wiki}[wiki]. -Follow the links in the {github-wiki}#release-notes[release notes] section to find the version that you want to upgrade to. - -Upgrading instructions are always the first item in the release notes. -If you are more than one release behind, please make sure that you also review the release notes of the versions that you jumped. - -You should always ensure that you are running a {github-wiki}/Supported-Versions[supported version] of Spring Boot. - - - -[[documentation.first-steps]] -== First Steps -If you are getting started with Spring Boot or 'Spring' in general, start with <>: - -* *From scratch:* <> | <> | <> -* *Tutorial:* <> | <> -* *Running your example:* <> | <> - - - -[[documentation.using]] -== Working with Spring Boot -Ready to actually start using Spring Boot? <>: - -* *Build systems:* <> | <> | <> | <> -* *Best practices:* <> | <> | <> | <> -* *Running your code:* <> | <> | <> | <> -* *Packaging your app:* <> -* *Spring Boot CLI:* <> - - - -[[documentation.features]] -== Learning About Spring Boot Features -Need more details about Spring Boot's core features? -<>: - -* *Core Features:* <> | <> | <> | <> -* *Web Applications:* <> | <> -* *Working with data:* <> | <> -* *Messaging:* <> | <> -* *Testing:* <> | <> | <> -* *Extending:* <> | <> - - - -[[documentation.actuator]] -== Moving to Production -When you are ready to push your Spring Boot application to production, we have <> that you might like: - -* *Management endpoints:* <> -* *Connection options:* <> | <> -* *Monitoring:* <> | <> | <> | <> - - - -[[documentation.advanced]] -== Advanced Topics -Finally, we have a few topics for more advanced users: - -* *Spring Boot Applications Deployment:* <> | <> -* *Build tool plugins:* <> | <> -* *Appendix:* <> | <> | <> | <> | <> | <> +include::documentation/advanced.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation/about.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation/about.adoc new file mode 100644 index 0000000000..8175ceb721 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation/about.adoc @@ -0,0 +1,11 @@ +[[documentation.about]] +== About the Documentation +The Spring Boot reference guide is available as: + +* {spring-boot-docs}/html/[Multi-page HTML] +* {spring-boot-docs}/htmlsingle/[Single page HTML] +* {spring-boot-docs}/pdf/spring-boot-reference.pdf[PDF] + +The latest copy is available at {spring-boot-current-docs}. + +Copies of this document may be made for your own use and for distribution to others, provided that you do not charge any fee for such copies and further provided that each copy contains this Copyright Notice, whether distributed in print or electronically. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation/actuator.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation/actuator.adoc new file mode 100644 index 0000000000..9baf497527 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation/actuator.adoc @@ -0,0 +1,7 @@ +[[documentation.actuator]] +== Moving to Production +When you are ready to push your Spring Boot application to production, we have <> that you might like: + +* *Management endpoints:* <> +* *Connection options:* <> | <> +* *Monitoring:* <> | <> | <> | <> diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation/advanced.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation/advanced.adoc new file mode 100644 index 0000000000..00f0c61aca --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation/advanced.adoc @@ -0,0 +1,7 @@ +[[documentation.advanced]] +== Advanced Topics +Finally, we have a few topics for more advanced users: + +* *Spring Boot Applications Deployment:* <> | <> +* *Build tool plugins:* <> | <> +* *Appendix:* <> | <> | <> | <> | <> | <> diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation/features.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation/features.adoc new file mode 100644 index 0000000000..0e6a8f8657 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation/features.adoc @@ -0,0 +1,11 @@ +[[documentation.features]] +== Learning About Spring Boot Features +Need more details about Spring Boot's core features? +<>: + +* *Core Features:* <> | <> | <> | <> +* *Web Applications:* <> | <> +* *Working with data:* <> | <> +* *Messaging:* <> | <> +* *Testing:* <> | <> | <> +* *Extending:* <> | <> diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation/first-steps.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation/first-steps.adoc new file mode 100644 index 0000000000..fb396ffd34 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation/first-steps.adoc @@ -0,0 +1,7 @@ +[[documentation.first-steps]] +== First Steps +If you are getting started with Spring Boot or 'Spring' in general, start with <>: + +* *From scratch:* <> | <> | <> +* *Tutorial:* <> | <> +* *Running your example:* <> | <> diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation/getting-help.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation/getting-help.adoc new file mode 100644 index 0000000000..5ba7182b64 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation/getting-help.adoc @@ -0,0 +1,16 @@ +[[documentation.getting-help]] +== Getting Help +If you have trouble with Spring Boot, we would like to help. + +* Try the <>. + They provide solutions to the most common questions. +* Learn the Spring basics. + Spring Boot builds on many other Spring projects. + Check the https://spring.io[spring.io] web-site for a wealth of reference documentation. + If you are starting out with Spring, try one of the https://spring.io/guides[guides]. +* Ask a question. + We monitor https://stackoverflow.com[stackoverflow.com] for questions tagged with https://stackoverflow.com/tags/spring-boot[`spring-boot`]. +* Report bugs with Spring Boot at https://github.com/spring-projects/spring-boot/issues. + +NOTE: All of Spring Boot is open source, including the documentation. +If you find problems with the docs or if you want to improve them, please {spring-boot-code}[get involved]. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation/upgrading.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation/upgrading.adoc new file mode 100644 index 0000000000..471205b6ce --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation/upgrading.adoc @@ -0,0 +1,9 @@ +[[documentation.upgrading]] +== Upgrading From an Earlier Version +Instructions for how to upgrade from earlier versions of Spring Boot are provided on the project {github-wiki}[wiki]. +Follow the links in the {github-wiki}#release-notes[release notes] section to find the version that you want to upgrade to. + +Upgrading instructions are always the first item in the release notes. +If you are more than one release behind, please make sure that you also review the release notes of the versions that you jumped. + +You should always ensure that you are running a {github-wiki}/Supported-Versions[supported version] of Spring Boot. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation/using.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation/using.adoc new file mode 100644 index 0000000000..c4c9fe1854 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/documentation/using.adoc @@ -0,0 +1,9 @@ +[[documentation.using]] +== Working with Spring Boot +Ready to actually start using Spring Boot? <>: + +* *Build systems:* <> | <> | <> | <> +* *Best practices:* <> | <> | <> | <> +* *Running your code:* <> | <> | <> | <> +* *Packaging your app:* <> +* *Spring Boot CLI:* <> diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/executable-jar.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/executable-jar.adoc index 69a69adaa9..250a5f41fc 100644 --- a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/executable-jar.adoc +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/executable-jar.adoc @@ -1,8 +1,10 @@ [appendix] -[[appendix.executable-jar]] +[[executable-jar]] = The Executable Jar Format include::attributes.adoc[] + + The `spring-boot-loader` modules lets Spring Boot support executable jar and war files. If you use the Maven plugin or the Gradle plugin, executable jars are automatically generated, and you generally do not need to know the details of how they work. @@ -10,339 +12,14 @@ If you need to create executable jars from a different build system or if you ar -[[appendix.executable-jar.nested-jars]] -== Nested JARs -Java does not provide any standard way to load nested jar files (that is, jar files that are themselves contained within a jar). -This can be problematic if you need to distribute a self-contained application that can be run from the command line without unpacking. +include::executable-jar/nested-jars.adoc[] -To solve this problem, many developers use "`shaded`" jars. -A shaded jar packages all classes, from all jars, into a single "`uber jar`". -The problem with shaded jars is that it becomes hard to see which libraries are actually in your application. -It can also be problematic if the same filename is used (but with different content) in multiple jars. -Spring Boot takes a different approach and lets you actually nest jars directly. +include::executable-jar/jarfile-class.adoc[] +include::executable-jar/launching.adoc[] +include::executable-jar/property-launcher.adoc[] -[[appendix.executable-jar.nested-jars.jar-structure]] -=== The Executable Jar File Structure -Spring Boot Loader-compatible jar files should be structured in the following way: - -[indent=0] ----- - example.jar - | - +-META-INF - | +-MANIFEST.MF - +-org - | +-springframework - | +-boot - | +-loader - | +- - +-BOOT-INF - +-classes - | +-mycompany - | +-project - | +-YourClasses.class - +-lib - +-dependency1.jar - +-dependency2.jar ----- - -Application classes should be placed in a nested `BOOT-INF/classes` directory. -Dependencies should be placed in a nested `BOOT-INF/lib` directory. - - - -[[appendix.executable-jar.nested-jars.war-structure]] -=== The Executable War File Structure -Spring Boot Loader-compatible war files should be structured in the following way: - -[indent=0] ----- - example.war - | - +-META-INF - | +-MANIFEST.MF - +-org - | +-springframework - | +-boot - | +-loader - | +- - +-WEB-INF - +-classes - | +-com - | +-mycompany - | +-project - | +-YourClasses.class - +-lib - | +-dependency1.jar - | +-dependency2.jar - +-lib-provided - +-servlet-api.jar - +-dependency3.jar ----- - -Dependencies should be placed in a nested `WEB-INF/lib` directory. -Any dependencies that are required when running embedded but are not required when deploying to a traditional web container should be placed in `WEB-INF/lib-provided`. - - - -[[appendix.executable-jar.nested-jars.index-files]] -=== Index Files -Spring Boot Loader-compatible jar and war archives can include additional index files under the `BOOT-INF/` directory. -A `classpath.idx` file can be provided for both jars and wars, and it provides the ordering that jars should be added to the classpath. -The `layers.idx` file can be used only for jars, and it allows a jar to be split into logical layers for Docker/OCI image creation. - -Index files follow a YAML compatible syntax so that they can be easily parsed by third-party tools. -These files, however, are _not_ parsed internally as YAML and they must be written in exactly the formats described below in order to be used. - - - -[[appendix.executable-jar.nested-jars.classpath-index]] -=== Classpath Index -The classpath index file can be provided in `BOOT-INF/classpath.idx`. -It provides a list of jar names (including the directory) in the order that they should be added to the classpath. -Each line must start with dash space (`"-·"`) and names must be in double quotes. - -For example, given the following jar: - -[indent=0] ----- - example.jar - | - +-META-INF - | +-... - +-BOOT-INF - +-classes - | +... - +-lib - +-dependency1.jar - +-dependency2.jar ----- - -The index file would look like this: - -[indent=0] ----- - - "BOOT-INF/lib/dependency2.jar" - - "BOOT-INF/lib/dependency1.jar" ----- - - - -[[appendix.executable-jar.nested-jars.layer-index]] -=== Layer Index -The layers index file can be provided in `BOOT-INF/layers.idx`. -It provides a list of layers and the parts of the jar that should be contained within them. -Layers are written in the order that they should be added to the Docker/OCI image. -Layers names are written as quoted strings prefixed with dash space (`"-·"`) and with a colon (`":"`) suffix. -Layer content is either a file or directory name written as a quoted string prefixed by space space dash space (`"··-·"`). -A directory name ends with `/`, a file name does not. -When a directory name is used it means that all files inside that directory are in the same layer. - -A typical example of a layers index would be: - -[indent=0] ----- - - "dependencies": - - "BOOT-INF/lib/dependency1.jar" - - "BOOT-INF/lib/dependency2.jar" - - "application": - - "BOOT-INF/classes/" - - "META-INF/" ----- - - - -[[appendix.executable-jar.jarfile-class]] -== Spring Boot's "`JarFile`" Class -The core class used to support loading nested jars is `org.springframework.boot.loader.jar.JarFile`. -It lets you load jar content from a standard jar file or from nested child jar data. -When first loaded, the location of each `JarEntry` is mapped to a physical file offset of the outer jar, as shown in the following example: - -[indent=0] ----- - myapp.jar - +-------------------+-------------------------+ - | /BOOT-INF/classes | /BOOT-INF/lib/mylib.jar | - |+-----------------+||+-----------+----------+| - || A.class ||| B.class | C.class || - |+-----------------+||+-----------+----------+| - +-------------------+-------------------------+ - ^ ^ ^ - 0063 3452 3980 ----- - -The preceding example shows how `A.class` can be found in `/BOOT-INF/classes` in `myapp.jar` at position `0063`. -`B.class` from the nested jar can actually be found in `myapp.jar` at position `3452`, and `C.class` is at position `3980`. - -Armed with this information, we can load specific nested entries by seeking to the appropriate part of the outer jar. -We do not need to unpack the archive, and we do not need to read all entry data into memory. - - - -[[appendix.executable-jar.jarfile-class.compatibilty]] -=== Compatibility with the Standard Java "`JarFile`" -Spring Boot Loader strives to remain compatible with existing code and libraries. -`org.springframework.boot.loader.jar.JarFile` extends from `java.util.jar.JarFile` and should work as a drop-in replacement. -The `getURL()` method returns a `URL` that opens a connection compatible with `java.net.JarURLConnection` and can be used with Java's `URLClassLoader`. - - - -[[appendix.executable-jar.launching]] -== Launching Executable Jars -The `org.springframework.boot.loader.Launcher` class is a special bootstrap class that is used as an executable jar's main entry point. -It is the actual `Main-Class` in your jar file, and it is used to setup an appropriate `URLClassLoader` and ultimately call your `main()` method. - -There are three launcher subclasses (`JarLauncher`, `WarLauncher`, and `PropertiesLauncher`). -Their purpose is to load resources (`.class` files and so on) from nested jar files or war files in directories (as opposed to those explicitly on the classpath). -In the case of `JarLauncher` and `WarLauncher`, the nested paths are fixed. -`JarLauncher` looks in `BOOT-INF/lib/`, and `WarLauncher` looks in `WEB-INF/lib/` and `WEB-INF/lib-provided/`. -You can add extra jars in those locations if you want more. -The `PropertiesLauncher` looks in `BOOT-INF/lib/` in your application archive by default. -You can add additional locations by setting an environment variable called `LOADER_PATH` or `loader.path` in `loader.properties` (which is a comma-separated list of directories, archives, or directories within archives). - - - -[[appendix.executable-jar.launching.manifest]] -=== Launcher Manifest -You need to specify an appropriate `Launcher` as the `Main-Class` attribute of `META-INF/MANIFEST.MF`. -The actual class that you want to launch (that is, the class that contains a `main` method) should be specified in the `Start-Class` attribute. - -The following example shows a typical `MANIFEST.MF` for an executable jar file: - -[indent=0] ----- - Main-Class: org.springframework.boot.loader.JarLauncher - Start-Class: com.mycompany.project.MyApplication ----- - -For a war file, it would be as follows: - -[indent=0] ----- - Main-Class: org.springframework.boot.loader.WarLauncher - Start-Class: com.mycompany.project.MyApplication ----- - -NOTE: You need not specify `Class-Path` entries in your manifest file. -The classpath is deduced from the nested jars. - - - -[[appendix.executable-jar.property-launcher]] -== PropertiesLauncher Features -`PropertiesLauncher` has a few special features that can be enabled with external properties (System properties, environment variables, manifest entries, or `loader.properties`). -The following table describes these properties: - -|=== -| Key | Purpose - -| `loader.path` -| Comma-separated Classpath, such as `lib,$\{HOME}/app/lib`. - Earlier entries take precedence, like a regular `-classpath` on the `javac` command line. - -| `loader.home` -| Used to resolve relative paths in `loader.path`. - For example, given `loader.path=lib`, then `${loader.home}/lib` is a classpath location (along with all jar files in that directory). - This property is also used to locate a `loader.properties` file, as in the following example `file:///opt/app` It defaults to `${user.dir}`. - -| `loader.args` -| Default arguments for the main method (space separated). - -| `loader.main` -| Name of main class to launch (for example, `com.app.Application`). - -| `loader.config.name` -| Name of properties file (for example, `launcher`). - It defaults to `loader`. - -| `loader.config.location` -| Path to properties file (for example, `classpath:loader.properties`). - It defaults to `loader.properties`. - -| `loader.system` -| Boolean flag to indicate that all properties should be added to System properties. - It defaults to `false`. -|=== - -When specified as environment variables or manifest entries, the following names should be used: - -|=== -| Key | Manifest entry | Environment variable - -| `loader.path` -| `Loader-Path` -| `LOADER_PATH` - -| `loader.home` -| `Loader-Home` -| `LOADER_HOME` - -| `loader.args` -| `Loader-Args` -| `LOADER_ARGS` - -| `loader.main` -| `Start-Class` -| `LOADER_MAIN` - -| `loader.config.location` -| `Loader-Config-Location` -| `LOADER_CONFIG_LOCATION` - -| `loader.system` -| `Loader-System` -| `LOADER_SYSTEM` -|=== - -TIP: Build plugins automatically move the `Main-Class` attribute to `Start-Class` when the fat jar is built. -If you use that, specify the name of the class to launch by using the `Main-Class` attribute and leaving out `Start-Class`. - -The following rules apply to working with `PropertiesLauncher`: - -* `loader.properties` is searched for in `loader.home`, then in the root of the classpath, and then in `classpath:/BOOT-INF/classes`. - The first location where a file with that name exists is used. -* `loader.home` is the directory location of an additional properties file (overriding the default) only when `loader.config.location` is not specified. -* `loader.path` can contain directories (which are scanned recursively for jar and zip files), archive paths, a directory within an archive that is scanned for jar files (for example, `dependencies.jar!/lib`), or wildcard patterns (for the default JVM behavior). - Archive paths can be relative to `loader.home` or anywhere in the file system with a `jar:file:` prefix. -* `loader.path` (if empty) defaults to `BOOT-INF/lib` (meaning a local directory or a nested one if running from an archive). - Because of this, `PropertiesLauncher` behaves the same as `JarLauncher` when no additional configuration is provided. -* `loader.path` can not be used to configure the location of `loader.properties` (the classpath used to search for the latter is the JVM classpath when `PropertiesLauncher` is launched). -* Placeholder replacement is done from System and environment variables plus the properties file itself on all values before use. -* The search order for properties (where it makes sense to look in more than one place) is environment variables, system properties, `loader.properties`, the exploded archive manifest, and the archive manifest. - - - -[[appendix.executable-jar.restrictions]] -== Executable Jar Restrictions -You need to consider the following restrictions when working with a Spring Boot Loader packaged application: - - - -[[appendix.executable-jar-zip-entry-compression]] -* Zip entry compression: -The `ZipEntry` for a nested jar must be saved by using the `ZipEntry.STORED` method. -This is required so that we can seek directly to individual content within the nested jar. -The content of the nested jar file itself can still be compressed, as can any other entries in the outer jar. - - - -[[appendix.executable-jar-system-classloader]] -* System classLoader: -Launched applications should use `Thread.getContextClassLoader()` when loading classes (most libraries and frameworks do so by default). -Trying to load nested jar classes with `ClassLoader.getSystemClassLoader()` fails. -`java.util.Logging` always uses the system classloader. -For this reason, you should consider a different logging implementation. - - - -[[appendix.executable-jar.alternatives]] -== Alternative Single Jar Solutions -If the preceding restrictions mean that you cannot use Spring Boot Loader, consider the following alternatives: - -* https://maven.apache.org/plugins/maven-shade-plugin/[Maven Shade Plugin] -* http://www.jdotsoft.com/JarClassLoader.php[JarClassLoader] -* https://sourceforge.net/projects/one-jar/[OneJar] -* https://imperceptiblethoughts.com/shadow/[Gradle Shadow Plugin] +include::executable-jar/restrictions.adoc[] +include::executable-jar/alternatives.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/executable-jar/alternatives.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/executable-jar/alternatives.adoc new file mode 100644 index 0000000000..8acf587fc5 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/executable-jar/alternatives.adoc @@ -0,0 +1,9 @@ +[[executable-jar.alternatives]] +== Alternative Single Jar Solutions +If the preceding restrictions mean that you cannot use Spring Boot Loader, consider the following alternatives: + +* https://maven.apache.org/plugins/maven-shade-plugin/[Maven Shade Plugin] +* http://www.jdotsoft.com/JarClassLoader.php[JarClassLoader] +* https://sourceforge.net/projects/one-jar/[OneJar] +* https://imperceptiblethoughts.com/shadow/[Gradle Shadow Plugin] + diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/executable-jar/jarfile-class.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/executable-jar/jarfile-class.adoc new file mode 100644 index 0000000000..b66ace993b --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/executable-jar/jarfile-class.adoc @@ -0,0 +1,32 @@ +[[executable-jar.jarfile-class]] +== Spring Boot's "`JarFile`" Class +The core class used to support loading nested jars is `org.springframework.boot.loader.jar.JarFile`. +It lets you load jar content from a standard jar file or from nested child jar data. +When first loaded, the location of each `JarEntry` is mapped to a physical file offset of the outer jar, as shown in the following example: + +[indent=0] +---- + myapp.jar + +-------------------+-------------------------+ + | /BOOT-INF/classes | /BOOT-INF/lib/mylib.jar | + |+-----------------+||+-----------+----------+| + || A.class ||| B.class | C.class || + |+-----------------+||+-----------+----------+| + +-------------------+-------------------------+ + ^ ^ ^ + 0063 3452 3980 +---- + +The preceding example shows how `A.class` can be found in `/BOOT-INF/classes` in `myapp.jar` at position `0063`. +`B.class` from the nested jar can actually be found in `myapp.jar` at position `3452`, and `C.class` is at position `3980`. + +Armed with this information, we can load specific nested entries by seeking to the appropriate part of the outer jar. +We do not need to unpack the archive, and we do not need to read all entry data into memory. + + + +[[executable-jar.jarfile-class.compatibilty]] +=== Compatibility with the Standard Java "`JarFile`" +Spring Boot Loader strives to remain compatible with existing code and libraries. +`org.springframework.boot.loader.jar.JarFile` extends from `java.util.jar.JarFile` and should work as a drop-in replacement. +The `getURL()` method returns a `URL` that opens a connection compatible with `java.net.JarURLConnection` and can be used with Java's `URLClassLoader`. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/executable-jar/launching.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/executable-jar/launching.adoc new file mode 100644 index 0000000000..92c280dbda --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/executable-jar/launching.adoc @@ -0,0 +1,38 @@ +[[executable-jar.launching]] +== Launching Executable Jars +The `org.springframework.boot.loader.Launcher` class is a special bootstrap class that is used as an executable jar's main entry point. +It is the actual `Main-Class` in your jar file, and it is used to setup an appropriate `URLClassLoader` and ultimately call your `main()` method. + +There are three launcher subclasses (`JarLauncher`, `WarLauncher`, and `PropertiesLauncher`). +Their purpose is to load resources (`.class` files and so on) from nested jar files or war files in directories (as opposed to those explicitly on the classpath). +In the case of `JarLauncher` and `WarLauncher`, the nested paths are fixed. +`JarLauncher` looks in `BOOT-INF/lib/`, and `WarLauncher` looks in `WEB-INF/lib/` and `WEB-INF/lib-provided/`. +You can add extra jars in those locations if you want more. +The `PropertiesLauncher` looks in `BOOT-INF/lib/` in your application archive by default. +You can add additional locations by setting an environment variable called `LOADER_PATH` or `loader.path` in `loader.properties` (which is a comma-separated list of directories, archives, or directories within archives). + + + +[[executable-jar.launching.manifest]] +=== Launcher Manifest +You need to specify an appropriate `Launcher` as the `Main-Class` attribute of `META-INF/MANIFEST.MF`. +The actual class that you want to launch (that is, the class that contains a `main` method) should be specified in the `Start-Class` attribute. + +The following example shows a typical `MANIFEST.MF` for an executable jar file: + +[indent=0] +---- + Main-Class: org.springframework.boot.loader.JarLauncher + Start-Class: com.mycompany.project.MyApplication +---- + +For a war file, it would be as follows: + +[indent=0] +---- + Main-Class: org.springframework.boot.loader.WarLauncher + Start-Class: com.mycompany.project.MyApplication +---- + +NOTE: You need not specify `Class-Path` entries in your manifest file. +The classpath is deduced from the nested jars. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/executable-jar/nested-jars.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/executable-jar/nested-jars.adoc new file mode 100644 index 0000000000..4fdd68ab2d --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/executable-jar/nested-jars.adoc @@ -0,0 +1,141 @@ +[[executable-jar.nested-jars]] +== Nested JARs +Java does not provide any standard way to load nested jar files (that is, jar files that are themselves contained within a jar). +This can be problematic if you need to distribute a self-contained application that can be run from the command line without unpacking. + +To solve this problem, many developers use "`shaded`" jars. +A shaded jar packages all classes, from all jars, into a single "`uber jar`". +The problem with shaded jars is that it becomes hard to see which libraries are actually in your application. +It can also be problematic if the same filename is used (but with different content) in multiple jars. +Spring Boot takes a different approach and lets you actually nest jars directly. + + + +[[executable-jar.nested-jars.jar-structure]] +=== The Executable Jar File Structure +Spring Boot Loader-compatible jar files should be structured in the following way: + +[indent=0] +---- + example.jar + | + +-META-INF + | +-MANIFEST.MF + +-org + | +-springframework + | +-boot + | +-loader + | +- + +-BOOT-INF + +-classes + | +-mycompany + | +-project + | +-YourClasses.class + +-lib + +-dependency1.jar + +-dependency2.jar +---- + +Application classes should be placed in a nested `BOOT-INF/classes` directory. +Dependencies should be placed in a nested `BOOT-INF/lib` directory. + + + +[[executable-jar.nested-jars.war-structure]] +=== The Executable War File Structure +Spring Boot Loader-compatible war files should be structured in the following way: + +[indent=0] +---- + example.war + | + +-META-INF + | +-MANIFEST.MF + +-org + | +-springframework + | +-boot + | +-loader + | +- + +-WEB-INF + +-classes + | +-com + | +-mycompany + | +-project + | +-YourClasses.class + +-lib + | +-dependency1.jar + | +-dependency2.jar + +-lib-provided + +-servlet-api.jar + +-dependency3.jar +---- + +Dependencies should be placed in a nested `WEB-INF/lib` directory. +Any dependencies that are required when running embedded but are not required when deploying to a traditional web container should be placed in `WEB-INF/lib-provided`. + + + +[[executable-jar.nested-jars.index-files]] +=== Index Files +Spring Boot Loader-compatible jar and war archives can include additional index files under the `BOOT-INF/` directory. +A `classpath.idx` file can be provided for both jars and wars, and it provides the ordering that jars should be added to the classpath. +The `layers.idx` file can be used only for jars, and it allows a jar to be split into logical layers for Docker/OCI image creation. + +Index files follow a YAML compatible syntax so that they can be easily parsed by third-party tools. +These files, however, are _not_ parsed internally as YAML and they must be written in exactly the formats described below in order to be used. + + + +[[executable-jar.nested-jars.classpath-index]] +=== Classpath Index +The classpath index file can be provided in `BOOT-INF/classpath.idx`. +It provides a list of jar names (including the directory) in the order that they should be added to the classpath. +Each line must start with dash space (`"-·"`) and names must be in double quotes. + +For example, given the following jar: + +[indent=0] +---- + example.jar + | + +-META-INF + | +-... + +-BOOT-INF + +-classes + | +... + +-lib + +-dependency1.jar + +-dependency2.jar +---- + +The index file would look like this: + +[indent=0] +---- + - "BOOT-INF/lib/dependency2.jar" + - "BOOT-INF/lib/dependency1.jar" +---- + + + +[[executable-jar.nested-jars.layer-index]] +=== Layer Index +The layers index file can be provided in `BOOT-INF/layers.idx`. +It provides a list of layers and the parts of the jar that should be contained within them. +Layers are written in the order that they should be added to the Docker/OCI image. +Layers names are written as quoted strings prefixed with dash space (`"-·"`) and with a colon (`":"`) suffix. +Layer content is either a file or directory name written as a quoted string prefixed by space space dash space (`"··-·"`). +A directory name ends with `/`, a file name does not. +When a directory name is used it means that all files inside that directory are in the same layer. + +A typical example of a layers index would be: + +[indent=0] +---- + - "dependencies": + - "BOOT-INF/lib/dependency1.jar" + - "BOOT-INF/lib/dependency2.jar" + - "application": + - "BOOT-INF/classes/" + - "META-INF/" +---- diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/executable-jar/property-launcher.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/executable-jar/property-launcher.adoc new file mode 100644 index 0000000000..e3f3dbdd02 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/executable-jar/property-launcher.adoc @@ -0,0 +1,81 @@ +[[executable-jar.property-launcher]] +== PropertiesLauncher Features +`PropertiesLauncher` has a few special features that can be enabled with external properties (System properties, environment variables, manifest entries, or `loader.properties`). +The following table describes these properties: + +|=== +| Key | Purpose + +| `loader.path` +| Comma-separated Classpath, such as `lib,$\{HOME}/app/lib`. + Earlier entries take precedence, like a regular `-classpath` on the `javac` command line. + +| `loader.home` +| Used to resolve relative paths in `loader.path`. + For example, given `loader.path=lib`, then `${loader.home}/lib` is a classpath location (along with all jar files in that directory). + This property is also used to locate a `loader.properties` file, as in the following example `file:///opt/app` It defaults to `${user.dir}`. + +| `loader.args` +| Default arguments for the main method (space separated). + +| `loader.main` +| Name of main class to launch (for example, `com.app.Application`). + +| `loader.config.name` +| Name of properties file (for example, `launcher`). + It defaults to `loader`. + +| `loader.config.location` +| Path to properties file (for example, `classpath:loader.properties`). + It defaults to `loader.properties`. + +| `loader.system` +| Boolean flag to indicate that all properties should be added to System properties. + It defaults to `false`. +|=== + +When specified as environment variables or manifest entries, the following names should be used: + +|=== +| Key | Manifest entry | Environment variable + +| `loader.path` +| `Loader-Path` +| `LOADER_PATH` + +| `loader.home` +| `Loader-Home` +| `LOADER_HOME` + +| `loader.args` +| `Loader-Args` +| `LOADER_ARGS` + +| `loader.main` +| `Start-Class` +| `LOADER_MAIN` + +| `loader.config.location` +| `Loader-Config-Location` +| `LOADER_CONFIG_LOCATION` + +| `loader.system` +| `Loader-System` +| `LOADER_SYSTEM` +|=== + +TIP: Build plugins automatically move the `Main-Class` attribute to `Start-Class` when the fat jar is built. +If you use that, specify the name of the class to launch by using the `Main-Class` attribute and leaving out `Start-Class`. + +The following rules apply to working with `PropertiesLauncher`: + +* `loader.properties` is searched for in `loader.home`, then in the root of the classpath, and then in `classpath:/BOOT-INF/classes`. + The first location where a file with that name exists is used. +* `loader.home` is the directory location of an additional properties file (overriding the default) only when `loader.config.location` is not specified. +* `loader.path` can contain directories (which are scanned recursively for jar and zip files), archive paths, a directory within an archive that is scanned for jar files (for example, `dependencies.jar!/lib`), or wildcard patterns (for the default JVM behavior). + Archive paths can be relative to `loader.home` or anywhere in the file system with a `jar:file:` prefix. +* `loader.path` (if empty) defaults to `BOOT-INF/lib` (meaning a local directory or a nested one if running from an archive). + Because of this, `PropertiesLauncher` behaves the same as `JarLauncher` when no additional configuration is provided. +* `loader.path` can not be used to configure the location of `loader.properties` (the classpath used to search for the latter is the JVM classpath when `PropertiesLauncher` is launched). +* Placeholder replacement is done from System and environment variables plus the properties file itself on all values before use. +* The search order for properties (where it makes sense to look in more than one place) is environment variables, system properties, `loader.properties`, the exploded archive manifest, and the archive manifest. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/executable-jar/restrictions.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/executable-jar/restrictions.adoc new file mode 100644 index 0000000000..f1be108422 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/executable-jar/restrictions.adoc @@ -0,0 +1,20 @@ +[[executable-jar.restrictions]] +== Executable Jar Restrictions +You need to consider the following restrictions when working with a Spring Boot Loader packaged application: + + + +[[executable-jar-zip-entry-compression]] +* Zip entry compression: +The `ZipEntry` for a nested jar must be saved by using the `ZipEntry.STORED` method. +This is required so that we can seek directly to individual content within the nested jar. +The content of the nested jar file itself can still be compressed, as can any other entries in the outer jar. + + + +[[executable-jar-system-classloader]] +* System classLoader: +Launched applications should use `Thread.getContextClassLoader()` when loading classes (most libraries and frameworks do so by default). +Trying to load nested jar classes with `ClassLoader.getSystemClassLoader()` fails. +`java.util.Logging` always uses the system classloader. +For this reason, you should consider a different logging implementation. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features.adoc index da1fcd9e5c..6d60adc5e5 100644 --- a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features.adoc +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features.adoc @@ -2,7664 +2,74 @@ = Spring Boot Features include::attributes.adoc[] + + This section dives into the details of Spring Boot. Here you can learn about the key features that you may want to use and customize. -If you have not already done so, you might want to read the "<>" and "<>" sections, so that you have a good grounding of the basics. +If you have not already done so, you might want to read the "<>" and "<>" sections, so that you have a good grounding of the basics. -[[features.spring-application]] -== SpringApplication -The `SpringApplication` class provides a convenient way to bootstrap a Spring application that is started from a `main()` method. -In many situations, you can delegate to the static `SpringApplication.run` method, as shown in the following example: +include::features/spring-application.adoc[] -[source,java,indent=0] ----- -include::{include-springbootfeatures}/springapplication/main/run/MyApplication.java[] ----- +include::features/external-config.adoc[] -When your application starts, you should see something similar to the following output: +include::features/profiles.adoc[] -[indent=0,subs="attributes"] ----- - . ____ _ __ _ _ - /\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \ -( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \ - \\/ ___)| |_)| | | | | || (_| | ) ) ) ) - ' |____| .__|_| |_|_| |_\__, | / / / / - =========|_|==============|___/=/_/_/_/ - :: Spring Boot :: v{spring-boot-version} +include::features/logging.adoc[] -2021-02-03 10:33:25.224 INFO 17321 --- [ main] o.s.b.d.s.s.SpringAppplicationExample : Starting SpringAppplicationExample using Java 1.8.0_232 on mycomputer with PID 17321 (/apps/myjar.jar started by pwebb) -2021-02-03 10:33:25.226 INFO 17900 --- [ main] o.s.b.d.s.s.SpringAppplicationExample : No active profile set, falling back to default profiles: default -2021-02-03 10:33:26.046 INFO 17321 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http) -2021-02-03 10:33:26.054 INFO 17900 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat] -2021-02-03 10:33:26.055 INFO 17900 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/9.0.41] -2021-02-03 10:33:26.097 INFO 17900 --- [ main] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext -2021-02-03 10:33:26.097 INFO 17900 --- [ main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 821 ms -2021-02-03 10:33:26.144 INFO 17900 --- [ main] s.tomcat.SampleTomcatApplication : ServletContext initialized -2021-02-03 10:33:26.376 INFO 17900 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path '' -2021-02-03 10:33:26.384 INFO 17900 --- [ main] o.s.b.d.s.s.SpringAppplicationExample : Started SampleTomcatApplication in 1.514 seconds (JVM running for 1.823) ----- +include::features/internationalization.adoc[] +include::features/json.adoc[] +include::features/developing-web-applications.adoc[] -By default, `INFO` logging messages are shown, including some relevant startup details, such as the user that launched the application. -If you need a log level other than `INFO`, you can set it, as described in <>. -The application version is determined using the implementation version from the main application class's package. -Startup information logging can be turned off by setting `spring.main.log-startup-info` to `false`. -This will also turn off logging of the application's active profiles. +include::features/graceful-shutdown.adoc[] -TIP: To add additional logging during startup, you can override `logStartupInfo(boolean)` in a subclass of `SpringApplication`. +include::features/rsocket.adoc[] +include::features/security.adoc[] +include::features/sql.adoc[] -[[features.spring-application.startup-failure]] -=== Startup Failure -If your application fails to start, registered `FailureAnalyzers` get a chance to provide a dedicated error message and a concrete action to fix the problem. -For instance, if you start a web application on port `8080` and that port is already in use, you should see something similar to the following message: +include::features/nosql.adoc[] -[indent=0] ----- - *************************** - APPLICATION FAILED TO START - *************************** +include::features/caching.adoc[] - Description: +include::features/messaging.adoc[] - Embedded servlet container failed to start. Port 8080 was already in use. +include::features/resttemplate.adoc[] - Action: +include::features/webclient.adoc[] - Identify and stop the process that's listening on port 8080 or configure this application to listen on another port. ----- +include::features/validation.adoc[] -NOTE: Spring Boot provides numerous `FailureAnalyzer` implementations, and you can <>. +include::features/email.adoc[] -If no failure analyzers are able to handle the exception, you can still display the full conditions report to better understand what went wrong. -To do so, you need to <> or <> for `org.springframework.boot.autoconfigure.logging.ConditionEvaluationReportLoggingListener`. +include::features/jta.adoc[] -For instance, if you are running your application by using `java -jar`, you can enable the `debug` property as follows: +include::features/hazelcast.adoc[] -[indent=0,subs="attributes"] ----- - $ java -jar myproject-0.0.1-SNAPSHOT.jar --debug ----- +include::features/quartz.adoc[] +include::features/task-execution-and-scheduling.adoc[] +include::features/spring-integration.adoc[] -[[features.spring-application.lazy-initialization]] -=== Lazy Initialization -`SpringApplication` allows an application to be initialized lazily. -When lazy initialization is enabled, beans are created as they are needed rather than during application startup. -As a result, enabling lazy initialization can reduce the time that it takes your application to start. -In a web application, enabling lazy initialization will result in many web-related beans not being initialized until an HTTP request is received. +include::features/spring-session.adoc[] -A downside of lazy initialization is that it can delay the discovery of a problem with the application. -If a misconfigured bean is initialized lazily, a failure will no longer occur during startup and the problem will only become apparent when the bean is initialized. -Care must also be taken to ensure that the JVM has sufficient memory to accommodate all of the application's beans and not just those that are initialized during startup. -For these reasons, lazy initialization is not enabled by default and it is recommended that fine-tuning of the JVM's heap size is done before enabling lazy initialization. +include::features/jmx.adoc[] -Lazy initialization can be enabled programmatically using the `lazyInitialization` method on `SpringApplicationBuilder` or the `setLazyInitialization` method on `SpringApplication`. -Alternatively, it can be enabled using the configprop:spring.main.lazy-initialization[] property as shown in the following example: +include::features/testing.adoc[] -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - main: - lazy-initialization: true ----- +include::features/websockets.adoc[] -TIP: If you want to disable lazy initialization for certain beans while using lazy initialization for the rest of the application, you can explicitly set their lazy attribute to false using the `@Lazy(false)` annotation. +include::features/webservices.adoc[] +include::features/developing-auto-configuration.adoc[] +include::features/kotlin.adoc[] -[[features.spring-application.banner]] -=== Customizing the Banner -The banner that is printed on start up can be changed by adding a `banner.txt` file to your classpath or by setting the configprop:spring.banner.location[] property to the location of such a file. -If the file has an encoding other than UTF-8, you can set `spring.banner.charset`. -In addition to a text file, you can also add a `banner.gif`, `banner.jpg`, or `banner.png` image file to your classpath or set the configprop:spring.banner.image.location[] property. -Images are converted into an ASCII art representation and printed above any text banner. +include::features/container-images.adoc[] -Inside your `banner.txt` file, you can use any of the following placeholders: - -.Banner variables -|=== -| Variable | Description - -| `${application.version}` -| The version number of your application, as declared in `MANIFEST.MF`. - For example, `Implementation-Version: 1.0` is printed as `1.0`. - -| `${application.formatted-version}` -| The version number of your application, as declared in `MANIFEST.MF` and formatted for display (surrounded with brackets and prefixed with `v`). - For example `(v1.0)`. - -| `${spring-boot.version}` -| The Spring Boot version that you are using. - For example `{spring-boot-version}`. - -| `${spring-boot.formatted-version}` -| The Spring Boot version that you are using, formatted for display (surrounded with brackets and prefixed with `v`). - For example `(v{spring-boot-version})`. - -| `${Ansi.NAME}` (or `${AnsiColor.NAME}`, `${AnsiBackground.NAME}`, `${AnsiStyle.NAME}`) -| Where `NAME` is the name of an ANSI escape code. - See {spring-boot-module-code}/ansi/AnsiPropertySource.java[`AnsiPropertySource`] for details. - -| `${application.title}` -| The title of your application, as declared in `MANIFEST.MF`. - For example `Implementation-Title: MyApp` is printed as `MyApp`. -|=== - -TIP: The `SpringApplication.setBanner(...)` method can be used if you want to generate a banner programmatically. -Use the `org.springframework.boot.Banner` interface and implement your own `printBanner()` method. - -You can also use the configprop:spring.main.banner-mode[] property to determine if the banner has to be printed on `System.out` (`console`), sent to the configured logger (`log`), or not produced at all (`off`). - -The printed banner is registered as a singleton bean under the following name: `springBootBanner`. - -[NOTE] -==== -The `${application.version}` and `${application.formatted-version}` properties are only available if you are using Spring Boot launchers. -The values won't be resolved if you are running an unpacked jar and starting it with `java -cp `. - -This is why we recommend that you always launch unpacked jars using `java org.springframework.boot.loader.JarLauncher`. -This will initialize the `application.*` banner variables before building the classpath and launching your app. -==== - - - -[[features.spring-application.customizing-spring-application]] -=== Customizing SpringApplication -If the `SpringApplication` defaults are not to your taste, you can instead create a local instance and customize it. -For example, to turn off the banner, you could write: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/springapplication/main/custom/MyApplication.java[] ----- - -NOTE: The constructor arguments passed to `SpringApplication` are configuration sources for Spring beans. -In most cases, these are references to `@Configuration` classes, but they could also be references to XML configuration or to packages that should be scanned. - -It is also possible to configure the `SpringApplication` by using an `application.properties` file. -See _<>_ for details. - -For a complete list of the configuration options, see the {spring-boot-module-api}/SpringApplication.html[`SpringApplication` Javadoc]. - - - -[[features.spring-application.fluent-builder-api]] -=== Fluent Builder API -If you need to build an `ApplicationContext` hierarchy (multiple contexts with a parent/child relationship) or if you prefer using a "`fluent`" builder API, you can use the `SpringApplicationBuilder`. - -The `SpringApplicationBuilder` lets you chain together multiple method calls and includes `parent` and `child` methods that let you create a hierarchy, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/springapplication/SpringApplicationBuilderExample.java[tag=*] ----- - -NOTE: There are some restrictions when creating an `ApplicationContext` hierarchy. -For example, Web components *must* be contained within the child context, and the same `Environment` is used for both parent and child contexts. -See the {spring-boot-module-api}/builder/SpringApplicationBuilder.html[`SpringApplicationBuilder` Javadoc] for full details. - - - -[[features.spring-application.application-availability]] -=== Application Availability -When deployed on platforms, applications can provide information about their availability to the platform using infrastructure such as https://kubernetes.io/docs/tasks/configure-pod-container/configure-liveness-readiness-startup-probes/[Kubernetes Probes]. -Spring Boot includes out-of-the box support for the commonly used "`liveness`" and "`readiness`" availability states. -If you are using Spring Boot's "`actuator`" support then these states are exposed as health endpoint groups. - -In addition, you can also obtain availability states by injecting the `ApplicationAvailability` interface into your own beans. - - - -[[features.spring-application.application-availability.liveness]] -==== Liveness State -The "`Liveness`" state of an application tells whether its internal state allows it to work correctly, or recover by itself if it's currently failing. -A broken "`Liveness`" state means that the application is in a state that it cannot recover from, and the infrastructure should restart the application. - -NOTE: In general, the "Liveness" state should not be based on external checks, such as <>. -If it did, a failing external system (a database, a Web API, an external cache) would trigger massive restarts and cascading failures across the platform. - -The internal state of Spring Boot applications is mostly represented by the Spring `ApplicationContext`. -If the application context has started successfully, Spring Boot assumes that the application is in a valid state. -An application is considered live as soon as the context has been refreshed, see <>. - - - -[[features.spring-application.application-availability.readiness]] -==== Readiness State -The "`Readiness`" state of an application tells whether the application is ready to handle traffic. -A failing "`Readiness`" state tells the platform that it should not route traffic to the application for now. -This typically happens during startup, while `CommandLineRunner` and `ApplicationRunner` components are being processed, or at any time if the application decides that it's too busy for additional traffic. - -An application is considered ready as soon as application and command-line runners have been called, see <>. - -TIP: Tasks expected to run during startup should be executed by `CommandLineRunner` and `ApplicationRunner` components instead of using Spring component lifecycle callbacks such as `@PostConstruct`. - - - -[[features.spring-application.application-availability.managing]] -==== Managing the Application Availability State -Application components can retrieve the current availability state at any time, by injecting the `ApplicationAvailability` interface and calling methods on it. -More often, applications will want to listen to state updates or update the state of the application. - -For example, we can export the "Readiness" state of the application to a file so that a Kubernetes "exec Probe" can look at this file: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/springapplication/availability/ReadinessStateExporter.java[] ----- - -We can also update the state of the application, when the application breaks and cannot recover: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/springapplication/availability/LocalCacheVerifier.java[] ----- - -Spring Boot provides <>. -You can get more guidance about <>. - - - -[[features.spring-application.application-events-and-listeners]] -=== Application Events and Listeners -In addition to the usual Spring Framework events, such as {spring-framework-api}/context/event/ContextRefreshedEvent.html[`ContextRefreshedEvent`], a `SpringApplication` sends some additional application events. - -[NOTE] -==== -Some events are actually triggered before the `ApplicationContext` is created, so you cannot register a listener on those as a `@Bean`. -You can register them with the `SpringApplication.addListeners(...)` method or the `SpringApplicationBuilder.listeners(...)` method. - -If you want those listeners to be registered automatically, regardless of the way the application is created, you can add a `META-INF/spring.factories` file to your project and reference your listener(s) by using the `org.springframework.context.ApplicationListener` key, as shown in the following example: - -[indent=0] ----- - org.springframework.context.ApplicationListener=com.example.project.MyListener ----- - -==== - -Application events are sent in the following order, as your application runs: - -. An `ApplicationStartingEvent` is sent at the start of a run but before any processing, except for the registration of listeners and initializers. -. An `ApplicationEnvironmentPreparedEvent` is sent when the `Environment` to be used in the context is known but before the context is created. -. An `ApplicationContextInitializedEvent` is sent when the `ApplicationContext` is prepared and ApplicationContextInitializers have been called but before any bean definitions are loaded. -. An `ApplicationPreparedEvent` is sent just before the refresh is started but after bean definitions have been loaded. -. An `ApplicationStartedEvent` is sent after the context has been refreshed but before any application and command-line runners have been called. -. An `AvailabilityChangeEvent` is sent right after with `LivenessState.CORRECT` to indicate that the application is considered as live. -. An `ApplicationReadyEvent` is sent after any <> have been called. -. An `AvailabilityChangeEvent` is sent right after with `ReadinessState.ACCEPTING_TRAFFIC` to indicate that the application is ready to service requests. -. An `ApplicationFailedEvent` is sent if there is an exception on startup. - -The above list only includes ``SpringApplicationEvent``s that are tied to a `SpringApplication`. -In addition to these, the following events are also published after `ApplicationPreparedEvent` and before `ApplicationStartedEvent`: - -- A `WebServerInitializedEvent` is sent after the `WebServer` is ready. - `ServletWebServerInitializedEvent` and `ReactiveWebServerInitializedEvent` are the servlet and reactive variants respectively. -- A `ContextRefreshedEvent` is sent when an `ApplicationContext` is refreshed. - -TIP: You often need not use application events, but it can be handy to know that they exist. -Internally, Spring Boot uses events to handle a variety of tasks. - -NOTE: Event listeners should not run potentially lengthy tasks as they execute in the same thread by default. -Consider using <> instead. - -Application events are sent by using Spring Framework's event publishing mechanism. -Part of this mechanism ensures that an event published to the listeners in a child context is also published to the listeners in any ancestor contexts. -As a result of this, if your application uses a hierarchy of `SpringApplication` instances, a listener may receive multiple instances of the same type of application event. - -To allow your listener to distinguish between an event for its context and an event for a descendant context, it should request that its application context is injected and then compare the injected context with the context of the event. -The context can be injected by implementing `ApplicationContextAware` or, if the listener is a bean, by using `@Autowired`. - - - -[[features.spring-application.web-environment]] -=== Web Environment -A `SpringApplication` attempts to create the right type of `ApplicationContext` on your behalf. -The algorithm used to determine a `WebApplicationType` is the following: - -* If Spring MVC is present, an `AnnotationConfigServletWebServerApplicationContext` is used -* If Spring MVC is not present and Spring WebFlux is present, an `AnnotationConfigReactiveWebServerApplicationContext` is used -* Otherwise, `AnnotationConfigApplicationContext` is used - -This means that if you are using Spring MVC and the new `WebClient` from Spring WebFlux in the same application, Spring MVC will be used by default. -You can override that easily by calling `setWebApplicationType(WebApplicationType)`. - -It is also possible to take complete control of the `ApplicationContext` type that is used by calling `setApplicationContextClass(...)`. - -TIP: It is often desirable to call `setWebApplicationType(WebApplicationType.NONE)` when using `SpringApplication` within a JUnit test. - - - -[[features.spring-application.application-arguments]] -=== Accessing Application Arguments -If you need to access the application arguments that were passed to `SpringApplication.run(...)`, you can inject a `org.springframework.boot.ApplicationArguments` bean. -The `ApplicationArguments` interface provides access to both the raw `String[]` arguments as well as parsed `option` and `non-option` arguments, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/springapplication/ApplicationArgumentsExample.java[] ----- - -TIP: Spring Boot also registers a `CommandLinePropertySource` with the Spring `Environment`. -This lets you also inject single application arguments by using the `@Value` annotation. - - - -[[features.spring-application.command-line-runner]] -=== Using the ApplicationRunner or CommandLineRunner -If you need to run some specific code once the `SpringApplication` has started, you can implement the `ApplicationRunner` or `CommandLineRunner` interfaces. -Both interfaces work in the same way and offer a single `run` method, which is called just before `SpringApplication.run(...)` completes. - -NOTE: This contract is well suited for tasks that should run after application startup but before it starts accepting traffic. - - -The `CommandLineRunner` interfaces provides access to application arguments as a string array, whereas the `ApplicationRunner` uses the `ApplicationArguments` interface discussed earlier. -The following example shows a `CommandLineRunner` with a `run` method: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/springapplication/CommandLineRunnerExample.java[] ----- - -If several `CommandLineRunner` or `ApplicationRunner` beans are defined that must be called in a specific order, you can additionally implement the `org.springframework.core.Ordered` interface or use the `org.springframework.core.annotation.Order` annotation. - - - -[[features.spring-application.application-exit]] -=== Application Exit -Each `SpringApplication` registers a shutdown hook with the JVM to ensure that the `ApplicationContext` closes gracefully on exit. -All the standard Spring lifecycle callbacks (such as the `DisposableBean` interface or the `@PreDestroy` annotation) can be used. - -In addition, beans may implement the `org.springframework.boot.ExitCodeGenerator` interface if they wish to return a specific exit code when `SpringApplication.exit()` is called. -This exit code can then be passed to `System.exit()` to return it as a status code, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/springapplication/exitcode/MyApplication.java[] ----- - -Also, the `ExitCodeGenerator` interface may be implemented by exceptions. -When such an exception is encountered, Spring Boot returns the exit code provided by the implemented `getExitCode()` method. - - - -[[features.spring-application.admin]] -=== Admin Features -It is possible to enable admin-related features for the application by specifying the configprop:spring.application.admin.enabled[] property. -This exposes the {spring-boot-module-code}/admin/SpringApplicationAdminMXBean.java[`SpringApplicationAdminMXBean`] on the platform `MBeanServer`. -You could use this feature to administer your Spring Boot application remotely. -This feature could also be useful for any service wrapper implementation. - -TIP: If you want to know on which HTTP port the application is running, get the property with a key of `local.server.port`. - - - -[[features.spring-application.startup-tracking]] -=== Application Startup tracking -During the application startup, the `SpringApplication` and the `ApplicationContext` perform many tasks related to the application lifecycle, -the beans lifecycle or even processing application events. -With {spring-framework-api}/core/metrics/ApplicationStartup.html[`ApplicationStartup`], Spring Framework {spring-framework-docs}/core.html#context-functionality-startup[allows you to track the application startup sequence with ``StartupStep``s]. -This data can be collected for profiling purposes, or just to have a better understanding of an application startup process. - -You can choose an `ApplicationStartup` implementation when setting up the `SpringApplication` instance. -For example, to use the `BufferingApplicationStartup`, you could write: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/springapplication/startup/MyApplication.java[tag=*] ----- - -The first available implementation, `FlightRecorderApplicationStartup` is provided by Spring Framework. -It adds Spring-specific startup events to a Java Flight Recorder session and is meant for profiling applications and correlating their Spring context lifecycle with JVM events (such as allocations, GCs, class loading...). -Once configured, you can record data by running the application with the Flight Recorder enabled: - -[source,bash,indent=0] ----- - $ java -XX:StartFlightRecording:filename=recording.jfr,duration=10s -jar demo.jar ----- - -Spring Boot ships with the `BufferingApplicationStartup` variant; this implementation is meant for buffering the startup steps and draining them into an external metrics system. -Applications can ask for the bean of type `BufferingApplicationStartup` in any component. -Additionally, Spring Boot Actuator will {spring-boot-actuator-restapi-docs}/#startup[expose a `startup` endpoint to expose this information as a JSON document]. - - - -[[features.external-config]] -== Externalized Configuration -Spring Boot lets you externalize your configuration so that you can work with the same application code in different environments. -You can use a variety of external configuration sources, include Java properties files, YAML files, environment variables, and command-line arguments. - -Property values can be injected directly into your beans by using the `@Value` annotation, accessed through Spring's `Environment` abstraction, or be <> through `@ConfigurationProperties`. - -Spring Boot uses a very particular `PropertySource` order that is designed to allow sensible overriding of values. -Properties are considered in the following order (with values from lower items overriding earlier ones): - -. Default properties (specified by setting `SpringApplication.setDefaultProperties`). -. {spring-framework-api}/context/annotation/PropertySource.html[`@PropertySource`] annotations on your `@Configuration` classes. - Please note that such property sources are not added to the `Environment` until the application context is being refreshed. - This is too late to configure certain properties such as `+logging.*+` and `+spring.main.*+` which are read before refresh begins. -. Config data (such as `application.properties` files) -. A `RandomValuePropertySource` that has properties only in `+random.*+`. -. OS environment variables. -. Java System properties (`System.getProperties()`). -. JNDI attributes from `java:comp/env`. -. `ServletContext` init parameters. -. `ServletConfig` init parameters. -. Properties from `SPRING_APPLICATION_JSON` (inline JSON embedded in an environment variable or system property). -. Command line arguments. -. `properties` attribute on your tests. - Available on {spring-boot-test-module-api}/context/SpringBootTest.html[`@SpringBootTest`] and the <>. -. {spring-framework-api}/test/context/TestPropertySource.html[`@TestPropertySource`] annotations on your tests. -. <> in the `$HOME/.config/spring-boot` directory when devtools is active. - -Config data files are considered in the following order: - -. <> packaged inside your jar (`application.properties` and YAML variants). -. <> packaged inside your jar (`application-\{profile}.properties` and YAML variants). -. <> outside of your packaged jar (`application.properties` and YAML variants). -. <> outside of your packaged jar (`application-\{profile}.properties` and YAML variants). - -NOTE: It is recommended to stick with one format for your entire application. -If you have configuration files with both `.properties` and `.yml` format in the same location, `.properties` takes precedence. - -To provide a concrete example, suppose you develop a `@Component` that uses a `name` property, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/externalizedconfiguration/valueinjection/MyBean.java[] ----- - -On your application classpath (for example, inside your jar) you can have an `application.properties` file that provides a sensible default property value for `name`. -When running in a new environment, an `application.properties` file can be provided outside of your jar that overrides the `name`. -For one-off testing, you can launch with a specific command line switch (for example, `java -jar app.jar --name="Spring"`). - -TIP: The `env` and `configprops` endpoints can be useful in determining why a property has a particular value. -You can use these two endpoints to diagnose unexpected property values. -See the "<>" section for details. - - - -[[features.external-config.command-line-args]] -=== Accessing Command Line Properties -By default, `SpringApplication` converts any command line option arguments (that is, arguments starting with `--`, such as `--server.port=9000`) to a `property` and adds them to the Spring `Environment`. -As mentioned previously, command line properties always take precedence over file based property sources. - -If you do not want command line properties to be added to the `Environment`, you can disable them by using `SpringApplication.setAddCommandLineProperties(false)`. - - - -[[features.external-config.application-json]] -=== JSON Application Properties -Environment variables and system properties often have restrictions that mean some property names cannot be used. -To help with this, Spring Boot allows you to encode a block of properties into a single JSON structure. - -When your application starts, any `spring.application.json` or `SPRING_APPLICATION_JSON` properties will be parsed and added to the `Environment`. - -For example, the `SPRING_APPLICATION_JSON` property can be supplied on the command line in a UN{asterisk}X shell as an environment variable: - -[indent=0] ----- - $ SPRING_APPLICATION_JSON='{"acme":{"name":"test"}}' java -jar myapp.jar ----- - -In the preceding example, you end up with `acme.name=test` in the Spring `Environment`. - -The same JSON can also be provided as a system property: - -[indent=0] ----- - $ java -Dspring.application.json='{"acme":{"name":"test"}}' -jar myapp.jar ----- - -Or you could supply the JSON by using a command line argument: - -[indent=0] ----- - $ java -jar myapp.jar --spring.application.json='{"acme":{"name":"test"}}' ----- - -If you are deploying to a classic Application Server, you could also use a JNDI variable named `java:comp/env/spring.application.json`. - -NOTE: Although `null` values from the JSON will be added to the resulting property source, the `PropertySourcesPropertyResolver` treats `null` properties as missing values. -This means that the JSON cannot override properties from lower order property sources with a `null` value. - - - -[[features.external-config.files]] -=== External Application Properties [[features.external-config.files]] -Spring Boot will automatically find and load `application.properties` and `application.yaml` files from the following locations when your application starts: - -. The classpath root -. The classpath `/config` package -. The current directory -. The `/config` subdirectory in the current directory -. Immediate child directories of the `/config` subdirectory - -The list is ordered by precedence (with values from lower items overriding earlier ones). -Documents from the loaded files are added as `PropertySources` to the Spring `Environment`. - -If you do not like `application` as the configuration file name, you can switch to another file name by specifying a configprop:spring.config.name[] environment property. -You can also refer to an explicit location by using the `spring.config.location` environment property (which is a comma-separated list of directory locations or file paths). -The following example shows how to specify a different file name: - -[indent=0] ----- - $ java -jar myproject.jar --spring.config.name=myproject ----- - -The following example shows how to specify two locations: - -[indent=0] ----- - $ java -jar myproject.jar --spring.config.location=optional:classpath:/default.properties,optional:classpath:/override.properties ----- - -TIP: Use the prefix `optional:` if the <> and you don't mind if they don't exist. - -WARNING: `spring.config.name`, `spring.config.location`, and `spring.config.additional-location` are used very early to determine which files have to be loaded. -They must be defined as an environment property (typically an OS environment variable, a system property, or a command-line argument). - -If `spring.config.location` contains directories (as opposed to files), they must end in `/` or the system-dependent `File.separator`. -At runtime they will be appended with the names generated from `spring.config.name` before being loaded. -If `spring.config.location` contains files, they are used as-is. - -Whether specified directly or contained in a directory, file references must include a file extension in their name. -Typical extensions that are supported out-of-the-box are `.properties`, `.yaml`, and `.yml`. - -When multiple locations are specified, the later ones can override the values of earlier ones. - -Locations configured by using `spring.config.location` replace the default locations. -For example, if `spring.config.location` is configured with the value `optional:classpath:/custom-config/,optional:file:./custom-config/`, the complete set of locations considered is: - -. `optional:classpath:custom-config/` -. `optional:file:./custom-config/` - -If you prefer to add additional locations, rather than replacing them, you can use `spring.config.additional-location`. -Properties loaded from additional locations can override those in the default locations. -For example, if `spring.config.additional-location` is configured with the value `optional:classpath:/custom-config/,optional:file:./custom-config/`, the complete set of locations considered is: - -. `optional:classpath:/` -. `optional:classpath:/config/` -. `optional:file:./` -. `optional:file:./config/` -. `optional:file:./config/*/` -. `optional:classpath:custom-config/` -. `optional:file:./custom-config/` - -This search ordering lets you specify default values in one configuration file and then selectively override those values in another. -You can provide default values for your application in `application.properties` (or whatever other basename you choose with `spring.config.name`) in one of the default locations. -These default values can then be overridden at runtime with a different file located in one of the custom locations. - -NOTE: If you use environment variables rather than system properties, most operating systems disallow period-separated key names, but you can use underscores instead (for example, configprop:spring.config.name[format=envvar] instead of configprop:spring.config.name[]). -See <> for details. - -NOTE: If your application runs in a servlet container or application server, then JNDI properties (in `java:comp/env`) or servlet context initialization parameters can be used instead of, or as well as, environment variables or system properties. - - - -[[features.external-config.files.optional-prefix]] -==== Optional Locations -By default, when a specified config data location does not exist, Spring Boot will throw a `ConfigDataLocationNotFoundException` and your application will not start. - -If you want to specify a location, but you don't mind if it doesn't always exist, you can use the `optional:` prefix. -You can use this prefix with the `spring.config.location` and `spring.config.additional-location` properties, as well as with <> declarations. - -For example, a `spring.config.import` value of `optional:file:./myconfig.properties` allows your application to start, even if the `myconfig.properties` file is missing. - -If you want to ignore all `ConfigDataLocationNotFoundExceptions` and always continue to start your application, you can use the `spring.config.on-not-found` property. -Set the value to `ignore` using `SpringApplication.setDefaultProperties(...)` or with a system/environment variable. - - - -[[features.external-config.files.wildcard-locations]] -==== Wildcard Locations -If a config file location includes the `{asterisk}` character for the last path segment, it is considered a wildcard location. -Wildcards are expanded when the config is loaded so that immediate subdirectories are also checked. -Wildcard locations are particularly useful in an environment such as Kubernetes when there are multiple sources of config properties. - -For example, if you have some Redis configuration and some MySQL configuration, you might want to keep those two pieces of configuration separate, while requiring that both those are present in an `application.properties` file. -This might result in two separate `application.properties` files mounted at different locations such as `/config/redis/application.properties` and `/config/mysql/application.properties`. -In such a case, having a wildcard location of `config/*/`, will result in both files being processed. - -By default, Spring Boot includes `config/*/` in the default search locations. -It means that all subdirectories of the `/config` directory outside of your jar will be searched. - -You can use wildcard locations yourself with the `spring.config.location` and `spring.config.additional-location` properties. - -NOTE: A wildcard location must contain only one `{asterisk}` and end with `{asterisk}/` for search locations that are directories or `*/` for search locations that are files. -Locations with wildcards are sorted alphabetically based on the absolute path of the file names. - -TIP: Wildcard locations only work with external directories. -You cannot use a wildcard in a `classpath:` location. - - - -[[features.external-config.files.profile-specific]] -==== Profile Specific Files -As well as `application` property files, Spring Boot will also attempt to load profile-specific files using the naming convention `application-\{profile}`. -For example, if your application activates a profile named `prod` and uses YAML files, then both `application.yml` and `application-prod.yml` will be considered. - -Profile-specific properties are loaded from the same locations as standard `application.properties`, with profile-specific files always overriding the non-specific ones. -If several profiles are specified, a last-wins strategy applies. -For example, if profiles `prod,live` are specified by the configprop:spring.profiles.active[] property, values in `application-prod.properties` can be overridden by those in `application-live.properties`. - -The `Environment` has a set of default profiles (by default, `[default]`) that are used if no active profiles are set. -In other words, if no profiles are explicitly activated, then properties from `application-default` are considered. - -NOTE: Properties files are only ever loaded once. -If you've already directly <> a profile specific property files then it won't be imported a second time. - - - -[[features.external-config.files.importing]] -==== Importing Additional Data -Application properties may import further config data from other locations using the `spring.config.import` property. -Imports are processed as they are discovered, and are treated as additional documents inserted immediately below the one that declares the import. - -For example, you might have the following in your classpath `application.properties` file: - -[source,yaml,indent=0,configblocks] ----- - spring: - application: - name: "myapp" - config: - import: "optional:file:./dev.properties" ----- - -This will trigger the import of a `dev.properties` file in current directory (if such a file exists). -Values from the imported `dev.properties` will take precedence over the file that triggered the import. -In the above example, the `dev.properties` could redefine `spring.application.name` to a different value. -An import will only be imported once no matter how many times it is declared. -The order an import is defined inside a single document within the properties/yaml file doesn't matter. -For instance, the two examples below produce the same result: - -[source,yaml,indent=0,configblocks] ----- - spring: - config: - import: my.properties - my: - property: value ----- - -[source,yaml,indent=0,configblocks] ----- - my: - property: value - spring: - config: - import: my.properties ----- - -In both of the above examples, the values from the `my.properties` file will take precedence over the file that triggered its import. - -Several locations can be specified under a single `spring.config.import` key. -Locations will be processed in the order that they are defined, with later imports taking precedence. - -[TIP] -==== -Spring Boot includes pluggable API that allows various different location addresses to be supported. -By default you can import Java Properties, YAML and "`<>`". - -Third-party jars can offer support for additional technologies (there's no requirement for files to be local). -For example, you can imagine config data being from external stores such as Consul, Apache ZooKeeper or Netflix Archaius. - -If you want to support your own locations, see the `ConfigDataLocationResolver` and `ConfigDataLoader` classes in the `org.springframework.boot.context.config` package. -==== - - - -[[features.external-config.files.importing-extensionless]] -==== Importing Extensionless Files -Some cloud platforms cannot add a file extension to volume mounted files. -To import these extensionless files, you need to give Spring Boot a hint so that it knows how to load them. -You can do this by putting an extension hint in square brackets. - -For example, suppose you have a `/etc/config/myconfig` file that you wish to import as yaml. -You can import it from your `application.properties` using the following: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - config: - import: "file:/etc/config/myconfig[.yaml]" ----- - - - -[[features.external-config.files.configtree]] -==== Using Configuration Trees -When running applications on a cloud platform (such as Kubernetes) you often need to read config values that the platform supplies. -It's not uncommon to use environment variables for such purposes, but this can have drawbacks, especially if the value is supposed to be kept secret. - -As an alternative to environment variables, many cloud platforms now allow you to map configuration into mounted data volumes. -For example, Kubernetes can volume mount both https://kubernetes.io/docs/tasks/configure-pod-container/configure-pod-configmap/#populate-a-volume-with-data-stored-in-a-configmap[`ConfigMaps`] and https://kubernetes.io/docs/concepts/configuration/secret/#using-secrets-as-files-from-a-pod[`Secrets`]. - -There are two common volume mount patterns that can be use: - -. A single file contains a complete set of properties (usually written as YAML). -. Multiple files are written to a directory tree, with the filename becoming the '`key`' and the contents becoming the '`value`'. - -For the first case, you can import the YAML or Properties file directly using `spring.config.import` as described <>. -For the second case, you need to use the `configtree:` prefix so that Spring Boot knows it needs to expose all the files as properties. - -As an example, let's imagine that Kubernetes has mounted the following volume: - -[indent=0] ----- - etc/ - config/ - myapp/ - username - password ----- - -The contents of the `username` file would be a config value, and the contents of `password` would be a secret. - -To import these properties, you can add the following to your `application.properties` or `application.yaml` file: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - config: - import: "optional:configtree:/etc/config/" ----- - -You can then access or inject `myapp.username` and `myapp.password` properties from the `Environment` in the usual way. - -TIP: Configuration tree values can be bound to both string `String` and `byte[]` types depending on the contents expected. - -If you have multiple config trees to import from the same parent folder you can use a wildcard shortcut. -Any `configtree:` location that ends with `/*/` will import all immediate children as config trees. - -For example, given the following volume: - -[indent=0] ----- - etc/ - config/ - dbconfig/ - db/ - username - password - mqconfig/ - mq/ - username - password ----- - -You can use `configtree:/etc/config/*/` as the import location: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - config: - import: "optional:configtree:/etc/config/*/" ----- - -This will add `db.username`, `db.password`, `mq.username` and `mq.password` properties. - -NOTE: Directories loaded using a wildcard are sorted alphabetically. -If you need a different order, then you should list each location as a separate import - - -Configuration trees can also be used for Docker secrets. -When a Docker swarm service is granted access to a secret, the secret gets mounted into the container. -For example, if a secret named `db.password` is mounted at location `/run/secrets/`, you can make `db.password` available to the Spring environment using the following: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - config: - import: "optional:configtree:/run/secrets/" ----- - - - -[[features.external-config.files.property-placeholders]] -==== Property Placeholders -The values in `application.properties` and `application.yml` are filtered through the existing `Environment` when they are used, so you can refer back to previously defined values (for example, from System properties). -The standard `$\{name}` property-placeholder syntax can be used anywhere within a value. - -For example, the following file will set `app.description` to "`MyApp is a Spring Boot application`": - -[source,yaml,indent=0,configblocks] ----- - app: - name: "MyApp" - description: "${app.name} is a Spring Boot application" ----- - -TIP: You can also use this technique to create "`short`" variants of existing Spring Boot properties. -See the _<>_ how-to for details. - - - -[[features.external-config.files.multi-document]] -==== Working with Multi-Document Files -Spring Boot allows you to split a single physical file into multiple logical documents which are each added independently. -Documents are processed in order, from top to bottom. -Later documents can override the properties defined in earlier ones. - -For `application.yml` files, the standard YAML multi-document syntax is used. -Three consecutive hyphens represent the end of one document, and the start of the next. - -For example, the following file has two logical documents: - -[source,yaml,indent=0] ----- - spring.application.name: MyApp - --- - spring.config.activate.on-cloud-platform: kubernetes - spring.application.name: MyCloudApp ----- - -For `application.properties` files a special `#---` comment is used to mark the document splits: - -[source,properties,indent=0] ----- - spring.application.name=MyApp - #--- - spring.config.activate.on-cloud-platform=kubernetes - spring.application.name=MyCloudApp ----- - -NOTE: Property file separators must not have any leading whitespace and must have exactly three hyphen characters. -The lines immediately before and after the separator must not be comments. - -TIP: Multi-document property files are often used in conjunction with activation properties such as `spring.config.activate.on-profile`. -See the <> for details. - -WARNING: Multi-document property files cannot be loaded by using the `@PropertySource` or `@TestPropertySource` annotations. - - - -[[features.external-config.files.activation-properties]] -==== Activation Properties -It's sometimes useful to only activate a given get of properties when certain conditions are met. -For example, you might have properties that are only relevant when a specific profile is active. - -You can conditionally activate a properties document using `spring.config.activate.*`. - -The following activation properties are available: - -.activation properties -[cols="1,4"] -|=== -| Property | Note - -| `on-profile` -| A profile expression that must match for the document to be active. - -| `on-cloud-platform` -| The `CloudPlatform` that must be detected for the document to be active. -|=== - -For example, the following specifies that the second document is only active when running on Kubernetes, and only when either the "`prod`" or "`staging`" profiles are active: - -[source,yaml,indent=0,configblocks] ----- - myprop: - always-set - --- - spring: - config: - activate: - on-cloud-platform: "kubernetes" - on-profile: "prod | staging" - myotherprop: sometimes-set ----- - - - -[[features.external-config.encrypting]] -=== Encrypting Properties -Spring Boot does not provide any built in support for encrypting property values, however, it does provide the hook points necessary to modify values contained in the Spring `Environment`. -The `EnvironmentPostProcessor` interface allows you to manipulate the `Environment` before the application starts. -See <> for details. - -If you're looking for a secure way to store credentials and passwords, the https://cloud.spring.io/spring-cloud-vault/[Spring Cloud Vault] project provides support for storing externalized configuration in https://www.vaultproject.io/[HashiCorp Vault]. - - - -[[features.external-config.yaml]] -=== Working with YAML -https://yaml.org[YAML] is a superset of JSON and, as such, is a convenient format for specifying hierarchical configuration data. -The `SpringApplication` class automatically supports YAML as an alternative to properties whenever you have the https://bitbucket.org/asomov/snakeyaml[SnakeYAML] library on your classpath. - -NOTE: If you use "`Starters`", SnakeYAML is automatically provided by `spring-boot-starter`. - - - -[[features.external-config.yaml.mapping-to-properties]] -==== Mapping YAML to Properties -YAML documents need to be converted from their hierarchical format to a flat structure that can be used with the Spring `Environment`. -For example, consider the following YAML document: - -[source,yaml,indent=0] ----- - environments: - dev: - url: https://dev.example.com - name: Developer Setup - prod: - url: https://another.example.com - name: My Cool App ----- - -In order to access these properties from the `Environment`, they would be flattened as follows: - -[source,properties,indent=0] ----- - environments.dev.url=https://dev.example.com - environments.dev.name=Developer Setup - environments.prod.url=https://another.example.com - environments.prod.name=My Cool App ----- - -Likewise, YAML lists also need to be flattened. -They are represented as property keys with `[index]` dereferencers. -For example, consider the following YAML: - -[source,yaml,indent=0] ----- - my: - servers: - - dev.example.com - - another.example.com ----- - -The preceding example would be transformed into these properties: - -[source,properties,indent=0] ----- - my.servers[0]=dev.example.com - my.servers[1]=another.example.com ----- - -TIP: Properties that use the `[index]` notation can be bound to Java `List` or `Set` objects using Spring Boot's `Binder` class. -For more details see the "`<>`" section below. - -WARNING: YAML files cannot be loaded by using the `@PropertySource` or `@TestPropertySource` annotations. -So, in the case that you need to load values that way, you need to use a properties file. - - - -[[features.external-config.yaml.directly-loading]] -[[features.external-config.yaml.directly-loading]] -==== Directly Loading YAML -Spring Framework provides two convenient classes that can be used to load YAML documents. -The `YamlPropertiesFactoryBean` loads YAML as `Properties` and the `YamlMapFactoryBean` loads YAML as a `Map`. - -You can also use the `YamlPropertySourceLoader` class if you want to load YAML as a Spring `PropertySource`. - - - -[[features.external-config.random-values]] -=== Configuring Random Values -The `RandomValuePropertySource` is useful for injecting random values (for example, into secrets or test cases). -It can produce integers, longs, uuids, or strings, as shown in the following example: - -[source,yaml,indent=0,configblocks] ----- - my: - secret: "${random.value}" - number: "${random.int}" - bignumber: "${random.long}" - uuid: "${random.uuid}" - number-less-than-ten: "${random.int(10)}" - number-in-range: "${random.int[1024,65536]}" ----- - -The `+random.int*+` syntax is `OPEN value (,max) CLOSE` where the `OPEN,CLOSE` are any character and `value,max` are integers. -If `max` is provided, then `value` is the minimum value and `max` is the maximum value (exclusive). - - - -[[features.external-config.system-environment]] -=== Configuring System Environment Properties -Spring Boot supports setting a prefix for environment properties. -This is useful if the system environment is shared by multiple Spring Boot applications with different configuration requirements. -The prefix for system environment properties can be set directly on `SpringApplication`. - -For example, if you set the prefix to `input`, a property such as `remote.timeout` will also be resolved as `input.remote.timeout` in the system environment. - - - -[[features.external-config.typesafe-configuration-properties]] -=== Type-safe Configuration Properties -Using the `@Value("$\{property}")` annotation to inject configuration properties can sometimes be cumbersome, especially if you are working with multiple properties or your data is hierarchical in nature. -Spring Boot provides an alternative method of working with properties that lets strongly typed beans govern and validate the configuration of your application. - -TIP: See also the <>. - - - -[[features.external-config.typesafe-configuration-properties.java-bean-binding]] -==== JavaBean properties binding -It is possible to bind a bean declaring standard JavaBean properties as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/externalizedconfiguration/javabeanbinding/AcmeProperties.java[] ----- - -The preceding POJO defines the following properties: - -* `acme.enabled`, with a value of `false` by default. -* `acme.remote-address`, with a type that can be coerced from `String`. -* `acme.security.username`, with a nested "security" object whose name is determined by the name of the property. - In particular, the return type is not used at all there and could have been `SecurityProperties`. -* `acme.security.password`. -* `acme.security.roles`, with a collection of `String` that defaults to `USER`. - -NOTE: The properties that map to `@ConfigurationProperties` classes available in Spring Boot, which are configured via properties files, YAML files, environment variables etc., are public API but the accessors (getters/setters) of the class itself are not meant to be used directly. - -[NOTE] -==== -Such arrangement relies on a default empty constructor and getters and setters are usually mandatory, since binding is through standard Java Beans property descriptors, just like in Spring MVC. -A setter may be omitted in the following cases: - -* Maps, as long as they are initialized, need a getter but not necessarily a setter, since they can be mutated by the binder. -* Collections and arrays can be accessed either through an index (typically with YAML) or by using a single comma-separated value (properties). - In the latter case, a setter is mandatory. - We recommend to always add a setter for such types. - If you initialize a collection, make sure it is not immutable (as in the preceding example). -* If nested POJO properties are initialized (like the `Security` field in the preceding example), a setter is not required. - If you want the binder to create the instance on the fly by using its default constructor, you need a setter. - -Some people use Project Lombok to add getters and setters automatically. -Make sure that Lombok does not generate any particular constructor for such a type, as it is used automatically by the container to instantiate the object. - -Finally, only standard Java Bean properties are considered and binding on static properties is not supported. -==== - - - -[[features.external-config.typesafe-configuration-properties.constructor-binding]] -==== Constructor binding -The example in the previous section can be rewritten in an immutable fashion as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/externalizedconfiguration/constructorbinding/AcmeProperties.java[] ----- - -In this setup, the `@ConstructorBinding` annotation is used to indicate that constructor binding should be used. -This means that the binder will expect to find a constructor with the parameters that you wish to have bound. - -Nested members of a `@ConstructorBinding` class (such as `Security` in the example above) will also be bound via their constructor. - -Default values can be specified using `@DefaultValue` and the same conversion service will be applied to coerce the `String` value to the target type of a missing property. -By default, if no properties are bound to `Security`, the `AcmeProperties` instance will contain a `null` value for `security`. -If you wish you return a non-null instance of `Security` even when no properties are bound to it, you can use an empty `@DefaultValue` annotation to do so: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/externalizedconfiguration/constructorbinding/nonnull/AcmeProperties.java[tag=*] ----- - - -NOTE: To use constructor binding the class must be enabled using `@EnableConfigurationProperties` or configuration property scanning. -You cannot use constructor binding with beans that are created by the regular Spring mechanisms (e.g. `@Component` beans, beans created via `@Bean` methods or beans loaded using `@Import`) - -TIP: If you have more than one constructor for your class you can also use `@ConstructorBinding` directly on the constructor that should be bound. - -NOTE: The use of `java.util.Optional` with `@ConfigurationProperties` is not recommended as it is primarily intended for use as a return type. -As such, it is not well-suited to configuration property injection. -For consistency with properties of other types, if you do declare an `Optional` property and it has no value, `null` rather than an empty `Optional` will be bound. - - - -[[features.external-config.typesafe-configuration-properties.enabling-annotated-types]] -==== Enabling @ConfigurationProperties-annotated types -Spring Boot provides infrastructure to bind `@ConfigurationProperties` types and register them as beans. -You can either enable configuration properties on a class-by-class basis or enable configuration property scanning that works in a similar manner to component scanning. - -Sometimes, classes annotated with `@ConfigurationProperties` might not be suitable for scanning, for example, if you're developing your own auto-configuration or you want to enable them conditionally. -In these cases, specify the list of types to process using the `@EnableConfigurationProperties` annotation. -This can be done on any `@Configuration` class, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/externalizedconfiguration/enable/MyConfiguration.java[] ----- - -To use configuration property scanning, add the `@ConfigurationPropertiesScan` annotation to your application. -Typically, it is added to the main application class that is annotated with `@SpringBootApplication` but it can be added to any `@Configuration` class. -By default, scanning will occur from the package of the class that declares the annotation. -If you want to define specific packages to scan, you can do so as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/externalizedconfiguration/enable/MyApplication.java[] ----- - -[NOTE] -==== -When the `@ConfigurationProperties` bean is registered using configuration property scanning or via `@EnableConfigurationProperties`, the bean has a conventional name: `-`, where `` is the environment key prefix specified in the `@ConfigurationProperties` annotation and `` is the fully qualified name of the bean. -If the annotation does not provide any prefix, only the fully qualified name of the bean is used. - -The bean name in the example above is `acme-com.example.AcmeProperties`. -==== - -We recommend that `@ConfigurationProperties` only deal with the environment and, in particular, does not inject other beans from the context. -For corner cases, setter injection can be used or any of the `*Aware` interfaces provided by the framework (such as `EnvironmentAware` if you need access to the `Environment`). -If you still want to inject other beans using the constructor, the configuration properties bean must be annotated with `@Component` and use JavaBean-based property binding. - - - -[[features.external-config.typesafe-configuration-properties.using-annotated-types]] -==== Using @ConfigurationProperties-annotated types -This style of configuration works particularly well with the `SpringApplication` external YAML configuration, as shown in the following example: - -[source,yaml,indent=0] ----- - acme: - remote-address: 192.168.1.1 - security: - username: admin - roles: - - USER - - ADMIN ----- - -To work with `@ConfigurationProperties` beans, you can inject them in the same way as any other bean, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/externalizedconfiguration/use/MyService.java[] ----- - -TIP: Using `@ConfigurationProperties` also lets you generate metadata files that can be used by IDEs to offer auto-completion for your own keys. -See the <> for details. - - - -[[features.external-config.typesafe-configuration-properties.3rd-party-configuration]] -==== Third-party Configuration -As well as using `@ConfigurationProperties` to annotate a class, you can also use it on public `@Bean` methods. -Doing so can be particularly useful when you want to bind properties to third-party components that are outside of your control. - -To configure a bean from the `Environment` properties, add `@ConfigurationProperties` to its bean registration, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/externalizedconfiguration/ThirdPartyConfiguration.java[] ----- - -Any JavaBean property defined with the `another` prefix is mapped onto that `AnotherComponent` bean in manner similar to the preceding `AcmeProperties` example. - - - -[[features.external-config.typesafe-configuration-properties.relaxed-binding]] -==== Relaxed Binding -Spring Boot uses some relaxed rules for binding `Environment` properties to `@ConfigurationProperties` beans, so there does not need to be an exact match between the `Environment` property name and the bean property name. -Common examples where this is useful include dash-separated environment properties (for example, `context-path` binds to `contextPath`), and capitalized environment properties (for example, `PORT` binds to `port`). - -As an example, consider the following `@ConfigurationProperties` class: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/externalizedconfiguration/relaxed/OwnerProperties.java[] ----- - -With the preceding code, the following properties names can all be used: - -.relaxed binding -[cols="1,4"] -|=== -| Property | Note - -| `acme.my-project.person.first-name` -| Kebab case, which is recommended for use in `.properties` and `.yml` files. - -| `acme.myProject.person.firstName` -| Standard camel case syntax. - -| `acme.my_project.person.first_name` -| Underscore notation, which is an alternative format for use in `.properties` and `.yml` files. - -| `ACME_MYPROJECT_PERSON_FIRSTNAME` -| Upper case format, which is recommended when using system environment variables. -|=== - -NOTE: The `prefix` value for the annotation _must_ be in kebab case (lowercase and separated by `-`, such as `acme.my-project.person`). - -.relaxed binding rules per property source -[cols="2,4,4"] -|=== -| Property Source | Simple | List - -| Properties Files -| Camel case, kebab case, or underscore notation -| Standard list syntax using `[ ]` or comma-separated values - -| YAML Files -| Camel case, kebab case, or underscore notation -| Standard YAML list syntax or comma-separated values - -| Environment Variables -| Upper case format with underscore as the delimiter (see <>). -| Numeric values surrounded by underscores (see <>) - -| System properties -| Camel case, kebab case, or underscore notation -| Standard list syntax using `[ ]` or comma-separated values -|=== - -TIP: We recommend that, when possible, properties are stored in lower-case kebab format, such as `my.property-name=acme`. - - - -[[features.external-config.typesafe-configuration-properties.relaxed-binding.maps]] -===== Binding Maps -When binding to `Map` properties you may need to use a special bracket notation so that the original `key` value is preserved. -If the key is not surrounded by `[]`, any characters that are not alpha-numeric, `-` or `.` are removed. - -For example, consider binding the following properties to a `Map`: - - -[source,properties,indent=0,role="primary"] -.Properties ----- - acme.map.[/key1]=value1 - acme.map.[/key2]=value2 - acme.map./key3=value3 ----- - -[source,yaml,indent=0,role="secondary"] -.Yaml ----- - acme: - map: - "[/key1]": "value1" - "[/key2]": "value2" - "/key3": "value3" ----- - -NOTE: For YAML files, the brackets need to be surrounded by quotes for the keys to be parsed properly. - -The properties above will bind to a `Map` with `/key1`, `/key2` and `key3` as the keys in the map. -The slash has been removed from `key3` because it wasn't surrounded by square brackets. - -You may also occasionally need to use the bracket notation if your `key` contains a `.` and you are binding to non-scalar value. -For example, binding `a.b=c` to `Map` will return a Map with the entry `{"a"={"b"="c"}}` whereas `[a.b]=c` will return a Map with the entry `{"a.b"="c"}`. - - - -[[features.external-config.typesafe-configuration-properties.relaxed-binding.environment-variables]] -===== Binding from Environment Variables -Most operating systems impose strict rules around the names that can be used for environment variables. -For example, Linux shell variables can contain only letters (`a` to `z` or `A` to `Z`), numbers (`0` to `9`) or the underscore character (`_`). -By convention, Unix shell variables will also have their names in UPPERCASE. - -Spring Boot's relaxed binding rules are, as much as possible, designed to be compatible with these naming restrictions. - -To convert a property name in the canonical-form to an environment variable name you can follow these rules: - -* Replace dots (`.`) with underscores (`_`). -* Remove any dashes (`-`). -* Convert to uppercase. - -For example, the configuration property `spring.main.log-startup-info` would be an environment variable named `SPRING_MAIN_LOGSTARTUPINFO`. - -Environment variables can also be used when binding to object lists. -To bind to a `List`, the element number should be surrounded with underscores in the variable name. - -For example, the configuration property `my.acme[0].other` would use an environment variable named `MY_ACME_0_OTHER`. - - - -[[features.external-config.typesafe-configuration-properties.merging-complex-types]] -==== Merging Complex Types -When lists are configured in more than one place, overriding works by replacing the entire list. - -For example, assume a `MyPojo` object with `name` and `description` attributes that are `null` by default. -The following example exposes a list of `MyPojo` objects from `AcmeProperties`: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/externalizedconfiguration/merge/list/AcmeProperties.java[tag=*] ----- - -Consider the following configuration: - -[source,yaml,indent=0,configblocks] ----- - acme: - list: - - name: "my name" - description: "my description" - --- - spring: - config: - activate: - on-profile: "dev" - acme: - list: - - name: "my another name" ----- - -If the `dev` profile is not active, `AcmeProperties.list` contains one `MyPojo` entry, as previously defined. -If the `dev` profile is enabled, however, the `list` _still_ contains only one entry (with a name of `my another name` and a description of `null`). -This configuration _does not_ add a second `MyPojo` instance to the list, and it does not merge the items. - -When a `List` is specified in multiple profiles, the one with the highest priority (and only that one) is used. -Consider the following example: - -[source,yaml,indent=0,configblocks] ----- - acme: - list: - - name: "my name" - description: "my description" - - name: "another name" - description: "another description" - --- - spring: - config: - activate: - on-profile: "dev" - acme: - list: - - name: "my another name" ----- - -In the preceding example, if the `dev` profile is active, `AcmeProperties.list` contains _one_ `MyPojo` entry (with a name of `my another name` and a description of `null`). -For YAML, both comma-separated lists and YAML lists can be used for completely overriding the contents of the list. - -For `Map` properties, you can bind with property values drawn from multiple sources. -However, for the same property in multiple sources, the one with the highest priority is used. -The following example exposes a `Map` from `AcmeProperties`: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/externalizedconfiguration/merge/map/AcmeProperties.java[tag=*] ----- - -Consider the following configuration: - -[source,yaml,indent=0,configblocks] ----- - acme: - map: - key1: - name: "my name 1" - description: "my description 1" - --- - spring: - config: - activate: - on-profile: "dev" - acme: - map: - key1: - name: "dev name 1" - key2: - name: "dev name 2" - description: "dev description 2" ----- - -If the `dev` profile is not active, `AcmeProperties.map` contains one entry with key `key1` (with a name of `my name 1` and a description of `my description 1`). -If the `dev` profile is enabled, however, `map` contains two entries with keys `key1` (with a name of `dev name 1` and a description of `my description 1`) and `key2` (with a name of `dev name 2` and a description of `dev description 2`). - -NOTE: The preceding merging rules apply to properties from all property sources, and not just files. - - - -[[features.external-config.typesafe-configuration-properties.conversion]] -==== Properties Conversion -Spring Boot attempts to coerce the external application properties to the right type when it binds to the `@ConfigurationProperties` beans. -If you need custom type conversion, you can provide a `ConversionService` bean (with a bean named `conversionService`) or custom property editors (through a `CustomEditorConfigurer` bean) or custom `Converters` (with bean definitions annotated as `@ConfigurationPropertiesBinding`). - -NOTE: As this bean is requested very early during the application lifecycle, make sure to limit the dependencies that your `ConversionService` is using. -Typically, any dependency that you require may not be fully initialized at creation time. -You may want to rename your custom `ConversionService` if it is not required for configuration keys coercion and only rely on custom converters qualified with `@ConfigurationPropertiesBinding`. - - - -[[features.external-config.typesafe-configuration-properties.conversion.durations]] -===== Converting Durations -Spring Boot has dedicated support for expressing durations. -If you expose a `java.time.Duration` property, the following formats in application properties are available: - -* A regular `long` representation (using milliseconds as the default unit unless a `@DurationUnit` has been specified) -* The standard ISO-8601 format {java-api}/java/time/Duration.html#parse-java.lang.CharSequence-[used by `java.time.Duration`] -* A more readable format where the value and the unit are coupled (e.g. `10s` means 10 seconds) - -Consider the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/externalizedconfiguration/duration/javabeanbinding/AppSystemProperties.java[] ----- - -To specify a session timeout of 30 seconds, `30`, `PT30S` and `30s` are all equivalent. -A read timeout of 500ms can be specified in any of the following form: `500`, `PT0.5S` and `500ms`. - -You can also use any of the supported units. -These are: - -* `ns` for nanoseconds -* `us` for microseconds -* `ms` for milliseconds -* `s` for seconds -* `m` for minutes -* `h` for hours -* `d` for days - -The default unit is milliseconds and can be overridden using `@DurationUnit` as illustrated in the sample above. - -If you prefer to use constructor binding, the same properties can be exposed, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/externalizedconfiguration/duration/constructorbinding/AppSystemProperties.java[] ----- - - -TIP: If you are upgrading a `Long` property, make sure to define the unit (using `@DurationUnit`) if it isn't milliseconds. -Doing so gives a transparent upgrade path while supporting a much richer format. - - - -[[features.external-config.typesafe-configuration-properties.conversion.periods]] -===== Converting periods -In addition to durations, Spring Boot can also work with `java.time.Period` type. -The following formats can be used in application properties: - -* An regular `int` representation (using days as the default unit unless a `@PeriodUnit` has been specified) -* The standard ISO-8601 format {java-api}/java/time/Period.html#parse-java.lang.CharSequence-[used by `java.time.Period`] -* A simpler format where the value and the unit pairs are coupled (e.g. `1y3d` means 1 year and 3 days) - -The following units are supported with the simple format: - -* `y` for years -* `m` for months -* `w` for weeks -* `d` for days - -NOTE: The `java.time.Period` type never actually stores the number of weeks, it is a shortcut that means "`7 days`". - - - -[[features.external-config.typesafe-configuration-properties.conversion.data-sizes]] -===== Converting Data Sizes -Spring Framework has a `DataSize` value type that expresses a size in bytes. -If you expose a `DataSize` property, the following formats in application properties are available: - -* A regular `long` representation (using bytes as the default unit unless a `@DataSizeUnit` has been specified) -* A more readable format where the value and the unit are coupled (e.g. `10MB` means 10 megabytes) - -Consider the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/externalizedconfiguration/datasize/javabeanbinding/AppIoProperties.java[] ----- - -To specify a buffer size of 10 megabytes, `10` and `10MB` are equivalent. -A size threshold of 256 bytes can be specified as `256` or `256B`. - -You can also use any of the supported units. -These are: - -* `B` for bytes -* `KB` for kilobytes -* `MB` for megabytes -* `GB` for gigabytes -* `TB` for terabytes - -The default unit is bytes and can be overridden using `@DataSizeUnit` as illustrated in the sample above. - -If you prefer to use constructor binding, the same properties can be exposed, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/externalizedconfiguration/datasize/constructorbinding/AppIoProperties.java[] ----- - -TIP: If you are upgrading a `Long` property, make sure to define the unit (using `@DataSizeUnit`) if it isn't bytes. -Doing so gives a transparent upgrade path while supporting a much richer format. - - - -[[features.external-config.typesafe-configuration-properties.validation]] -==== @ConfigurationProperties Validation -Spring Boot attempts to validate `@ConfigurationProperties` classes whenever they are annotated with Spring's `@Validated` annotation. -You can use JSR-303 `javax.validation` constraint annotations directly on your configuration class. -To do so, ensure that a compliant JSR-303 implementation is on your classpath and then add constraint annotations to your fields, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/externalizedconfiguration/validate/AcmeProperties.java[] ----- - -TIP: You can also trigger validation by annotating the `@Bean` method that creates the configuration properties with `@Validated`. - -To ensure that validation is always triggered for nested properties, even when no properties are found, the associated field must be annotated with `@Valid`. -The following example builds on the preceding `AcmeProperties` example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/externalizedconfiguration/validate/nested/AcmeProperties.java[] ----- - -You can also add a custom Spring `Validator` by creating a bean definition called `configurationPropertiesValidator`. -The `@Bean` method should be declared `static`. -The configuration properties validator is created very early in the application's lifecycle, and declaring the `@Bean` method as static lets the bean be created without having to instantiate the `@Configuration` class. -Doing so avoids any problems that may be caused by early instantiation. - -TIP: The `spring-boot-actuator` module includes an endpoint that exposes all `@ConfigurationProperties` beans. -Point your web browser to `/actuator/configprops` or use the equivalent JMX endpoint. -See the "<>" section for details. - - - -[[features.external-config.typesafe-configuration-properties.vs-value-annotation]] -==== @ConfigurationProperties vs. @Value -The `@Value` annotation is a core container feature, and it does not provide the same features as type-safe configuration properties. -The following table summarizes the features that are supported by `@ConfigurationProperties` and `@Value`: - -[cols="4,2,2"] -|=== -| Feature |`@ConfigurationProperties` |`@Value` - -| <> -| Yes -| Limited (see <>) - -| <> -| Yes -| No - -| `SpEL` evaluation -| No -| Yes -|=== - -NOTE: [[boot-features-external-config-vs-value-note]] If you do want to use `@Value`, we recommend that you refer to property names using their canonical form (kebab-case using only lowercase letters). -This will allow Spring Boot to use the same logic as it does when relaxed binding `@ConfigurationProperties`. -For example, `@Value("{demo.item-price}")` will pick up `demo.item-price` and `demo.itemPrice` forms from the `application.properties` file, as well as `DEMO_ITEMPRICE` from the system environment. -If you used `@Value("{demo.itemPrice}")` instead, `demo.item-price` and `DEMO_ITEMPRICE` would not be considered. - -If you define a set of configuration keys for your own components, we recommend you group them in a POJO annotated with `@ConfigurationProperties`. -Doing so will provide you with structured, type-safe object that you can inject into your own beans. - -`SpEL` expressions from <> are not processed at time of parsing these files and populating the environment. -However, it is possible to write a `SpEL` expression in `@Value`. -If the value of a property from an application property file is a `SpEL` expression, it will be evaluated when consumed via `@Value`. - - - -[[features.profiles]] -== Profiles -Spring Profiles provide a way to segregate parts of your application configuration and make it be available only in certain environments. -Any `@Component`, `@Configuration` or `@ConfigurationProperties` can be marked with `@Profile` to limit when it is loaded, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/profiles/ProductionConfiguration.java[] ----- - -NOTE: If `@ConfigurationProperties` beans are registered via `@EnableConfigurationProperties` instead of automatic scanning, the `@Profile` annotation needs to be specified on the `@Configuration` class that has the `@EnableConfigurationProperties` annotation. -In the case where `@ConfigurationProperties` are scanned, `@Profile` can be specified on the `@ConfigurationProperties` class itself. - -You can use a configprop:spring.profiles.active[] `Environment` property to specify which profiles are active. -You can specify the property in any of the ways described earlier in this chapter. -For example, you could include it in your `application.properties`, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - profiles: - active: "dev,hsqldb" ----- - -You could also specify it on the command line by using the following switch: `--spring.profiles.active=dev,hsqldb`. - - - -[[features.profiles.adding-active-profiles]] -=== Adding Active Profiles -The configprop:spring.profiles.active[] property follows the same ordering rules as other properties: The highest `PropertySource` wins. -This means that you can specify active profiles in `application.properties` and then *replace* them by using the command line switch. - -Sometimes, it is useful to have properties that *add* to the active profiles rather than replace them. -The `SpringApplication` entry point has a Java API for setting additional profiles (that is, on top of those activated by the configprop:spring.profiles.active[] property). -See the `setAdditionalProfiles()` method in {spring-boot-module-api}/SpringApplication.html[SpringApplication]. -Profile groups, which are described in the <> can also be used to add active profiles if a given profile is active. - - - -[[features.profiles.groups]] -=== Profile Groups -Occasionally the profiles that you define and use in your application are too fine-grained and become cumbersome to use. -For example, you might have `proddb` and `prodmq` profiles that you use to enable database and messaging features independently. - -To help with this, Spring Boot lets you define profile groups. -A profile group allows you to define a logical name for a related group of profiles. - -For example, we can create a `production` group that consists of our `proddb` and `prodmq` profiles. - -[source,yaml,indent=0,configblocks] ----- - spring: - profiles: - group: - production: - - "proddb" - - "prodmq" ----- - -Our application can now be started using `--spring.profiles.active=production` to active the `production`, `proddb` and `prodmq` profiles in one hit. - - - -[[features.profiles.programmatically-setting-profiles]] -=== Programmatically Setting Profiles -You can programmatically set active profiles by calling `SpringApplication.setAdditionalProfiles(...)` before your application runs. -It is also possible to activate profiles by using Spring's `ConfigurableEnvironment` interface. - - - -[[features.profiles.profile-specific-configuration-files]] -=== Profile-specific Configuration Files -Profile-specific variants of both `application.properties` (or `application.yml`) and files referenced through `@ConfigurationProperties` are considered as files and loaded. -See "<>" for details. - - - -[[features.logging]] -== Logging -Spring Boot uses https://commons.apache.org/logging[Commons Logging] for all internal logging but leaves the underlying log implementation open. -Default configurations are provided for {java-api}/java/util/logging/package-summary.html[Java Util Logging], https://logging.apache.org/log4j/2.x/[Log4J2], and https://logback.qos.ch/[Logback]. -In each case, loggers are pre-configured to use console output with optional file output also available. - -By default, if you use the "`Starters`", Logback is used for logging. -Appropriate Logback routing is also included to ensure that dependent libraries that use Java Util Logging, Commons Logging, Log4J, or SLF4J all work correctly. - -TIP: There are a lot of logging frameworks available for Java. -Do not worry if the above list seems confusing. -Generally, you do not need to change your logging dependencies and the Spring Boot defaults work just fine. - -TIP: When you deploy your application to a servlet container or application server, logging performed via the Java Util Logging API is not routed into your application's logs. -This prevents logging performed by the container or other applications that have been deployed to it from appearing in your application's logs. - - - -[[features.logging.log-format]] -=== Log Format -The default log output from Spring Boot resembles the following example: - -[indent=0] ----- -2019-03-05 10:57:51.112 INFO 45469 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet Engine: Apache Tomcat/7.0.52 -2019-03-05 10:57:51.253 INFO 45469 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext -2019-03-05 10:57:51.253 INFO 45469 --- [ost-startStop-1] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 1358 ms -2019-03-05 10:57:51.698 INFO 45469 --- [ost-startStop-1] o.s.b.c.e.ServletRegistrationBean : Mapping servlet: 'dispatcherServlet' to [/] -2019-03-05 10:57:51.702 INFO 45469 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean : Mapping filter: 'hiddenHttpMethodFilter' to: [/*] ----- - -The following items are output: - -* Date and Time: Millisecond precision and easily sortable. -* Log Level: `ERROR`, `WARN`, `INFO`, `DEBUG`, or `TRACE`. -* Process ID. -* A `---` separator to distinguish the start of actual log messages. -* Thread name: Enclosed in square brackets (may be truncated for console output). -* Logger name: This is usually the source class name (often abbreviated). -* The log message. - -NOTE: Logback does not have a `FATAL` level. -It is mapped to `ERROR`. - - - -[[features.logging.console-output]] -=== Console Output -The default log configuration echoes messages to the console as they are written. -By default, `ERROR`-level, `WARN`-level, and `INFO`-level messages are logged. -You can also enable a "`debug`" mode by starting your application with a `--debug` flag. - -[indent=0] ----- - $ java -jar myapp.jar --debug ----- - -NOTE: You can also specify `debug=true` in your `application.properties`. - -When the debug mode is enabled, a selection of core loggers (embedded container, Hibernate, and Spring Boot) are configured to output more information. -Enabling the debug mode does _not_ configure your application to log all messages with `DEBUG` level. - -Alternatively, you can enable a "`trace`" mode by starting your application with a `--trace` flag (or `trace=true` in your `application.properties`). -Doing so enables trace logging for a selection of core loggers (embedded container, Hibernate schema generation, and the whole Spring portfolio). - - - -[[features.logging.console-output.color-coded]] -==== Color-coded Output -If your terminal supports ANSI, color output is used to aid readability. -You can set `spring.output.ansi.enabled` to a {spring-boot-module-api}/ansi/AnsiOutput.Enabled.html[supported value] to override the auto-detection. - -Color coding is configured by using the `%clr` conversion word. -In its simplest form, the converter colors the output according to the log level, as shown in the following example: - -[source,indent=0] ----- -%clr(%5p) ----- - -The following table describes the mapping of log levels to colors: - -|=== -| Level | Color - -| `FATAL` -| Red - -| `ERROR` -| Red - -| `WARN` -| Yellow - -| `INFO` -| Green - -| `DEBUG` -| Green - -| `TRACE` -| Green -|=== - -Alternatively, you can specify the color or style that should be used by providing it as an option to the conversion. -For example, to make the text yellow, use the following setting: - -[source,indent=0] ----- -%clr(%d{yyyy-MM-dd HH:mm:ss.SSS}){yellow} ----- - -The following colors and styles are supported: - -* `blue` -* `cyan` -* `faint` -* `green` -* `magenta` -* `red` -* `yellow` - - - -[[features.logging.file-output]] -=== File Output -By default, Spring Boot logs only to the console and does not write log files. -If you want to write log files in addition to the console output, you need to set a configprop:logging.file.name[] or configprop:logging.file.path[] property (for example, in your `application.properties`). - -The following table shows how the `logging.*` properties can be used together: - -.Logging properties -[cols="1,1,1,4"] -|=== -| configprop:logging.file.name[] | configprop:logging.file.path[] | Example | Description - -| _(none)_ -| _(none)_ -| -| Console only logging. - -| Specific file -| _(none)_ -| `my.log` -| Writes to the specified log file. - Names can be an exact location or relative to the current directory. - -| _(none)_ -| Specific directory -| `/var/log` -| Writes `spring.log` to the specified directory. - Names can be an exact location or relative to the current directory. -|=== - -Log files rotate when they reach 10 MB and, as with console output, `ERROR`-level, `WARN`-level, and `INFO`-level messages are logged by default. - -TIP: Logging properties are independent of the actual logging infrastructure. -As a result, specific configuration keys (such as `logback.configurationFile` for Logback) are not managed by spring Boot. - - - -[[features.logging.file-rotation]] -=== File Rotation -If you are using the Logback, it's possible to fine-tune log rotation settings using your `application.properties` or `application.yaml` file. -For all other logging system, you'll need to configure rotation settings directly yourself (for example, if you use Log4J2 then you could add a `log4j.xml` file). - -The following rotation policy properties are supported: - -|=== -| Name | Description - -| configprop:logging.logback.rollingpolicy.file-name-pattern[] -| The filename pattern used to create log archives. - -| configprop:logging.logback.rollingpolicy.clean-history-on-start[] -| If log archive cleanup should occur when the application starts. - -| configprop:logging.logback.rollingpolicy.max-file-size[] -| The maximum size of log file before it's archived. - -| configprop:logging.logback.rollingpolicy.total-size-cap[] -| The maximum amount of size log archives can take before being deleted. - -| configprop:logging.logback.rollingpolicy.max-history[] -| The number of days to keep log archives (defaults to 7) -|=== - - - -[[features.logging.log-levels]] -=== Log Levels -All the supported logging systems can have the logger levels set in the Spring `Environment` (for example, in `application.properties`) by using `+logging.level.=+` where `level` is one of TRACE, DEBUG, INFO, WARN, ERROR, FATAL, or OFF. -The `root` logger can be configured by using `logging.level.root`. - -The following example shows potential logging settings in `application.properties`: - -[source,properties,indent=0,subs="verbatim,quotes,attributes",configprops,role="primary"] -.Properties ----- - logging.level.root=warn - logging.level.org.springframework.web=debug - logging.level.org.hibernate=error ----- - -[source,properties,indent=0,subs="verbatim,quotes,attributes",role="secondary"] -.Yaml ----- - logging: - level: - root: "warn" - org.springframework.web: "debug" - org.hibernate: "error" ----- - -It's also possible to set logging levels using environment variables. -For example, `LOGGING_LEVEL_ORG_SPRINGFRAMEWORK_WEB=DEBUG` will set `org.springframework.web` to `DEBUG`. - -NOTE: The above approach will only work for package level logging. -Since relaxed binding always converts environment variables to lowercase, it's not possible to configure logging for an individual class in this way. -If you need to configure logging for a class, you can use <> variable. - - - -[[features.logging.log-groups]] -=== Log Groups -It's often useful to be able to group related loggers together so that they can all be configured at the same time. -For example, you might commonly change the logging levels for _all_ Tomcat related loggers, but you can't easily remember top level packages. - -To help with this, Spring Boot allows you to define logging groups in your Spring `Environment`. -For example, here's how you could define a "`tomcat`" group by adding it to your `application.properties`: - -[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] ----- - logging: - group: - tomcat: "org.apache.catalina,org.apache.coyote,org.apache.tomcat" ----- - -Once defined, you can change the level for all the loggers in the group with a single line: - -[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] ----- - logging: - level: - tomcat: "trace" ----- - -Spring Boot includes the following pre-defined logging groups that can be used out-of-the-box: - -[cols="1,4"] -|=== -| Name | Loggers - -| web -| `org.springframework.core.codec`, `org.springframework.http`, `org.springframework.web`, `org.springframework.boot.actuate.endpoint.web`, `org.springframework.boot.web.servlet.ServletContextInitializerBeans` - -| sql -| `org.springframework.jdbc.core`, `org.hibernate.SQL`, `org.jooq.tools.LoggerListener` -|=== - - - -[[features.logging.shutdown-hook]] -=== Using a Log Shutdown Hook -In order to release logging resources when your application terminates, a shutdown hook that will trigger log system cleanup when the JVM exits is provided. -This shutdown hook is registered automatically unless your application is deployed as a war file. -If your application has complex context hierarchies the shutdown hook may not meet your needs. -If it does not, disable the shutdown hook and investigate the options provided directly by the underlying logging system. -For example, Logback offers http://logback.qos.ch/manual/loggingSeparation.html[context selectors] which allow each Logger to be created in its own context. -You can use the configprop:logging.register-shutdown-hook[] property to disable the shutdown hook. -Setting it to `false` will disable the registration. -You can set the property in your `application.properties` or `application.yaml` file: - -[source,yaml,indent=0,configprops,configblocks] ----- - logging: - register-shutdown-hook: false ----- - - - -[[features.logging.custom-log-configuration]] -=== Custom Log Configuration -The various logging systems can be activated by including the appropriate libraries on the classpath and can be further customized by providing a suitable configuration file in the root of the classpath or in a location specified by the following Spring `Environment` property: configprop:logging.config[]. - -You can force Spring Boot to use a particular logging system by using the `org.springframework.boot.logging.LoggingSystem` system property. -The value should be the fully qualified class name of a `LoggingSystem` implementation. -You can also disable Spring Boot's logging configuration entirely by using a value of `none`. - -NOTE: Since logging is initialized *before* the `ApplicationContext` is created, it is not possible to control logging from `@PropertySources` in Spring `@Configuration` files. -The only way to change the logging system or disable it entirely is via System properties. - -Depending on your logging system, the following files are loaded: - -|=== -| Logging System | Customization - -| Logback -| `logback-spring.xml`, `logback-spring.groovy`, `logback.xml`, or `logback.groovy` - -| Log4j2 -| `log4j2-spring.xml` or `log4j2.xml` - -| JDK (Java Util Logging) -| `logging.properties` -|=== - -NOTE: When possible, we recommend that you use the `-spring` variants for your logging configuration (for example, `logback-spring.xml` rather than `logback.xml`). -If you use standard configuration locations, Spring cannot completely control log initialization. - -WARNING: There are known classloading issues with Java Util Logging that cause problems when running from an 'executable jar'. -We recommend that you avoid it when running from an 'executable jar' if at all possible. - -To help with the customization, some other properties are transferred from the Spring `Environment` to System properties, as described in the following table: - -|=== -| Spring Environment | System Property | Comments - -| configprop:logging.exception-conversion-word[] -| `LOG_EXCEPTION_CONVERSION_WORD` -| The conversion word used when logging exceptions. - -| configprop:logging.file.name[] -| `LOG_FILE` -| If defined, it is used in the default log configuration. - -| configprop:logging.file.path[] -| `LOG_PATH` -| If defined, it is used in the default log configuration. - -| configprop:logging.pattern.console[] -| `CONSOLE_LOG_PATTERN` -| The log pattern to use on the console (stdout). - -| configprop:logging.pattern.dateformat[] -| `LOG_DATEFORMAT_PATTERN` -| Appender pattern for log date format. - -| configprop:logging.charset.console[] -| `CONSOLE_LOG_CHARSET` -| The charset to use for console logging. - -| configprop:logging.pattern.file[] -| `FILE_LOG_PATTERN` -| The log pattern to use in a file (if `LOG_FILE` is enabled). - -| configprop:logging.charset.file[] -| `FILE_LOG_CHARSET` -| The charset to use for file logging (if `LOG_FILE` is enabled). - -| configprop:logging.pattern.level[] -| `LOG_LEVEL_PATTERN` -| The format to use when rendering the log level (default `%5p`). - -| `PID` -| `PID` -| The current process ID (discovered if possible and when not already defined as an OS environment variable). -|=== - -If you're using Logback, the following properties are also transferred: - -|=== -| Spring Environment | System Property | Comments - -| configprop:logging.logback.rollingpolicy.file-name-pattern[] -| `LOGBACK_ROLLINGPOLICY_FILE_NAME_PATTERN` -| Pattern for rolled-over log file names (default `$\{LOG_FILE}.%d\{yyyy-MM-dd}.%i.gz`). - -| configprop:logging.logback.rollingpolicy.clean-history-on-start[] -| `LOGBACK_ROLLINGPOLICY_CLEAN_HISTORY_ON_START` -| Whether to clean the archive log files on startup. - -| configprop:logging.logback.rollingpolicy.max-file-size[] -| `LOGBACK_ROLLINGPOLICY_MAX_FILE_SIZE` -| Maximum log file size. - -| configprop:logging.logback.rollingpolicy.total-size-cap[] -| `LOGBACK_ROLLINGPOLICY_TOTAL_SIZE_CAP` -| Total size of log backups to be kept. - -| configprop:logging.logback.rollingpolicy.max-history[] -| `LOGBACK_ROLLINGPOLICY_MAX_HISTORY` -| Maximum number of archive log files to keep. -|=== - - -All the supported logging systems can consult System properties when parsing their configuration files. -See the default configurations in `spring-boot.jar` for examples: - -* {spring-boot-code}/spring-boot-project/spring-boot/src/main/resources/org/springframework/boot/logging/logback/defaults.xml[Logback] -* {spring-boot-code}/spring-boot-project/spring-boot/src/main/resources/org/springframework/boot/logging/log4j2/log4j2.xml[Log4j 2] -* {spring-boot-code}/spring-boot-project/spring-boot/src/main/resources/org/springframework/boot/logging/java/logging-file.properties[Java Util logging] - -[TIP] -==== -If you want to use a placeholder in a logging property, you should use <> and not the syntax of the underlying framework. -Notably, if you use Logback, you should use `:` as the delimiter between a property name and its default value and not use `:-`. -==== - -[TIP] -==== -You can add MDC and other ad-hoc content to log lines by overriding only the `LOG_LEVEL_PATTERN` (or `logging.pattern.level` with Logback). -For example, if you use `logging.pattern.level=user:%X\{user} %5p`, then the default log format contains an MDC entry for "user", if it exists, as shown in the following example. - -[indent=0] ----- - 2019-08-30 12:30:04.031 user:someone INFO 22174 --- [ nio-8080-exec-0] demo.Controller - Handling authenticated request ----- -==== - - - -[[features.logging.logback-extensions]] -=== Logback Extensions -Spring Boot includes a number of extensions to Logback that can help with advanced configuration. -You can use these extensions in your `logback-spring.xml` configuration file. - -NOTE: Because the standard `logback.xml` configuration file is loaded too early, you cannot use extensions in it. -You need to either use `logback-spring.xml` or define a configprop:logging.config[] property. - -WARNING: The extensions cannot be used with Logback's https://logback.qos.ch/manual/configuration.html#autoScan[configuration scanning]. -If you attempt to do so, making changes to the configuration file results in an error similar to one of the following being logged: - -[indent=0] ----- - ERROR in ch.qos.logback.core.joran.spi.Interpreter@4:71 - no applicable action for [springProperty], current ElementPath is [[configuration][springProperty]] - ERROR in ch.qos.logback.core.joran.spi.Interpreter@4:71 - no applicable action for [springProfile], current ElementPath is [[configuration][springProfile]] ----- - - - -[[features.logging.logback-extensions.profile-specific]] -==== Profile-specific Configuration -The `` tag lets you optionally include or exclude sections of configuration based on the active Spring profiles. -Profile sections are supported anywhere within the `` element. -Use the `name` attribute to specify which profile accepts the configuration. -The `` tag can contain a profile name (for example `staging`) or a profile expression. -A profile expression allows for more complicated profile logic to be expressed, for example `production & (eu-central | eu-west)`. -Check the {spring-framework-docs}/core.html#beans-definition-profiles-java[reference guide] for more details. -The following listing shows three sample profiles: - -[source,xml,indent=0] ----- - - - - - - - - - - - ----- - - - -[[features.logging.logback-extensions.environment-properties]] -==== Environment Properties -The `` tag lets you expose properties from the Spring `Environment` for use within Logback. -Doing so can be useful if you want to access values from your `application.properties` file in your Logback configuration. -The tag works in a similar way to Logback's standard `` tag. -However, rather than specifying a direct `value`, you specify the `source` of the property (from the `Environment`). -If you need to store the property somewhere other than in `local` scope, you can use the `scope` attribute. -If you need a fallback value (in case the property is not set in the `Environment`), you can use the `defaultValue` attribute. -The following example shows how to expose properties for use within Logback: - -[source,xml,indent=0] ----- - - - ${fluentHost} - ... - ----- - -NOTE: The `source` must be specified in kebab case (such as `my.property-name`). -However, properties can be added to the `Environment` by using the relaxed rules. - - - -[[features.internationalization]] -== Internationalization -Spring Boot supports localized messages so that your application can cater to users of different language preferences. -By default, Spring Boot looks for the presence of a `messages` resource bundle at the root of the classpath. - -NOTE: The auto-configuration applies when the default properties file for the configured resource bundle is available (i.e. `messages.properties` by default). -If your resource bundle contains only language-specific properties files, you are required to add the default. -If no properties file is found that matches any of the configured base names, there will be no auto-configured `MessageSource`. - -The basename of the resource bundle as well as several other attributes can be configured using the `spring.messages` namespace, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - messages: - basename: "messages,config.i18n.messages" - fallback-to-system-locale: false ----- - -TIP: `spring.messages.basename` supports comma-separated list of locations, either a package qualifier or a resource resolved from the classpath root. - -See {spring-boot-autoconfigure-module-code}/context/MessageSourceProperties.java[`MessageSourceProperties`] for more supported options. - - - -[[features.json]] -== JSON -Spring Boot provides integration with three JSON mapping libraries: - -- Gson -- Jackson -- JSON-B - -Jackson is the preferred and default library. - - - -[[features.json.jackson]] -=== Jackson -Auto-configuration for Jackson is provided and Jackson is part of `spring-boot-starter-json`. -When Jackson is on the classpath an `ObjectMapper` bean is automatically configured. -Several configuration properties are provided for <>. - - - -[[features.json.gson]] -=== Gson -Auto-configuration for Gson is provided. -When Gson is on the classpath a `Gson` bean is automatically configured. -Several `+spring.gson.*+` configuration properties are provided for customizing the configuration. -To take more control, one or more `GsonBuilderCustomizer` beans can be used. - - - -[[features.json.json-b]] -=== JSON-B -Auto-configuration for JSON-B is provided. -When the JSON-B API and an implementation are on the classpath a `Jsonb` bean will be automatically configured. -The preferred JSON-B implementation is Apache Johnzon for which dependency management is provided. - - - -[[features.developing-web-applications]] -== Developing Web Applications -Spring Boot is well suited for web application development. -You can create a self-contained HTTP server by using embedded Tomcat, Jetty, Undertow, or Netty. -Most web applications use the `spring-boot-starter-web` module to get up and running quickly. -You can also choose to build reactive web applications by using the `spring-boot-starter-webflux` module. - -If you have not yet developed a Spring Boot web application, you can follow the "Hello World!" example in the _<>_ section. - - - -[[features.developing-web-applications.spring-mvc]] -=== The "`Spring Web MVC Framework`" -The {spring-framework-docs}/web.html#mvc[Spring Web MVC framework] (often referred to as "`Spring MVC`") is a rich "`model view controller`" web framework. -Spring MVC lets you create special `@Controller` or `@RestController` beans to handle incoming HTTP requests. -Methods in your controller are mapped to HTTP by using `@RequestMapping` annotations. - -The following code shows a typical `@RestController` that serves JSON data: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/webapplications/servlet/MyRestController.java[] ----- - -Spring MVC is part of the core Spring Framework, and detailed information is available in the {spring-framework-docs}/web.html#mvc[reference documentation]. -There are also several guides that cover Spring MVC available at https://spring.io/guides. - - - -[[features.developing-web-applications.spring-mvc.auto-configuration]] -==== Spring MVC Auto-configuration -Spring Boot provides auto-configuration for Spring MVC that works well with most applications. - -The auto-configuration adds the following features on top of Spring's defaults: - -* Inclusion of `ContentNegotiatingViewResolver` and `BeanNameViewResolver` beans. -* Support for serving static resources, including support for WebJars (covered <>)). -* Automatic registration of `Converter`, `GenericConverter`, and `Formatter` beans. -* Support for `HttpMessageConverters` (covered <>). -* Automatic registration of `MessageCodesResolver` (covered <>). -* Static `index.html` support. -* Automatic use of a `ConfigurableWebBindingInitializer` bean (covered <>). - -If you want to keep those Spring Boot MVC customizations and make more {spring-framework-docs}/web.html#mvc[MVC customizations] (interceptors, formatters, view controllers, and other features), you can add your own `@Configuration` class of type `WebMvcConfigurer` but *without* `@EnableWebMvc`. - -If you want to provide custom instances of `RequestMappingHandlerMapping`, `RequestMappingHandlerAdapter`, or `ExceptionHandlerExceptionResolver`, and still keep the Spring Boot MVC customizations, you can declare a bean of type `WebMvcRegistrations` and use it to provide custom instances of those components. - -If you want to take complete control of Spring MVC, you can add your own `@Configuration` annotated with `@EnableWebMvc`, or alternatively add your own `@Configuration`-annotated `DelegatingWebMvcConfiguration` as described in the Javadoc of `@EnableWebMvc`. - -[NOTE] -==== -Spring MVC uses a different `ConversionService` to the one used to convert values from your `application.properties` or `application.yaml` file. -It means that `Period`, `Duration` and `DataSize` converters are not available and that `@DurationUnit` and `@DataSizeUnit` annotations will be ignored. - -If you want to customize the `ConversionService` used by Spring MVC, you can provide a `WebMvcConfigurer` bean with an `addFormatters` method. -From this method you can register any converter that you like, or you can delegate to the static methods available on `ApplicationConversionService`. -==== - - - -[[features.developing-web-applications.spring-mvc.message-converters]] -==== HttpMessageConverters -Spring MVC uses the `HttpMessageConverter` interface to convert HTTP requests and responses. -Sensible defaults are included out of the box. -For example, objects can be automatically converted to JSON (by using the Jackson library) or XML (by using the Jackson XML extension, if available, or by using JAXB if the Jackson XML extension is not available). -By default, strings are encoded in `UTF-8`. - -If you need to add or customize converters, you can use Spring Boot's `HttpMessageConverters` class, as shown in the following listing: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/webapplications/HttpMessageConvertersConfiguration.java[] ----- - -Any `HttpMessageConverter` bean that is present in the context is added to the list of converters. -You can also override default converters in the same way. - - - -[[features.developing-web-applications.spring-mvc.json]] -==== Custom JSON Serializers and Deserializers -If you use Jackson to serialize and deserialize JSON data, you might want to write your own `JsonSerializer` and `JsonDeserializer` classes. -Custom serializers are usually https://github.com/FasterXML/jackson-docs/wiki/JacksonHowToCustomSerializers[registered with Jackson through a module], but Spring Boot provides an alternative `@JsonComponent` annotation that makes it easier to directly register Spring Beans. - -You can use the `@JsonComponent` annotation directly on `JsonSerializer`, `JsonDeserializer` or `KeyDeserializer` implementations. -You can also use it on classes that contain serializers/deserializers as inner classes, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/webapplications/json/MyJsonComponent.java[] ----- - -All `@JsonComponent` beans in the `ApplicationContext` are automatically registered with Jackson. -Because `@JsonComponent` is meta-annotated with `@Component`, the usual component-scanning rules apply. - -Spring Boot also provides {spring-boot-module-code}/jackson/JsonObjectSerializer.java[`JsonObjectSerializer`] and {spring-boot-module-code}/jackson/JsonObjectDeserializer.java[`JsonObjectDeserializer`] base classes that provide useful alternatives to the standard Jackson versions when serializing objects. -See {spring-boot-module-api}/jackson/JsonObjectSerializer.html[`JsonObjectSerializer`] and {spring-boot-module-api}/jackson/JsonObjectDeserializer.html[`JsonObjectDeserializer`] in the Javadoc for details. - -The example above can be rewritten to use `JsonObjectSerializer`/`JsonObjectDeserializer` as follows: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/webapplications/json/object/MyJsonComponent.java[] ----- - - - -[[features.developing-web-applications.spring-mvc.message-codes]] -==== MessageCodesResolver -Spring MVC has a strategy for generating error codes for rendering error messages from binding errors: `MessageCodesResolver`. -If you set the configprop:spring.mvc.message-codes-resolver-format[] property `PREFIX_ERROR_CODE` or `POSTFIX_ERROR_CODE`, Spring Boot creates one for you (see the enumeration in {spring-framework-api}/validation/DefaultMessageCodesResolver.Format.html[`DefaultMessageCodesResolver.Format`]). - - - -[[features.developing-web-applications.spring-mvc.static-content]] -==== Static Content -By default, Spring Boot serves static content from a directory called `/static` (or `/public` or `/resources` or `/META-INF/resources`) in the classpath or from the root of the `ServletContext`. -It uses the `ResourceHttpRequestHandler` from Spring MVC so that you can modify that behavior by adding your own `WebMvcConfigurer` and overriding the `addResourceHandlers` method. - -In a stand-alone web application, the default servlet from the container is also enabled and acts as a fallback, serving content from the root of the `ServletContext` if Spring decides not to handle it. -Most of the time, this does not happen (unless you modify the default MVC configuration), because Spring can always handle requests through the `DispatcherServlet`. - -By default, resources are mapped on `+/**+`, but you can tune that with the configprop:spring.mvc.static-path-pattern[] property. -For instance, relocating all resources to `/resources/**` can be achieved as follows: - -[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] ----- - spring: - mvc: - static-path-pattern: "/resources/**" ----- - -You can also customize the static resource locations by using the configprop:spring.web.resources.static-locations[] property (replacing the default values with a list of directory locations). -The root Servlet context path, `"/"`, is automatically added as a location as well. - -In addition to the "`standard`" static resource locations mentioned earlier, a special case is made for https://www.webjars.org/[Webjars content]. -Any resources with a path in `+/webjars/**+` are served from jar files if they are packaged in the Webjars format. - -TIP: Do not use the `src/main/webapp` directory if your application is packaged as a jar. -Although this directory is a common standard, it works *only* with war packaging, and it is silently ignored by most build tools if you generate a jar. - -Spring Boot also supports the advanced resource handling features provided by Spring MVC, allowing use cases such as cache-busting static resources or using version agnostic URLs for Webjars. - -To use version agnostic URLs for Webjars, add the `webjars-locator-core` dependency. -Then declare your Webjar. -Using jQuery as an example, adding `"/webjars/jquery/jquery.min.js"` results in `"/webjars/jquery/x.y.z/jquery.min.js"` where `x.y.z` is the Webjar version. - -NOTE: If you use JBoss, you need to declare the `webjars-locator-jboss-vfs` dependency instead of the `webjars-locator-core`. -Otherwise, all Webjars resolve as a `404`. - -To use cache busting, the following configuration configures a cache busting solution for all static resources, effectively adding a content hash, such as ``, in URLs: - -[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] ----- - spring: - web: - resources: - chain: - strategy: - content: - enabled: true - paths: "/**" ----- - -NOTE: Links to resources are rewritten in templates at runtime, thanks to a `ResourceUrlEncodingFilter` that is auto-configured for Thymeleaf and FreeMarker. -You should manually declare this filter when using JSPs. -Other template engines are currently not automatically supported but can be with custom template macros/helpers and the use of the {spring-framework-api}/web/servlet/resource/ResourceUrlProvider.html[`ResourceUrlProvider`]. - -When loading resources dynamically with, for example, a JavaScript module loader, renaming files is not an option. -That is why other strategies are also supported and can be combined. -A "fixed" strategy adds a static version string in the URL without changing the file name, as shown in the following example: - -[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] ----- - spring: - web: - resources: - chain: - strategy: - content: - enabled: true - paths: "/**" - fixed: - enabled: true - paths: "/js/lib/" - version: "v12" ----- - -With this configuration, JavaScript modules located under `"/js/lib/"` use a fixed versioning strategy (`"/v12/js/lib/mymodule.js"`), while other resources still use the content one (``). - -See {spring-boot-autoconfigure-module-code}/web/ResourceProperties.java[`ResourceProperties`] for more supported options. - -[TIP] -==== -This feature has been thoroughly described in a dedicated https://spring.io/blog/2014/07/24/spring-framework-4-1-handling-static-web-resources[blog post] and in Spring Framework's {spring-framework-docs}/web.html#mvc-config-static-resources[reference documentation]. -==== - - - -[[features.developing-web-applications.spring-mvc.welcome-page]] -==== Welcome Page -Spring Boot supports both static and templated welcome pages. -It first looks for an `index.html` file in the configured static content locations. -If one is not found, it then looks for an `index` template. -If either is found, it is automatically used as the welcome page of the application. - - - -[[features.developing-web-applications.spring-mvc.content-negotiation]] -==== Path Matching and Content Negotiation -Spring MVC can map incoming HTTP requests to handlers by looking at the request path and matching it to the mappings defined in your application (for example, `@GetMapping` annotations on Controller methods). - -Spring Boot chooses to disable suffix pattern matching by default, which means that requests like `"GET /projects/spring-boot.json"` won't be matched to `@GetMapping("/projects/spring-boot")` mappings. -This is considered as a {spring-framework-docs}/web.html#mvc-ann-requestmapping-suffix-pattern-match[best practice for Spring MVC applications]. -This feature was mainly useful in the past for HTTP clients which did not send proper "Accept" request headers; we needed to make sure to send the correct Content Type to the client. -Nowadays, Content Negotiation is much more reliable. - -There are other ways to deal with HTTP clients that don't consistently send proper "Accept" request headers. -Instead of using suffix matching, we can use a query parameter to ensure that requests like `"GET /projects/spring-boot?format=json"` will be mapped to `@GetMapping("/projects/spring-boot")`: - -[source,yaml,indent=0,subs="verbatim,quotes,attributes",configblocks] ----- - spring: - mvc: - contentnegotiation: - favor-parameter: true ----- - -Or if you prefer to use a different parameter name: - -[source,properties,indent=0,subs="verbatim,quotes,attributes"] ----- - spring: - mvc: - contentnegotiation: - favor-parameter: true - parameter-name: "myparam" ----- - -Most standard media types are supported out-of-the-box, but you can also define new ones: - -[source,yaml,indent=0,subs="verbatim,quotes,attributes",configblocks] ----- - spring: - mvc: - contentnegotiation: - media-types: - markdown: "text/markdown" ----- - - - -Suffix pattern matching is deprecated and will be removed in a future release. -If you understand the caveats and would still like your application to use suffix pattern matching, the following configuration is required: - -[source,yaml,indent=0,subs="verbatim,quotes,attributes",configblocks] ----- - spring: - mvc: - contentnegotiation: - favor-path-extension: true - pathmatch: - use-suffix-pattern: true ----- - -Alternatively, rather than open all suffix patterns, it's more secure to only support registered suffix patterns: - -[source,yaml,indent=0,subs="verbatim,quotes,attributes",configblocks] ----- - spring: - mvc: - contentnegotiation: - favor-path-extension: true - pathmatch: - use-registered-suffix-pattern: true ----- - -As of Spring Framework 5.3, Spring MVC supports several implementation strategies for matching request paths to Controller handlers. -It was previously only supporting the `AntPathMatcher` strategy, but it now also offers `PathPatternParser`. -Spring Boot now provides a configuration property to choose and opt in the new strategy: - -[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] ----- - spring: - mvc: - pathmatch: - matching-strategy: "path-pattern-parser" ----- - -For more details on why you should consider this new implementation, please check out the -https://spring.io/blog/2020/06/30/url-matching-with-pathpattern-in-spring-mvc[dedicated blog post]. - -NOTE: `PathPatternParser` is an optimized implementation but restricts usage of -{spring-framework-docs}/web.html#mvc-ann-requestmapping-uri-templates[some path patterns variants] -and is incompatible with suffix pattern matching (configprop:spring.mvc.pathmatch.use-suffix-pattern[deprecated], -configprop:spring.mvc.pathmatch.use-registered-suffix-pattern[deprecated]) or mapping the `DispatcherServlet` -with a Servlet prefix (configprop:spring.mvc.servlet.path[]). - - - -[[features.developing-web-applications.spring-mvc.binding-initializer]] -==== ConfigurableWebBindingInitializer -Spring MVC uses a `WebBindingInitializer` to initialize a `WebDataBinder` for a particular request. -If you create your own `ConfigurableWebBindingInitializer` `@Bean`, Spring Boot automatically configures Spring MVC to use it. - - - -[[features.developing-web-applications.spring-mvc.template-engines]] -==== Template Engines -As well as REST web services, you can also use Spring MVC to serve dynamic HTML content. -Spring MVC supports a variety of templating technologies, including Thymeleaf, FreeMarker, and JSPs. -Also, many other templating engines include their own Spring MVC integrations. - -Spring Boot includes auto-configuration support for the following templating engines: - - * https://freemarker.apache.org/docs/[FreeMarker] - * https://docs.groovy-lang.org/docs/next/html/documentation/template-engines.html#_the_markuptemplateengine[Groovy] - * https://www.thymeleaf.org[Thymeleaf] - * https://mustache.github.io/[Mustache] - -TIP: If possible, JSPs should be avoided. -There are several <> when using them with embedded servlet containers. - -When you use one of these templating engines with the default configuration, your templates are picked up automatically from `src/main/resources/templates`. - -TIP: Depending on how you run your application, your IDE may order the classpath differently. -Running your application in the IDE from its main method results in a different ordering than when you run your application by using Maven or Gradle or from its packaged jar. -This can cause Spring Boot to fail to find the expected template. -If you have this problem, you can reorder the classpath in the IDE to place the module's classes and resources first. - - - -[[features.developing-web-applications.spring-mvc.error-handling]] -==== Error Handling -By default, Spring Boot provides an `/error` mapping that handles all errors in a sensible way, and it is registered as a "`global`" error page in the servlet container. -For machine clients, it produces a JSON response with details of the error, the HTTP status, and the exception message. -For browser clients, there is a "`whitelabel`" error view that renders the same data in HTML format (to customize it, add a `View` that resolves to `error`). - -There are a number of `server.error` properties that can be set if you want to customize the default error handling behavior. -See the <> section of the Appendix. - -To replace the default behavior completely, you can implement `ErrorController` and register a bean definition of that type or add a bean of type `ErrorAttributes` to use the existing mechanism but replace the contents. - -TIP: The `BasicErrorController` can be used as a base class for a custom `ErrorController`. -This is particularly useful if you want to add a handler for a new content type (the default is to handle `text/html` specifically and provide a fallback for everything else). -To do so, extend `BasicErrorController`, add a public method with a `@RequestMapping` that has a `produces` attribute, and create a bean of your new type. - -You can also define a class annotated with `@ControllerAdvice` to customize the JSON document to return for a particular controller and/or exception type, as shown in the following example: - -[source,java,indent=0,subs="verbatim,quotes,attributes"] ----- -include::{include-springbootfeatures}/webapplications/servlet/MyControllerAdvice.java[] ----- - -In the preceding example, if `YourException` is thrown by a controller defined in the same package as `AcmeController`, a JSON representation of the `CustomErrorType` POJO is used instead of the `ErrorAttributes` representation. - -In some cases, errors handled at the controller level are not recorded by the <>. -Applications can ensure that such exceptions are recorded with the request metrics by setting the handled exception as a request attribute: - -[source,java,indent=0,subs="verbatim,quotes,attributes"] ----- -include::{include-springbootfeatures}/webapplications/servlet/MyController.java[] ----- - - - -[[features.developing-web-applications.spring-mvc.error-handling.error-pages]] -===== Custom Error Pages -If you want to display a custom HTML error page for a given status code, you can add a file to an `/error` directory. -Error pages can either be static HTML (that is, added under any of the static resource directories) or be built by using templates. -The name of the file should be the exact status code or a series mask. - -For example, to map `404` to a static HTML file, your directory structure would be as follows: - -[source,indent=0,subs="verbatim,quotes,attributes"] ----- - src/ - +- main/ - +- java/ - | + - +- resources/ - +- public/ - +- error/ - | +- 404.html - +- ----- - -To map all `5xx` errors by using a FreeMarker template, your directory structure would be as follows: - -[source,indent=0,subs="verbatim,quotes,attributes"] ----- - src/ - +- main/ - +- java/ - | + - +- resources/ - +- templates/ - +- error/ - | +- 5xx.ftlh - +- ----- - -For more complex mappings, you can also add beans that implement the `ErrorViewResolver` interface, as shown in the following example: - -[source,java,indent=0,subs="verbatim,quotes,attributes"] ----- -include::{include-springbootfeatures}/webapplications/servlet/MyErrorViewResolver.java[] ----- - -You can also use regular Spring MVC features such as {spring-framework-docs}/web.html#mvc-exceptionhandlers[`@ExceptionHandler` methods] and {spring-framework-docs}/web.html#mvc-ann-controller-advice[`@ControllerAdvice`]. -The `ErrorController` then picks up any unhandled exceptions. - - - -[[features.developing-web-applications.spring-mvc.error-handling.error-pages-without-spring-mvc]] -===== Mapping Error Pages outside of Spring MVC -For applications that do not use Spring MVC, you can use the `ErrorPageRegistrar` interface to directly register `ErrorPages`. -This abstraction works directly with the underlying embedded servlet container and works even if you do not have a Spring MVC `DispatcherServlet`. - -[source,java,indent=0,subs="verbatim,quotes,attributes"] ----- -include::{include-springbootfeatures}/webapplications/servlet/ErrorPageConfiguration.java[] ----- - -NOTE: If you register an `ErrorPage` with a path that ends up being handled by a `Filter` (as is common with some non-Spring web frameworks, like Jersey and Wicket), then the `Filter` has to be explicitly registered as an `ERROR` dispatcher, as shown in the following example: - -[source,java,indent=0,subs="verbatim,quotes,attributes"] ----- -include::{include-springbootfeatures}/webapplications/servlet/ServletFilterConfiguration.java[] ----- - -Note that the default `FilterRegistrationBean` does not include the `ERROR` dispatcher type. - - - -[[features.developing-web-applications.spring-mvc.error-handling.in-a-war-deployment]] -===== Error handling in a war deployment -When deployed to a servlet container, Spring Boot uses its error page filter to forward a request with an error status to the appropriate error page. -This is necessary as the Servlet specification does not provide an API for registering error pages. -Depending on the container that you are deploying your war file to and the technologies that your application uses, some additional configuration may be required. - -The error page filter can only forward the request to the correct error page if the response has not already been committed. -By default, WebSphere Application Server 8.0 and later commits the response upon successful completion of a servlet's service method. -You should disable this behavior by setting `com.ibm.ws.webcontainer.invokeFlushAfterService` to `false`. - -If you are using Spring Security and want to access the principal in an error page, you must configure Spring Security's filter to be invoked on error dispatches. -To do so, set the `spring.security.filter.dispatcher-types` property to `async, error, forward, request`. - - - -[[features.developing-web-applications.spring-mvc.spring-hateoas]] -==== Spring HATEOAS -If you develop a RESTful API that makes use of hypermedia, Spring Boot provides auto-configuration for Spring HATEOAS that works well with most applications. -The auto-configuration replaces the need to use `@EnableHypermediaSupport` and registers a number of beans to ease building hypermedia-based applications, including a `LinkDiscoverers` (for client side support) and an `ObjectMapper` configured to correctly marshal responses into the desired representation. -The `ObjectMapper` is customized by setting the various `spring.jackson.*` properties or, if one exists, by a `Jackson2ObjectMapperBuilder` bean. - -You can take control of Spring HATEOAS's configuration by using `@EnableHypermediaSupport`. -Note that doing so disables the `ObjectMapper` customization described earlier. - - - -[[features.developing-web-applications.spring-mvc.cors]] -==== CORS Support -https://en.wikipedia.org/wiki/Cross-origin_resource_sharing[Cross-origin resource sharing] (CORS) is a https://www.w3.org/TR/cors/[W3C specification] implemented by https://caniuse.com/#feat=cors[most browsers] that lets you specify in a flexible way what kind of cross-domain requests are authorized., instead of using some less secure and less powerful approaches such as IFRAME or JSONP. - -As of version 4.2, Spring MVC {spring-framework-docs}/web.html#mvc-cors[supports CORS]. -Using {spring-framework-docs}/web.html#mvc-cors-controller[controller method CORS configuration] with {spring-framework-api}/web/bind/annotation/CrossOrigin.html[`@CrossOrigin`] annotations in your Spring Boot application does not require any specific configuration. -{spring-framework-docs}/web.html#mvc-cors-global[Global CORS configuration] can be defined by registering a `WebMvcConfigurer` bean with a customized `addCorsMappings(CorsRegistry)` method, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/webapplications/servlet/CorsConfiguration.java[] ----- - - - -[[features.developing-web-applications.spring-webflux]] -=== The "`Spring WebFlux Framework`" -Spring WebFlux is the new reactive web framework introduced in Spring Framework 5.0. -Unlike Spring MVC, it does not require the Servlet API, is fully asynchronous and non-blocking, and implements the https://www.reactive-streams.org/[Reactive Streams] specification through https://projectreactor.io/[the Reactor project]. - -Spring WebFlux comes in two flavors: functional and annotation-based. -The annotation-based one is quite close to the Spring MVC model, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/webapplications/webflux/MyRestController.java[] ----- - -"`WebFlux.fn`", the functional variant, separates the routing configuration from the actual handling of the requests, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/webapplications/webflux/fn/RoutingConfiguration.java[] ----- - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/webapplications/webflux/fn/UserHandler.java[] ----- - -WebFlux is part of the Spring Framework and detailed information is available in its {spring-framework-docs}/web-reactive.html#webflux-fn[reference documentation]. - -TIP: You can define as many `RouterFunction` beans as you like to modularize the definition of the router. -Beans can be ordered if you need to apply a precedence. - -To get started, add the `spring-boot-starter-webflux` module to your application. - -NOTE: Adding both `spring-boot-starter-web` and `spring-boot-starter-webflux` modules in your application results in Spring Boot auto-configuring Spring MVC, not WebFlux. -This behavior has been chosen because many Spring developers add `spring-boot-starter-webflux` to their Spring MVC application to use the reactive `WebClient`. -You can still enforce your choice by setting the chosen application type to `SpringApplication.setWebApplicationType(WebApplicationType.REACTIVE)`. - - - -[[features.developing-web-applications.spring-webflux.auto-configuration]] -==== Spring WebFlux Auto-configuration -Spring Boot provides auto-configuration for Spring WebFlux that works well with most applications. - -The auto-configuration adds the following features on top of Spring's defaults: - -* Configuring codecs for `HttpMessageReader` and `HttpMessageWriter` instances (described <>). -* Support for serving static resources, including support for WebJars (described <>). - -If you want to keep Spring Boot WebFlux features and you want to add additional {spring-framework-docs}/web-reactive.html#webflux-config[WebFlux configuration], you can add your own `@Configuration` class of type `WebFluxConfigurer` but *without* `@EnableWebFlux`. - -If you want to take complete control of Spring WebFlux, you can add your own `@Configuration` annotated with `@EnableWebFlux`. - - - -[[features.developing-web-applications.spring-webflux.httpcodecs]] -==== HTTP Codecs with HttpMessageReaders and HttpMessageWriters -Spring WebFlux uses the `HttpMessageReader` and `HttpMessageWriter` interfaces to convert HTTP requests and responses. -They are configured with `CodecConfigurer` to have sensible defaults by looking at the libraries available in your classpath. - -Spring Boot provides dedicated configuration properties for codecs, `+spring.codec.*+`. -It also applies further customization by using `CodecCustomizer` instances. -For example, `+spring.jackson.*+` configuration keys are applied to the Jackson codec. - -If you need to add or customize codecs, you can create a custom `CodecCustomizer` component, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/webapplications/webflux/CodecConfiguration.java[] ----- - -You can also leverage <>. - - - -[[features.developing-web-applications.spring-webflux.static-content]] -==== Static Content -By default, Spring Boot serves static content from a directory called `/static` (or `/public` or `/resources` or `/META-INF/resources`) in the classpath. -It uses the `ResourceWebHandler` from Spring WebFlux so that you can modify that behavior by adding your own `WebFluxConfigurer` and overriding the `addResourceHandlers` method. - -By default, resources are mapped on `+/**+`, but you can tune that by setting the configprop:spring.webflux.static-path-pattern[] property. -For instance, relocating all resources to `/resources/**` can be achieved as follows: - -[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] ----- - spring: - webflux: - static-path-pattern: "/resources/**" ----- - -You can also customize the static resource locations by using `spring.web.resources.static-locations`. -Doing so replaces the default values with a list of directory locations. -If you do so, the default welcome page detection switches to your custom locations. -So, if there is an `index.html` in any of your locations on startup, it is the home page of the application. - -In addition to the "`standard`" static resource locations listed earlier, a special case is made for https://www.webjars.org/[Webjars content]. -Any resources with a path in `+/webjars/**+` are served from jar files if they are packaged in the Webjars format. - -TIP: Spring WebFlux applications do not strictly depend on the Servlet API, so they cannot be deployed as war files and do not use the `src/main/webapp` directory. - - - -[[features.developing-web-applications.spring-webflux.welcome-page]] -==== Welcome Page -Spring Boot supports both static and templated welcome pages. -It first looks for an `index.html` file in the configured static content locations. -If one is not found, it then looks for an `index` template. -If either is found, it is automatically used as the welcome page of the application. - - - -[[features.developing-web-applications.spring-webflux.template-engines]] -==== Template Engines -As well as REST web services, you can also use Spring WebFlux to serve dynamic HTML content. -Spring WebFlux supports a variety of templating technologies, including Thymeleaf, FreeMarker, and Mustache. - -Spring Boot includes auto-configuration support for the following templating engines: - - * https://freemarker.apache.org/docs/[FreeMarker] - * https://www.thymeleaf.org[Thymeleaf] - * https://mustache.github.io/[Mustache] - -When you use one of these templating engines with the default configuration, your templates are picked up automatically from `src/main/resources/templates`. - - - -[[features.developing-web-applications.spring-webflux.error-handling]] -==== Error Handling -Spring Boot provides a `WebExceptionHandler` that handles all errors in a sensible way. -Its position in the processing order is immediately before the handlers provided by WebFlux, which are considered last. -For machine clients, it produces a JSON response with details of the error, the HTTP status, and the exception message. -For browser clients, there is a "`whitelabel`" error handler that renders the same data in HTML format. -You can also provide your own HTML templates to display errors (see the <>). - -The first step to customizing this feature often involves using the existing mechanism but replacing or augmenting the error contents. -For that, you can add a bean of type `ErrorAttributes`. - -To change the error handling behavior, you can implement `ErrorWebExceptionHandler` and register a bean definition of that type. -Because a `WebExceptionHandler` is quite low-level, Spring Boot also provides a convenient `AbstractErrorWebExceptionHandler` to let you handle errors in a WebFlux functional way, as shown in the following example: - -[source,java,indent=0,subs="verbatim,quotes,attributes"] ----- -include::{include-springbootfeatures}/webapplications/webflux/CustomErrorWebExceptionHandler.java[] ----- - -For a more complete picture, you can also subclass `DefaultErrorWebExceptionHandler` directly and override specific methods. - -In some cases, errors handled at the controller or handler function level are not recorded by the <>. -Applications can ensure that such exceptions are recorded with the request metrics by setting the handled exception as a request attribute: - -[source,java,indent=0,subs="verbatim,quotes,attributes"] ----- -include::{include-springbootfeatures}/webapplications/webflux/ExceptionHandlingController.java[] ----- - - - -[[features.developing-web-applications.spring-webflux.error-handling.error-pages]] -===== Custom Error Pages -If you want to display a custom HTML error page for a given status code, you can add a file to an `/error` directory. -Error pages can either be static HTML (that is, added under any of the static resource directories) or built with templates. -The name of the file should be the exact status code or a series mask. - -For example, to map `404` to a static HTML file, your directory structure would be as follows: - -[source,indent=0,subs="verbatim,quotes,attributes"] ----- - src/ - +- main/ - +- java/ - | + - +- resources/ - +- public/ - +- error/ - | +- 404.html - +- ----- - -To map all `5xx` errors by using a Mustache template, your directory structure would be as follows: - -[source,indent=0,subs="verbatim,quotes,attributes"] ----- - src/ - +- main/ - +- java/ - | + - +- resources/ - +- templates/ - +- error/ - | +- 5xx.mustache - +- ----- - - - -[[features.developing-web-applications.spring-webflux.web-filters]] -==== Web Filters -Spring WebFlux provides a `WebFilter` interface that can be implemented to filter HTTP request-response exchanges. -`WebFilter` beans found in the application context will be automatically used to filter each exchange. - -Where the order of the filters is important they can implement `Ordered` or be annotated with `@Order`. -Spring Boot auto-configuration may configure web filters for you. -When it does so, the orders shown in the following table will be used: - -|=== -| Web Filter | Order - -| `MetricsWebFilter` -| `Ordered.HIGHEST_PRECEDENCE + 1` - -| `WebFilterChainProxy` (Spring Security) -| `-100` - -| `HttpTraceWebFilter` -| `Ordered.LOWEST_PRECEDENCE - 10` -|=== - - - -[[features.developing-web-applications.jersey]] -=== JAX-RS and Jersey -If you prefer the JAX-RS programming model for REST endpoints, you can use one of the available implementations instead of Spring MVC. -https://jersey.github.io/[Jersey] and https://cxf.apache.org/[Apache CXF] work quite well out of the box. -CXF requires you to register its `Servlet` or `Filter` as a `@Bean` in your application context. -Jersey has some native Spring support, so we also provide auto-configuration support for it in Spring Boot, together with a starter. - -To get started with Jersey, include the `spring-boot-starter-jersey` as a dependency and then you need one `@Bean` of type `ResourceConfig` in which you register all the endpoints, as shown in the following example: - -[source,java,indent=0,subs="verbatim,quotes,attributes"] ----- -include::{include-springbootfeatures}/webapplications/jersey/JerseyConfig.java[] ----- - -WARNING: Jersey's support for scanning executable archives is rather limited. -For example, it cannot scan for endpoints in a package found in a <> or in `WEB-INF/classes` when running an executable war file. -To avoid this limitation, the `packages` method should not be used, and endpoints should be registered individually by using the `register` method, as shown in the preceding example. - -For more advanced customizations, you can also register an arbitrary number of beans that implement `ResourceConfigCustomizer`. - -All the registered endpoints should be `@Components` with HTTP resource annotations (`@GET` and others), as shown in the following example: - -[source,java,indent=0,subs="verbatim,quotes,attributes"] ----- -include::{include-springbootfeatures}/webapplications/jersey/Endpoint.java[] ----- - -Since the `Endpoint` is a Spring `@Component`, its lifecycle is managed by Spring and you can use the `@Autowired` annotation to inject dependencies and use the `@Value` annotation to inject external configuration. -By default, the Jersey servlet is registered and mapped to `/*`. -You can change the mapping by adding `@ApplicationPath` to your `ResourceConfig`. - -By default, Jersey is set up as a Servlet in a `@Bean` of type `ServletRegistrationBean` named `jerseyServletRegistration`. -By default, the servlet is initialized lazily, but you can customize that behavior by setting `spring.jersey.servlet.load-on-startup`. -You can disable or override that bean by creating one of your own with the same name. -You can also use a filter instead of a servlet by setting `spring.jersey.type=filter` (in which case, the `@Bean` to replace or override is `jerseyFilterRegistration`). -The filter has an `@Order`, which you can set with `spring.jersey.filter.order`. -Both the servlet and the filter registrations can be given init parameters by using `spring.jersey.init.*` to specify a map of properties. - - - -[[features.developing-web-applications.embedded-container]] -=== Embedded Servlet Container Support -Spring Boot includes support for embedded https://tomcat.apache.org/[Tomcat], https://www.eclipse.org/jetty/[Jetty], and https://github.com/undertow-io/undertow[Undertow] servers. -Most developers use the appropriate "`Starter`" to obtain a fully configured instance. -By default, the embedded server listens for HTTP requests on port `8080`. - - - -[[features.developing-web-applications.embedded-container.servlets-filters-listeners]] -==== Servlets, Filters, and listeners -When using an embedded servlet container, you can register servlets, filters, and all the listeners (such as `HttpSessionListener`) from the Servlet spec, either by using Spring beans or by scanning for Servlet components. - - - -[[features.developing-web-applications.embedded-container.servlets-filters-listeners.beans]] -===== Registering Servlets, Filters, and Listeners as Spring Beans -Any `Servlet`, `Filter`, or servlet `*Listener` instance that is a Spring bean is registered with the embedded container. -This can be particularly convenient if you want to refer to a value from your `application.properties` during configuration. - -By default, if the context contains only a single Servlet, it is mapped to `/`. -In the case of multiple servlet beans, the bean name is used as a path prefix. -Filters map to `+/*+`. - -If convention-based mapping is not flexible enough, you can use the `ServletRegistrationBean`, `FilterRegistrationBean`, and `ServletListenerRegistrationBean` classes for complete control. - -It is usually safe to leave Filter beans unordered. -If a specific order is required, you should annotate the `Filter` with `@Order` or make it implement `Ordered`. -You cannot configure the order of a `Filter` by annotating its bean method with `@Order`. -If you cannot change the `Filter` class to add `@Order` or implement `Ordered`, you must define a `FilterRegistrationBean` for the `Filter` and set the registration bean's order using the `setOrder(int)` method. -Avoid configuring a Filter that reads the request body at `Ordered.HIGHEST_PRECEDENCE`, since it might go against the character encoding configuration of your application. -If a Servlet filter wraps the request, it should be configured with an order that is less than or equal to `OrderedFilter.REQUEST_WRAPPER_FILTER_MAX_ORDER`. - -TIP: To see the order of every `Filter` in your application, enable debug level logging for the `web` <> (`logging.level.web=debug`). -Details of the registered filters, including their order and URL patterns, will then be logged at startup. - -WARNING: Take care when registering `Filter` beans since they are initialized very early in the application lifecycle. -If you need to register a `Filter` that interacts with other beans, consider using a {spring-boot-module-api}/web/servlet/DelegatingFilterProxyRegistrationBean.html[`DelegatingFilterProxyRegistrationBean`] instead. - - - -[[features.developing-web-applications.embedded-container.context-initializer]] -==== Servlet Context Initialization -Embedded servlet containers do not directly execute the Servlet 3.0+ `javax.servlet.ServletContainerInitializer` interface or Spring's `org.springframework.web.WebApplicationInitializer` interface. -This is an intentional design decision intended to reduce the risk that third party libraries designed to run inside a war may break Spring Boot applications. - -If you need to perform servlet context initialization in a Spring Boot application, you should register a bean that implements the `org.springframework.boot.web.servlet.ServletContextInitializer` interface. -The single `onStartup` method provides access to the `ServletContext` and, if necessary, can easily be used as an adapter to an existing `WebApplicationInitializer`. - - - -[[features.developing-web-applications.embedded-container.context-initializer.scanning]] -===== Scanning for Servlets, Filters, and listeners -When using an embedded container, automatic registration of classes annotated with `@WebServlet`, `@WebFilter`, and `@WebListener` can be enabled by using `@ServletComponentScan`. - -TIP: `@ServletComponentScan` has no effect in a standalone container, where the container's built-in discovery mechanisms are used instead. - - - -[[features.developing-web-applications.embedded-container.application-context]] -==== The ServletWebServerApplicationContext -Under the hood, Spring Boot uses a different type of `ApplicationContext` for embedded servlet container support. -The `ServletWebServerApplicationContext` is a special type of `WebApplicationContext` that bootstraps itself by searching for a single `ServletWebServerFactory` bean. -Usually a `TomcatServletWebServerFactory`, `JettyServletWebServerFactory`, or `UndertowServletWebServerFactory` has been auto-configured. - -NOTE: You usually do not need to be aware of these implementation classes. -Most applications are auto-configured, and the appropriate `ApplicationContext` and `ServletWebServerFactory` are created on your behalf. - - - -[[features.developing-web-applications.embedded-container.customizing]] -==== Customizing Embedded Servlet Containers -Common servlet container settings can be configured by using Spring `Environment` properties. -Usually, you would define the properties in your `application.properties` or `application.yaml` file. - -Common server settings include: - -* Network settings: Listen port for incoming HTTP requests (`server.port`), interface address to bind to `server.address`, and so on. -* Session settings: Whether the session is persistent (`server.servlet.session.persistent`), session timeout (`server.servlet.session.timeout`), location of session data (`server.servlet.session.store-dir`), and session-cookie configuration (`server.servlet.session.cookie.*`). -* Error management: Location of the error page (`server.error.path`) and so on. -* <> -* <> - -Spring Boot tries as much as possible to expose common settings, but this is not always possible. -For those cases, dedicated namespaces offer server-specific customizations (see `server.tomcat` and `server.undertow`). -For instance, <> can be configured with specific features of the embedded servlet container. - -TIP: See the {spring-boot-autoconfigure-module-code}/web/ServerProperties.java[`ServerProperties`] class for a complete list. - - - -[[features.developing-web-applications.embedded-container.customizing.programmatic]] -===== Programmatic Customization -If you need to programmatically configure your embedded servlet container, you can register a Spring bean that implements the `WebServerFactoryCustomizer` interface. -`WebServerFactoryCustomizer` provides access to the `ConfigurableServletWebServerFactory`, which includes numerous customization setter methods. -The following example shows programmatically setting the port: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/webapplications/embeddedservletcontainer/CustomizationBean.java[] ----- - -`TomcatServletWebServerFactory`, `JettyServletWebServerFactory` and `UndertowServletWebServerFactory` are dedicated variants of `ConfigurableServletWebServerFactory` that have additional customization setter methods for Tomcat, Jetty and Undertow respectively. -The following example shows how to customize `TomcatServletWebServerFactory` that provides access to Tomcat-specific configuration options: - -[source,java,indent=0,subs="verbatim,quotes,attributes"] ----- -include::{include-springbootfeatures}/webapplications/embeddedservletcontainer/TomcatServerCustomizer.java[] ----- - - - -[[features.developing-web-applications.embedded-container.customizing.direct]] -===== Customizing ConfigurableServletWebServerFactory Directly -For more advanced use cases that require you to extend from `ServletWebServerFactory`, you can expose a bean of such type yourself. - -Setters are provided for many configuration options. -Several protected method "`hooks`" are also provided should you need to do something more exotic. -See the {spring-boot-module-api}/web/servlet/server/ConfigurableServletWebServerFactory.html[source code documentation] for details. - -NOTE: Auto-configured customizers are still applied on your custom factory, so use that option carefully. - - - -[[features.developing-web-applications.embedded-container.jsp-limitations]] -==== JSP Limitations -When running a Spring Boot application that uses an embedded servlet container (and is packaged as an executable archive), there are some limitations in the JSP support. - -* With Jetty and Tomcat, it should work if you use war packaging. - An executable war will work when launched with `java -jar`, and will also be deployable to any standard container. - JSPs are not supported when using an executable jar. - -* Undertow does not support JSPs. - -* Creating a custom `error.jsp` page does not override the default view for <>. - <> should be used instead. - - - -[[features.developing-web-applications.reactive-server]] -=== Embedded Reactive Server Support -Spring Boot includes support for the following embedded reactive web servers: Reactor Netty, Tomcat, Jetty, and Undertow. -Most developers use the appropriate “Starter” to obtain a fully configured instance. -By default, the embedded server listens for HTTP requests on port 8080. - - - -[[features.developing-web-applications.reactive-server-resources-configuration]] -=== Reactive Server Resources Configuration -When auto-configuring a Reactor Netty or Jetty server, Spring Boot will create specific beans that will provide HTTP resources to the server instance: `ReactorResourceFactory` or `JettyResourceFactory`. - -By default, those resources will be also shared with the Reactor Netty and Jetty clients for optimal performances, given: - -* the same technology is used for server and client -* the client instance is built using the `WebClient.Builder` bean auto-configured by Spring Boot - -Developers can override the resource configuration for Jetty and Reactor Netty by providing a custom `ReactorResourceFactory` or `JettyResourceFactory` bean - this will be applied to both clients and servers. - -You can learn more about the resource configuration on the client side in the <>. - - - -[[features.graceful-shutdown]] -== Graceful shutdown -Graceful shutdown is supported with all four embedded web servers (Jetty, Reactor Netty, Tomcat, and Undertow) and with both reactive and Servlet-based web applications. -It occurs as part of closing the application context and is performed in the earliest phase of stopping `SmartLifecycle` beans. -This stop processing uses a timeout which provides a grace period during which existing requests will be allowed to complete but no new requests will be permitted. -The exact way in which new requests are not permitted varies depending on the web server that is being used. -Jetty, Reactor Netty, and Tomcat will stop accepting requests at the network layer. -Undertow will accept requests but respond immediately with a service unavailable (503) response. - -NOTE: Graceful shutdown with Tomcat requires Tomcat 9.0.33 or later. - -To enable graceful shutdown, configure the configprop:server.shutdown[] property, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- -server: - shutdown: "graceful" ----- - -To configure the timeout period, configure the configprop:spring.lifecycle.timeout-per-shutdown-phase[] property, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- -spring: - lifecycle: - timeout-per-shutdown-phase: "20s" ----- - -IMPORTANT: Using graceful shutdown with your IDE may not work properly if it does not send a proper `SIGTERM` signal. -Refer to the documentation of your IDE for more details. - - - -[[features.rsocket]] -== RSocket -https://rsocket.io[RSocket] is a binary protocol for use on byte stream transports. -It enables symmetric interaction models via async message passing over a single connection. - - -The `spring-messaging` module of the Spring Framework provides support for RSocket requesters and responders, both on the client and on the server side. -See the {spring-framework-docs}/web-reactive.html#rsocket-spring[RSocket section] of the Spring Framework reference for more details, including an overview of the RSocket protocol. - - - -[[features.rsocket.strategies-auto-configuration]] -=== RSocket Strategies Auto-configuration -Spring Boot auto-configures an `RSocketStrategies` bean that provides all the required infrastructure for encoding and decoding RSocket payloads. -By default, the auto-configuration will try to configure the following (in order): - -. https://cbor.io/[CBOR] codecs with Jackson -. JSON codecs with Jackson - -The `spring-boot-starter-rsocket` starter provides both dependencies. -Check out the <> to know more about customization possibilities. - -Developers can customize the `RSocketStrategies` component by creating beans that implement the `RSocketStrategiesCustomizer` interface. -Note that their `@Order` is important, as it determines the order of codecs. - - - -[[features.rsocket.server-auto-configuration]] -=== RSocket server Auto-configuration -Spring Boot provides RSocket server auto-configuration. -The required dependencies are provided by the `spring-boot-starter-rsocket`. - -Spring Boot allows exposing RSocket over WebSocket from a WebFlux server, or standing up an independent RSocket server. -This depends on the type of application and its configuration. - -For WebFlux application (i.e. of type `WebApplicationType.REACTIVE`), the RSocket server will be plugged into the Web Server only if the following properties match: - -[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] ----- - spring: - rsocket: - server: - mapping-path: "/rsocket" - transport: "websocket" ----- - -WARNING: Plugging RSocket into a web server is only supported with Reactor Netty, as RSocket itself is built with that library. - -Alternatively, an RSocket TCP or websocket server is started as an independent, embedded server. -Besides the dependency requirements, the only required configuration is to define a port for that server: - -[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] ----- - spring: - rsocket: - server: - port: 9898 ----- - - - -[[features.rsocket.messaging]] -=== Spring Messaging RSocket support -Spring Boot will auto-configure the Spring Messaging infrastructure for RSocket. - -This means that Spring Boot will create a `RSocketMessageHandler` bean that will handle RSocket requests to your application. - - - -[[features.rsocket.requester]] -=== Calling RSocket Services with RSocketRequester -Once the `RSocket` channel is established between server and client, any party can send or receive requests to the other. - -As a server, you can get injected with an `RSocketRequester` instance on any handler method of an RSocket `@Controller`. -As a client, you need to configure and establish an RSocket connection first. -Spring Boot auto-configures an `RSocketRequester.Builder` for such cases with the expected codecs. - -The `RSocketRequester.Builder` instance is a prototype bean, meaning each injection point will provide you with a new instance . -This is done on purpose since this builder is stateful and you shouldn't create requesters with different setups using the same instance. - -The following code shows a typical example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/rsocket/MyService.java[] ----- - - - -[[features.security]] -== Security -If {spring-security}[Spring Security] is on the classpath, then web applications are secured by default. -Spring Boot relies on Spring Security’s content-negotiation strategy to determine whether to use `httpBasic` or `formLogin`. -To add method-level security to a web application, you can also add `@EnableGlobalMethodSecurity` with your desired settings. -Additional information can be found in the {spring-security-docs}#jc-method[Spring Security Reference Guide]. - -The default `UserDetailsService` has a single user. -The user name is `user`, and the password is random and is printed at INFO level when the application starts, as shown in the following example: - -[indent=0] ----- - Using generated security password: 78fa095d-3f4c-48b1-ad50-e24c31d5cf35 ----- - -NOTE: If you fine-tune your logging configuration, ensure that the `org.springframework.boot.autoconfigure.security` category is set to log `INFO`-level messages. -Otherwise, the default password is not printed. - -You can change the username and password by providing a `spring.security.user.name` and `spring.security.user.password`. - -The basic features you get by default in a web application are: - -* A `UserDetailsService` (or `ReactiveUserDetailsService` in case of a WebFlux application) bean with in-memory store and a single user with a generated password (see {spring-boot-module-api}/autoconfigure/security/SecurityProperties.User.html[`SecurityProperties.User`] for the properties of the user). -* Form-based login or HTTP Basic security (depending on the `Accept` header in the request) for the entire application (including actuator endpoints if actuator is on the classpath). -* A `DefaultAuthenticationEventPublisher` for publishing authentication events. - -You can provide a different `AuthenticationEventPublisher` by adding a bean for it. - - - -[[features.security.spring-mvc]] -=== MVC Security -The default security configuration is implemented in `SecurityAutoConfiguration` and `UserDetailsServiceAutoConfiguration`. -`SecurityAutoConfiguration` imports `SpringBootWebSecurityConfiguration` for web security and `UserDetailsServiceAutoConfiguration` configures authentication, which is also relevant in non-web applications. -To switch off the default web application security configuration completely or to combine multiple Spring Security components such as OAuth2 Client and Resource Server, add a bean of type `SecurityFilterChain` (doing so does not disable the `UserDetailsService` configuration or Actuator's security). - -To also switch off the `UserDetailsService` configuration, you can add a bean of type `UserDetailsService`, `AuthenticationProvider`, or `AuthenticationManager`. - -Access rules can be overridden by adding a custom `SecurityFilterChain` or `WebSecurityConfigurerAdapter` bean. -Spring Boot provides convenience methods that can be used to override access rules for actuator endpoints and static resources. -`EndpointRequest` can be used to create a `RequestMatcher` that is based on the configprop:management.endpoints.web.base-path[] property. -`PathRequest` can be used to create a `RequestMatcher` for resources in commonly used locations. - - - -[[features.security.spring-webflux]] -=== WebFlux Security -Similar to Spring MVC applications, you can secure your WebFlux applications by adding the `spring-boot-starter-security` dependency. -The default security configuration is implemented in `ReactiveSecurityAutoConfiguration` and `UserDetailsServiceAutoConfiguration`. -`ReactiveSecurityAutoConfiguration` imports `WebFluxSecurityConfiguration` for web security and `UserDetailsServiceAutoConfiguration` configures authentication, which is also relevant in non-web applications. -To switch off the default web application security configuration completely, you can add a bean of type `WebFilterChainProxy` (doing so does not disable the `UserDetailsService` configuration or Actuator's security). - -To also switch off the `UserDetailsService` configuration, you can add a bean of type `ReactiveUserDetailsService` or `ReactiveAuthenticationManager`. - -Access rules and the use of multiple Spring Security components such as OAuth 2 Client and Resource Server can be configured by adding a custom `SecurityWebFilterChain` bean. -Spring Boot provides convenience methods that can be used to override access rules for actuator endpoints and static resources. -`EndpointRequest` can be used to create a `ServerWebExchangeMatcher` that is based on the configprop:management.endpoints.web.base-path[] property. - -`PathRequest` can be used to create a `ServerWebExchangeMatcher` for resources in commonly used locations. - -For example, you can customize your security configuration by adding something like: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/security/CustomWebFluxSecurityConfiguration.java[] ----- - - - -[[features.security.oauth2]] -=== OAuth2 -https://oauth.net/2/[OAuth2] is a widely used authorization framework that is supported by Spring. - - - -[[features.security.oauth2.client]] -==== Client -If you have `spring-security-oauth2-client` on your classpath, you can take advantage of some auto-configuration to set up an OAuth2/Open ID Connect clients. -This configuration makes use of the properties under `OAuth2ClientProperties`. -The same properties are applicable to both servlet and reactive applications. - -You can register multiple OAuth2 clients and providers under the `spring.security.oauth2.client` prefix, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - security: - oauth2: - client: - registration: - my-client-1: - client-id: "abcd" - client-secret: "password" - client-name: "Client for user scope" - provider: "my-oauth-provider" - scope: "user" - redirect-uri: "https://my-redirect-uri.com" - client-authentication-method: "basic" - authorization-grant-type: "authorization-code" - - my-client-2: - client-id: "abcd" - client-secret: "password" - client-name: "Client for email scope" - provider: "my-oauth-provider" - scope: "email" - redirect-uri: "https://my-redirect-uri.com" - client-authentication-method: "basic" - authorization-grant-type: "authorization_code" - - provider: - my-oauth-provider: - authorization-uri: "https://my-auth-server/oauth/authorize" - token-uri: "https://my-auth-server/oauth/token" - user-info-uri: "https://my-auth-server/userinfo" - user-info-authentication-method: "header" - jwk-set-uri: "https://my-auth-server/token_keys" - user-name-attribute: "name" ----- - -For OpenID Connect providers that support https://openid.net/specs/openid-connect-discovery-1_0.html[OpenID Connect discovery], the configuration can be further simplified. -The provider needs to be configured with an `issuer-uri` which is the URI that the it asserts as its Issuer Identifier. -For example, if the `issuer-uri` provided is "https://example.com", then an `OpenID Provider Configuration Request` will be made to "https://example.com/.well-known/openid-configuration". -The result is expected to be an `OpenID Provider Configuration Response`. -The following example shows how an OpenID Connect Provider can be configured with the `issuer-uri`: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - security: - oauth2: - client: - provider: - oidc-provider: - issuer-uri: "https://dev-123456.oktapreview.com/oauth2/default/" ----- - -By default, Spring Security's `OAuth2LoginAuthenticationFilter` only processes URLs matching `/login/oauth2/code/*`. -If you want to customize the `redirect-uri` to use a different pattern, you need to provide configuration to process that custom pattern. -For example, for servlet applications, you can add your own `SecurityFilterChain` that resembles the following: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/security/OAuthClientConfiguration.java[] ----- - -TIP: Spring Boot auto-configures an `InMemoryOAuth2AuthorizedClientService` which is used by Spring Security for the management of client registrations. -The `InMemoryOAuth2AuthorizedClientService` has limited capabilities and we recommend using it only for development environments. -For production environments, consider using a `JdbcOAuth2AuthorizedClientService` or creating your own implementation of `OAuth2AuthorizedClientService`. - - - -[[features.security.oauth2.client.common-providers]] -===== OAuth2 client registration for common providers -For common OAuth2 and OpenID providers, including Google, Github, Facebook, and Okta, we provide a set of provider defaults (`google`, `github`, `facebook`, and `okta`, respectively). - -If you do not need to customize these providers, you can set the `provider` attribute to the one for which you need to infer defaults. -Also, if the key for the client registration matches a default supported provider, Spring Boot infers that as well. - -In other words, the two configurations in the following example use the Google provider: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - security: - oauth2: - client: - registration: - my-client: - client-id: "abcd" - client-secret: "password" - provider: "google" - google: - client-id: "abcd" - client-secret: "password" ----- - - - -[[features.security.oauth2.server]] -==== Resource Server -If you have `spring-security-oauth2-resource-server` on your classpath, Spring Boot can set up an OAuth2 Resource Server. -For JWT configuration, a JWK Set URI or OIDC Issuer URI needs to be specified, as shown in the following examples: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - security: - oauth2: - resourceserver: - jwt: - jwk-set-uri: "https://example.com/oauth2/default/v1/keys" ----- - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - security: - oauth2: - resourceserver: - jwt: - issuer-uri: "https://dev-123456.oktapreview.com/oauth2/default/" ----- - -NOTE: If the authorization server does not support a JWK Set URI, you can configure the resource server with the Public Key used for verifying the signature of the JWT. -This can be done using the configprop:spring.security.oauth2.resourceserver.jwt.public-key-location[] property, where the value needs to point to a file containing the public key in the PEM-encoded x509 format. - -The same properties are applicable for both servlet and reactive applications. - -Alternatively, you can define your own `JwtDecoder` bean for servlet applications or a `ReactiveJwtDecoder` for reactive applications. - -In cases where opaque tokens are used instead of JWTs, you can configure the following properties to validate tokens via introspection: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - security: - oauth2: - resourceserver: - opaquetoken: - introspection-uri: "https://example.com/check-token" - client-id: "my-client-id" - client-secret: "my-client-secret" ----- - -Again, the same properties are applicable for both servlet and reactive applications. - -Alternatively, you can define your own `OpaqueTokenIntrospector` bean for servlet applications or a `ReactiveOpaqueTokenIntrospector` for reactive applications. - - - -[[features.security.oauth2.authorization-server]] -==== Authorization Server -Currently, Spring Security does not provide support for implementing an OAuth 2.0 Authorization Server. -However, this functionality is available from the {spring-security-oauth2}[Spring Security OAuth] project, which will eventually be superseded by Spring Security completely. -Until then, you can use the `spring-security-oauth2-autoconfigure` module to easily set up an OAuth 2.0 authorization server; see its https://docs.spring.io/spring-security-oauth2-boot/[documentation] for instructions. - - - -[[features.security.saml2]] -=== SAML 2.0 - - - -[[features.security.saml2.relying-party]] -==== Relying Party -If you have `spring-security-saml2-service-provider` on your classpath, you can take advantage of some auto-configuration to set up a SAML 2.0 Relying Party. -This configuration makes use of the properties under `Saml2RelyingPartyProperties`. - -A relying party registration represents a paired configuration between an Identity Provider, IDP, and a Service Provider, SP. -You can register multiple relying parties under the `spring.security.saml2.relyingparty` prefix, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - security: - saml2: - relyingparty: - registration: - my-relying-party1: - signing: - credentials: - - private-key-location: "path-to-private-key" - certificate-location: "path-to-certificate" - decryption: - credentials: - - private-key-location: "path-to-private-key" - certificate-location: "path-to-certificate" - identityprovider: - verification: - credentials: - - certificate-location: "path-to-verification-cert" - entity-id: "remote-idp-entity-id1" - sso-url: "https://remoteidp1.sso.url" - my-relying-party2: - signing: - credentials: - - private-key-location: "path-to-private-key" - certificate-location: "path-to-certificate" - decryption: - credentials: - - private-key-location: "path-to-private-key" - certificate-location: "path-to-certificate" - identityprovider: - verification: - credentials: - - certificate-location: "path-to-other-verification-cert" - entity-id: "remote-idp-entity-id2" - sso-url: "https://remoteidp2.sso.url" ----- - - - -[[features.security.actuator]] -=== Actuator Security -For security purposes, all actuators other than `/health` are disabled by default. -The configprop:management.endpoints.web.exposure.include[] property can be used to enable the actuators. - -If Spring Security is on the classpath and no other `WebSecurityConfigurerAdapter` or `SecurityFilterChain` bean is present, all actuators other than `/health` are secured by Spring Boot auto-configuration. -If you define a custom `WebSecurityConfigurerAdapter` or `SecurityFilterChain` bean, Spring Boot auto-configuration will back off and you will be in full control of actuator access rules. - -NOTE: Before setting the `management.endpoints.web.exposure.include`, ensure that the exposed actuators do not contain sensitive information and/or are secured by placing them behind a firewall or by something like Spring Security. - - - -[[features.security.actuator.csrf]] -==== Cross Site Request Forgery Protection -Since Spring Boot relies on Spring Security's defaults, CSRF protection is turned on by default. -This means that the actuator endpoints that require a `POST` (shutdown and loggers endpoints), `PUT` or `DELETE` will get a 403 forbidden error when the default security configuration is in use. - -NOTE: We recommend disabling CSRF protection completely only if you are creating a service that is used by non-browser clients. - -Additional information about CSRF protection can be found in the {spring-security-docs}#csrf[Spring Security Reference Guide]. - - - -[[features.sql]] -== Working with SQL Databases -The {spring-framework}[Spring Framework] provides extensive support for working with SQL databases, from direct JDBC access using `JdbcTemplate` to complete "`object relational mapping`" technologies such as Hibernate. -{spring-data}[Spring Data] provides an additional level of functionality: creating `Repository` implementations directly from interfaces and using conventions to generate queries from your method names. - - - -[[features.sql.datasource]] -=== Configure a DataSource -Java's `javax.sql.DataSource` interface provides a standard method of working with database connections. -Traditionally, a 'DataSource' uses a `URL` along with some credentials to establish a database connection. - -TIP: See <> for more advanced examples, typically to take full control over the configuration of the DataSource. - - - -[[features.sql.datasource.embedded]] -==== Embedded Database Support -It is often convenient to develop applications by using an in-memory embedded database. -Obviously, in-memory databases do not provide persistent storage. -You need to populate your database when your application starts and be prepared to throw away data when your application ends. - -TIP: The "`How-to`" section includes a <>. - -Spring Boot can auto-configure embedded https://www.h2database.com[H2], http://hsqldb.org/[HSQL], and https://db.apache.org/derby/[Derby] databases. -You need not provide any connection URLs. -You need only include a build dependency to the embedded database that you want to use. -If there are multiple embedded databases on the classpath, set the configprop:spring.datasource.embedded-database-connection[] configuration property to control which one is used. -Setting the property to `none` disables auto-configuration of an embedded database. - -[NOTE] -==== -If you are using this feature in your tests, you may notice that the same database is reused by your whole test suite regardless of the number of application contexts that you use. -If you want to make sure that each context has a separate embedded database, you should set `spring.datasource.generate-unique-name` to `true`. -==== - -For example, the typical POM dependencies would be as follows: - -[source,xml,indent=0] ----- - - org.springframework.boot - spring-boot-starter-data-jpa - - - org.hsqldb - hsqldb - runtime - ----- - -NOTE: You need a dependency on `spring-jdbc` for an embedded database to be auto-configured. -In this example, it is pulled in transitively through `spring-boot-starter-data-jpa`. - -TIP: If, for whatever reason, you do configure the connection URL for an embedded database, take care to ensure that the database's automatic shutdown is disabled. -If you use H2, you should use `DB_CLOSE_ON_EXIT=FALSE` to do so. -If you use HSQLDB, you should ensure that `shutdown=true` is not used. -Disabling the database's automatic shutdown lets Spring Boot control when the database is closed, thereby ensuring that it happens once access to the database is no longer needed. - - - -[[features.sql.datasource.production]] -==== Connection to a Production Database -Production database connections can also be auto-configured by using a pooling `DataSource`. - - - -[[features.sql.datasource.configuration]] -==== DataSource Configuration -DataSource configuration is controlled by external configuration properties in `+spring.datasource.*+`. -For example, you might declare the following section in `application.properties`: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - datasource: - url: "jdbc:mysql://localhost/test" - username: "dbuser" - password: "dbpass" ----- - -NOTE: You should at least specify the URL by setting the configprop:spring.datasource.url[] property. -Otherwise, Spring Boot tries to auto-configure an embedded database. - -TIP: Spring Boot can deduce the JDBC driver class for most databases from the URL. -If you need to specify a specific class, you can use the configprop:spring.datasource.driver-class-name[] property. - -NOTE: For a pooling `DataSource` to be created, we need to be able to verify that a valid `Driver` class is available, so we check for that before doing anything. -In other words, if you set `spring.datasource.driver-class-name=com.mysql.jdbc.Driver`, then that class has to be loadable. - -See {spring-boot-autoconfigure-module-code}/jdbc/DataSourceProperties.java[`DataSourceProperties`] for more of the supported options. -These are the standard options that work regardless of <>. -It is also possible to fine-tune implementation-specific settings by using their respective prefix (`+spring.datasource.hikari.*+`, `+spring.datasource.tomcat.*+`, `+spring.datasource.dbcp2.*+`, and `+spring.datasource.oracleucp.*+`). -Refer to the documentation of the connection pool implementation you are using for more details. - -For instance, if you use the {tomcat-docs}/jdbc-pool.html#Common_Attributes[Tomcat connection pool], you could customize many additional settings, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - datasource: - tomcat: - max-wait: 10000 - max-active: 50 - test-on-borrow: true ----- - -This will set the pool to wait 10000 ms before throwing an exception if no connection is available, limit the maximum number of connections to 50 and validate the connection before borrowing it from the pool. - - - -[[features.sql.datasource.connection-pool]] -==== Supported Connection Pools -Spring Boot uses the following algorithm for choosing a specific implementation: - -. We prefer https://github.com/brettwooldridge/HikariCP[HikariCP] for its performance and concurrency. -If HikariCP is available, we always choose it. -. Otherwise, if the Tomcat pooling `DataSource` is available, we use it. -. Otherwise, if https://commons.apache.org/proper/commons-dbcp/[Commons DBCP2] is available, we use it. -. If none of HikariCP, Tomcat, and DBCP2 are available and if Oracle UCP is available, we use it. - -NOTE: If you use the `spring-boot-starter-jdbc` or `spring-boot-starter-data-jpa` "`starters`", you automatically get a dependency to `HikariCP`. - -You can bypass that algorithm completely and specify the connection pool to use by setting the configprop:spring.datasource.type[] property. -This is especially important if you run your application in a Tomcat container, as `tomcat-jdbc` is provided by default. - -Additional connection pools can always be configured manually, using `DataSourceBuilder`. -If you define your own `DataSource` bean, auto-configuration does not occur. -The following connection pools are supported by `DataSourceBuilder`: - -* HikariCP -* Tomcat pooling `Datasource` -* Commons DBCP2 -* Oracle UCP & `OracleDataSource` -* Spring Framework's `SimpleDriverDataSource` -* H2 `JdbcDataSource` -* PostgreSQL `PGSimpleDataSource` - - - -[[features.sql.datasource.jndi]] -==== Connection to a JNDI DataSource -If you deploy your Spring Boot application to an Application Server, you might want to configure and manage your DataSource by using your Application Server's built-in features and access it by using JNDI. - -The configprop:spring.datasource.jndi-name[] property can be used as an alternative to the configprop:spring.datasource.url[], configprop:spring.datasource.username[], and configprop:spring.datasource.password[] properties to access the `DataSource` from a specific JNDI location. -For example, the following section in `application.properties` shows how you can access a JBoss AS defined `DataSource`: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - datasource: - jndi-name: "java:jboss/datasources/customers" ----- - - - -[[features.sql.jdbc-template]] -=== Using JdbcTemplate -Spring's `JdbcTemplate` and `NamedParameterJdbcTemplate` classes are auto-configured, and you can `@Autowire` them directly into your own beans, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/sql/jdbctemplate/MyBean.java[] ----- - -You can customize some properties of the template by using the `spring.jdbc.template.*` properties, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - jdbc: - template: - max-rows: 500 ----- - -NOTE: The `NamedParameterJdbcTemplate` reuses the same `JdbcTemplate` instance behind the scenes. -If more than one `JdbcTemplate` is defined and no primary candidate exists, the `NamedParameterJdbcTemplate` is not auto-configured. - - - -[[features.sql.jpa-and-spring-data]] -=== JPA and Spring Data JPA -The Java Persistence API is a standard technology that lets you "`map`" objects to relational databases. -The `spring-boot-starter-data-jpa` POM provides a quick way to get started. -It provides the following key dependencies: - -* Hibernate: One of the most popular JPA implementations. -* Spring Data JPA: Helps you to implement JPA-based repositories. -* Spring ORM: Core ORM support from the Spring Framework. - -TIP: We do not go into too many details of JPA or {spring-data}[Spring Data] here. -You can follow the https://spring.io/guides/gs/accessing-data-jpa/["`Accessing Data with JPA`"] guide from https://spring.io and read the {spring-data-jpa}[Spring Data JPA] and https://hibernate.org/orm/documentation/[Hibernate] reference documentation. - - - -[[features.sql.jpa-and-spring-data.entity-classes]] -==== Entity Classes -Traditionally, JPA "`Entity`" classes are specified in a `persistence.xml` file. -With Spring Boot, this file is not necessary and "`Entity Scanning`" is used instead. -By default, all packages below your main configuration class (the one annotated with `@EnableAutoConfiguration` or `@SpringBootApplication`) are searched. - -Any classes annotated with `@Entity`, `@Embeddable`, or `@MappedSuperclass` are considered. -A typical entity class resembles the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/sql/jpa/City.java[] ----- - -TIP: You can customize entity scanning locations by using the `@EntityScan` annotation. -See the "`<>`" how-to. - - - -[[features.sql.jpa-and-spring-data.repositories]] -==== Spring Data JPA Repositories -{spring-data-jpa}[Spring Data JPA] repositories are interfaces that you can define to access data. -JPA queries are created automatically from your method names. -For example, a `CityRepository` interface might declare a `findAllByState(String state)` method to find all the cities in a given state. - -For more complex queries, you can annotate your method with Spring Data's {spring-data-jpa-api}/repository/Query.html[`Query`] annotation. - -Spring Data repositories usually extend from the {spring-data-commons-api}/repository/Repository.html[`Repository`] or {spring-data-commons-api}/repository/CrudRepository.html[`CrudRepository`] interfaces. -If you use auto-configuration, repositories are searched from the package containing your main configuration class (the one annotated with `@EnableAutoConfiguration` or `@SpringBootApplication`) down. - -The following example shows a typical Spring Data repository interface definition: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/sql/jpa/CityRepository.java[] ----- - -Spring Data JPA repositories support three different modes of bootstrapping: default, deferred, and lazy. -To enable deferred or lazy bootstrapping, set the configprop:spring.data.jpa.repositories.bootstrap-mode[] property to `deferred` or `lazy` respectively. -When using deferred or lazy bootstrapping, the auto-configured `EntityManagerFactoryBuilder` will use the context's `AsyncTaskExecutor`, if any, as the bootstrap executor. -If more than one exists, the one named `applicationTaskExecutor` will be used. - -[NOTE] -==== -When using deferred or lazy bootstrapping, make sure to defer any access to the JPA infrastructure after the application context bootstrap phase. -You can use `SmartInitializingSingleton` to invoke any initialization that requires the JPA infrastructure. -For JPA components (such as converters) that are created as Spring beans, use `ObjectProvider` to delay the resolution of dependencies, if any. -==== - -TIP: We have barely scratched the surface of Spring Data JPA. -For complete details, see the {spring-data-jdbc-docs}[Spring Data JPA reference documentation]. - - - -[[features.sql.jpa-and-spring-data.creating-and-dropping]] -==== Creating and Dropping JPA Databases -By default, JPA databases are automatically created *only* if you use an embedded database (H2, HSQL, or Derby). -You can explicitly configure JPA settings by using `+spring.jpa.*+` properties. -For example, to create and drop tables you can add the following line to your `application.properties`: - -[indent=0] ----- - spring.jpa.hibernate.ddl-auto=create-drop ----- - -NOTE: Hibernate's own internal property name for this (if you happen to remember it better) is `hibernate.hbm2ddl.auto`. -You can set it, along with other Hibernate native properties, by using `+spring.jpa.properties.*+` (the prefix is stripped before adding them to the entity manager). -The following line shows an example of setting JPA properties for Hibernate: - -[indent=0] ----- - spring.jpa.properties.hibernate.globally_quoted_identifiers=true ----- - -The line in the preceding example passes a value of `true` for the `hibernate.globally_quoted_identifiers` property to the Hibernate entity manager. - -By default, the DDL execution (or validation) is deferred until the `ApplicationContext` has started. -There is also a `spring.jpa.generate-ddl` flag, but it is not used if Hibernate auto-configuration is active, because the `ddl-auto` settings are more fine-grained. - - - -[[features.sql.jpa-and-spring-data.open-entity-manager-in-view]] -==== Open EntityManager in View -If you are running a web application, Spring Boot by default registers {spring-framework-api}/orm/jpa/support/OpenEntityManagerInViewInterceptor.html[`OpenEntityManagerInViewInterceptor`] to apply the "`Open EntityManager in View`" pattern, to allow for lazy loading in web views. -If you do not want this behavior, you should set `spring.jpa.open-in-view` to `false` in your `application.properties`. - - - -[[features.sql.jdbc]] -=== Spring Data JDBC -Spring Data includes repository support for JDBC and will automatically generate SQL for the methods on `CrudRepository`. -For more advanced queries, a `@Query` annotation is provided. - -Spring Boot will auto-configure Spring Data's JDBC repositories when the necessary dependencies are on the classpath. -They can be added to your project with a single dependency on `spring-boot-starter-data-jdbc`. -If necessary, you can take control of Spring Data JDBC's configuration by adding the `@EnableJdbcRepositories` annotation or a `JdbcConfiguration` subclass to your application. - -TIP: For complete details of Spring Data JDBC, please refer to the {spring-data-jdbc-docs}[reference documentation]. - - - -[[features.sql.h2-web-console]] -=== Using H2's Web Console -The https://www.h2database.com[H2 database] provides a https://www.h2database.com/html/quickstart.html#h2_console[browser-based console] that Spring Boot can auto-configure for you. -The console is auto-configured when the following conditions are met: - -* You are developing a servlet-based web application. -* `com.h2database:h2` is on the classpath. -* You are using <>. - -TIP: If you are not using Spring Boot's developer tools but would still like to make use of H2's console, you can configure the configprop:spring.h2.console.enabled[] property with a value of `true`. - -NOTE: The H2 console is only intended for use during development, so you should take care to ensure that `spring.h2.console.enabled` is not set to `true` in production. - - - -[[features.sql.h2-web-console.custom-path]] -==== Changing the H2 Console's Path -By default, the console is available at `/h2-console`. -You can customize the console's path by using the configprop:spring.h2.console.path[] property. - - - -[[features.sql.jooq]] -=== Using jOOQ -jOOQ Object Oriented Querying (https://www.jooq.org/[jOOQ]) is a popular product from https://www.datageekery.com/[Data Geekery] which generates Java code from your database and lets you build type-safe SQL queries through its fluent API. -Both the commercial and open source editions can be used with Spring Boot. - - - -[[features.sql.jooq.codegen]] -==== Code Generation -In order to use jOOQ type-safe queries, you need to generate Java classes from your database schema. -You can follow the instructions in the {jooq-docs}/#jooq-in-7-steps-step3[jOOQ user manual]. -If you use the `jooq-codegen-maven` plugin and you also use the `spring-boot-starter-parent` "`parent POM`", you can safely omit the plugin's `` tag. -You can also use Spring Boot-defined version variables (such as `h2.version`) to declare the plugin's database dependency. -The following listing shows an example: - -[source,xml,indent=0] ----- - - org.jooq - jooq-codegen-maven - - ... - - - - com.h2database - h2 - ${h2.version} - - - - - org.h2.Driver - jdbc:h2:~/yourdatabase - - - ... - - - ----- - - - -[[features.sql.jooq.dslcontext]] -==== Using DSLContext -The fluent API offered by jOOQ is initiated through the `org.jooq.DSLContext` interface. -Spring Boot auto-configures a `DSLContext` as a Spring Bean and connects it to your application `DataSource`. -To use the `DSLContext`, you can inject it, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/sql/jooq/JooqExample.java[tag=!method] ----- - -TIP: The jOOQ manual tends to use a variable named `create` to hold the `DSLContext`. - -You can then use the `DSLContext` to construct your queries, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/sql/jooq/JooqExample.java[tag=method] ----- - - - -[[features.sql.jooq.sqldialect]] -==== jOOQ SQL Dialect -Unless the configprop:spring.jooq.sql-dialect[] property has been configured, Spring Boot determines the SQL dialect to use for your datasource. -If Spring Boot could not detect the dialect, it uses `DEFAULT`. - -NOTE: Spring Boot can only auto-configure dialects supported by the open source version of jOOQ. - - - -[[features.sql.jooq.customizing]] -==== Customizing jOOQ -More advanced customizations can be achieved by defining your own `DefaultConfigurationCustomizer` bean that will be invoked prior to creating the `org.jooq.Configuration` `@Bean`. -This takes precedence to anything that is applied by the auto-configuration. - -You can also create your own `org.jooq.Configuration` `@Bean` if you want to take complete control of the jOOQ configuration. - - - -[[features.sql.r2dbc]] -=== Using R2DBC -The Reactive Relational Database Connectivity (https://r2dbc.io[R2DBC]) project brings reactive programming APIs to relational databases. -R2DBC's `io.r2dbc.spi.Connection` provides a standard method of working with non-blocking database connections. -Connections are provided via a `ConnectionFactory`, similar to a `DataSource` with jdbc. - -`ConnectionFactory` configuration is controlled by external configuration properties in `+spring.r2dbc.*+`. -For example, you might declare the following section in `application.properties`: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - r2dbc: - url: "r2dbc:postgresql://localhost/test" - username: "dbuser" - password: "dbpass" ----- - -TIP: You do not need to specify a driver class name, since Spring Boot obtains the driver from R2DBC's Connection Factory discovery. - -NOTE: At least the url should be provided. -Information specified in the URL takes precedence over individual properties, i.e. `name`, `username`, `password` and pooling options. - -TIP: The "`How-to`" section includes a <>. - -To customize the connections created by a `ConnectionFactory`, i.e., set specific parameters that you do not want (or cannot) configure in your central database configuration, you can use a `ConnectionFactoryOptionsBuilderCustomizer` `@Bean`. -The following example shows how to manually override the database port while the rest of the options is taken from the application configuration: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/sql/r2dbc/CustomizeR2dbcPortConfiguration.java[tag=*] ----- - -The following examples show how to set some PostgreSQL connection options: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/sql/r2dbc/CustomizeR2dbcPostgresOptionsConfiguration.java[tag=*] ----- - -When a `ConnectionFactory` bean is available, the regular JDBC `DataSource` auto-configuration backs off. -If you want to retain the JDBC `DataSource` auto-configuration, and are comfortable with the risk of using the blocking JDBC API in a reactive application, add `@Import(DataSourceAutoConfiguration.class)` on a `@Configuration` class in your application to re-enable it. - - - -[[features.sql.r2dbc.embedded]] -==== Embedded Database Support -Similarly to <>, Spring Boot can automatically configure an embedded database for reactive usage. -You need not provide any connection URLs. -You need only include a build dependency to the embedded database that you want to use, as shown in the following example: - -[source,xml,indent=0] ----- - - io.r2dbc - r2dbc-h2 - runtime - ----- - -[NOTE] -==== -If you are using this feature in your tests, you may notice that the same database is reused by your whole test suite regardless of the number of application contexts that you use. -If you want to make sure that each context has a separate embedded database, you should set `spring.r2dbc.generate-unique-name` to `true`. -==== - - - -[[features.sql.r2dbc.using-database-client]] -==== Using DatabaseClient -A `DatabaseClient` bean is auto-configured, and you can `@Autowire` it directly into your own beans, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/sql/r2dbc/databaseclient/MyBean.java[tag=*] ----- - - - -[[features.sql.r2dbc.repositories]] -==== Spring Data R2DBC Repositories -https://spring.io/projects/spring-data-r2dbc[Spring Data R2DBC] repositories are interfaces that you can define to access data. -Queries are created automatically from your method names. -For example, a `CityRepository` interface might declare a `findAllByState(String state)` method to find all the cities in a given state. - -For more complex queries, you can annotate your method with Spring Data's {spring-data-r2dbc-api}/repository/Query.html[`Query`] annotation. - -Spring Data repositories usually extend from the {spring-data-commons-api}/repository/Repository.html[`Repository`] or {spring-data-commons-api}/repository/CrudRepository.html[`CrudRepository`] interfaces. -If you use auto-configuration, repositories are searched from the package containing your main configuration class (the one annotated with `@EnableAutoConfiguration` or `@SpringBootApplication`) down. - -The following example shows a typical Spring Data repository interface definition: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/sql/r2dbc/CityRepository.java[tag=*] ----- - -TIP: We have barely scratched the surface of Spring Data R2DBC. For complete details, see the {spring-data-r2dbc-docs}[Spring Data R2DBC reference documentation]. - - - -[[features.nosql]] -== Working with NoSQL Technologies -Spring Data provides additional projects that help you access a variety of NoSQL technologies, including: - -* {spring-data-mongodb}[MongoDB] -* {spring-data-neo4j}[Neo4J] -* {spring-data-elasticsearch}[Elasticsearch] -* {spring-data-redis}[Redis] -* {spring-data-gemfire}[GemFire] or {spring-data-geode}[Geode] -* {spring-data-cassandra}[Cassandra] -* {spring-data-couchbase}[Couchbase] -* {spring-data-ldap}[LDAP] - -Spring Boot provides auto-configuration for Redis, MongoDB, Neo4j, Elasticsearch, Solr Cassandra, Couchbase, and LDAP. -You can make use of the other projects, but you must configure them yourself. -Refer to the appropriate reference documentation at {spring-data}. - - - -[[features.nosql.redis]] -=== Redis -https://redis.io/[Redis] is a cache, message broker, and richly-featured key-value store. -Spring Boot offers basic auto-configuration for the https://github.com/lettuce-io/lettuce-core/[Lettuce] and https://github.com/xetorthio/jedis/[Jedis] client libraries and the abstractions on top of them provided by https://github.com/spring-projects/spring-data-redis[Spring Data Redis]. - -There is a `spring-boot-starter-data-redis` "`Starter`" for collecting the dependencies in a convenient way. -By default, it uses https://github.com/lettuce-io/lettuce-core/[Lettuce]. -That starter handles both traditional and reactive applications. - -TIP: We also provide a `spring-boot-starter-data-redis-reactive` "`Starter`" for consistency with the other stores with reactive support. - - - -[[features.nosql.redis.connecting]] -==== Connecting to Redis -You can inject an auto-configured `RedisConnectionFactory`, `StringRedisTemplate`, or vanilla `RedisTemplate` instance as you would any other Spring Bean. -By default, the instance tries to connect to a Redis server at `localhost:6379`. -The following listing shows an example of such a bean: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/nosql/redis/MyBean.java[] ----- - -TIP: You can also register an arbitrary number of beans that implement `LettuceClientConfigurationBuilderCustomizer` for more advanced customizations. -If you use Jedis, `JedisClientConfigurationBuilderCustomizer` is also available. - -If you add your own `@Bean` of any of the auto-configured types, it replaces the default (except in the case of `RedisTemplate`, when the exclusion is based on the bean name, `redisTemplate`, not its type). -By default, if `commons-pool2` is on the classpath, you get a pooled connection factory. - - - -[[features.nosql.mongodb]] -=== MongoDB -https://www.mongodb.com/[MongoDB] is an open-source NoSQL document database that uses a JSON-like schema instead of traditional table-based relational data. -Spring Boot offers several conveniences for working with MongoDB, including the `spring-boot-starter-data-mongodb` and `spring-boot-starter-data-mongodb-reactive` "`Starters`". - - - -[[features.nosql.mongodb.connecting]] -==== Connecting to a MongoDB Database -To access MongoDB databases, you can inject an auto-configured `org.springframework.data.mongodb.MongoDatabaseFactory`. -By default, the instance tries to connect to a MongoDB server at `mongodb://localhost/test`. -The following example shows how to connect to a MongoDB database: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/nosql/mongodb/databasefactory/MyBean.java[] ----- - -If you have defined your own `MongoClient`, it will be used to auto-configure a suitable `MongoDatabaseFactory`. - -The auto-configured `MongoClient` is created using a `MongoClientSettings` bean. -If you have defined your own `MongoClientSettings`, it will be used without modification and the `spring.data.mongodb` properties will be ignored. -Otherwise a `MongoClientSettings` will be auto-configured and will have the `spring.data.mongodb` properties applied to it. -In either case, you can declare one or more `MongoClientSettingsBuilderCustomizer` beans to fine-tune the `MongoClientSettings` configuration. -Each will be called in order with the `MongoClientSettings.Builder` that is used to build the `MongoClientSettings`. - -You can set the configprop:spring.data.mongodb.uri[] property to change the URL and configure additional settings such as the _replica set_, as shown in the following example: - -[source,properties,indent=0,configprops] ----- - spring.data.mongodb.uri=mongodb://user:secret@mongo1.example.com:12345,mongo2.example.com:23456/test ----- - -Alternatively, you can specify connection details using discrete properties. -For example, you might declare the following settings in your `application.properties`: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - data: - mongodb: - host: "mongoserver.example.com" - port: 27017 - database: "test" - username: "user" - password: "secret" ----- - -TIP: If `spring.data.mongodb.port` is not specified, the default of `27017` is used. -You could delete this line from the example shown earlier. - -TIP: If you do not use Spring Data MongoDB, you can inject a `MongoClient` bean instead of using `MongoDatabaseFactory`. -If you want to take complete control of establishing the MongoDB connection, you can also declare your own `MongoDatabaseFactory` or `MongoClient` bean. - -NOTE: If you are using the reactive driver, Netty is required for SSL. -The auto-configuration configures this factory automatically if Netty is available and the factory to use hasn't been customized already. - - - -[[features.nosql.mongodb.template]] -==== MongoTemplate -{spring-data-mongodb}[Spring Data MongoDB] provides a {spring-data-mongodb-api}/core/MongoTemplate.html[`MongoTemplate`] class that is very similar in its design to Spring's `JdbcTemplate`. -As with `JdbcTemplate`, Spring Boot auto-configures a bean for you to inject the template, as follows: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/nosql/mongodb/template/MyBean.java[] ----- - -See the {spring-data-mongodb-api}/core/MongoOperations.html[`MongoOperations` Javadoc] for complete details. - - - -[[features.nosql.mongodb.repositories]] -[[features.nosql.mongodb.repositories]] -==== Spring Data MongoDB Repositories -Spring Data includes repository support for MongoDB. -As with the JPA repositories discussed earlier, the basic principle is that queries are constructed automatically, based on method names. - -In fact, both Spring Data JPA and Spring Data MongoDB share the same common infrastructure. -You could take the JPA example from earlier and, assuming that `City` is now a MongoDB data class rather than a JPA `@Entity`, it works in the same way, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/nosql/mongodb/data/CityRepository.java[] ----- - -TIP: You can customize document scanning locations by using the `@EntityScan` annotation. - -TIP: For complete details of Spring Data MongoDB, including its rich object mapping technologies, refer to its {spring-data-mongodb}[reference documentation]. - - - -[[features.nosql.mongodb.embedded]] -==== Embedded Mongo -Spring Boot offers auto-configuration for https://github.com/flapdoodle-oss/de.flapdoodle.embed.mongo[Embedded Mongo]. -To use it in your Spring Boot application, add a dependency on `de.flapdoodle.embed:de.flapdoodle.embed.mongo`. - -The port that Mongo listens on can be configured by setting the configprop:spring.data.mongodb.port[] property. -To use a randomly allocated free port, use a value of 0. -The `MongoClient` created by `MongoAutoConfiguration` is automatically configured to use the randomly allocated port. - -NOTE: If you do not configure a custom port, the embedded support uses a random port (rather than 27017) by default. - -If you have SLF4J on the classpath, the output produced by Mongo is automatically routed to a logger named `org.springframework.boot.autoconfigure.mongo.embedded.EmbeddedMongo`. - -You can declare your own `IMongodConfig` and `IRuntimeConfig` beans to take control of the Mongo instance's configuration and logging routing. -The download configuration can be customized by declaring a `DownloadConfigBuilderCustomizer` bean. - - - -[[features.nosql.neo4j]] -=== Neo4j -https://neo4j.com/[Neo4j] is an open-source NoSQL graph database that uses a rich data model of nodes connected by first class relationships, which is better suited for connected big data than traditional RDBMS approaches. -Spring Boot offers several conveniences for working with Neo4j, including the `spring-boot-starter-data-neo4j` "`Starter`". - - - -[[features.nosql.neo4j.connecting]] -==== Connecting to a Neo4j Database -To access a Neo4j server, you can inject an auto-configured `org.neo4j.driver.Driver`. -By default, the instance tries to connect to a Neo4j server at `localhost:7687` using the Bolt protocol. -The following example shows how to inject a Neo4j `Driver` that gives you access, amongst other things, to a `Session`: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/nosql/neo4j/driver/MyBean.java[] ----- - -You can configure various aspects of the driver using `spring.neo4j.*` properties. -The following example shows how to configure the uri and credentials to use: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - neo4j: - uri: "bolt://my-server:7687" - authentication: - username: "neo4j" - password: "secret" ----- - -The auto-configured `Driver` is created using `ConfigBuilder`. -To fine-tune its configuration, declare one or more `ConfigBuilderCustomizer` beans. -Each will be called in order with the `ConfigBuilder` that is used to build the `Driver`. - - - -[[features.nosql.neo4j.repositories]] -==== Spring Data Neo4j Repositories -Spring Data includes repository support for Neo4j. -For complete details of Spring Data Neo4j, refer to the {spring-data-neo4j-docs}[reference documentation]. - -Spring Data Neo4j shares the common infrastructure with Spring Data JPA as many other Spring Data modules do. -You could take the JPA example from earlier and define `City` as Spring Data Neo4j `@Node` rather than JPA `@Entity` and the repository abstraction works in the same way, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/nosql/neo4j/data/CityRepository.java[] ----- - -The `spring-boot-starter-data-neo4j` "`Starter`" enables the repository support as well as transaction management. -Spring Boot supports both classic and reactive Neo4j repositories, using the `Neo4jTemplate` or `ReactiveNeo4jTemplate` beans. -When Project Reactor is available on the classpath, the reactive style is also auto-configured. - -You can customize the locations to look for repositories and entities by using `@EnableNeo4jRepositories` and `@EntityScan` respectively on a `@Configuration`-bean. - -[NOTE] -==== -In an application using the reactive style, a `ReactiveTransactionManager` is not auto-configured. -To enable transaction management, the following bean must be defined in your configuration: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/nosql/Neo4jReactiveTransactionManagerConfiguration.java[] ----- -==== - - - -[[features.nosql.solr]] -=== Solr -https://lucene.apache.org/solr/[Apache Solr] is a search engine. -Spring Boot offers basic auto-configuration for the Solr 5 client library. - - - -[[features.nosql.solr.connecting]] -==== Connecting to Solr -You can inject an auto-configured `SolrClient` instance as you would any other Spring bean. -By default, the instance tries to connect to a server at `http://localhost:8983/solr`. -The following example shows how to inject a Solr bean: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/nosql/solr/client/MyBean.java[] ----- - -If you add your own `@Bean` of type `SolrClient`, it replaces the default. - - - -[[features.nosql.elasticsearch]] -=== Elasticsearch -https://www.elastic.co/products/elasticsearch[Elasticsearch] is an open source, distributed, RESTful search and analytics engine. -Spring Boot offers basic auto-configuration for Elasticsearch. - -Spring Boot supports several clients: - -* The official Java "Low Level" and "High Level" REST clients -* The `ReactiveElasticsearchClient` provided by Spring Data Elasticsearch - -Spring Boot provides a dedicated "`Starter`", `spring-boot-starter-data-elasticsearch`. - - - -[[features.nosql.elasticsearch.connecting-using-rest]] -==== Connecting to Elasticsearch using REST clients -Elasticsearch ships https://www.elastic.co/guide/en/elasticsearch/client/java-rest/current/index.html[two different REST clients] that you can use to query a cluster: the "Low Level" client and the "High Level" client. -Spring Boot provides support for the "High Level" client, which ships with `org.elasticsearch.client:elasticsearch-rest-high-level-client`. - -If you have this dependency on the classpath, Spring Boot will auto-configure and register a `RestHighLevelClient` bean that by default targets `http://localhost:9200`. -You can further tune how `RestHighLevelClient` is configured, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - elasticsearch: - rest: - uris: "https://search.example.com:9200" - read-timeout: "10s" - username: "user" - password: "secret" ----- - -You can also register an arbitrary number of beans that implement `RestClientBuilderCustomizer` for more advanced customizations. -To take full control over the registration, define a `RestClientBuilder` bean. - -TIP: If your application needs access to a "Low Level" `RestClient`, you can get it by calling `client.getLowLevelClient()` on the auto-configured `RestHighLevelClient`. - -Additionally, if `elasticsearch-rest-client-sniffer` is on the classpath, a `Sniffer` is auto-configured to automatically discover nodes from a running Elasticsearch cluster and set them to the `RestHighLevelClient` bean. -You can further tune how `Sniffer` is configured, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - elasticsearch: - rest: - sniffer: - interval: 10m - delay-after-failure: 30s ----- - - - -[[features.nosql.elasticsearch.connecting-using-reactive-rest]] -==== Connecting to Elasticsearch using Reactive REST clients -{spring-data-elasticsearch}[Spring Data Elasticsearch] ships `ReactiveElasticsearchClient` for querying Elasticsearch instances in a reactive fashion. -It is built on top of WebFlux's `WebClient`, so both `spring-boot-starter-elasticsearch` and `spring-boot-starter-webflux` dependencies are useful to enable this support. - -By default, Spring Boot will auto-configure and register a `ReactiveElasticsearchClient` -bean that targets `http://localhost:9200`. -You can further tune how it is configured, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - data: - elasticsearch: - client: - reactive: - endpoints: "search.example.com:9200" - use-ssl: true - socket-timeout: "10s" - username: "user" - password: "secret" ----- - -If the configuration properties are not enough and you'd like to fully control the client -configuration, you can register a custom `ClientConfiguration` bean. - - - -[[features.nosql.elasticsearch.connecting-using-spring-data]] -==== Connecting to Elasticsearch by Using Spring Data -To connect to Elasticsearch, a `RestHighLevelClient` bean must be defined, -auto-configured by Spring Boot or manually provided by the application (see previous sections). -With this configuration in place, an -`ElasticsearchRestTemplate` can be injected like any other Spring bean, -as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/nosql/elasticsearch/template/MyBean.java[] ----- - -In the presence of `spring-data-elasticsearch` and the required dependencies for using a `WebClient` (typically `spring-boot-starter-webflux`), Spring Boot can also auto-configure a <> and a `ReactiveElasticsearchTemplate` as beans. -They are the reactive equivalent of the other REST clients. - - - -[[features.nosql.elasticsearch.repositories]] -==== Spring Data Elasticsearch Repositories -Spring Data includes repository support for Elasticsearch. -As with the JPA repositories discussed earlier, the basic principle is that queries are constructed for you automatically based on method names. - -In fact, both Spring Data JPA and Spring Data Elasticsearch share the same common infrastructure. -You could take the JPA example from earlier and, assuming that `City` is now an Elasticsearch `@Document` class rather than a JPA `@Entity`, it works in the same way. - -TIP: For complete details of Spring Data Elasticsearch, refer to the {spring-data-elasticsearch-docs}[reference documentation]. - -Spring Boot supports both classic and reactive Elasticsearch repositories, using the `ElasticsearchRestTemplate` or `ReactiveElasticsearchTemplate` beans. -Most likely those beans are auto-configured by Spring Boot given the required dependencies are present. - -If you wish to use your own template for backing the Elasticsearch repositories, you can add your own `ElasticsearchRestTemplate` or `ElasticsearchOperations` `@Bean`, as long as it is named `"elasticsearchTemplate"`. -Same applies to `ReactiveElasticsearchTemplate` and `ReactiveElasticsearchOperations`, with the bean name `"reactiveElasticsearchTemplate"`. - -You can choose to disable the repositories support with the following property: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - data: - elasticsearch: - repositories: - enabled: false ----- - - - -[[features.nosql.cassandra]] -=== Cassandra -https://cassandra.apache.org/[Cassandra] is an open source, distributed database management system designed to handle large amounts of data across many commodity servers. -Spring Boot offers auto-configuration for Cassandra and the abstractions on top of it provided by https://github.com/spring-projects/spring-data-cassandra[Spring Data Cassandra]. -There is a `spring-boot-starter-data-cassandra` "`Starter`" for collecting the dependencies in a convenient way. - - - -[[features.nosql.cassandra.connecting]] -==== Connecting to Cassandra -You can inject an auto-configured `CassandraTemplate` or a Cassandra `CqlSession` instance as you would with any other Spring Bean. -The `spring.data.cassandra.*` properties can be used to customize the connection. -Generally, you provide `keyspace-name` and `contact-points` as well the local datacenter name, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - data: - cassandra: - keyspace-name: "mykeyspace" - contact-points: "cassandrahost1:9042,cassandrahost2:9042" - local-datacenter: "datacenter1" ----- - -If the port is the same for all your contact points you can use a shortcut and only specify the host names, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - data: - cassandra: - keyspace-name: "mykeyspace" - contact-points: "cassandrahost1,cassandrahost2" - local-datacenter: "datacenter1" ----- - -TIP: Those two examples are identical as the port default to `9042`. -If you need to configure the port, use `spring.data.cassandra.port`. - -[NOTE] -==== -The Cassandra driver has its own configuration infrastructure that loads an `application.conf` at the root of the classpath. - -Spring Boot does not look for such a file by default but can load one using `spring.data.cassandra.config`. -If a property is both present in `+spring.data.cassandra.*+` and the configuration file, the value in `+spring.data.cassandra.*+` takes precedence. - -For more advanced driver customizations, you can register an arbitrary number of beans that implement `DriverConfigLoaderBuilderCustomizer`. -The `CqlSession` can be customized with a bean of type `CqlSessionBuilderCustomizer`. -==== - -NOTE: If you're using `CqlSessionBuilder` to create multiple `CqlSession` beans, keep in mind the builder is mutable so make sure to inject a fresh copy for each session. - -The following code listing shows how to inject a Cassandra bean: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/nosql/cassandra/template/MyBean.java[] ----- - -If you add your own `@Bean` of type `CassandraTemplate`, it replaces the default. - - - -[[features.nosql.cassandra.repositories]] -==== Spring Data Cassandra Repositories -Spring Data includes basic repository support for Cassandra. -Currently, this is more limited than the JPA repositories discussed earlier and needs to annotate finder methods with `@Query`. - -TIP: For complete details of Spring Data Cassandra, refer to the https://docs.spring.io/spring-data/cassandra/docs/[reference documentation]. - - - -[[features.nosql.couchbase]] -=== Couchbase -https://www.couchbase.com/[Couchbase] is an open-source, distributed, multi-model NoSQL document-oriented database that is optimized for interactive applications. -Spring Boot offers auto-configuration for Couchbase and the abstractions on top of it provided by https://github.com/spring-projects/spring-data-couchbase[Spring Data Couchbase]. -There are `spring-boot-starter-data-couchbase` and `spring-boot-starter-data-couchbase-reactive` "`Starters`" for collecting the dependencies in a convenient way. - - - -[[features.nosql.couchbase.connecting]] -==== Connecting to Couchbase -You can get a `Cluster` by adding the Couchbase SDK and some configuration. -The `spring.couchbase.*` properties can be used to customize the connection. -Generally, you provide the https://github.com/couchbaselabs/sdk-rfcs/blob/master/rfc/0011-connection-string.md[connection string], username, and password, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - couchbase: - connection-string: "couchbase://192.168.1.123" - username: "user" - password: "secret" ----- - -It is also possible to customize some of the `ClusterEnvironment` settings. -For instance, the following configuration changes the timeout to use to open a new `Bucket` and enables SSL support: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - couchbase: - env: - timeouts: - connect: "3s" - ssl: - key-store: "/location/of/keystore.jks" - key-store-password: "secret" ----- - -TIP: Check the `spring.couchbase.env.*` properties for more details. -To take more control, one or more `ClusterEnvironmentBuilderCustomizer` beans can be used. - - - -[[features.nosql.couchbase.repositories]] -==== Spring Data Couchbase Repositories -Spring Data includes repository support for Couchbase. -For complete details of Spring Data Couchbase, refer to the {spring-data-couchbase-docs}[reference documentation]. - -You can inject an auto-configured `CouchbaseTemplate` instance as you would with any other Spring Bean, provided a `CouchbaseClientFactory` bean is available. -This happens when a `Cluster` is available, as described above, and a bucket name has been specified: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - data: - couchbase: - bucket-name: "my-bucket" ----- - -The following examples shows how to inject a `CouchbaseTemplate` bean: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/nosql/couchbase/template/MyBean.java[] ----- - -There are a few beans that you can define in your own configuration to override those provided by the auto-configuration: - -* A `CouchbaseMappingContext` `@Bean` with a name of `couchbaseMappingContext`. -* A `CustomConversions` `@Bean` with a name of `couchbaseCustomConversions`. -* A `CouchbaseTemplate` `@Bean` with a name of `couchbaseTemplate`. - -To avoid hard-coding those names in your own config, you can reuse `BeanNames` provided by Spring Data Couchbase. -For instance, you can customize the converters to use, as follows: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/nosql/couchbase/CouchbaseConversionsConfiguration.java[] ----- - - - -[[features.nosql.ldap]] -=== LDAP -https://en.wikipedia.org/wiki/Lightweight_Directory_Access_Protocol[LDAP] (Lightweight Directory Access Protocol) is an open, vendor-neutral, industry standard application protocol for accessing and maintaining distributed directory information services over an IP network. -Spring Boot offers auto-configuration for any compliant LDAP server as well as support for the embedded in-memory LDAP server from https://ldap.com/unboundid-ldap-sdk-for-java/[UnboundID]. - -LDAP abstractions are provided by https://github.com/spring-projects/spring-data-ldap[Spring Data LDAP]. -There is a `spring-boot-starter-data-ldap` "`Starter`" for collecting the dependencies in a convenient way. - - - -[[features.nosql.ldap.connecting]] -==== Connecting to an LDAP Server -To connect to an LDAP server, make sure you declare a dependency on the `spring-boot-starter-data-ldap` "`Starter`" or `spring-ldap-core` and then declare the URLs of your server in your application.properties, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - ldap: - urls: "ldap://myserver:1235" - username: "admin" - password: "secret" ----- - -If you need to customize connection settings, you can use the `spring.ldap.base` and `spring.ldap.base-environment` properties. - -An `LdapContextSource` is auto-configured based on these settings. -If a `DirContextAuthenticationStrategy` bean is available, it is associated to the auto-configured `LdapContextSource`. -If you need to customize it, for instance to use a `PooledContextSource`, you can still inject the auto-configured `LdapContextSource`. -Make sure to flag your customized `ContextSource` as `@Primary` so that the auto-configured `LdapTemplate` uses it. - - - -[[features.nosql.ldap.repositories]] -==== Spring Data LDAP Repositories -Spring Data includes repository support for LDAP. -For complete details of Spring Data LDAP, refer to the https://docs.spring.io/spring-data/ldap/docs/1.0.x/reference/html/[reference documentation]. - -You can also inject an auto-configured `LdapTemplate` instance as you would with any other Spring Bean, as shown in the following example: - - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/nosql/ldap/template/MyBean.java[] ----- - - - -[[features.nosql.ldap.embedded]] -==== Embedded In-memory LDAP Server -For testing purposes, Spring Boot supports auto-configuration of an in-memory LDAP server from https://ldap.com/unboundid-ldap-sdk-for-java/[UnboundID]. -To configure the server, add a dependency to `com.unboundid:unboundid-ldapsdk` and declare a configprop:spring.ldap.embedded.base-dn[] property, as follows: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - ldap: - embedded: - base-dn: "dc=spring,dc=io" ----- - -[NOTE] -==== -It is possible to define multiple base-dn values, however, since distinguished names usually contain commas, they must be defined using the correct notation. - -In yaml files, you can use the yaml list notation. In properties files, you must include the index as part of the property name: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring.ldap.embedded.base-dn: - - dc=spring,dc=io - - dc=pivotal,dc=io ----- -==== - -By default, the server starts on a random port and triggers the regular LDAP support. -There is no need to specify a configprop:spring.ldap.urls[] property. - -If there is a `schema.ldif` file on your classpath, it is used to initialize the server. -If you want to load the initialization script from a different resource, you can also use the configprop:spring.ldap.embedded.ldif[] property. - -By default, a standard schema is used to validate `LDIF` files. -You can turn off validation altogether by setting the configprop:spring.ldap.embedded.validation.enabled[] property. -If you have custom attributes, you can use configprop:spring.ldap.embedded.validation.schema[] to define your custom attribute types or object classes. - - - -[[features.nosql.influxdb]] -=== InfluxDB -https://www.influxdata.com/[InfluxDB] is an open-source time series database optimized for fast, high-availability storage and retrieval of time series data in fields such as operations monitoring, application metrics, Internet-of-Things sensor data, and real-time analytics. - - - -[[features.nosql.influxdb.connecting]] -==== Connecting to InfluxDB -Spring Boot auto-configures an `InfluxDB` instance, provided the `influxdb-java` client is on the classpath and the URL of the database is set, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - influx: - url: "https://172.0.0.1:8086" ----- - -If the connection to InfluxDB requires a user and password, you can set the `spring.influx.user` and `spring.influx.password` properties accordingly. - -InfluxDB relies on OkHttp. -If you need to tune the http client `InfluxDB` uses behind the scenes, you can register an `InfluxDbOkHttpClientBuilderProvider` bean. - -If you need more control over the configuration, consider registering an `InfluxDbCustomizer` bean. - - - -[[features.caching]] -== Caching -The Spring Framework provides support for transparently adding caching to an application. -At its core, the abstraction applies caching to methods, thus reducing the number of executions based on the information available in the cache. -The caching logic is applied transparently, without any interference to the invoker. -Spring Boot auto-configures the cache infrastructure as long as caching support is enabled via the `@EnableCaching` annotation. - -NOTE: Check the {spring-framework-docs}/integration.html#cache[relevant section] of the Spring Framework reference for more details. - -In a nutshell, to add caching to an operation of your service add the relevant annotation to its method, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/caching/MathService.java[] ----- - -This example demonstrates the use of caching on a potentially costly operation. -Before invoking `computePiDecimal`, the abstraction looks for an entry in the `piDecimals` cache that matches the `i` argument. -If an entry is found, the content in the cache is immediately returned to the caller, and the method is not invoked. -Otherwise, the method is invoked, and the cache is updated before returning the value. - -CAUTION: You can also use the standard JSR-107 (JCache) annotations (such as `@CacheResult`) transparently. -However, we strongly advise you to not mix and match the Spring Cache and JCache annotations. - -If you do not add any specific cache library, Spring Boot auto-configures a <> that uses concurrent maps in memory. -When a cache is required (such as `piDecimals` in the preceding example), this provider creates it for you. -The simple provider is not really recommended for production usage, but it is great for getting started and making sure that you understand the features. -When you have made up your mind about the cache provider to use, please make sure to read its documentation to figure out how to configure the caches that your application uses. -Nearly all providers require you to explicitly configure every cache that you use in the application. -Some offer a way to customize the default caches defined by the configprop:spring.cache.cache-names[] property. - -TIP: It is also possible to transparently {spring-framework-docs}/integration.html#cache-annotations-put[update] or {spring-framework-docs}/integration.html#cache-annotations-evict[evict] data from the cache. - - - -[[features.caching.provider]] -=== Supported Cache Providers -The cache abstraction does not provide an actual store and relies on abstraction materialized by the `org.springframework.cache.Cache` and `org.springframework.cache.CacheManager` interfaces. - -If you have not defined a bean of type `CacheManager` or a `CacheResolver` named `cacheResolver` (see {spring-framework-api}/cache/annotation/CachingConfigurer.html[`CachingConfigurer`]), Spring Boot tries to detect the following providers (in the indicated order): - -. <> -. <> (EhCache 3, Hazelcast, Infinispan, and others) -. <> -. <> -. <> -. <> -. <> -. <> -. <> - -TIP: It is also possible to _force_ a particular cache provider by setting the configprop:spring.cache.type[] property. -Use this property if you need to <> in certain environment (such as tests). - -TIP: Use the `spring-boot-starter-cache` "`Starter`" to quickly add basic caching dependencies. -The starter brings in `spring-context-support`. -If you add dependencies manually, you must include `spring-context-support` in order to use the JCache, EhCache 2.x, or Caffeine support. - -If the `CacheManager` is auto-configured by Spring Boot, you can further tune its configuration before it is fully initialized by exposing a bean that implements the `CacheManagerCustomizer` interface. -The following example sets a flag to say that `null` values should be passed down to the underlying map: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/caching/CacheManagerCustomizerConfiguration.java[] ----- - -NOTE: In the preceding example, an auto-configured `ConcurrentMapCacheManager` is expected. -If that is not the case (either you provided your own config or a different cache provider was auto-configured), the customizer is not invoked at all. -You can have as many customizers as you want, and you can also order them by using `@Order` or `Ordered`. - - - -[[features.caching.provider.generic]] -==== Generic -Generic caching is used if the context defines _at least_ one `org.springframework.cache.Cache` bean. -A `CacheManager` wrapping all beans of that type is created. - - - -[[features.caching.provider.jcache]] -==== JCache (JSR-107) -https://jcp.org/en/jsr/detail?id=107[JCache] is bootstrapped through the presence of a `javax.cache.spi.CachingProvider` on the classpath (that is, a JSR-107 compliant caching library exists on the classpath), and the `JCacheCacheManager` is provided by the `spring-boot-starter-cache` "`Starter`". -Various compliant libraries are available, and Spring Boot provides dependency management for Ehcache 3, Hazelcast, and Infinispan. -Any other compliant library can be added as well. - -It might happen that more than one provider is present, in which case the provider must be explicitly specified. -Even if the JSR-107 standard does not enforce a standardized way to define the location of the configuration file, Spring Boot does its best to accommodate setting a cache with implementation details, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - # Only necessary if more than one provider is present - spring: - cache: - jcache: - provider: "com.acme.MyCachingProvider" - config: "classpath:acme.xml" ----- - -NOTE: When a cache library offers both a native implementation and JSR-107 support, Spring Boot prefers the JSR-107 support, so that the same features are available if you switch to a different JSR-107 implementation. - -TIP: Spring Boot has <>. -If a single `HazelcastInstance` is available, it is automatically reused for the `CacheManager` as well, unless the configprop:spring.cache.jcache.config[] property is specified. - -There are two ways to customize the underlying `javax.cache.cacheManager`: - -* Caches can be created on startup by setting the configprop:spring.cache.cache-names[] property. - If a custom `javax.cache.configuration.Configuration` bean is defined, it is used to customize them. -* `org.springframework.boot.autoconfigure.cache.JCacheManagerCustomizer` beans are invoked with the reference of the `CacheManager` for full customization. - -TIP: If a standard `javax.cache.CacheManager` bean is defined, it is wrapped automatically in an `org.springframework.cache.CacheManager` implementation that the abstraction expects. -No further customization is applied to it. - - - -[[features.caching.provider.ehcache2]] -==== EhCache 2.x -https://www.ehcache.org/[EhCache] 2.x is used if a file named `ehcache.xml` can be found at the root of the classpath. -If EhCache 2.x is found, the `EhCacheCacheManager` provided by the `spring-boot-starter-cache` "`Starter`" is used to bootstrap the cache manager. -An alternate configuration file can be provided as well, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - cache: - ehcache: - config: "classpath:config/another-config.xml" ----- - - - -[[features.caching.provider.hazelcast]] -==== Hazelcast -Spring Boot has <>. -If a `HazelcastInstance` has been auto-configured, it is automatically wrapped in a `CacheManager`. - - - -[[features.caching.provider.infinispan]] -==== Infinispan -https://infinispan.org/[Infinispan] has no default configuration file location, so it must be specified explicitly. -Otherwise, the default bootstrap is used. - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - cache: - infinispan: - config: "infinispan.xml" ----- - -Caches can be created on startup by setting the configprop:spring.cache.cache-names[] property. -If a custom `ConfigurationBuilder` bean is defined, it is used to customize the caches. - -NOTE: The support of Infinispan in Spring Boot is restricted to the embedded mode and is quite basic. -If you want more options, you should use the official Infinispan Spring Boot starter instead. -See https://github.com/infinispan/infinispan-spring-boot[Infinispan's documentation] for more details. - - - -[[features.caching.provider.couchbase]] -==== Couchbase -If Spring Data Couchbase is available and Couchbase is <>, a `CouchbaseCacheManager` is auto-configured. -It is possible to create additional caches on startup by setting the configprop:spring.cache.cache-names[] property and cache defaults can be configured by using `spring.cache.couchbase.*` properties. -For instance, the following configuration creates `cache1` and `cache2` caches with an entry _expiration_ of 10 minutes: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - cache: - cache-names: "cache1,cache2" - couchbase: - expiration: "10m" ----- - -If you need more control over the configuration, consider registering a `CouchbaseCacheManagerBuilderCustomizer` bean. -The following example shows a customizer that configures a specific entry expiration for `cache1` and `cache2`: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/nosql/CouchbaseCacheManagerConfiguration.java[] ----- - - - -[[features.caching.provider.redis]] -==== Redis -If https://redis.io/[Redis] is available and configured, a `RedisCacheManager` is auto-configured. -It is possible to create additional caches on startup by setting the configprop:spring.cache.cache-names[] property and cache defaults can be configured by using `spring.cache.redis.*` properties. -For instance, the following configuration creates `cache1` and `cache2` caches with a _time to live_ of 10 minutes: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - cache: - cache-names: "cache1,cache2" - redis: - time-to-live: "10m" ----- - -NOTE: By default, a key prefix is added so that, if two separate caches use the same key, Redis does not have overlapping keys and cannot return invalid values. -We strongly recommend keeping this setting enabled if you create your own `RedisCacheManager`. - -TIP: You can take full control of the default configuration by adding a `RedisCacheConfiguration` `@Bean` of your own. -This can be useful if you're looking for customizing the default serialization strategy. - -If you need more control over the configuration, consider registering a `RedisCacheManagerBuilderCustomizer` bean. -The following example shows a customizer that configures a specific time to live for `cache1` and `cache2`: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/nosql/RedisCacheManagerConfiguration.java[] ----- - - - -[[features.caching.provider.caffeine]] -==== Caffeine -https://github.com/ben-manes/caffeine[Caffeine] is a Java 8 rewrite of Guava's cache that supersedes support for Guava. -If Caffeine is present, a `CaffeineCacheManager` (provided by the `spring-boot-starter-cache` "`Starter`") is auto-configured. -Caches can be created on startup by setting the configprop:spring.cache.cache-names[] property and can be customized by one of the following (in the indicated order): - -. A cache spec defined by `spring.cache.caffeine.spec` -. A `com.github.benmanes.caffeine.cache.CaffeineSpec` bean is defined -. A `com.github.benmanes.caffeine.cache.Caffeine` bean is defined - -For instance, the following configuration creates `cache1` and `cache2` caches with a maximum size of 500 and a _time to live_ of 10 minutes - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - cache: - cache-names: "cache1,cache2" - caffeine: - spec: "maximumSize=500,expireAfterAccess=600s" ----- - -If a `com.github.benmanes.caffeine.cache.CacheLoader` bean is defined, it is automatically associated to the `CaffeineCacheManager`. -Since the `CacheLoader` is going to be associated with _all_ caches managed by the cache manager, it must be defined as `CacheLoader`. -The auto-configuration ignores any other generic type. - - - -[[features.caching.provider.simple]] -==== Simple -If none of the other providers can be found, a simple implementation using a `ConcurrentHashMap` as the cache store is configured. -This is the default if no caching library is present in your application. -By default, caches are created as needed, but you can restrict the list of available caches by setting the `cache-names` property. -For instance, if you want only `cache1` and `cache2` caches, set the `cache-names` property as follows: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - cache: - cache-names: "cache1,cache2" ----- - -If you do so and your application uses a cache not listed, then it fails at runtime when the cache is needed, but not on startup. -This is similar to the way the "real" cache providers behave if you use an undeclared cache. - - - -[[features.caching.provider.none]] -==== None -When `@EnableCaching` is present in your configuration, a suitable cache configuration is expected as well. -If you need to disable caching altogether in certain environments, force the cache type to `none` to use a no-op implementation, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - cache: - type: "none" ----- - - - -[[features.messaging]] -== Messaging -The Spring Framework provides extensive support for integrating with messaging systems, from simplified use of the JMS API using `JmsTemplate` to a complete infrastructure to receive messages asynchronously. -Spring AMQP provides a similar feature set for the Advanced Message Queuing Protocol. -Spring Boot also provides auto-configuration options for `RabbitTemplate` and RabbitMQ. -Spring WebSocket natively includes support for STOMP messaging, and Spring Boot has support for that through starters and a small amount of auto-configuration. -Spring Boot also has support for Apache Kafka. - - - -[[features.messaging.jms]] -=== JMS -The `javax.jms.ConnectionFactory` interface provides a standard method of creating a `javax.jms.Connection` for interacting with a JMS broker. -Although Spring needs a `ConnectionFactory` to work with JMS, you generally need not use it directly yourself and can instead rely on higher level messaging abstractions. -(See the {spring-framework-docs}/integration.html#jms[relevant section] of the Spring Framework reference documentation for details.) -Spring Boot also auto-configures the necessary infrastructure to send and receive messages. - - - -[[features.messaging.jms.activemq]] -==== ActiveMQ Support -When https://activemq.apache.org/[ActiveMQ] is available on the classpath, Spring Boot can also configure a `ConnectionFactory`. -If the broker is present, an embedded broker is automatically started and configured (provided no broker URL is specified through configuration). - -NOTE: If you use `spring-boot-starter-activemq`, the necessary dependencies to connect or embed an ActiveMQ instance are provided, as is the Spring infrastructure to integrate with JMS. - -ActiveMQ configuration is controlled by external configuration properties in `+spring.activemq.*+`. -For example, you might declare the following section in `application.properties`: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - activemq: - broker-url: "tcp://192.168.1.210:9876" - user: "admin" - password: "secret" ----- - -By default, a `CachingConnectionFactory` wraps the native `ConnectionFactory` with sensible settings that you can control by external configuration properties in `+spring.jms.*+`: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - jms: - cache: - session-cache-size: 5 ----- - -If you'd rather use native pooling, you can do so by adding a dependency to `org.messaginghub:pooled-jms` and configuring the `JmsPoolConnectionFactory` accordingly, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - activemq: - pool: - enabled: true - max-connections: 50 ----- - -TIP: See {spring-boot-autoconfigure-module-code}/jms/activemq/ActiveMQProperties.java[`ActiveMQProperties`] for more of the supported options. -You can also register an arbitrary number of beans that implement `ActiveMQConnectionFactoryCustomizer` for more advanced customizations. - -By default, ActiveMQ creates a destination if it does not yet exist so that destinations are resolved against their provided names. - - - -[[features.messaging.jms.artemis]] -==== ActiveMQ Artemis Support -Spring Boot can auto-configure a `ConnectionFactory` when it detects that https://activemq.apache.org/components/artemis/[ActiveMQ Artemis] is available on the classpath. -If the broker is present, an embedded broker is automatically started and configured (unless the mode property has been explicitly set). -The supported modes are `embedded` (to make explicit that an embedded broker is required and that an error should occur if the broker is not available on the classpath) and `native` (to connect to a broker using the `netty` transport protocol). -When the latter is configured, Spring Boot configures a `ConnectionFactory` that connects to a broker running on the local machine with the default settings. - -NOTE: If you use `spring-boot-starter-artemis`, the necessary dependencies to connect to an existing ActiveMQ Artemis instance are provided, as well as the Spring infrastructure to integrate with JMS. -Adding `org.apache.activemq:artemis-jms-server` to your application lets you use embedded mode. - -ActiveMQ Artemis configuration is controlled by external configuration properties in `+spring.artemis.*+`. -For example, you might declare the following section in `application.properties`: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - artemis: - mode: native - broker-url: "tcp://192.168.1.210:9876" - user: "admin" - password: "secret" ----- - -When embedding the broker, you can choose if you want to enable persistence and list the destinations that should be made available. -These can be specified as a comma-separated list to create them with the default options, or you can define bean(s) of type `org.apache.activemq.artemis.jms.server.config.JMSQueueConfiguration` or `org.apache.activemq.artemis.jms.server.config.TopicConfiguration`, for advanced queue and topic configurations, respectively. - -By default, a `CachingConnectionFactory` wraps the native `ConnectionFactory` with sensible settings that you can control by external configuration properties in `+spring.jms.*+`: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - jms: - cache: - session-cache-size: 5 ----- - -If you'd rather use native pooling, you can do so by adding a dependency to `org.messaginghub:pooled-jms` and configuring the `JmsPoolConnectionFactory` accordingly, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - artemis: - pool: - enabled: true - max-connections: 50 ----- - -See {spring-boot-autoconfigure-module-code}/jms/artemis/ArtemisProperties.java[`ArtemisProperties`] for more supported options. - -No JNDI lookup is involved, and destinations are resolved against their names, using either the `name` attribute in the Artemis configuration or the names provided through configuration. - - - -[[features.messaging.jms.jndi]] -==== Using a JNDI ConnectionFactory -If you are running your application in an application server, Spring Boot tries to locate a JMS `ConnectionFactory` by using JNDI. -By default, the `java:/JmsXA` and `java:/XAConnectionFactory` location are checked. -You can use the configprop:spring.jms.jndi-name[] property if you need to specify an alternative location, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - jms: - jndi-name: "java:/MyConnectionFactory" ----- - - - -[[features.messaging.jms.sending]] -==== Sending a Message -Spring's `JmsTemplate` is auto-configured, and you can autowire it directly into your own beans, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/messaging/jms/template/MyBean.java[] ----- - -NOTE: {spring-framework-api}/jms/core/JmsMessagingTemplate.html[`JmsMessagingTemplate`] can be injected in a similar manner. -If a `DestinationResolver` or a `MessageConverter` bean is defined, it is associated automatically to the auto-configured `JmsTemplate`. - - - -[[features.messaging.jms.receiving]] -==== Receiving a Message -When the JMS infrastructure is present, any bean can be annotated with `@JmsListener` to create a listener endpoint. -If no `JmsListenerContainerFactory` has been defined, a default one is configured automatically. -If a `DestinationResolver`, a `MessageConverter`, or a `javax.jms.ExceptionListener` beans are defined, they are associated automatically with the default factory. - -By default, the default factory is transactional. -If you run in an infrastructure where a `JtaTransactionManager` is present, it is associated to the listener container by default. -If not, the `sessionTransacted` flag is enabled. -In that latter scenario, you can associate your local data store transaction to the processing of an incoming message by adding `@Transactional` on your listener method (or a delegate thereof). -This ensures that the incoming message is acknowledged, once the local transaction has completed. -This also includes sending response messages that have been performed on the same JMS session. - -The following component creates a listener endpoint on the `someQueue` destination: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/messaging/jms/receiving/MyBean.java[] ----- - -TIP: See {spring-framework-api}/jms/annotation/EnableJms.html[the Javadoc of `@EnableJms`] for more details. - -If you need to create more `JmsListenerContainerFactory` instances or if you want to override the default, Spring Boot provides a `DefaultJmsListenerContainerFactoryConfigurer` that you can use to initialize a `DefaultJmsListenerContainerFactory` with the same settings as the one that is auto-configured. - -For instance, the following example exposes another factory that uses a specific `MessageConverter`: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/messaging/jms/receiving/custom/JmsConfiguration.java[] ----- - -Then you can use the factory in any `@JmsListener`-annotated method as follows: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/messaging/jms/receiving/custom/MyBean.java[] ----- - - - -[[features.messaging.amqp]] -=== AMQP -The Advanced Message Queuing Protocol (AMQP) is a platform-neutral, wire-level protocol for message-oriented middleware. -The Spring AMQP project applies core Spring concepts to the development of AMQP-based messaging solutions. -Spring Boot offers several conveniences for working with AMQP through RabbitMQ, including the `spring-boot-starter-amqp` "`Starter`". - - - -[[features.messaging.amqp.rabbitmq]] -==== RabbitMQ support -https://www.rabbitmq.com/[RabbitMQ] is a lightweight, reliable, scalable, and portable message broker based on the AMQP protocol. -Spring uses `RabbitMQ` to communicate through the AMQP protocol. - -RabbitMQ configuration is controlled by external configuration properties in `+spring.rabbitmq.*+`. -For example, you might declare the following section in `application.properties`: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - rabbitmq: - host: "localhost" - port: 5672 - username: "admin" - password: "secret" ----- - -Alternatively, you could configure the same connection using the `addresses` attribute: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - rabbitmq: - addresses: "amqp://admin:secret@localhost" ----- - -NOTE: When specifying addresses that way, the `host` and `port` properties are ignored. -If the address uses the `amqps` protocol, SSL support is enabled automatically. - -See {spring-boot-autoconfigure-module-code}/amqp/RabbitProperties.java[`RabbitProperties`] for more of the supported property-based configuration options. -To configure lower-level details of the RabbitMQ `ConnectionFactory` that is used by Spring AMQP, define a `ConnectionFactoryCustomizer` bean. - -If a `ConnectionNameStrategy` bean exists in the context, it will be automatically used to name connections created by the auto-configured `CachingConnectionFactory`. - -TIP: See https://spring.io/blog/2010/06/14/understanding-amqp-the-protocol-used-by-rabbitmq/[Understanding AMQP, the protocol used by RabbitMQ] for more details. - - - -[[features.messaging.amqp.sending]] -==== Sending a Message -Spring's `AmqpTemplate` and `AmqpAdmin` are auto-configured, and you can autowire them directly into your own beans, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/messaging/amqp/sending/MyBean.java[] ----- - -NOTE: {spring-amqp-api}/rabbit/core/RabbitMessagingTemplate.html[`RabbitMessagingTemplate`] can be injected in a similar manner. -If a `MessageConverter` bean is defined, it is associated automatically to the auto-configured `AmqpTemplate`. - -If necessary, any `org.springframework.amqp.core.Queue` that is defined as a bean is automatically used to declare a corresponding queue on the RabbitMQ instance. - -To retry operations, you can enable retries on the `AmqpTemplate` (for example, in the event that the broker connection is lost): - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - rabbitmq: - template: - retry: - enabled: true - initial-interval: "2s" ----- - -Retries are disabled by default. -You can also customize the `RetryTemplate` programmatically by declaring a `RabbitRetryTemplateCustomizer` bean. - -If you need to create more `RabbitTemplate` instances or if you want to override the default, Spring Boot provides a `RabbitTemplateConfigurer` bean that you can use to initialize a `RabbitTemplate` with the same settings as the factories used by the auto-configuration. - - - -[[features.messaging.amqp.receiving]] -==== Receiving a Message -When the Rabbit infrastructure is present, any bean can be annotated with `@RabbitListener` to create a listener endpoint. -If no `RabbitListenerContainerFactory` has been defined, a default `SimpleRabbitListenerContainerFactory` is automatically configured and you can switch to a direct container using the configprop:spring.rabbitmq.listener.type[] property. -If a `MessageConverter` or a `MessageRecoverer` bean is defined, it is automatically associated with the default factory. - -The following sample component creates a listener endpoint on the `someQueue` queue: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/messaging/amqp/receiving/MyBean.java[] ----- - -TIP: See {spring-amqp-api}/rabbit/annotation/EnableRabbit.html[the Javadoc of `@EnableRabbit`] for more details. - -If you need to create more `RabbitListenerContainerFactory` instances or if you want to override the default, Spring Boot provides a `SimpleRabbitListenerContainerFactoryConfigurer` and a `DirectRabbitListenerContainerFactoryConfigurer` that you can use to initialize a `SimpleRabbitListenerContainerFactory` and a `DirectRabbitListenerContainerFactory` with the same settings as the factories used by the auto-configuration. - -TIP: It does not matter which container type you chose. -Those two beans are exposed by the auto-configuration. - -For instance, the following configuration class exposes another factory that uses a specific `MessageConverter`: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/messaging/amqp/receiving/custom/RabbitConfiguration.java[] ----- - -Then you can use the factory in any `@RabbitListener`-annotated method, as follows: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/messaging/amqp/receiving/custom/MyBean.java[] ----- - -You can enable retries to handle situations where your listener throws an exception. -By default, `RejectAndDontRequeueRecoverer` is used, but you can define a `MessageRecoverer` of your own. -When retries are exhausted, the message is rejected and either dropped or routed to a dead-letter exchange if the broker is configured to do so. -By default, retries are disabled. -You can also customize the `RetryTemplate` programmatically by declaring a `RabbitRetryTemplateCustomizer` bean. - -IMPORTANT: By default, if retries are disabled and the listener throws an exception, the delivery is retried indefinitely. -You can modify this behavior in two ways: Set the `defaultRequeueRejected` property to `false` so that zero re-deliveries are attempted or throw an `AmqpRejectAndDontRequeueException` to signal the message should be rejected. -The latter is the mechanism used when retries are enabled and the maximum number of delivery attempts is reached. - - - -[[features.messaging.kafka]] -=== Apache Kafka Support -https://kafka.apache.org/[Apache Kafka] is supported by providing auto-configuration of the `spring-kafka` project. - -Kafka configuration is controlled by external configuration properties in `spring.kafka.*`. -For example, you might declare the following section in `application.properties`: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - kafka: - bootstrap-servers: "localhost:9092" - consumer: - group-id: "myGroup" ----- - -TIP: To create a topic on startup, add a bean of type `NewTopic`. -If the topic already exists, the bean is ignored. - -See {spring-boot-autoconfigure-module-code}/kafka/KafkaProperties.java[`KafkaProperties`] for more supported options. - - - -[[features.messaging.kafka.sending]] -==== Sending a Message -Spring's `KafkaTemplate` is auto-configured, and you can autowire it directly in your own beans, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/messaging/kafka/sending/MyBean.java[] ----- - -NOTE: If the property configprop:spring.kafka.producer.transaction-id-prefix[] is defined, a `KafkaTransactionManager` is automatically configured. -Also, if a `RecordMessageConverter` bean is defined, it is automatically associated to the auto-configured `KafkaTemplate`. - - - -[[features.messaging.kafka.receiving]] -==== Receiving a Message -When the Apache Kafka infrastructure is present, any bean can be annotated with `@KafkaListener` to create a listener endpoint. -If no `KafkaListenerContainerFactory` has been defined, a default one is automatically configured with keys defined in `spring.kafka.listener.*`. - -The following component creates a listener endpoint on the `someTopic` topic: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/messaging/kafka/receiving/MyBean.java[] ----- - -If a `KafkaTransactionManager` bean is defined, it is automatically associated to the container factory. -Similarly, if a `RecordFilterStrategy`, `ErrorHandler`, `AfterRollbackProcessor` or `ConsumerAwareRebalanceListener` bean is defined, it is automatically associated to the default factory. - -Depending on the listener type, a `RecordMessageConverter` or `BatchMessageConverter` bean is associated to the default factory. -If only a `RecordMessageConverter` bean is present for a batch listener, it is wrapped in a `BatchMessageConverter`. - -TIP: A custom `ChainedKafkaTransactionManager` must be marked `@Primary` as it usually references the auto-configured `KafkaTransactionManager` bean. - - - -[[features.messaging.kafka.streams]] -==== Kafka Streams -Spring for Apache Kafka provides a factory bean to create a `StreamsBuilder` object and manage the lifecycle of its streams. -Spring Boot auto-configures the required `KafkaStreamsConfiguration` bean as long as `kafka-streams` is on the classpath and Kafka Streams is enabled via the `@EnableKafkaStreams` annotation. - -Enabling Kafka Streams means that the application id and bootstrap servers must be set. -The former can be configured using `spring.kafka.streams.application-id`, defaulting to `spring.application.name` if not set. -The latter can be set globally or specifically overridden only for streams. - -Several additional properties are available using dedicated properties; other arbitrary Kafka properties can be set using the `spring.kafka.streams.properties` namespace. -See also <> for more information. - -To use the factory bean, wire `StreamsBuilder` into your `@Bean` as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/messaging/KafkaStreamsConfiguration.java[] ----- - -By default, the streams managed by the `StreamBuilder` object it creates are started automatically. -You can customize this behaviour using the configprop:spring.kafka.streams.auto-startup[] property. - - - -[[features.messaging.kafka.additional-properties]] -==== Additional Kafka Properties -The properties supported by auto configuration are shown in <>. -Note that, for the most part, these properties (hyphenated or camelCase) map directly to the Apache Kafka dotted properties. -Refer to the Apache Kafka documentation for details. - -The first few of these properties apply to all components (producers, consumers, admins, and streams) but can be specified at the component level if you wish to use different values. -Apache Kafka designates properties with an importance of HIGH, MEDIUM, or LOW. -Spring Boot auto-configuration supports all HIGH importance properties, some selected MEDIUM and LOW properties, and any properties that do not have a default value. - -Only a subset of the properties supported by Kafka are available directly through the `KafkaProperties` class. -If you wish to configure the producer or consumer with additional properties that are not directly supported, use the following properties: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - kafka: - properties: - "[prop.one]": "first" - admin: - properties: - "[prop.two]": "second" - consumer: - properties: - "[prop.three]": "third" - producer: - properties: - "[prop.four]": "fourth" - streams: - properties: - "[prop.five]": "fifth" ----- - -This sets the common `prop.one` Kafka property to `first` (applies to producers, consumers and admins), the `prop.two` admin property to `second`, the `prop.three` consumer property to `third`, the `prop.four` producer property to `fourth` and the `prop.five` streams property to `fifth`. - -You can also configure the Spring Kafka `JsonDeserializer` as follows: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - kafka: - consumer: - value-deserializer: "org.springframework.kafka.support.serializer.JsonDeserializer" - properties: - "[spring.json.value.default.type]": "com.example.Invoice" - "[spring.json.trusted.packages]": "com.example,org.acme" ----- - -Similarly, you can disable the `JsonSerializer` default behavior of sending type information in headers: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - kafka: - producer: - value-serializer: "org.springframework.kafka.support.serializer.JsonSerializer" - properties: - "[spring.json.add.type.headers]": false ----- - -IMPORTANT: Properties set in this way override any configuration item that Spring Boot explicitly supports. - - - -[[features.messaging.kafka.embedded]] -==== Testing with Embedded Kafka -Spring for Apache Kafka provides a convenient way to test projects with an embedded Apache Kafka broker. -To use this feature, annotate a test class with `@EmbeddedKafka` from the `spring-kafka-test` module. -For more information, please see the Spring for Apache Kafka {spring-kafka-docs}#embedded-kafka-annotation[reference manual]. - -To make Spring Boot auto-configuration work with the aforementioned embedded Apache Kafka broker, you need to remap a system property for embedded broker addresses (populated by the `EmbeddedKafkaBroker`) into the Spring Boot configuration property for Apache Kafka. -There are several ways to do that: - -* Provide a system property to map embedded broker addresses into configprop:spring.kafka.bootstrap-servers[] in the test class: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/messaging/kafka/test/property/MyTest.java[tag=*] ----- - -* Configure a property name on the `@EmbeddedKafka` annotation: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/messaging/kafka/test/annotation/MyTest.java[] ----- - -* Use a placeholder in configuration properties: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - kafka: - bootstrap-servers: "${spring.embedded.kafka.brokers}" ----- - - - -[[features.resttemplate]] -== Calling REST Services with RestTemplate -If you need to call remote REST services from your application, you can use the Spring Framework's {spring-framework-api}/web/client/RestTemplate.html[`RestTemplate`] class. -Since `RestTemplate` instances often need to be customized before being used, Spring Boot does not provide any single auto-configured `RestTemplate` bean. -It does, however, auto-configure a `RestTemplateBuilder`, which can be used to create `RestTemplate` instances when needed. -The auto-configured `RestTemplateBuilder` ensures that sensible `HttpMessageConverters` are applied to `RestTemplate` instances. - -The following code shows a typical example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/resttemplate/MyService.java[] ----- - -TIP: `RestTemplateBuilder` includes a number of useful methods that can be used to quickly configure a `RestTemplate`. -For example, to add BASIC auth support, you can use `builder.basicAuthentication("user", "password").build()`. - - - -[[features.resttemplate.customization]] -=== RestTemplate Customization -There are three main approaches to `RestTemplate` customization, depending on how broadly you want the customizations to apply. - -To make the scope of any customizations as narrow as possible, inject the auto-configured `RestTemplateBuilder` and then call its methods as required. -Each method call returns a new `RestTemplateBuilder` instance, so the customizations only affect this use of the builder. - -To make an application-wide, additive customization, use a `RestTemplateCustomizer` bean. -All such beans are automatically registered with the auto-configured `RestTemplateBuilder` and are applied to any templates that are built with it. - -The following example shows a customizer that configures the use of a proxy for all hosts except `192.168.0.5`: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/resttemplate/RestTemplateProxyCustomizer.java[] ----- - -Finally, you can also create your own `RestTemplateBuilder` bean. -To prevent switching off the auto-configuration of a `RestTemplateBuilder` and prevent any `RestTemplateCustomizer` beans from being used, make sure to configure your custom instance with a `RestTemplateBuilderConfigurer`. -The following example exposes a `RestTemplateBuilder` with what Spring Boot would auto-configure, except that custom connect and read timeouts are also specified: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/resttemplate/RestTemplateBuilderConfiguration.java[] ----- - -The most extreme (and rarely used) option is to create your own `RestTemplateBuilder` bean without using a configurer. -Doing so switches off the auto-configuration of a `RestTemplateBuilder` and prevents any `RestTemplateCustomizer` beans from being used. - - - -[[features.webclient]] -== Calling REST Services with WebClient -If you have Spring WebFlux on your classpath, you can also choose to use `WebClient` to call remote REST services. -Compared to `RestTemplate`, this client has a more functional feel and is fully reactive. -You can learn more about the `WebClient` in the dedicated {spring-framework-docs}/web-reactive.html#webflux-client[section in the Spring Framework docs]. - -Spring Boot creates and pre-configures a `WebClient.Builder` for you; it is strongly advised to inject it in your components and use it to create `WebClient` instances. -Spring Boot is configuring that builder to share HTTP resources, reflect codecs setup in the same fashion as the server ones (see <>), and more. - -The following code shows a typical example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/webclient/MyService.java[] ----- - - - -[[features.webclient.runtime]] -=== WebClient Runtime -Spring Boot will auto-detect which `ClientHttpConnector` to use to drive `WebClient`, depending on the libraries available on the application classpath. -For now, Reactor Netty and Jetty RS client are supported. - -The `spring-boot-starter-webflux` starter depends on `io.projectreactor.netty:reactor-netty` by default, which brings both server and client implementations. -If you choose to use Jetty as a reactive server instead, you should add a dependency on the Jetty Reactive HTTP client library, `org.eclipse.jetty:jetty-reactive-httpclient`. -Using the same technology for server and client has it advantages, as it will automatically share HTTP resources between client and server. - -Developers can override the resource configuration for Jetty and Reactor Netty by providing a custom `ReactorResourceFactory` or `JettyResourceFactory` bean - this will be applied to both clients and servers. - -If you wish to override that choice for the client, you can define your own `ClientHttpConnector` bean and have full control over the client configuration. - -You can learn more about the {spring-framework-docs}/web-reactive.html#webflux-client-builder[`WebClient` configuration options in the Spring Framework reference documentation]. - - - -[[features.webclient.customization]] -=== WebClient Customization -There are three main approaches to `WebClient` customization, depending on how broadly you want the customizations to apply. - -To make the scope of any customizations as narrow as possible, inject the auto-configured `WebClient.Builder` and then call its methods as required. -`WebClient.Builder` instances are stateful: Any change on the builder is reflected in all clients subsequently created with it. -If you want to create several clients with the same builder, you can also consider cloning the builder with `WebClient.Builder other = builder.clone();`. - -To make an application-wide, additive customization to all `WebClient.Builder` instances, you can declare `WebClientCustomizer` beans and change the `WebClient.Builder` locally at the point of injection. - -Finally, you can fall back to the original API and use `WebClient.create()`. -In that case, no auto-configuration or `WebClientCustomizer` is applied. - - - -[[features.validation]] -== Validation -The method validation feature supported by Bean Validation 1.1 is automatically enabled as long as a JSR-303 implementation (such as Hibernate validator) is on the classpath. -This lets bean methods be annotated with `javax.validation` constraints on their parameters and/or on their return value. -Target classes with such annotated methods need to be annotated with the `@Validated` annotation at the type level for their methods to be searched for inline constraint annotations. - -For instance, the following service triggers the validation of the first argument, making sure its size is between 8 and 10: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/validation/MyBean.java[] ----- - - - -[[features.email]] -== Sending Email -The Spring Framework provides an abstraction for sending email by using the `JavaMailSender` interface, and Spring Boot provides auto-configuration for it as well as a starter module. - -TIP: See the {spring-framework-docs}/integration.html#mail[reference documentation] for a detailed explanation of how you can use `JavaMailSender`. - -If `spring.mail.host` and the relevant libraries (as defined by `spring-boot-starter-mail`) are available, a default `JavaMailSender` is created if none exists. -The sender can be further customized by configuration items from the `spring.mail` namespace. -See {spring-boot-autoconfigure-module-code}/mail/MailProperties.java[`MailProperties`] for more details. - -In particular, certain default timeout values are infinite, and you may want to change that to avoid having a thread blocked by an unresponsive mail server, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - mail: - properties: - "[mail.smtp.connectiontimeout]": 5000 - "[mail.smtp.timeout]": 3000 - "[mail.smtp.writetimeout]": 5000 ----- - -It is also possible to configure a `JavaMailSender` with an existing `Session` from JNDI: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - mail: - jndi-name: "mail/Session" ----- - -When a `jndi-name` is set, it takes precedence over all other Session-related settings. - - - -[[features.jta]] -== Distributed Transactions with JTA -Spring Boot supports distributed JTA transactions across multiple XA resources by using an https://www.atomikos.com/[Atomikos] embedded transaction manager. -JTA transactions are also supported when deploying to a suitable Java EE Application Server. - -When a JTA environment is detected, Spring's `JtaTransactionManager` is used to manage transactions. -Auto-configured JMS, DataSource, and JPA beans are upgraded to support XA transactions. -You can use standard Spring idioms, such as `@Transactional`, to participate in a distributed transaction. -If you are within a JTA environment and still want to use local transactions, you can set the configprop:spring.jta.enabled[] property to `false` to disable the JTA auto-configuration. - - - -[[features.jta.atomikos]] -=== Using an Atomikos Transaction Manager -https://www.atomikos.com/[Atomikos] is a popular open source transaction manager which can be embedded into your Spring Boot application. -You can use the `spring-boot-starter-jta-atomikos` starter to pull in the appropriate Atomikos libraries. -Spring Boot auto-configures Atomikos and ensures that appropriate `depends-on` settings are applied to your Spring beans for correct startup and shutdown ordering. - -By default, Atomikos transaction logs are written to a `transaction-logs` directory in your application's home directory (the directory in which your application jar file resides). -You can customize the location of this directory by setting a configprop:spring.jta.log-dir[] property in your `application.properties` file. -Properties starting with `spring.jta.atomikos.properties` can also be used to customize the Atomikos `UserTransactionServiceImp`. -See the {spring-boot-module-api}/jta/atomikos/AtomikosProperties.html[`AtomikosProperties` Javadoc] for complete details. - -NOTE: To ensure that multiple transaction managers can safely coordinate the same resource managers, each Atomikos instance must be configured with a unique ID. -By default, this ID is the IP address of the machine on which Atomikos is running. -To ensure uniqueness in production, you should configure the configprop:spring.jta.transaction-manager-id[] property with a different value for each instance of your application. - - - -[[features.jta.javaee]] -=== Using a Java EE Managed Transaction Manager -If you package your Spring Boot application as a `war` or `ear` file and deploy it to a Java EE application server, you can use your application server's built-in transaction manager. -Spring Boot tries to auto-configure a transaction manager by looking at common JNDI locations (`java:comp/UserTransaction`, `java:comp/TransactionManager`, and so on). -If you use a transaction service provided by your application server, you generally also want to ensure that all resources are managed by the server and exposed over JNDI. -Spring Boot tries to auto-configure JMS by looking for a `ConnectionFactory` at the JNDI path (`java:/JmsXA` or `java:/XAConnectionFactory`), and you can use the <> to configure your `DataSource`. - - - -[[features.jta.mixing-xa-and-non-xa-connections]] -=== Mixing XA and Non-XA JMS Connections -When using JTA, the primary JMS `ConnectionFactory` bean is XA-aware and participates in distributed transactions. -You can inject into your bean without needing to use any `@Qualifier`: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/jta/primary/MyBean.java[tag=*] ----- - -In some situations, you might want to process certain JMS messages by using a non-XA `ConnectionFactory`. -For example, your JMS processing logic might take longer than the XA timeout. - -If you want to use a non-XA `ConnectionFactory`, you can the `nonXaJmsConnectionFactory` bean: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/jta/nonxa/MyBean.java[tag=*] ----- - -For consistency, the `jmsConnectionFactory` bean is also provided by using the bean alias `xaJmsConnectionFactory`: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/jta/xa/MyBean.java[tag=*] ----- - - - -[[features.jta.supporting-alternative-embedded-transaction-manager]] -=== Supporting an Alternative Embedded Transaction Manager -The {spring-boot-module-code}/jms/XAConnectionFactoryWrapper.java[`XAConnectionFactoryWrapper`] and {spring-boot-module-code}/jdbc/XADataSourceWrapper.java[`XADataSourceWrapper`] interfaces can be used to support alternative embedded transaction managers. -The interfaces are responsible for wrapping `XAConnectionFactory` and `XADataSource` beans and exposing them as regular `ConnectionFactory` and `DataSource` beans, which transparently enroll in the distributed transaction. -DataSource and JMS auto-configuration use JTA variants, provided you have a `JtaTransactionManager` bean and appropriate XA wrapper beans registered within your `ApplicationContext`. - -The {spring-boot-module-code}/jta/atomikos/AtomikosXAConnectionFactoryWrapper.java[AtomikosXAConnectionFactoryWrapper] and {spring-boot-module-code}/jta/atomikos/AtomikosXADataSourceWrapper.java[AtomikosXADataSourceWrapper] provide good examples of how to write XA wrappers. - - - -[[features.hazelcast]] -== Hazelcast -If https://hazelcast.com/[Hazelcast] is on the classpath and a suitable configuration is found, Spring Boot auto-configures a `HazelcastInstance` that you can inject in your application. - -Spring Boot first attempts to create a client by checking the following configuration options: - -* The presence of a `com.hazelcast.client.config.ClientConfig` bean. -* A configuration file defined by the configprop:spring.hazelcast.config[] property. -* The presence of the `hazelcast.client.config` system property. -* A `hazelcast-client.xml` in the working directory or at the root of the classpath. -* A `hazelcast-client.yaml` in the working directory or at the root of the classpath. - -NOTE: Spring Boot supports both Hazelcast 4 and Hazelcast 3. -If you downgrade to Hazelcast 3, `hazelcast-client` should be added to the classpath to configure a client. - -If a client can't be created, Spring Boot attempts to configure an embedded server. -If you define a `com.hazelcast.config.Config` bean, Spring Boot uses that. -If your configuration defines an instance name, Spring Boot tries to locate an existing instance rather than creating a new one. - -You could also specify the Hazelcast configuration file to use through configuration, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - hazelcast: - config: "classpath:config/my-hazelcast.xml" ----- - -Otherwise, Spring Boot tries to find the Hazelcast configuration from the default locations: `hazelcast.xml` in the working directory or at the root of the classpath, or a `.yaml` counterpart in the same locations. -We also check if the `hazelcast.config` system property is set. -See the https://docs.hazelcast.org/docs/latest/manual/html-single/[Hazelcast documentation] for more details. - -NOTE: Spring Boot also has <>. -If caching is enabled, the `HazelcastInstance` is automatically wrapped in a `CacheManager` implementation. - - - -[[features.quartz]] -== Quartz Scheduler -Spring Boot offers several conveniences for working with the https://www.quartz-scheduler.org/[Quartz scheduler], including the `spring-boot-starter-quartz` "`Starter`". -If Quartz is available, a `Scheduler` is auto-configured (through the `SchedulerFactoryBean` abstraction). - -Beans of the following types are automatically picked up and associated with the `Scheduler`: - -* `JobDetail`: defines a particular Job. - `JobDetail` instances can be built with the `JobBuilder` API. -* `Calendar`. -* `Trigger`: defines when a particular job is triggered. - -By default, an in-memory `JobStore` is used. -However, it is possible to configure a JDBC-based store if a `DataSource` bean is available in your application and if the configprop:spring.quartz.job-store-type[] property is configured accordingly, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - quartz: - job-store-type: "jdbc" ----- - -When the JDBC store is used, the schema can be initialized on startup, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - quartz: - jdbc: - initialize-schema: "always" ----- - -WARNING: By default, the database is detected and initialized by using the standard scripts provided with the Quartz library. -These scripts drop existing tables, deleting all triggers on every restart. -It is also possible to provide a custom script by setting the configprop:spring.quartz.jdbc.schema[] property. - -To have Quartz use a `DataSource` other than the application's main `DataSource`, declare a `DataSource` bean, annotating its `@Bean` method with `@QuartzDataSource`. -Doing so ensures that the Quartz-specific `DataSource` is used by both the `SchedulerFactoryBean` and for schema initialization. -Similarly, to have Quartz use a `TransactionManager` other than the application's main `TransactionManager` declare a `TransactionManager` bean, annotating its `@Bean` method with `@QuartzTransactionManager`. - -By default, jobs created by configuration will not overwrite already registered jobs that have been read from a persistent job store. -To enable overwriting existing job definitions set the configprop:spring.quartz.overwrite-existing-jobs[] property. - -Quartz Scheduler configuration can be customized using `spring.quartz` properties and `SchedulerFactoryBeanCustomizer` beans, which allow programmatic `SchedulerFactoryBean` customization. -Advanced Quartz configuration properties can be customized using `spring.quartz.properties.*`. - -NOTE: In particular, an `Executor` bean is not associated with the scheduler as Quartz offers a way to configure the scheduler via `spring.quartz.properties`. -If you need to customize the task executor, consider implementing `SchedulerFactoryBeanCustomizer`. - -Jobs can define setters to inject data map properties. -Regular beans can also be injected in a similar manner, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/quartz/SampleJob.java[] ----- - - - -[[features.task-execution-and-scheduling]] -== Task Execution and Scheduling -In the absence of an `Executor` bean in the context, Spring Boot auto-configures a `ThreadPoolTaskExecutor` with sensible defaults that can be automatically associated to asynchronous task execution (`@EnableAsync`) and Spring MVC asynchronous request processing. - -[TIP] -==== -If you have defined a custom `Executor` in the context, regular task execution (i.e. `@EnableAsync`) will use it transparently but the Spring MVC support will not be configured as it requires an `AsyncTaskExecutor` implementation (named `applicationTaskExecutor`). -Depending on your target arrangement, you could change your `Executor` into a `ThreadPoolTaskExecutor` or define both a `ThreadPoolTaskExecutor` and an `AsyncConfigurer` wrapping your custom `Executor`. - -The auto-configured `TaskExecutorBuilder` allows you to easily create instances that reproduce what the auto-configuration does by default. -==== - -The thread pool uses 8 core threads that can grow and shrink according to the load. -Those default settings can be fine-tuned using the `spring.task.execution` namespace, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - task: - execution: - pool: - max-size: 16 - queue-capacity: 100 - keep-alive: "10s" ----- - -This changes the thread pool to use a bounded queue so that when the queue is full (100 tasks), the thread pool increases to maximum 16 threads. -Shrinking of the pool is more aggressive as threads are reclaimed when they are idle for 10 seconds (rather than 60 seconds by default). - -A `ThreadPoolTaskScheduler` can also be auto-configured if need to be associated to scheduled task execution (e.g. `@EnableScheduling`). -The thread pool uses one thread by default and its settings can be fine-tuned using the `spring.task.scheduling` namespace, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - task: - scheduling: - thread-name-prefix: "scheduling-" - pool: - size: 2 ----- - -Both a `TaskExecutorBuilder` bean and a `TaskSchedulerBuilder` bean are made available in the context if a custom executor or scheduler needs to be created. - - - -[[features.spring-integration]] -== Spring Integration -Spring Boot offers several conveniences for working with {spring-integration}[Spring Integration], including the `spring-boot-starter-integration` "`Starter`". -Spring Integration provides abstractions over messaging and also other transports such as HTTP, TCP, and others. -If Spring Integration is available on your classpath, it is initialized through the `@EnableIntegration` annotation. - -Spring Integration polling logic relies <>. - -Spring Boot also configures some features that are triggered by the presence of additional Spring Integration modules. -If `spring-integration-jmx` is also on the classpath, message processing statistics are published over JMX. -If `spring-integration-jdbc` is available, the default database schema can be created on startup, as shown in the following line: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - integration: - jdbc: - initialize-schema: "always" ----- - -If `spring-integration-rsocket` is available, developers can configure an RSocket server using `"spring.rsocket.server.*"` properties and let it use `IntegrationRSocketEndpoint` or `RSocketOutboundGateway` components to handle incoming RSocket messages. -This infrastructure can handle Spring Integration RSocket channel adapters and `@MessageMapping` handlers (given `"spring.integration.rsocket.server.message-mapping-enabled"` is configured). - -Spring Boot can also auto-configure an `ClientRSocketConnector` using configuration properties: - -[source,yaml,indent=0,configprops,configblocks] ----- - # Connecting to a RSocket server over TCP - spring: - integration: - rsocket: - client: - host: "example.org" - port: 9898 ----- - -[source,yaml,indent=0,configprops,configblocks] ----- - # Connecting to a RSocket Server over WebSocket - spring: - integration: - rsocket: - client: - uri: "ws://example.org" ----- - -See the {spring-boot-autoconfigure-module-code}/integration/IntegrationAutoConfiguration.java[`IntegrationAutoConfiguration`] and {spring-boot-autoconfigure-module-code}/integration/IntegrationProperties.java[`IntegrationProperties`] classes for more details. - -By default, if a Micrometer `meterRegistry` bean is present, Spring Integration metrics will be managed by Micrometer. -If you wish to use legacy Spring Integration metrics, add a `DefaultMetricsFactory` bean to the application context. - - - -[[features.spring-session]] -== Spring Session -Spring Boot provides {spring-session}[Spring Session] auto-configuration for a wide range of data stores. -When building a Servlet web application, the following stores can be auto-configured: - -* JDBC -* Redis -* Hazelcast -* MongoDB - -The Servlet auto-configuration replaces the need to use `@Enable*HttpSession`. - -When building a reactive web application, the following stores can be auto-configured: - -* Redis -* MongoDB - -The reactive auto-configuration replaces the need to use `@Enable*WebSession`. - -If a single Spring Session module is present on the classpath, Spring Boot uses that store implementation automatically. -If you have more than one implementation, you must choose the {spring-boot-autoconfigure-module-code}/session/StoreType.java[`StoreType`] that you wish to use to store the sessions. -For instance, to use JDBC as the back-end store, you can configure your application as follows: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - session: - store-type: "jdbc" ----- - -TIP: You can disable Spring Session by setting the `store-type` to `none`. - -Each store has specific additional settings. -For instance, it is possible to customize the name of the table for the JDBC store, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - session: - jdbc: - table-name: "SESSIONS" ----- - -For setting the timeout of the session you can use the configprop:spring.session.timeout[] property. -If that property is not set with a Servlet web application, the auto-configuration falls back to the value of configprop:server.servlet.session.timeout[]. - - -You can take control over Spring Session's configuration using `@Enable*HttpSession` (Servlet) or `@Enable*WebSession` (Reactive). -This will cause the auto-configuration to back off. -Spring Session can then be configured using the annotation's attributes rather than the previously described configuration properties. - - - -[[features.jmx]] -== Monitoring and Management over JMX -Java Management Extensions (JMX) provide a standard mechanism to monitor and manage applications. -Spring Boot exposes the most suitable `MBeanServer` as a bean with an ID of `mbeanServer`. -Any of your beans that are annotated with Spring JMX annotations (`@ManagedResource`, `@ManagedAttribute`, or `@ManagedOperation`) are exposed to it. - -If your platform provides a standard `MBeanServer`, Spring Boot will use that and default to the VM `MBeanServer` if necessary. -If all that fails, a new `MBeanServer` will be created. - -See the {spring-boot-autoconfigure-module-code}/jmx/JmxAutoConfiguration.java[`JmxAutoConfiguration`] class for more details. - - - -[[features.testing]] -== Testing -Spring Boot provides a number of utilities and annotations to help when testing your application. -Test support is provided by two modules: `spring-boot-test` contains core items, and `spring-boot-test-autoconfigure` supports auto-configuration for tests. - -Most developers use the `spring-boot-starter-test` "`Starter`", which imports both Spring Boot test modules as well as JUnit Jupiter, AssertJ, Hamcrest, and a number of other useful libraries. - -[TIP] -==== -If you have tests that use JUnit 4, JUnit 5's vintage engine can be used to run them. -To use the vintage engine, add a dependency on `junit-vintage-engine`, as shown in the following example: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - org.junit.vintage - junit-vintage-engine - test - - - org.hamcrest - hamcrest-core - - - ----- -==== - -`hamcrest-core` is excluded in favor of `org.hamcrest:hamcrest` that is part of `spring-boot-starter-test`. - - - -[[features.testing.test-scope-dependencies]] -=== Test Scope Dependencies -The `spring-boot-starter-test` "`Starter`" (in the `test` `scope`) contains the following provided libraries: - -* https://junit.org/junit5/[JUnit 5]: The de-facto standard for unit testing Java applications. -* {spring-framework-docs}/testing.html#integration-testing[Spring Test] & Spring Boot Test: Utilities and integration test support for Spring Boot applications. -* https://assertj.github.io/doc/[AssertJ]: A fluent assertion library. -* https://github.com/hamcrest/JavaHamcrest[Hamcrest]: A library of matcher objects (also known as constraints or predicates). -* https://site.mockito.org/[Mockito]: A Java mocking framework. -* https://github.com/skyscreamer/JSONassert[JSONassert]: An assertion library for JSON. -* https://github.com/jayway/JsonPath[JsonPath]: XPath for JSON. - -We generally find these common libraries to be useful when writing tests. -If these libraries do not suit your needs, you can add additional test dependencies of your own. - - - -[[features.testing.spring-applications]] -=== Testing Spring Applications -One of the major advantages of dependency injection is that it should make your code easier to unit test. -You can instantiate objects by using the `new` operator without even involving Spring. -You can also use _mock objects_ instead of real dependencies. - -Often, you need to move beyond unit testing and start integration testing (with a Spring `ApplicationContext`). -It is useful to be able to perform integration testing without requiring deployment of your application or needing to connect to other infrastructure. - -The Spring Framework includes a dedicated test module for such integration testing. -You can declare a dependency directly to `org.springframework:spring-test` or use the `spring-boot-starter-test` "`Starter`" to pull it in transitively. - -If you have not used the `spring-test` module before, you should start by reading the {spring-framework-docs}/testing.html#testing[relevant section] of the Spring Framework reference documentation. - - - -[[features.testing.spring-boot-applications]] -=== Testing Spring Boot Applications -A Spring Boot application is a Spring `ApplicationContext`, so nothing very special has to be done to test it beyond what you would normally do with a vanilla Spring context. - -NOTE: External properties, logging, and other features of Spring Boot are installed in the context by default only if you use `SpringApplication` to create it. - -Spring Boot provides a `@SpringBootTest` annotation, which can be used as an alternative to the standard `spring-test` `@ContextConfiguration` annotation when you need Spring Boot features. -The annotation works by <>. -In addition to `@SpringBootTest` a number of other annotations are also provided for <> of an application. - -TIP: If you are using JUnit 4, don't forget to also add `@RunWith(SpringRunner.class)` to your test, otherwise the annotations will be ignored. -If you are using JUnit 5, there's no need to add the equivalent `@ExtendWith(SpringExtension.class)` as `@SpringBootTest` and the other `@…Test` annotations are already annotated with it. - -By default, `@SpringBootTest` will not start a server. -You can use the `webEnvironment` attribute of `@SpringBootTest` to further refine how your tests run: - -* `MOCK`(Default) : Loads a web `ApplicationContext` and provides a mock web environment. - Embedded servers are not started when using this annotation. - If a web environment is not available on your classpath, this mode transparently falls back to creating a regular non-web `ApplicationContext`. - It can be used in conjunction with <> for mock-based testing of your web application. -* `RANDOM_PORT`: Loads a `WebServerApplicationContext` and provides a real web environment. - Embedded servers are started and listen on a random port. -* `DEFINED_PORT`: Loads a `WebServerApplicationContext` and provides a real web environment. - Embedded servers are started and listen on a defined port (from your `application.properties`) or on the default port of `8080`. -* `NONE`: Loads an `ApplicationContext` by using `SpringApplication` but does not provide _any_ web environment (mock or otherwise). - -NOTE: If your test is `@Transactional`, it rolls back the transaction at the end of each test method by default. -However, as using this arrangement with either `RANDOM_PORT` or `DEFINED_PORT` implicitly provides a real servlet environment, the HTTP client and server run in separate threads and, thus, in separate transactions. -Any transaction initiated on the server does not roll back in this case. - -NOTE: `@SpringBootTest` with `webEnvironment = WebEnvironment.RANDOM_PORT` will also start the management server on a separate random port if your application uses a different port for the management server. - - - -[[features.testing.spring-boot-applications.detecting-web-app-type]] -==== Detecting Web Application Type -If Spring MVC is available, a regular MVC-based application context is configured. -If you have only Spring WebFlux, we'll detect that and configure a WebFlux-based application context instead. - -If both are present, Spring MVC takes precedence. -If you want to test a reactive web application in this scenario, you must set the configprop:spring.main.web-application-type[] property: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/detection/MyWebFluxTests.java[] ----- - - - -[[features.testing.spring-boot-applications.detecting-configuration]] -==== Detecting Test Configuration -If you are familiar with the Spring Test Framework, you may be used to using `@ContextConfiguration(classes=...)` in order to specify which Spring `@Configuration` to load. -Alternatively, you might have often used nested `@Configuration` classes within your test. - -When testing Spring Boot applications, this is often not required. -Spring Boot's `@*Test` annotations search for your primary configuration automatically whenever you do not explicitly define one. - -The search algorithm works up from the package that contains the test until it finds a class annotated with `@SpringBootApplication` or `@SpringBootConfiguration`. -As long as you <> in a sensible way, your main configuration is usually found. - -[NOTE] -==== -If you use a <>, you should avoid adding configuration settings that are specific to a particular area on the <>. - -The underlying component scan configuration of `@SpringBootApplication` defines exclude filters that are used to make sure slicing works as expected. -If you are using an explicit `@ComponentScan` directive on your `@SpringBootApplication`-annotated class, be aware that those filters will be disabled. -If you are using slicing, you should define them again. -==== - -If you want to customize the primary configuration, you can use a nested `@TestConfiguration` class. -Unlike a nested `@Configuration` class, which would be used instead of your application's primary configuration, a nested `@TestConfiguration` class is used in addition to your application's primary configuration. - -NOTE: Spring's test framework caches application contexts between tests. -Therefore, as long as your tests share the same configuration (no matter how it is discovered), the potentially time-consuming process of loading the context happens only once. - - - -[[features.testing.spring-boot-applications.excluding-configuration]] -==== Excluding Test Configuration -If your application uses component scanning (for example, if you use `@SpringBootApplication` or `@ComponentScan`), you may find top-level configuration classes that you created only for specific tests accidentally get picked up everywhere. - -As we <>, `@TestConfiguration` can be used on an inner class of a test to customize the primary configuration. -When placed on a top-level class, `@TestConfiguration` indicates that classes in `src/test/java` should not be picked up by scanning. -You can then import that class explicitly where it is required, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/excluding/MyTests.java[] ----- - -NOTE: If you directly use `@ComponentScan` (that is, not through `@SpringBootApplication`) you need to register the `TypeExcludeFilter` with it. -See {spring-boot-module-api}/context/TypeExcludeFilter.html[the Javadoc] for details. - - - -[[features.testing.spring-boot-applications.using-application-arguments]] -==== Using Application Arguments -If your application expects <>, you can -have `@SpringBootTest` inject them using the `args` attribute. - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/ApplicationArgumentTests.java[] ----- - - - -[[features.testing.spring-boot-applications.with-mock-environment]] -==== Testing with a mock environment -By default, `@SpringBootTest` does not start the server. -If you have web endpoints that you want to test against this mock environment, you can additionally configure {spring-framework-docs}/testing.html#spring-mvc-test-framework[`MockMvc`] as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/MockMvcTests.java[] ----- - -TIP: If you want to focus only on the web layer and not start a complete `ApplicationContext`, consider <>. - -Alternatively, you can configure a {spring-framework-docs}/testing.html#webtestclient-tests[`WebTestClient`] as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/MockWebTestClientTests.java[] ----- - -[TIP] -==== -Testing within a mocked environment is usually faster than running with a full Servlet container. -However, since mocking occurs at the Spring MVC layer, code that relies on lower-level Servlet container behavior cannot be directly tested with MockMvc. - -For example, Spring Boot's error handling is based on the "`error page`" support provided by the Servlet container. -This means that, whilst you can test your MVC layer throws and handles exceptions as expected, you cannot directly test that a specific <> is rendered. -If you need to test these lower-level concerns, you can start a fully running server as described in the next section. -==== - - - -[[features.testing.spring-boot-applications.with-running-server]] -==== Testing with a running server -If you need to start a full running server, we recommend that you use random ports. -If you use `@SpringBootTest(webEnvironment=WebEnvironment.RANDOM_PORT)`, an available port is picked at random each time your test runs. - -The `@LocalServerPort` annotation can be used to <> into your test. -For convenience, tests that need to make REST calls to the started server can additionally `@Autowire` a {spring-framework-docs}/testing.html#webtestclient-tests[`WebTestClient`], which resolves relative links to the running server and comes with a dedicated API for verifying responses, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/RandomPortWebTestClientTests.java[] ----- - -This setup requires `spring-webflux` on the classpath. -If you can't or won't add webflux, Spring Boot also provides a `TestRestTemplate` facility: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/RandomPortTestRestTemplateTests.java[] ----- - - - -[[features.testing.spring-boot-applications.customizing-web-test-client]] -==== Customizing WebTestClient -To customize the `WebTestClient` bean, configure a `WebTestClientBuilderCustomizer` bean. -Any such beans are called with the `WebTestClient.Builder` that is used to create the `WebTestClient`. - - - -[[features.testing.spring-boot-applications.jmx]] -==== Using JMX -As the test context framework caches context, JMX is disabled by default to prevent identical components to register on the same domain. -If such test needs access to an `MBeanServer`, consider marking it dirty as well: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/jmx/SampleJmxTests.java[] ----- - - - -[[features.testing.spring-boot-applications.metrics]] -==== Using Metrics -Regardless of your classpath, meter registries, except the in-memory backed, are not auto-configured when using `@SpringBootTest`. - -If you need to export metrics to a different backend as part of an integration test, annotate it with `@AutoConfigureMetrics`. - - - -[[features.testing.spring-boot-applications.mocking-beans]] -==== Mocking and Spying Beans -When running tests, it is sometimes necessary to mock certain components within your application context. -For example, you may have a facade over some remote service that is unavailable during development. -Mocking can also be useful when you want to simulate failures that might be hard to trigger in a real environment. - -Spring Boot includes a `@MockBean` annotation that can be used to define a Mockito mock for a bean inside your `ApplicationContext`. -You can use the annotation to add new beans or replace a single existing bean definition. -The annotation can be used directly on test classes, on fields within your test, or on `@Configuration` classes and fields. -When used on a field, the instance of the created mock is also injected. -Mock beans are automatically reset after each test method. - -[NOTE] -==== -If your test uses one of Spring Boot's test annotations (such as `@SpringBootTest`), this feature is automatically enabled. -To use this feature with a different arrangement, listeners must be explicitly added, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/mocking/listener/MyTests.java[] ----- - -==== - -The following example replaces an existing `RemoteService` bean with a mock implementation: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/mocking/MyTests.java[] ----- - -NOTE: `@MockBean` cannot be used to mock the behavior of a bean that's exercised during application context refresh. -By the time the test is executed, the application context refresh has completed and it is too late to configure the mocked behavior. -We recommend using a `@Bean` method to create and configure the mock in this situation. - -Additionally, you can use `@SpyBean` to wrap any existing bean with a Mockito `spy`. -See the {spring-boot-test-module-api}/mock/mockito/SpyBean.html[Javadoc] for full details. - -NOTE: CGLib proxies, such as those created for scoped beans, declare the proxied methods as `final`. -This stops Mockito from functioning correctly as it cannot mock or spy on `final` methods in its default configuration. -If you want to mock or spy on such a bean, configure Mockito to use its inline mock maker by adding `org.mockito:mockito-inline` to your application's test dependencies. -This allows Mockito to mock and spy on `final` methods. - -NOTE: While Spring's test framework caches application contexts between tests and reuses a context for tests sharing the same configuration, the use of `@MockBean` or `@SpyBean` influences the cache key, which will most likely increase the number of contexts. - -TIP: If you are using `@SpyBean` to spy on a bean with `@Cacheable` methods that refer to parameters by name, your application must be compiled with `-parameters`. -This ensures that the parameter names are available to the caching infrastructure once the bean has been spied upon. - -TIP: When you are using `@SpyBean` to spy on a bean that is proxied by Spring, you may need to remove Spring's proxy in some situations, for example when setting expectations using `given` or `when`. -Use `AopTestUtils.getTargetObject(yourProxiedSpy)` to do so. - - - -[[features.testing.spring-boot-applications.autoconfigured-tests]] -==== Auto-configured Tests -Spring Boot's auto-configuration system works well for applications but can sometimes be a little too much for tests. -It often helps to load only the parts of the configuration that are required to test a "`slice`" of your application. -For example, you might want to test that Spring MVC controllers are mapping URLs correctly, and you do not want to involve database calls in those tests, or you might want to test JPA entities, and you are not interested in the web layer when those tests run. - -The `spring-boot-test-autoconfigure` module includes a number of annotations that can be used to automatically configure such "`slices`". -Each of them works in a similar way, providing a `@...Test` annotation that loads the `ApplicationContext` and one or more `@AutoConfigure...` annotations that can be used to customize auto-configuration settings. - -NOTE: Each slice restricts component scan to appropriate components and loads a very restricted set of auto-configuration classes. -If you need to exclude one of them, most `@...Test` annotations provide an `excludeAutoConfiguration` attribute. -Alternatively, you can use `@ImportAutoConfiguration#exclude`. - -NOTE: Including multiple "`slices`" by using several `@...Test` annotations in one test is not supported. -If you need multiple "`slices`", pick one of the `@...Test` annotations and include the `@AutoConfigure...` annotations of the other "`slices`" by hand. - -TIP: It is also possible to use the `@AutoConfigure...` annotations with the standard `@SpringBootTest` annotation. -You can use this combination if you are not interested in "`slicing`" your application but you want some of the auto-configured test beans. - - - -[[features.testing.spring-boot-applications.json-tests]] -==== Auto-configured JSON Tests -To test that object JSON serialization and deserialization is working as expected, you can use the `@JsonTest` annotation. -`@JsonTest` auto-configures the available supported JSON mapper, which can be one of the following libraries: - -* Jackson `ObjectMapper`, any `@JsonComponent` beans and any Jackson ``Module``s -* `Gson` -* `Jsonb` - -TIP: A list of the auto-configurations that are enabled by `@JsonTest` can be <>. - -If you need to configure elements of the auto-configuration, you can use the `@AutoConfigureJsonTesters` annotation. - -Spring Boot includes AssertJ-based helpers that work with the JSONAssert and JsonPath libraries to check that JSON appears as expected. -The `JacksonTester`, `GsonTester`, `JsonbTester`, and `BasicJsonTester` classes can be used for Jackson, Gson, Jsonb, and Strings respectively. -Any helper fields on the test class can be `@Autowired` when using `@JsonTest`. -The following example shows a test class for Jackson: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/json/MyJsonTests.java[] ----- - -NOTE: JSON helper classes can also be used directly in standard unit tests. -To do so, call the `initFields` method of the helper in your `@Before` method if you do not use `@JsonTest`. - -If you're using Spring Boot's AssertJ-based helpers to assert on a number value at a given JSON path, you might not be able to use `isEqualTo` depending on the type. -Instead, you can use AssertJ's `satisfies` to assert that the value matches the given condition. -For instance, the following example asserts that the actual number is a float value close to `0.15` within an offset of `0.01`. - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/json/AssertJ.java[tag=*] ----- - - - -[[features.testing.spring-boot-applications.spring-mvc-tests]] -==== Auto-configured Spring MVC Tests -To test whether Spring MVC controllers are working as expected, use the `@WebMvcTest` annotation. -`@WebMvcTest` auto-configures the Spring MVC infrastructure and limits scanned beans to `@Controller`, `@ControllerAdvice`, `@JsonComponent`, `Converter`, `GenericConverter`, `Filter`, `HandlerInterceptor`, `WebMvcConfigurer`, and `HandlerMethodArgumentResolver`. -Regular `@Component` and `@ConfigurationProperties` beans are not scanned when the `@WebMvcTest` annotation is used. -`@EnableConfigurationProperties` can be used to include `@ConfigurationProperties` beans. - -TIP: A list of the auto-configuration settings that are enabled by `@WebMvcTest` can be <>. - -TIP: If you need to register extra components, such as the Jackson `Module`, you can import additional configuration classes by using `@Import` on your test. - -Often, `@WebMvcTest` is limited to a single controller and is used in combination with `@MockBean` to provide mock implementations for required collaborators. - -`@WebMvcTest` also auto-configures `MockMvc`. -Mock MVC offers a powerful way to quickly test MVC controllers without needing to start a full HTTP server. - -TIP: You can also auto-configure `MockMvc` in a non-`@WebMvcTest` (such as `@SpringBootTest`) by annotating it with `@AutoConfigureMockMvc`. -The following example uses `MockMvc`: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/mvc/MyControllerTests.java[] ----- - -TIP: If you need to configure elements of the auto-configuration (for example, when servlet filters should be applied) you can use attributes in the `@AutoConfigureMockMvc` annotation. - -If you use HtmlUnit or Selenium, auto-configuration also provides an HtmlUnit `WebClient` bean and/or a Selenium `WebDriver` bean. -The following example uses HtmlUnit: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/mvc/MyHtmlUnitTests.java[] ----- - -NOTE: By default, Spring Boot puts `WebDriver` beans in a special "`scope`" to ensure that the driver exits after each test and that a new instance is injected. -If you do not want this behavior, you can add `@Scope("singleton")` to your `WebDriver` `@Bean` definition. - -WARNING: The `webDriver` scope created by Spring Boot will replace any user defined scope of the same name. -If you define your own `webDriver` scope you may find it stops working when you use `@WebMvcTest`. - -If you have Spring Security on the classpath, `@WebMvcTest` will also scan `WebSecurityConfigurer` beans. -Instead of disabling security completely for such tests, you can use Spring Security's test support. -More details on how to use Spring Security's `MockMvc` support can be found in this _<>_ how-to section. - -TIP: Sometimes writing Spring MVC tests is not enough; Spring Boot can help you run <>. - - - -[[features.testing.spring-boot-applications.spring-webflux-tests]] -==== Auto-configured Spring WebFlux Tests -To test that {spring-framework-docs}/web-reactive.html[Spring WebFlux] controllers are working as expected, you can use the `@WebFluxTest` annotation. -`@WebFluxTest` auto-configures the Spring WebFlux infrastructure and limits scanned beans to `@Controller`, `@ControllerAdvice`, `@JsonComponent`, `Converter`, `GenericConverter`, `WebFilter`, and `WebFluxConfigurer`. -Regular `@Component` and `@ConfigurationProperties` beans are not scanned when the `@WebFluxTest` annotation is used. -`@EnableConfigurationProperties` can be used to include `@ConfigurationProperties` beans. - -TIP: A list of the auto-configurations that are enabled by `@WebFluxTest` can be <>. - -TIP: If you need to register extra components, such as Jackson `Module`, you can import additional configuration classes using `@Import` on your test. - -Often, `@WebFluxTest` is limited to a single controller and used in combination with the `@MockBean` annotation to provide mock implementations for required collaborators. - -`@WebFluxTest` also auto-configures {spring-framework-docs}/testing.html#webtestclient[`WebTestClient`], which offers a powerful way to quickly test WebFlux controllers without needing to start a full HTTP server. - -TIP: You can also auto-configure `WebTestClient` in a non-`@WebFluxTest` (such as `@SpringBootTest`) by annotating it with `@AutoConfigureWebTestClient`. -The following example shows a class that uses both `@WebFluxTest` and a `WebTestClient`: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/webflux/MyControllerTests.java[] ----- - -TIP: This setup is only supported by WebFlux applications as using `WebTestClient` in a mocked web application only works with WebFlux at the moment. - -NOTE: `@WebFluxTest` cannot detect routes registered via the functional web framework. -For testing `RouterFunction` beans in the context, consider importing your `RouterFunction` yourself via `@Import` or using `@SpringBootTest`. - -NOTE: `@WebFluxTest` cannot detect custom security configuration registered via a `@Bean` of type `SecurityWebFilterChain`. -To include that in your test, you will need to import the configuration that registers the bean via `@Import` or use `@SpringBootTest`. - -TIP: Sometimes writing Spring WebFlux tests is not enough; Spring Boot can help you run <>. - - - -[[features.testing.spring-boot-applications.autoconfigured-spring-data-cassandra]] -==== Auto-configured Data Cassandra Tests -You can use `@DataCassandraTest` to test Cassandra applications. -By default, it configures a `CassandraTemplate`, scans for `@Table` classes, and configures Spring Data Cassandra repositories. -Regular `@Component` and `@ConfigurationProperties` beans are not scanned when the `@DataCassandraTest` annotation is used. -`@EnableConfigurationProperties` can be used to include `@ConfigurationProperties` beans. -(For more about using Cassandra with Spring Boot, see "<>", earlier in this chapter.) - -TIP: A list of the auto-configuration settings that are enabled by `@DataCassandraTest` can be <>. - -The following example shows a typical setup for using Cassandra tests in Spring Boot: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/data/cassandra/MyDataCassandraTests.java[] ----- - - - -[[features.testing.spring-boot-applications.autoconfigured-spring-data-jpa]] -==== Auto-configured Data JPA Tests -You can use the `@DataJpaTest` annotation to test JPA applications. -By default, it scans for `@Entity` classes and configures Spring Data JPA repositories. -If an embedded database is available on the classpath, it configures one as well. -SQL queries are logged by default by setting the `spring.jpa.show-sql` property to `true`. -This can be disabled using the `showSql()` attribute of the annotation. - -Regular `@Component` and `@ConfigurationProperties` beans are not scanned when the `@DataJpaTest` annotation is used. -`@EnableConfigurationProperties` can be used to include `@ConfigurationProperties` beans. - -TIP: A list of the auto-configuration settings that are enabled by `@DataJpaTest` can be <>. - -By default, data JPA tests are transactional and roll back at the end of each test. -See the {spring-framework-docs}/testing.html#testcontext-tx-enabling-transactions[relevant section] in the Spring Framework Reference Documentation for more details. -If that is not what you want, you can disable transaction management for a test or for the whole class as follows: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/data/jpa/MyNonTransactionalTests.java[] ----- - -Data JPA tests may also inject a {spring-boot-test-autoconfigure-module-code}/orm/jpa/TestEntityManager.java[`TestEntityManager`] bean, which provides an alternative to the standard JPA `EntityManager` that is specifically designed for tests. -If you want to use `TestEntityManager` outside of `@DataJpaTest` instances, you can also use the `@AutoConfigureTestEntityManager` annotation. -A `JdbcTemplate` is also available if you need that. -The following example shows the `@DataJpaTest` annotation in use: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/data/jpa/MyRepositoryTests.java[] ----- - -In-memory embedded databases generally work well for tests, since they are fast and do not require any installation. -If, however, you prefer to run tests against a real database you can use the `@AutoConfigureTestDatabase` annotation, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/data/jpa/db/MyRepositoryTests.java[] ----- - - - -[[features.testing.spring-boot-applications.autoconfigured-jdbc]] -==== Auto-configured JDBC Tests -`@JdbcTest` is similar to `@DataJpaTest` but is for tests that only require a `DataSource` and do not use Spring Data JDBC. -By default, it configures an in-memory embedded database and a `JdbcTemplate`. -Regular `@Component` and `@ConfigurationProperties` beans are not scanned when the `@JdbcTest` annotation is used. -`@EnableConfigurationProperties` can be used to include `@ConfigurationProperties` beans. - -TIP: A list of the auto-configurations that are enabled by `@JdbcTest` can be <>. - -By default, JDBC tests are transactional and roll back at the end of each test. -See the {spring-framework-docs}/testing.html#testcontext-tx-enabling-transactions[relevant section] in the Spring Framework Reference Documentation for more details. -If that is not what you want, you can disable transaction management for a test or for the whole class, as follows: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/data/jdbc/MyTransactionalTests.java[] ----- - -If you prefer your test to run against a real database, you can use the `@AutoConfigureTestDatabase` annotation in the same way as for `DataJpaTest`. -(See "<>".) - - - -[[features.testing.spring-boot-applications.autoconfigured-spring-data-jdbc]] -==== Auto-configured Data JDBC Tests -`@DataJdbcTest` is similar to `@JdbcTest` but is for tests that use Spring Data JDBC repositories. -By default, it configures an in-memory embedded database, a `JdbcTemplate`, and Spring Data JDBC repositories. -Regular `@Component` and `@ConfigurationProperties` beans are not scanned when the `@DataJdbcTest` annotation is used. -`@EnableConfigurationProperties` can be used to include `@ConfigurationProperties` beans. - -TIP: A list of the auto-configurations that are enabled by `@DataJdbcTest` can be <>. - -By default, Data JDBC tests are transactional and roll back at the end of each test. -See the {spring-framework-docs}/testing.html#testcontext-tx-enabling-transactions[relevant section] in the Spring Framework Reference Documentation for more details. -If that is not what you want, you can disable transaction management for a test or for the whole test class as <>. - -If you prefer your test to run against a real database, you can use the `@AutoConfigureTestDatabase` annotation in the same way as for `DataJpaTest`. -(See "<>".) - - - -[[features.testing.spring-boot-applications.autoconfigured-jooq]] -==== Auto-configured jOOQ Tests -You can use `@JooqTest` in a similar fashion as `@JdbcTest` but for jOOQ-related tests. -As jOOQ relies heavily on a Java-based schema that corresponds with the database schema, the existing `DataSource` is used. -If you want to replace it with an in-memory database, you can use `@AutoConfigureTestDatabase` to override those settings. -(For more about using jOOQ with Spring Boot, see "<>", earlier in this chapter.) -Regular `@Component` and `@ConfigurationProperties` beans are not scanned when the `@JooqTest` annotation is used. -`@EnableConfigurationProperties` can be used to include `@ConfigurationProperties` beans. - -TIP: A list of the auto-configurations that are enabled by `@JooqTest` can be <>. - -`@JooqTest` configures a `DSLContext`. -The following example shows the `@JooqTest` annotation in use: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/jooq/MyJooqTests.java[] ----- - -JOOQ tests are transactional and roll back at the end of each test by default. -If that is not what you want, you can disable transaction management for a test or for the whole test class as <>. - - - -[[features.testing.spring-boot-applications.autoconfigured-spring-data-mongodb]] -==== Auto-configured Data MongoDB Tests -You can use `@DataMongoTest` to test MongoDB applications. -By default, it configures an in-memory embedded MongoDB (if available), configures a `MongoTemplate`, scans for `@Document` classes, and configures Spring Data MongoDB repositories. -Regular `@Component` and `@ConfigurationProperties` beans are not scanned when the `@DataMongoTest` annotation is used. -`@EnableConfigurationProperties` can be used to include `@ConfigurationProperties` beans. -(For more about using MongoDB with Spring Boot, see "<>", earlier in this chapter.) - -TIP: A list of the auto-configuration settings that are enabled by `@DataMongoTest` can be <>. - -The following class shows the `@DataMongoTest` annotation in use: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/data/mongodb/MyDataMongoDbTests.java[] ----- - -In-memory embedded MongoDB generally works well for tests, since it is fast and does not require any developer installation. -If, however, you prefer to run tests against a real MongoDB server, you should exclude the embedded MongoDB auto-configuration, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/data/mongodb/db/MyDataMongoDbTests.java[] ----- - - - -[[features.testing.spring-boot-applications.autoconfigured-spring-data-neo4j]] -==== Auto-configured Data Neo4j Tests -You can use `@DataNeo4jTest` to test Neo4j applications. -By default, it scans for `@Node` classes, and configures Spring Data Neo4j repositories. -Regular `@Component` and `@ConfigurationProperties` beans are not scanned when the `@DataNeo4jTest` annotation is used. -`@EnableConfigurationProperties` can be used to include `@ConfigurationProperties` beans. -(For more about using Neo4J with Spring Boot, see "<>", earlier in this chapter.) - -TIP: A list of the auto-configuration settings that are enabled by `@DataNeo4jTest` can be <>. - -The following example shows a typical setup for using Neo4J tests in Spring Boot: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/data/neo4j/MyDataNeo4jTests.java[] ----- - -By default, Data Neo4j tests are transactional and roll back at the end of each test. -See the {spring-framework-docs}/testing.html#testcontext-tx-enabling-transactions[relevant section] in the Spring Framework Reference Documentation for more details. -If that is not what you want, you can disable transaction management for a test or for the whole class, as follows: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/data/neo4j/tx/MyDataNeo4jTests.java[] ----- - -NOTE: Transactional tests are not supported with reactive access. -If you are using this style, you must configure `@DataNeo4jTest` tests as described above. - - - -[[features.testing.spring-boot-applications.autoconfigured-spring-data-redis]] -==== Auto-configured Data Redis Tests -You can use `@DataRedisTest` to test Redis applications. -By default, it scans for `@RedisHash` classes and configures Spring Data Redis repositories. -Regular `@Component` and `@ConfigurationProperties` beans are not scanned when the `@DataRedisTest` annotation is used. -`@EnableConfigurationProperties` can be used to include `@ConfigurationProperties` beans. -(For more about using Redis with Spring Boot, see "<>", earlier in this chapter.) - -TIP: A list of the auto-configuration settings that are enabled by `@DataRedisTest` can be <>. - -The following example shows the `@DataRedisTest` annotation in use: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/data/redis/MyDataRedisTests.java[] ----- - - - -[[features.testing.spring-boot-applications.autoconfigured-spring-data-ldap]] -==== Auto-configured Data LDAP Tests -You can use `@DataLdapTest` to test LDAP applications. -By default, it configures an in-memory embedded LDAP (if available), configures an `LdapTemplate`, scans for `@Entry` classes, and configures Spring Data LDAP repositories. -Regular `@Component` and `@ConfigurationProperties` beans are not scanned when the `@DataLdapTest` annotation is used. -`@EnableConfigurationProperties` can be used to include `@ConfigurationProperties` beans. -(For more about using LDAP with Spring Boot, see "<>", earlier in this chapter.) - -TIP: A list of the auto-configuration settings that are enabled by `@DataLdapTest` can be <>. - -The following example shows the `@DataLdapTest` annotation in use: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/data/ldap/MyDataLdapTests.java[] ----- - -In-memory embedded LDAP generally works well for tests, since it is fast and does not require any developer installation. -If, however, you prefer to run tests against a real LDAP server, you should exclude the embedded LDAP auto-configuration, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/data/ldap/server/MyDataLdapTests.java[] ----- - - - -[[features.testing.spring-boot-applications.autoconfigured-rest-client]] -==== Auto-configured REST Clients -You can use the `@RestClientTest` annotation to test REST clients. -By default, it auto-configures Jackson, GSON, and Jsonb support, configures a `RestTemplateBuilder`, and adds support for `MockRestServiceServer`. -Regular `@Component` and `@ConfigurationProperties` beans are not scanned when the `@RestClientTest` annotation is used. -`@EnableConfigurationProperties` can be used to include `@ConfigurationProperties` beans. - -TIP: A list of the auto-configuration settings that are enabled by `@RestClientTest` can be <>. - -The specific beans that you want to test should be specified by using the `value` or `components` attribute of `@RestClientTest`, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/restclient/MyRestClientTests.java[] ----- - - - -[[features.testing.spring-boot-applications.autoconfigured-spring-restdocs]] -==== Auto-configured Spring REST Docs Tests -You can use the `@AutoConfigureRestDocs` annotation to use {spring-restdocs}[Spring REST Docs] in your tests with Mock MVC, REST Assured, or WebTestClient. -It removes the need for the JUnit extension in Spring REST Docs. - -`@AutoConfigureRestDocs` can be used to override the default output directory (`target/generated-snippets` if you are using Maven or `build/generated-snippets` if you are using Gradle). -It can also be used to configure the host, scheme, and port that appears in any documented URIs. - - - -[[features.testing.spring-boot-applications.autoconfigured-spring-restdocs.with-mock-mvc]] -===== Auto-configured Spring REST Docs Tests with Mock MVC -`@AutoConfigureRestDocs` customizes the `MockMvc` bean to use Spring REST Docs when testing Servlet-based web applications. -You can inject it by using `@Autowired` and use it in your tests as you normally would when using Mock MVC and Spring REST Docs, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/restdocs/mvc/UserDocumentationTests.java[] ----- - -If you require more control over Spring REST Docs configuration than offered by the attributes of `@AutoConfigureRestDocs`, you can use a `RestDocsMockMvcConfigurationCustomizer` bean, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/restdocs/mvc/CustomizationConfiguration.java[] ----- - -If you want to make use of Spring REST Docs support for a parameterized output directory, you can create a `RestDocumentationResultHandler` bean. -The auto-configuration calls `alwaysDo` with this result handler, thereby causing each `MockMvc` call to automatically generate the default snippets. -The following example shows a `RestDocumentationResultHandler` being defined: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/restdocs/mvc/ResultHandlerConfiguration.java[] ----- - - - -[[features.testing.spring-boot-applications.autoconfigured-spring-restdocs.with-web-test-client]] -===== Auto-configured Spring REST Docs Tests with WebTestClient -`@AutoConfigureRestDocs` can also be used with `WebTestClient` when testing reactive web applications. -You can inject it by using `@Autowired` and use it in your tests as you normally would when using `@WebFluxTest` and Spring REST Docs, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/restdocs/webclient/UsersDocumentationTests.java[] ----- - -If you require more control over Spring REST Docs configuration than offered by the attributes of `@AutoConfigureRestDocs`, you can use a `RestDocsWebTestClientConfigurationCustomizer` bean, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/restdocs/webclient/AdvancedRestDocsConfiguration.java[] ----- - - - -[[features.testing.spring-boot-applications.autoconfigured-spring-restdocs.with-rest-assured]] -===== Auto-configured Spring REST Docs Tests with REST Assured -`@AutoConfigureRestDocs` makes a `RequestSpecification` bean, preconfigured to use Spring REST Docs, available to your tests. -You can inject it by using `@Autowired` and use it in your tests as you normally would when using REST Assured and Spring REST Docs, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/restdocs/restassured/UserDocumentationTests.java[] ----- - -If you require more control over Spring REST Docs configuration than offered by the attributes of `@AutoConfigureRestDocs`, a `RestDocsRestAssuredConfigurationCustomizer` bean can be used, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/restdocs/restassured/AdvancedRestDocsConfiguration.java[] ----- - - - -[[features.testing.spring-boot-applications.autoconfigured-webservices]] -==== Auto-configured Spring Web Services Tests -You can use `@WebServiceClientTest` to test applications that use call web services using the Spring Web Services project. -By default, it configures a mock `WebServiceServer` bean and automatically customizes your `WebServiceTemplateBuilder`. -(For more about using Web Services with Spring Boot, see "<>", earlier in this chapter.) - - -TIP: A list of the auto-configuration settings that are enabled by `@WebServiceClientTest` can be <>. - -The following example shows the `@WebServiceClientTest` annotation in use: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/webservices/MyWebServiceClientTests.java[] ----- - - - -[[features.testing.spring-boot-applications.additional-autoconfiguration-and-slicing]] -==== Additional Auto-configuration and Slicing -Each slice provides one or more `@AutoConfigure...` annotations that namely defines the auto-configurations that should be included as part of a slice. -Additional auto-configurations can be added on a test-by-test basis by creating a custom `@AutoConfigure...` annotation or by adding `@ImportAutoConfiguration` to the test as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/slicing/ExampleJdbcTests.java[] ----- - -NOTE: Make sure to not use the regular `@Import` annotation to import auto-configurations as they are handled in a specific way by Spring Boot. - -Alternatively, additional auto-configurations can be added for any use of a slice annotation by registering them in `META-INF/spring.factories` as shown in the following example: - -[indent=0] ----- - org.springframework.boot.test.autoconfigure.jdbc.JdbcTest=com.example.IntegrationAutoConfiguration ----- - -TIP: A slice or `@AutoConfigure...` annotation can be customized this way as long as it is meta-annotated with `@ImportAutoConfiguration`. - - - -[[features.testing.spring-boot-applications.user-configuration-and-slicing]] -==== User Configuration and Slicing -If you <> in a sensible way, your `@SpringBootApplication` class is <> as the configuration of your tests. - -It then becomes important not to litter the application's main class with configuration settings that are specific to a particular area of its functionality. - -Assume that you are using Spring Batch and you rely on the auto-configuration for it. -You could define your `@SpringBootApplication` as follows: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/slicing/SampleApplication.java[] ----- - -Because this class is the source configuration for the test, any slice test actually tries to start Spring Batch, which is definitely not what you want to do. -A recommended approach is to move that area-specific configuration to a separate `@Configuration` class at the same level as your application, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/slicing/BatchConfiguration.java[] ----- - -NOTE: Depending on the complexity of your application, you may either have a single `@Configuration` class for your customizations or one class per domain area. -The latter approach lets you enable it in one of your tests, if necessary, with the `@Import` annotation. - -Test slices exclude `@Configuration` classes from scanning. -For example, for a `@WebMvcTest`, the following configuration will not include the given `WebMvcConfigurer` bean in the application context loaded by the test slice: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/slicing/WebConfiguration.java[] ----- - -The configuration below will, however, cause the custom `WebMvcConfigurer` to be loaded by the test slice. - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/slicing/TestWebMvcConfigurer.java[] ----- - -Another source of confusion is classpath scanning. -Assume that, while you structured your code in a sensible way, you need to scan an additional package. -Your application may resemble the following code: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/applications/slicing/scan/SampleApplication.java[] ----- - -Doing so effectively overrides the default component scan directive with the side effect of scanning those two packages regardless of the slice that you chose. -For instance, a `@DataJpaTest` seems to suddenly scan components and user configurations of your application. -Again, moving the custom directive to a separate class is a good way to fix this issue. - -TIP: If this is not an option for you, you can create a `@SpringBootConfiguration` somewhere in the hierarchy of your test so that it is used instead. -Alternatively, you can specify a source for your test, which disables the behavior of finding a default one. - - - -[[features.testing.spring-boot-applications.spock]] -==== Using Spock to Test Spring Boot Applications -If you wish to use Spock to test a Spring Boot application, you should add a dependency on Spock's `spock-spring` module to your application's build. -`spock-spring` integrates Spring's test framework into Spock. -See https://spockframework.org/spock/docs/2.0-M4/modules.html#_spring_module[the documentation for Spock's Spring module] for further details. - -NOTE: As of Spring Boot 2.5.x and its support for Groovy 3.x you have two options to make use of Spock: -Either use the latest Spock 2.0 milestone or release that is compatible with Groovy 3.x or stick with Spock 1.3 and downgrade Spring Boot's Groovy version to 2.5.x. - - - -[[features.testing.utilities]] -=== Test Utilities -A few test utility classes that are generally useful when testing your application are packaged as part of `spring-boot`. - - - -[[features.testing.utilities.config-data-application-context-initializer]] -==== ConfigDataApplicationContextInitializer -`ConfigDataApplicationContextInitializer` is an `ApplicationContextInitializer` that you can apply to your tests to load Spring Boot `application.properties` files. -You can use it when you do not need the full set of features provided by `@SpringBootTest`, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/utils/MyConfigFileTests.java[] ----- - -NOTE: Using `ConfigDataApplicationContextInitializer` alone does not provide support for `@Value("${...}")` injection. -Its only job is to ensure that `application.properties` files are loaded into Spring's `Environment`. -For `@Value` support, you need to either additionally configure a `PropertySourcesPlaceholderConfigurer` or use `@SpringBootTest`, which auto-configures one for you. - - - -[[features.testing.utilities.test-property-values]] -==== TestPropertyValues -`TestPropertyValues` lets you quickly add properties to a `ConfigurableEnvironment` or `ConfigurableApplicationContext`. -You can call it with `key=value` strings, as follows: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/utils/MyEnvironmentTests.java[tag=*] ----- - - - -[[features.testing.utilities.output-capture]] -==== OutputCapture -`OutputCapture` is a JUnit `Extension` that you can use to capture `System.out` and `System.err` output. -To use add `@ExtendWith(OutputCaptureExtension.class)` and inject `CapturedOutput` as an argument to your test class constructor or test method as follows: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/OutputCaptureTests.java[] ----- - - - -[[features.testing.utilities.test-rest-template]] -==== TestRestTemplate -`TestRestTemplate` is a convenience alternative to Spring's `RestTemplate` that is useful in integration tests. -You can get a vanilla template or one that sends Basic HTTP authentication (with a username and password). -In either case, the template behaves in a test-friendly way by not throwing exceptions on server-side errors. - -TIP: Spring Framework 5.0 provides a new `WebTestClient` that works for <> and both <>. -It provides a fluent API for assertions, unlike `TestRestTemplate`. - -It is recommended, but not mandatory, to use the Apache HTTP Client (version 4.3.2 or better). -If you have that on your classpath, the `TestRestTemplate` responds by configuring the client appropriately. -If you do use Apache's HTTP client, some additional test-friendly features are enabled: - -* Redirects are not followed (so you can assert the response location). -* Cookies are ignored (so the template is stateless). - -`TestRestTemplate` can be instantiated directly in your integration tests, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/utils/testresttemplate/MyTest.java[] ----- - -Alternatively, if you use the `@SpringBootTest` annotation with `WebEnvironment.RANDOM_PORT` or `WebEnvironment.DEFINED_PORT`, you can inject a fully configured `TestRestTemplate` and start using it. -If necessary, additional customizations can be applied through the `RestTemplateBuilder` bean. -Any URLs that do not specify a host and port automatically connect to the embedded server, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/webclient/SampleWebClientTests.java[] ----- - - - -[[features.websockets]] -== WebSockets -Spring Boot provides WebSockets auto-configuration for embedded Tomcat, Jetty, and Undertow. -If you deploy a war file to a standalone container, Spring Boot assumes that the container is responsible for the configuration of its WebSocket support. - -Spring Framework provides {spring-framework-docs}/web.html#websocket[rich WebSocket support] for MVC web applications that can be easily accessed through the `spring-boot-starter-websocket` module. - -WebSocket support is also available for {spring-framework-docs}/web-reactive.html#webflux-websocket[reactive web applications] and requires to include the WebSocket API alongside `spring-boot-starter-webflux`: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - javax.websocket - javax.websocket-api - ----- - - - -[[features.webservices]] -== Web Services -Spring Boot provides Web Services auto-configuration so that all you must do is define your `Endpoints`. - -The {spring-webservices-docs}[Spring Web Services features] can be easily accessed with the `spring-boot-starter-webservices` module. - -`SimpleWsdl11Definition` and `SimpleXsdSchema` beans can be automatically created for your WSDLs and XSDs respectively. -To do so, configure their location, as shown in the following example: - - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - webservices: - wsdl-locations: "classpath:/wsdl" ----- - - - -[[features.webservices.template]] -=== Calling Web Services with WebServiceTemplate -If you need to call remote Web services from your application, you can use the {spring-webservices-docs}#client-web-service-template[`WebServiceTemplate`] class. -Since `WebServiceTemplate` instances often need to be customized before being used, Spring Boot does not provide any single auto-configured `WebServiceTemplate` bean. -It does, however, auto-configure a `WebServiceTemplateBuilder`, which can be used to create `WebServiceTemplate` instances when needed. - -The following code shows a typical example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/webservices/MyService.java[] ----- - -By default, `WebServiceTemplateBuilder` detects a suitable HTTP-based `WebServiceMessageSender` using the available HTTP client libraries on the classpath. -You can also customize read and connection timeouts as follows: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/webservices/MyWebServiceTemplateConfiguration.java[] ----- - - - -[[features.developing-auto-configuration]] -== Creating Your Own Auto-configuration -If you work in a company that develops shared libraries, or if you work on an open-source or commercial library, you might want to develop your own auto-configuration. -Auto-configuration classes can be bundled in external jars and still be picked-up by Spring Boot. - -Auto-configuration can be associated to a "`starter`" that provides the auto-configuration code as well as the typical libraries that you would use with it. -We first cover what you need to know to build your own auto-configuration and then we move on to the <>. - -TIP: A https://github.com/snicoll-demos/spring-boot-master-auto-configuration[demo project] is available to showcase how you can create a starter step-by-step. - - - -[[features.developing-auto-configuration.understanding-auto-configured-beans]] -=== Understanding Auto-configured Beans -Under the hood, auto-configuration is implemented with standard `@Configuration` classes. -Additional `@Conditional` annotations are used to constrain when the auto-configuration should apply. -Usually, auto-configuration classes use `@ConditionalOnClass` and `@ConditionalOnMissingBean` annotations. -This ensures that auto-configuration applies only when relevant classes are found and when you have not declared your own `@Configuration`. - -You can browse the source code of {spring-boot-autoconfigure-module-code}[`spring-boot-autoconfigure`] to see the `@Configuration` classes that Spring provides (see the {spring-boot-code}/spring-boot-project/spring-boot-autoconfigure/src/main/resources/META-INF/spring.factories[`META-INF/spring.factories`] file). - - - -[[features.developing-auto-configuration.locating-auto-configuration-candidates]] -=== Locating Auto-configuration Candidates -Spring Boot checks for the presence of a `META-INF/spring.factories` file within your published jar. -The file should list your configuration classes under the `EnableAutoConfiguration` key, as shown in the following example: - -[indent=0] ----- - org.springframework.boot.autoconfigure.EnableAutoConfiguration=\ - com.mycorp.libx.autoconfigure.LibXAutoConfiguration,\ - com.mycorp.libx.autoconfigure.LibXWebAutoConfiguration ----- - -NOTE: Auto-configurations must be loaded that way _only_. -Make sure that they are defined in a specific package space and that they are never the target of component scanning. -Furthermore, auto-configuration classes should not enable component scanning to find additional components. -Specific ``@Import``s should be used instead. - -You can use the {spring-boot-autoconfigure-module-code}/AutoConfigureAfter.java[`@AutoConfigureAfter`] or {spring-boot-autoconfigure-module-code}/AutoConfigureBefore.java[`@AutoConfigureBefore`] annotations if your configuration needs to be applied in a specific order. -For example, if you provide web-specific configuration, your class may need to be applied after `WebMvcAutoConfiguration`. - -If you want to order certain auto-configurations that should not have any direct knowledge of each other, you can also use `@AutoConfigureOrder`. -That annotation has the same semantic as the regular `@Order` annotation but provides a dedicated order for auto-configuration classes. - -As with standard `@Configuration` classes, the order in which auto-configuration classes are applied only affects the order in which their beans are defined. -The order in which those beans are subsequently created is unaffected and is determined by each bean's dependencies and any `@DependsOn` relationships. - - - -[[features.developing-auto-configuration.condition-annotations]] -=== Condition Annotations -You almost always want to include one or more `@Conditional` annotations on your auto-configuration class. -The `@ConditionalOnMissingBean` annotation is one common example that is used to allow developers to override auto-configuration if they are not happy with your defaults. - -Spring Boot includes a number of `@Conditional` annotations that you can reuse in your own code by annotating `@Configuration` classes or individual `@Bean` methods. -These annotations include: - -* <> -* <> -* <> -* <> -* <> -* <> - - - -[[features.developing-auto-configuration.condition-annotations.class-conditions]] -==== Class Conditions -The `@ConditionalOnClass` and `@ConditionalOnMissingClass` annotations let `@Configuration` classes be included based on the presence or absence of specific classes. -Due to the fact that annotation metadata is parsed by using https://asm.ow2.io/[ASM], you can use the `value` attribute to refer to the real class, even though that class might not actually appear on the running application classpath. -You can also use the `name` attribute if you prefer to specify the class name by using a `String` value. - -This mechanism does not apply the same way to `@Bean` methods where typically the return type is the target of the condition: before the condition on the method applies, the JVM will have loaded the class and potentially processed method references which will fail if the class is not present. - -To handle this scenario, a separate `@Configuration` class can be used to isolate the condition, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/creatingautoconfiguration/classconditions/MyAutoConfiguration.java[] ----- - -TIP: If you use `@ConditionalOnClass` or `@ConditionalOnMissingClass` as a part of a meta-annotation to compose your own composed annotations, you must use `name` as referring to the class in such a case is not handled. - - - -[[features.developing-auto-configuration.condition-annotations.bean-conditions]] -==== Bean Conditions -The `@ConditionalOnBean` and `@ConditionalOnMissingBean` annotations let a bean be included based on the presence or absence of specific beans. -You can use the `value` attribute to specify beans by type or `name` to specify beans by name. -The `search` attribute lets you limit the `ApplicationContext` hierarchy that should be considered when searching for beans. - -When placed on a `@Bean` method, the target type defaults to the return type of the method, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/creatingautoconfiguration/beanconditions/MyAutoConfiguration.java[] ----- - -In the preceding example, the `myService` bean is going to be created if no bean of type `MyService` is already contained in the `ApplicationContext`. - -TIP: You need to be very careful about the order in which bean definitions are added, as these conditions are evaluated based on what has been processed so far. -For this reason, we recommend using only `@ConditionalOnBean` and `@ConditionalOnMissingBean` annotations on auto-configuration classes (since these are guaranteed to load after any user-defined bean definitions have been added). - -NOTE: `@ConditionalOnBean` and `@ConditionalOnMissingBean` do not prevent `@Configuration` classes from being created. -The only difference between using these conditions at the class level and marking each contained `@Bean` method with the annotation is that the former prevents registration of the `@Configuration` class as a bean if the condition does not match. - -TIP: When declaring a `@Bean` method, provide as much type information as possible in the method's return type. -For example, if your bean's concrete class implements an interface the bean method's return type should be the concrete class and not the interface. -Providing as much type information as possible in `@Bean` methods is particularly important when using bean conditions as their evaluation can only rely upon to type information that's available in the method signature. - - - -[[features.developing-auto-configuration.condition-annotations.property-conditions]] -==== Property Conditions -The `@ConditionalOnProperty` annotation lets configuration be included based on a Spring Environment property. -Use the `prefix` and `name` attributes to specify the property that should be checked. -By default, any property that exists and is not equal to `false` is matched. -You can also create more advanced checks by using the `havingValue` and `matchIfMissing` attributes. - - - -[[features.developing-auto-configuration.condition-annotations.resource-conditions]] -==== Resource Conditions -The `@ConditionalOnResource` annotation lets configuration be included only when a specific resource is present. -Resources can be specified by using the usual Spring conventions, as shown in the following example: `file:/home/user/test.dat`. - - - -[[features.developing-auto-configuration.condition-annotations.web-application-conditions]] -==== Web Application Conditions -The `@ConditionalOnWebApplication` and `@ConditionalOnNotWebApplication` annotations let configuration be included depending on whether the application is a "`web application`". -A servlet-based web application is any application that uses a Spring `WebApplicationContext`, defines a `session` scope, or has a `ConfigurableWebEnvironment`. -A reactive web application is any application that uses a `ReactiveWebApplicationContext`, or has a `ConfigurableReactiveWebEnvironment`. - -The `@ConditionalOnWarDeployment` annotation lets configuration be included depending on whether the application is a traditional WAR application that is deployed to a container. -This condition will not match for applications that are run with an embedded server. - - - -[[features.developing-auto-configuration.condition-annotations.spel-conditions]] -==== SpEL Expression Conditions -The `@ConditionalOnExpression` annotation lets configuration be included based on the result of a {spring-framework-docs}/core.html#expressions[SpEL expression]. - - - -[[features.developing-auto-configuration.testing]] -=== Testing your Auto-configuration -An auto-configuration can be affected by many factors: user configuration (`@Bean` definition and `Environment` customization), condition evaluation (presence of a particular library), and others. -Concretely, each test should create a well defined `ApplicationContext` that represents a combination of those customizations. -`ApplicationContextRunner` provides a great way to achieve that. - -`ApplicationContextRunner` is usually defined as a field of the test class to gather the base, common configuration. -The following example makes sure that `UserServiceAutoConfiguration` is always invoked: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/UserServiceAutoConfigurationTests.java[tag=runner] ----- - -TIP: If multiple auto-configurations have to be defined, there is no need to order their declarations as they are invoked in the exact same order as when running the application. - -Each test can use the runner to represent a particular use case. -For instance, the sample below invokes a user configuration (`UserConfiguration`) and checks that the auto-configuration backs off properly. -Invoking `run` provides a callback context that can be used with `AssertJ`. - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/UserServiceAutoConfigurationTests.java[tag=test-user-config] ----- - -It is also possible to easily customize the `Environment`, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/UserServiceAutoConfigurationTests.java[tag=test-env] ----- - -The runner can also be used to display the `ConditionEvaluationReport`. -The report can be printed at `INFO` or `DEBUG` level. -The following example shows how to use the `ConditionEvaluationReportLoggingListener` to print the report in auto-configuration tests. - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/ConditionEvaluationReportTests.java[tag=*] ----- - - - -[[features.developing-auto-configuration.testing.simulating-a-web-context]] -==== Simulating a Web Context -If you need to test an auto-configuration that only operates in a Servlet or Reactive web application context, use the `WebApplicationContextRunner` or `ReactiveWebApplicationContextRunner` respectively. - - - -[[features.developing-auto-configuration.testing.overriding-classpath]] -==== Overriding the Classpath -It is also possible to test what happens when a particular class and/or package is not present at runtime. -Spring Boot ships with a `FilteredClassLoader` that can easily be used by the runner. -In the following example, we assert that if `UserService` is not present, the auto-configuration is properly disabled: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/testing/UserServiceAutoConfigurationTests.java[tag=test-classloader] ----- - - - -[[features.developing-auto-configuration.custom-starter]] -=== Creating Your Own Starter -A typical Spring Boot starter contains code to auto-configure and customize the infrastructure of a given technology, let's call that "acme". -To make it easily extensible, a number of configuration keys in a dedicated namespace can be exposed to the environment. -Finally, a single "starter" dependency is provided to help users get started as easily as possible. - -Concretely, a custom starter can contain the following: - -* The `autoconfigure` module that contains the auto-configuration code for "acme". -* The `starter` module that provides a dependency to the `autoconfigure` module as well as "acme" and any additional dependencies that are typically useful. -In a nutshell, adding the starter should provide everything needed to start using that library. - -This separation in two modules is in no way necessary. -If "acme" has several flavours, options or optional features, then it is better to separate the auto-configuration as you can clearly express the fact some features are optional. -Besides, you have the ability to craft a starter that provides an opinion about those optional dependencies. -At the same time, others can rely only on the `autoconfigure` module and craft their own starter with different opinions. - -If the auto-configuration is relatively straightforward and does not have optional feature, merging the two modules in the starter is definitely an option. - - - -[[features.developing-auto-configuration.custom-starter.naming]] -==== Naming -You should make sure to provide a proper namespace for your starter. -Do not start your module names with `spring-boot`, even if you use a different Maven `groupId`. -We may offer official support for the thing you auto-configure in the future. - -As a rule of thumb, you should name a combined module after the starter. -For example, assume that you are creating a starter for "acme" and that you name the auto-configure module `acme-spring-boot` and the starter `acme-spring-boot-starter`. -If you only have one module that combines the two, name it `acme-spring-boot-starter`. - - - -[[features.developing-auto-configuration.custom-starter.configuration-keys]] -==== Configuration keys -If your starter provides configuration keys, use a unique namespace for them. -In particular, do not include your keys in the namespaces that Spring Boot uses (such as `server`, `management`, `spring`, and so on). -If you use the same namespace, we may modify these namespaces in the future in ways that break your modules. -As a rule of thumb, prefix all your keys with a namespace that you own (e.g. `acme`). - -Make sure that configuration keys are documented by adding field javadoc for each property, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/creatingautoconfiguration/configurationkeys/AcmeProperties.java[] ----- - -NOTE: You should only use plain text with `@ConfigurationProperties` field Javadoc, since they are not processed before being added to the JSON. - -Here are some rules we follow internally to make sure descriptions are consistent: - -* Do not start the description by "The" or "A". -* For `boolean` types, start the description with "Whether" or "Enable". -* For collection-based types, start the description with "Comma-separated list" -* Use `java.time.Duration` rather than `long` and describe the default unit if it differs from milliseconds, e.g. "If a duration suffix is not specified, seconds will be used". -* Do not provide the default value in the description unless it has to be determined at runtime. - -Make sure to <> so that IDE assistance is available for your keys as well. -You may want to review the generated metadata (`META-INF/spring-configuration-metadata.json`) to make sure your keys are properly documented. -Using your own starter in a compatible IDE is also a good idea to validate that quality of the metadata. - - - -[[features.developing-auto-configuration.custom-starter.autoconfigure-module]] -==== The "`autoconfigure`" Module -The `autoconfigure` module contains everything that is necessary to get started with the library. -It may also contain configuration key definitions (such as `@ConfigurationProperties`) and any callback interface that can be used to further customize how the components are initialized. - -TIP: You should mark the dependencies to the library as optional so that you can include the `autoconfigure` module in your projects more easily. -If you do it that way, the library is not provided and, by default, Spring Boot backs off. - -Spring Boot uses an annotation processor to collect the conditions on auto-configurations in a metadata file (`META-INF/spring-autoconfigure-metadata.properties`). -If that file is present, it is used to eagerly filter auto-configurations that do not match, which will improve startup time. -It is recommended to add the following dependency in a module that contains auto-configurations: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - org.springframework.boot - spring-boot-autoconfigure-processor - true - ----- - -If you have defined auto-configurations directly in your application, make sure to configure the `spring-boot-maven-plugin` to prevent the `repackage` goal from adding the dependency into the fat jar: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - - - - org.springframework.boot - spring-boot-maven-plugin - - - - org.springframework.boot - spring-boot-autoconfigure-processor - - - - - - - ----- - -With Gradle 4.5 and earlier, the dependency should be declared in the `compileOnly` configuration, as shown in the following example: - -[source,groovy,indent=0,subs="verbatim,quotes,attributes"] ----- - dependencies { - compileOnly "org.springframework.boot:spring-boot-autoconfigure-processor" - } ----- - -With Gradle 4.6 and later, the dependency should be declared in the `annotationProcessor` configuration, as shown in the following example: - -[source,groovy,indent=0,subs="verbatim,quotes,attributes"] ----- - dependencies { - annotationProcessor "org.springframework.boot:spring-boot-autoconfigure-processor" - } ----- - - - -[[features.developing-auto-configuration.custom-starter.starter-module]] -==== Starter Module -The starter is really an empty jar. -Its only purpose is to provide the necessary dependencies to work with the library. -You can think of it as an opinionated view of what is required to get started. - -Do not make assumptions about the project in which your starter is added. -If the library you are auto-configuring typically requires other starters, mention them as well. -Providing a proper set of _default_ dependencies may be hard if the number of optional dependencies is high, as you should avoid including dependencies that are unnecessary for a typical usage of the library. -In other words, you should not include optional dependencies. - -NOTE: Either way, your starter must reference the core Spring Boot starter (`spring-boot-starter`) directly or indirectly (i.e. no need to add it if your starter relies on another starter). -If a project is created with only your custom starter, Spring Boot's core features will be honoured by the presence of the core starter. - - - -[[features.kotlin]] -== Kotlin support -https://kotlinlang.org[Kotlin] is a statically-typed language targeting the JVM (and other platforms) which allows writing concise and elegant code while providing {kotlin-docs}java-interop.html[interoperability] with existing libraries written in Java. - -Spring Boot provides Kotlin support by leveraging the support in other Spring projects such as Spring Framework, Spring Data, and Reactor. -See the {spring-framework-docs}/languages.html#kotlin[Spring Framework Kotlin support documentation] for more information. - -The easiest way to start with Spring Boot and Kotlin is to follow https://spring.io/guides/tutorials/spring-boot-kotlin/[this comprehensive tutorial]. -You can create new Kotlin projects via https://start.spring.io/#!language=kotlin[start.spring.io]. -Feel free to join the #spring channel of https://slack.kotlinlang.org/[Kotlin Slack] or ask a question with the `spring` and `kotlin` tags on https://stackoverflow.com/questions/tagged/spring+kotlin[Stack Overflow] if you need support. - - - -[[features.kotlin.requirements]] -=== Requirements -Spring Boot supports Kotlin 1.3.x. -To use Kotlin, `org.jetbrains.kotlin:kotlin-stdlib` and `org.jetbrains.kotlin:kotlin-reflect` must be present on the classpath. -The `kotlin-stdlib` variants `kotlin-stdlib-jdk7` and `kotlin-stdlib-jdk8` can also be used. - -Since https://discuss.kotlinlang.org/t/classes-final-by-default/166[Kotlin classes are final by default], you are likely to want to configure {kotlin-docs}compiler-plugins.html#spring-support[kotlin-spring] plugin in order to automatically open Spring-annotated classes so that they can be proxied. - -https://github.com/FasterXML/jackson-module-kotlin[Jackson's Kotlin module] is required for serializing / deserializing JSON data in Kotlin. -It is automatically registered when found on the classpath. -A warning message is logged if Jackson and Kotlin are present but the Jackson Kotlin module is not. - -TIP: These dependencies and plugins are provided by default if one bootstraps a Kotlin project on https://start.spring.io/#!language=kotlin[start.spring.io]. - - - -[[features.kotlin.null-safety]] -=== Null-safety -One of Kotlin's key features is {kotlin-docs}null-safety.html[null-safety]. -It deals with `null` values at compile time rather than deferring the problem to runtime and encountering a `NullPointerException`. -This helps to eliminate a common source of bugs without paying the cost of wrappers like `Optional`. -Kotlin also allows using functional constructs with nullable values as described in this https://www.baeldung.com/kotlin-null-safety[comprehensive guide to null-safety in Kotlin]. - -Although Java does not allow one to express null-safety in its type system, Spring Framework, Spring Data, and Reactor now provide null-safety of their API via tooling-friendly annotations. -By default, types from Java APIs used in Kotlin are recognized as {kotlin-docs}java-interop.html#null-safety-and-platform-types[platform types] for which null-checks are relaxed. -{kotlin-docs}java-interop.html#jsr-305-support[Kotlin's support for JSR 305 annotations] combined with nullability annotations provide null-safety for the related Spring API in Kotlin. - -The JSR 305 checks can be configured by adding the `-Xjsr305` compiler flag with the following options: `-Xjsr305={strict|warn|ignore}`. -The default behavior is the same as `-Xjsr305=warn`. -The `strict` value is required to have null-safety taken in account in Kotlin types inferred from Spring API but should be used with the knowledge that Spring API nullability declaration could evolve even between minor releases and more checks may be added in the future). - -WARNING: Generic type arguments, varargs and array elements nullability are not yet supported. -See https://jira.spring.io/browse/SPR-15942[SPR-15942] for up-to-date information. -Also be aware that Spring Boot's own API is {github-issues}10712[not yet annotated]. - - - -[[features.kotlin.api]] -=== Kotlin API - - - -[[features.kotlin.api.?run-application]] -==== runApplication -Spring Boot provides an idiomatic way to run an application with `runApplication(*args)` as shown in the following example: - -[source,kotlin,indent=0] ----- - import org.springframework.boot.autoconfigure.SpringBootApplication - import org.springframework.boot.runApplication - - @SpringBootApplication - class MyApplication - - fun main(args: Array) { - runApplication(*args) - } ----- - -This is a drop-in replacement for `SpringApplication.run(MyApplication::class.java, *args)`. -It also allows customization of the application as shown in the following example: - -[source,kotlin,indent=0] ----- - runApplication(*args) { - setBannerMode(OFF) - } ----- - - - -[[features.kotlin.api.extensions]] -==== Extensions -Kotlin {kotlin-docs}extensions.html[extensions] provide the ability to extend existing classes with additional functionality. -The Spring Boot Kotlin API makes use of these extensions to add new Kotlin specific conveniences to existing APIs. - -`TestRestTemplate` extensions, similar to those provided by Spring Framework for `RestOperations` in Spring Framework, are provided. -Among other things, the extensions make it possible to take advantage of Kotlin reified type parameters. - - - -[[features.kotlin.dependency-management]] -=== Dependency management -In order to avoid mixing different versions of Kotlin dependencies on the classpath, Spring Boot imports the Kotlin BOM. - -With Maven, the Kotlin version can be customized via the `kotlin.version` property and plugin management is provided for `kotlin-maven-plugin`. -With Gradle, the Spring Boot plugin automatically aligns the `kotlin.version` with the version of the Kotlin plugin. - -Spring Boot also manages the version of Coroutines dependencies by importing the Kotlin Coroutines BOM. -The version can be customized via the `kotlin-coroutines.version` property. - -TIP: `org.jetbrains.kotlinx:kotlinx-coroutines-reactor` dependency is provided by default if one bootstraps a Kotlin project with at least one reactive dependency on https://start.spring.io/#!language=kotlin[start.spring.io]. - - - -[[features.kotlin.configuration-properties]] -=== @ConfigurationProperties -`@ConfigurationProperties` when used in combination with <> supports classes with immutable `val` properties as shown in the following example: - -[source,kotlin,indent=0] ----- -@ConstructorBinding -@ConfigurationProperties("example.kotlin") -data class KotlinExampleProperties( - val name: String, - val description: String, - val myService: MyService) { - - data class MyService( - val apiToken: String, - val uri: URI - ) -} ----- - -TIP: To generate <> using the annotation processor, {kotlin-docs}kapt.html[`kapt` should be configured] with the `spring-boot-configuration-processor` dependency. -Note that some features (such as detecting the default value or deprecated items) are not working due to limitations in the model kapt provides. - - - -[[features.kotlin.testing]] -=== Testing -While it is possible to use JUnit 4 to test Kotlin code, JUnit 5 is provided by default and is recommended. -JUnit 5 enables a test class to be instantiated once and reused for all of the class's tests. -This makes it possible to use `@BeforeAll` and `@AfterAll` annotations on non-static methods, which is a good fit for Kotlin. - -To mock Kotlin classes, https://mockk.io/[MockK] is recommended. -If you need the `Mockk` equivalent of the Mockito specific <>, you can use https://github.com/Ninja-Squad/springmockk[SpringMockK] which provides similar `@MockkBean` and `@SpykBean` annotations. - - - -[[features.kotlin.resources]] -=== Resources - - - -[[features.kotlin.resources.further-reading]] -==== Further reading -* {kotlin-docs}[Kotlin language reference] -* https://kotlinlang.slack.com/[Kotlin Slack] (with a dedicated #spring channel) -* https://stackoverflow.com/questions/tagged/spring+kotlin[Stackoverflow with `spring` and `kotlin` tags] -* https://try.kotlinlang.org/[Try Kotlin in your browser] -* https://blog.jetbrains.com/kotlin/[Kotlin blog] -* https://kotlin.link/[Awesome Kotlin] -* https://spring.io/guides/tutorials/spring-boot-kotlin/[Tutorial: building web applications with Spring Boot and Kotlin] -* https://spring.io/blog/2016/02/15/developing-spring-boot-applications-with-kotlin[Developing Spring Boot applications with Kotlin] -* https://spring.io/blog/2016/03/20/a-geospatial-messenger-with-kotlin-spring-boot-and-postgresql[A Geospatial Messenger with Kotlin, Spring Boot and PostgreSQL] -* https://spring.io/blog/2017/01/04/introducing-kotlin-support-in-spring-framework-5-0[Introducing Kotlin support in Spring Framework 5.0] -* https://spring.io/blog/2017/08/01/spring-framework-5-kotlin-apis-the-functional-way[Spring Framework 5 Kotlin APIs, the functional way] - - - -[[features.kotlin.resources.examples]] -==== Examples -* https://github.com/sdeleuze/spring-boot-kotlin-demo[spring-boot-kotlin-demo]: regular Spring Boot + Spring Data JPA project -* https://github.com/mixitconf/mixit[mixit]: Spring Boot 2 + WebFlux + Reactive Spring Data MongoDB -* https://github.com/sdeleuze/spring-kotlin-fullstack[spring-kotlin-fullstack]: WebFlux Kotlin fullstack example with Kotlin2js for frontend instead of JavaScript or TypeScript -* https://github.com/spring-petclinic/spring-petclinic-kotlin[spring-petclinic-kotlin]: Kotlin version of the Spring PetClinic Sample Application -* https://github.com/sdeleuze/spring-kotlin-deepdive[spring-kotlin-deepdive]: a step by step migration for Boot 1.0 + Java to Boot 2.0 + Kotlin -* https://github.com/sdeleuze/spring-boot-coroutines-demo[spring-boot-coroutines-demo]: Coroutines sample project - - - -[[features.container-images]] -== Container Images -It is easily possible to package a Spring Boot fat jar as a docker image. -However, there are various downsides to copying and running the fat jar as is in the docker image. -There’s always a certain amount of overhead when running a fat jar without unpacking it, and in a containerized environment this can be noticeable. -The other issue is that putting your application's code and all its dependencies in one layer in the Docker image is sub-optimal. -Since you probably recompile your code more often than you upgrade the version of Spring Boot you use, it’s often better to separate things a bit more. -If you put jar files in the layer before your application classes, Docker often only needs to change the very bottom layer and can pick others up from its cache. - - - -[[features.container-images.layering]] -=== Layering Docker Images -To make it easier to create optimized Docker images, Spring Boot supports adding a layer index file to the jar. -It provides a list of layers and the parts of the jar that should be contained within them. -The list of layers in the index is ordered based on the order in which the layers should be added to the Docker/OCI image. -Out-of-the-box, the following layers are supported: - -* `dependencies` (for regular released dependencies) -* `spring-boot-loader` (for everything under `org/springframework/boot/loader`) -* `snapshot-dependencies` (for snapshot dependencies) -* `application` (for application classes and resources) - -The following shows an example of a `layers.idx` file: - -[source,yaml,indent=0] ----- - - "dependencies": - - BOOT-INF/lib/library1.jar - - BOOT-INF/lib/library2.jar - - "spring-boot-loader": - - org/springframework/boot/loader/JarLauncher.class - - org/springframework/boot/loader/jar/JarEntry.class - - "snapshot-dependencies": - - BOOT-INF/lib/library3-SNAPSHOT.jar - - "application": - - META-INF/MANIFEST.MF - - BOOT-INF/classes/a/b/C.class ----- - -This layering is designed to separate code based on how likely it is to change between application builds. -Library code is less likely to change between builds, so it is placed in its own layers to allow tooling to re-use the layers from cache. -Application code is more likely to change between builds so it is isolated in a separate layer. - -Spring Boot also supports layering for war files with the help of a `layers.idx`. - -For Maven, refer to the {spring-boot-maven-plugin-docs}#repackage-layers[packaging layered jar or war section] for more details on adding a layer index to the archive. -For Gradle, refer to the {spring-boot-gradle-plugin-docs}#packaging-layered-archives[packaging layered jar or war section] of the Gradle plugin documentation. - - - -[[features.container-images.building]] -=== Building Container Images -Spring Boot applications can be containerized <>, or by <>. - - - -[[features.container-images.building.dockerfiles]] -==== Dockerfiles -While it is possible to convert a Spring Boot fat jar into a docker image with just a few lines in the Dockerfile, we will use the <> to create an optimized docker image. -When you create a jar containing the layers index file, the `spring-boot-jarmode-layertools` jar will be added as a dependency to your jar. -With this jar on the classpath, you can launch your application in a special mode which allows the bootstrap code to run something entirely different from your application, for example, something that extracts the layers. - -CAUTION: The `layertools` mode can not be used with a <> that includes a launch script. -Disable launch script configuration when building a jar file that is intended to be used with `layertools`. - -Here’s how you can launch your jar with a `layertools` jar mode: - ----- -$ java -Djarmode=layertools -jar my-app.jar ----- - -This will provide the following output: - ----- -Usage: - java -Djarmode=layertools -jar my-app.jar - -Available commands: - list List layers from the jar that can be extracted - extract Extracts layers from the jar for image creation - help Help about any command ----- - -The `extract` command can be used to easily split the application into layers to be added to the dockerfile. -Here's an example of a Dockerfile using `jarmode`. - ----- -FROM adoptopenjdk:11-jre-hotspot as builder -WORKDIR application -ARG JAR_FILE=target/*.jar -COPY ${JAR_FILE} application.jar -RUN java -Djarmode=layertools -jar application.jar extract - -FROM adoptopenjdk:11-jre-hotspot -WORKDIR application -COPY --from=builder application/dependencies/ ./ -COPY --from=builder application/spring-boot-loader/ ./ -COPY --from=builder application/snapshot-dependencies/ ./ -COPY --from=builder application/application/ ./ -ENTRYPOINT ["java", "org.springframework.boot.loader.JarLauncher"] ----- - -Assuming the above `Dockerfile` is in the current directory, your docker image can be built with `docker build .`, or optionally specifying the path to your application jar, as shown in the following example: - -[indent=0] ----- - docker build --build-arg JAR_FILE=path/to/myapp.jar . ----- - -This is a multi-stage dockerfile. -The builder stage extracts the directories that are needed later. -Each of the `COPY` commands relates to the layers extracted by the jarmode. - -Of course, a Dockerfile can be written without using the jarmode. -You can use some combination of `unzip` and `mv` to move things to the right layer but jarmode simplifies that. - - - -[[features.container-images.building.buildpacks]] -==== Cloud Native Buildpacks -Dockerfiles are just one way to build docker images. -Another way to build docker images is directly from your Maven or Gradle plugin, using buildpacks. -If you’ve ever used an application platform such as Cloud Foundry or Heroku then you’ve probably used a buildpack. -Buildpacks are the part of the platform that takes your application and converts it into something that the platform can actually run. -For example, Cloud Foundry’s Java buildpack will notice that you’re pushing a `.jar` file and automatically add a relevant JRE. - -With Cloud Native Buildpacks, you can create Docker compatible images that you can run anywhere. -Spring Boot includes buildpack support directly for both Maven and Gradle. -This means you can just type a single command and quickly get a sensible image into your locally running Docker daemon. - -Refer to the individual plugin documentation on how to use buildpacks with {spring-boot-maven-plugin-docs}#build-image[Maven] and {spring-boot-gradle-plugin-docs}#build-image[Gradle]. - -NOTE: The https://github.com/paketo-buildpacks/spring-boot[Paketo Spring Boot buildpack] has also been updated to support the `layers.idx` file so any customization that is applied to it will be reflected in the image created by the buildpack. - -NOTE: In order to achieve reproducible builds and container image caching, Buildpacks can manipulate the application resources metadata (such as the file "last modified" information). -You should ensure that your application does not rely on that metadata at runtime. -Spring Boot can use that information when serving static resources, but this can be disabled with configprop:spring.web.resources.cache.use-last-modified[] - - - -[[features.whats-next]] -== What to Read Next -If you want to learn more about any of the classes discussed in this section, you can check out the {spring-boot-api}/[Spring Boot API documentation] or you can browse the {spring-boot-code}[source code directly]. -If you have specific questions, take a look at the <> section. - -If you are comfortable with Spring Boot's core features, you can continue on and read about <>. +include::features/whats-next.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/caching.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/caching.adoc new file mode 100644 index 0000000000..382dea25f3 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/caching.adoc @@ -0,0 +1,272 @@ +[[features.caching]] +== Caching +The Spring Framework provides support for transparently adding caching to an application. +At its core, the abstraction applies caching to methods, thus reducing the number of executions based on the information available in the cache. +The caching logic is applied transparently, without any interference to the invoker. +Spring Boot auto-configures the cache infrastructure as long as caching support is enabled via the `@EnableCaching` annotation. + +NOTE: Check the {spring-framework-docs}/integration.html#cache[relevant section] of the Spring Framework reference for more details. + +In a nutshell, to add caching to an operation of your service add the relevant annotation to its method, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/caching/MathService.java[] +---- + +This example demonstrates the use of caching on a potentially costly operation. +Before invoking `computePiDecimal`, the abstraction looks for an entry in the `piDecimals` cache that matches the `i` argument. +If an entry is found, the content in the cache is immediately returned to the caller, and the method is not invoked. +Otherwise, the method is invoked, and the cache is updated before returning the value. + +CAUTION: You can also use the standard JSR-107 (JCache) annotations (such as `@CacheResult`) transparently. +However, we strongly advise you to not mix and match the Spring Cache and JCache annotations. + +If you do not add any specific cache library, Spring Boot auto-configures a <> that uses concurrent maps in memory. +When a cache is required (such as `piDecimals` in the preceding example), this provider creates it for you. +The simple provider is not really recommended for production usage, but it is great for getting started and making sure that you understand the features. +When you have made up your mind about the cache provider to use, please make sure to read its documentation to figure out how to configure the caches that your application uses. +Nearly all providers require you to explicitly configure every cache that you use in the application. +Some offer a way to customize the default caches defined by the configprop:spring.cache.cache-names[] property. + +TIP: It is also possible to transparently {spring-framework-docs}/integration.html#cache-annotations-put[update] or {spring-framework-docs}/integration.html#cache-annotations-evict[evict] data from the cache. + + + +[[features.caching.provider]] +=== Supported Cache Providers +The cache abstraction does not provide an actual store and relies on abstraction materialized by the `org.springframework.cache.Cache` and `org.springframework.cache.CacheManager` interfaces. + +If you have not defined a bean of type `CacheManager` or a `CacheResolver` named `cacheResolver` (see {spring-framework-api}/cache/annotation/CachingConfigurer.html[`CachingConfigurer`]), Spring Boot tries to detect the following providers (in the indicated order): + +. <> +. <> (EhCache 3, Hazelcast, Infinispan, and others) +. <> +. <> +. <> +. <> +. <> +. <> +. <> + +TIP: It is also possible to _force_ a particular cache provider by setting the configprop:spring.cache.type[] property. +Use this property if you need to <> in certain environment (such as tests). + +TIP: Use the `spring-boot-starter-cache` "`Starter`" to quickly add basic caching dependencies. +The starter brings in `spring-context-support`. +If you add dependencies manually, you must include `spring-context-support` in order to use the JCache, EhCache 2.x, or Caffeine support. + +If the `CacheManager` is auto-configured by Spring Boot, you can further tune its configuration before it is fully initialized by exposing a bean that implements the `CacheManagerCustomizer` interface. +The following example sets a flag to say that `null` values should be passed down to the underlying map: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/caching/CacheManagerCustomizerConfiguration.java[] +---- + +NOTE: In the preceding example, an auto-configured `ConcurrentMapCacheManager` is expected. +If that is not the case (either you provided your own config or a different cache provider was auto-configured), the customizer is not invoked at all. +You can have as many customizers as you want, and you can also order them by using `@Order` or `Ordered`. + + + +[[features.caching.provider.generic]] +==== Generic +Generic caching is used if the context defines _at least_ one `org.springframework.cache.Cache` bean. +A `CacheManager` wrapping all beans of that type is created. + + + +[[features.caching.provider.jcache]] +==== JCache (JSR-107) +https://jcp.org/en/jsr/detail?id=107[JCache] is bootstrapped through the presence of a `javax.cache.spi.CachingProvider` on the classpath (that is, a JSR-107 compliant caching library exists on the classpath), and the `JCacheCacheManager` is provided by the `spring-boot-starter-cache` "`Starter`". +Various compliant libraries are available, and Spring Boot provides dependency management for Ehcache 3, Hazelcast, and Infinispan. +Any other compliant library can be added as well. + +It might happen that more than one provider is present, in which case the provider must be explicitly specified. +Even if the JSR-107 standard does not enforce a standardized way to define the location of the configuration file, Spring Boot does its best to accommodate setting a cache with implementation details, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + # Only necessary if more than one provider is present + spring: + cache: + jcache: + provider: "com.acme.MyCachingProvider" + config: "classpath:acme.xml" +---- + +NOTE: When a cache library offers both a native implementation and JSR-107 support, Spring Boot prefers the JSR-107 support, so that the same features are available if you switch to a different JSR-107 implementation. + +TIP: Spring Boot has <>. +If a single `HazelcastInstance` is available, it is automatically reused for the `CacheManager` as well, unless the configprop:spring.cache.jcache.config[] property is specified. + +There are two ways to customize the underlying `javax.cache.cacheManager`: + +* Caches can be created on startup by setting the configprop:spring.cache.cache-names[] property. + If a custom `javax.cache.configuration.Configuration` bean is defined, it is used to customize them. +* `org.springframework.boot.autoconfigure.cache.JCacheManagerCustomizer` beans are invoked with the reference of the `CacheManager` for full customization. + +TIP: If a standard `javax.cache.CacheManager` bean is defined, it is wrapped automatically in an `org.springframework.cache.CacheManager` implementation that the abstraction expects. +No further customization is applied to it. + + + +[[features.caching.provider.ehcache2]] +==== EhCache 2.x +https://www.ehcache.org/[EhCache] 2.x is used if a file named `ehcache.xml` can be found at the root of the classpath. +If EhCache 2.x is found, the `EhCacheCacheManager` provided by the `spring-boot-starter-cache` "`Starter`" is used to bootstrap the cache manager. +An alternate configuration file can be provided as well, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + cache: + ehcache: + config: "classpath:config/another-config.xml" +---- + + + +[[features.caching.provider.hazelcast]] +==== Hazelcast +Spring Boot has <>. +If a `HazelcastInstance` has been auto-configured, it is automatically wrapped in a `CacheManager`. + + + +[[features.caching.provider.infinispan]] +==== Infinispan +https://infinispan.org/[Infinispan] has no default configuration file location, so it must be specified explicitly. +Otherwise, the default bootstrap is used. + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + cache: + infinispan: + config: "infinispan.xml" +---- + +Caches can be created on startup by setting the configprop:spring.cache.cache-names[] property. +If a custom `ConfigurationBuilder` bean is defined, it is used to customize the caches. + +NOTE: The support of Infinispan in Spring Boot is restricted to the embedded mode and is quite basic. +If you want more options, you should use the official Infinispan Spring Boot starter instead. +See https://github.com/infinispan/infinispan-spring-boot[Infinispan's documentation] for more details. + + + +[[features.caching.provider.couchbase]] +==== Couchbase +If Spring Data Couchbase is available and Couchbase is <>, a `CouchbaseCacheManager` is auto-configured. +It is possible to create additional caches on startup by setting the configprop:spring.cache.cache-names[] property and cache defaults can be configured by using `spring.cache.couchbase.*` properties. +For instance, the following configuration creates `cache1` and `cache2` caches with an entry _expiration_ of 10 minutes: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + cache: + cache-names: "cache1,cache2" + couchbase: + expiration: "10m" +---- + +If you need more control over the configuration, consider registering a `CouchbaseCacheManagerBuilderCustomizer` bean. +The following example shows a customizer that configures a specific entry expiration for `cache1` and `cache2`: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/nosql/CouchbaseCacheManagerConfiguration.java[] +---- + + + +[[features.caching.provider.redis]] +==== Redis +If https://redis.io/[Redis] is available and configured, a `RedisCacheManager` is auto-configured. +It is possible to create additional caches on startup by setting the configprop:spring.cache.cache-names[] property and cache defaults can be configured by using `spring.cache.redis.*` properties. +For instance, the following configuration creates `cache1` and `cache2` caches with a _time to live_ of 10 minutes: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + cache: + cache-names: "cache1,cache2" + redis: + time-to-live: "10m" +---- + +NOTE: By default, a key prefix is added so that, if two separate caches use the same key, Redis does not have overlapping keys and cannot return invalid values. +We strongly recommend keeping this setting enabled if you create your own `RedisCacheManager`. + +TIP: You can take full control of the default configuration by adding a `RedisCacheConfiguration` `@Bean` of your own. +This can be useful if you're looking for customizing the default serialization strategy. + +If you need more control over the configuration, consider registering a `RedisCacheManagerBuilderCustomizer` bean. +The following example shows a customizer that configures a specific time to live for `cache1` and `cache2`: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/nosql/RedisCacheManagerConfiguration.java[] +---- + + + +[[features.caching.provider.caffeine]] +==== Caffeine +https://github.com/ben-manes/caffeine[Caffeine] is a Java 8 rewrite of Guava's cache that supersedes support for Guava. +If Caffeine is present, a `CaffeineCacheManager` (provided by the `spring-boot-starter-cache` "`Starter`") is auto-configured. +Caches can be created on startup by setting the configprop:spring.cache.cache-names[] property and can be customized by one of the following (in the indicated order): + +. A cache spec defined by `spring.cache.caffeine.spec` +. A `com.github.benmanes.caffeine.cache.CaffeineSpec` bean is defined +. A `com.github.benmanes.caffeine.cache.Caffeine` bean is defined + +For instance, the following configuration creates `cache1` and `cache2` caches with a maximum size of 500 and a _time to live_ of 10 minutes + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + cache: + cache-names: "cache1,cache2" + caffeine: + spec: "maximumSize=500,expireAfterAccess=600s" +---- + +If a `com.github.benmanes.caffeine.cache.CacheLoader` bean is defined, it is automatically associated to the `CaffeineCacheManager`. +Since the `CacheLoader` is going to be associated with _all_ caches managed by the cache manager, it must be defined as `CacheLoader`. +The auto-configuration ignores any other generic type. + + + +[[features.caching.provider.simple]] +==== Simple +If none of the other providers can be found, a simple implementation using a `ConcurrentHashMap` as the cache store is configured. +This is the default if no caching library is present in your application. +By default, caches are created as needed, but you can restrict the list of available caches by setting the `cache-names` property. +For instance, if you want only `cache1` and `cache2` caches, set the `cache-names` property as follows: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + cache: + cache-names: "cache1,cache2" +---- + +If you do so and your application uses a cache not listed, then it fails at runtime when the cache is needed, but not on startup. +This is similar to the way the "real" cache providers behave if you use an undeclared cache. + + + +[[features.caching.provider.none]] +==== None +When `@EnableCaching` is present in your configuration, a suitable cache configuration is expected as well. +If you need to disable caching altogether in certain environments, force the cache type to `none` to use a no-op implementation, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + cache: + type: "none" +---- diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/container-images.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/container-images.adoc new file mode 100644 index 0000000000..1146b9b56a --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/container-images.adoc @@ -0,0 +1,138 @@ +[[features.container-images]] +== Container Images +It is easily possible to package a Spring Boot fat jar as a docker image. +However, there are various downsides to copying and running the fat jar as is in the docker image. +There’s always a certain amount of overhead when running a fat jar without unpacking it, and in a containerized environment this can be noticeable. +The other issue is that putting your application's code and all its dependencies in one layer in the Docker image is sub-optimal. +Since you probably recompile your code more often than you upgrade the version of Spring Boot you use, it’s often better to separate things a bit more. +If you put jar files in the layer before your application classes, Docker often only needs to change the very bottom layer and can pick others up from its cache. + + + +[[features.container-images.layering]] +=== Layering Docker Images +To make it easier to create optimized Docker images, Spring Boot supports adding a layer index file to the jar. +It provides a list of layers and the parts of the jar that should be contained within them. +The list of layers in the index is ordered based on the order in which the layers should be added to the Docker/OCI image. +Out-of-the-box, the following layers are supported: + +* `dependencies` (for regular released dependencies) +* `spring-boot-loader` (for everything under `org/springframework/boot/loader`) +* `snapshot-dependencies` (for snapshot dependencies) +* `application` (for application classes and resources) + +The following shows an example of a `layers.idx` file: + +[source,yaml,indent=0] +---- + - "dependencies": + - BOOT-INF/lib/library1.jar + - BOOT-INF/lib/library2.jar + - "spring-boot-loader": + - org/springframework/boot/loader/JarLauncher.class + - org/springframework/boot/loader/jar/JarEntry.class + - "snapshot-dependencies": + - BOOT-INF/lib/library3-SNAPSHOT.jar + - "application": + - META-INF/MANIFEST.MF + - BOOT-INF/classes/a/b/C.class +---- + +This layering is designed to separate code based on how likely it is to change between application builds. +Library code is less likely to change between builds, so it is placed in its own layers to allow tooling to re-use the layers from cache. +Application code is more likely to change between builds so it is isolated in a separate layer. + +Spring Boot also supports layering for war files with the help of a `layers.idx`. + +For Maven, refer to the {spring-boot-maven-plugin-docs}#repackage-layers[packaging layered jar or war section] for more details on adding a layer index to the archive. +For Gradle, refer to the {spring-boot-gradle-plugin-docs}#packaging-layered-archives[packaging layered jar or war section] of the Gradle plugin documentation. + + + +[[features.container-images.building]] +=== Building Container Images +Spring Boot applications can be containerized <>, or by <>. + + + +[[features.container-images.building.dockerfiles]] +==== Dockerfiles +While it is possible to convert a Spring Boot fat jar into a docker image with just a few lines in the Dockerfile, we will use the <> to create an optimized docker image. +When you create a jar containing the layers index file, the `spring-boot-jarmode-layertools` jar will be added as a dependency to your jar. +With this jar on the classpath, you can launch your application in a special mode which allows the bootstrap code to run something entirely different from your application, for example, something that extracts the layers. + +CAUTION: The `layertools` mode can not be used with a <> that includes a launch script. +Disable launch script configuration when building a jar file that is intended to be used with `layertools`. + +Here’s how you can launch your jar with a `layertools` jar mode: + +---- +$ java -Djarmode=layertools -jar my-app.jar +---- + +This will provide the following output: + +---- +Usage: + java -Djarmode=layertools -jar my-app.jar + +Available commands: + list List layers from the jar that can be extracted + extract Extracts layers from the jar for image creation + help Help about any command +---- + +The `extract` command can be used to easily split the application into layers to be added to the dockerfile. +Here's an example of a Dockerfile using `jarmode`. + +---- +FROM adoptopenjdk:11-jre-hotspot as builder +WORKDIR application +ARG JAR_FILE=target/*.jar +COPY ${JAR_FILE} application.jar +RUN java -Djarmode=layertools -jar application.jar extract + +FROM adoptopenjdk:11-jre-hotspot +WORKDIR application +COPY --from=builder application/dependencies/ ./ +COPY --from=builder application/spring-boot-loader/ ./ +COPY --from=builder application/snapshot-dependencies/ ./ +COPY --from=builder application/application/ ./ +ENTRYPOINT ["java", "org.springframework.boot.loader.JarLauncher"] +---- + +Assuming the above `Dockerfile` is in the current directory, your docker image can be built with `docker build .`, or optionally specifying the path to your application jar, as shown in the following example: + +[indent=0] +---- + docker build --build-arg JAR_FILE=path/to/myapp.jar . +---- + +This is a multi-stage dockerfile. +The builder stage extracts the directories that are needed later. +Each of the `COPY` commands relates to the layers extracted by the jarmode. + +Of course, a Dockerfile can be written without using the jarmode. +You can use some combination of `unzip` and `mv` to move things to the right layer but jarmode simplifies that. + + + +[[features.container-images.building.buildpacks]] +==== Cloud Native Buildpacks +Dockerfiles are just one way to build docker images. +Another way to build docker images is directly from your Maven or Gradle plugin, using buildpacks. +If you’ve ever used an application platform such as Cloud Foundry or Heroku then you’ve probably used a buildpack. +Buildpacks are the part of the platform that takes your application and converts it into something that the platform can actually run. +For example, Cloud Foundry’s Java buildpack will notice that you’re pushing a `.jar` file and automatically add a relevant JRE. + +With Cloud Native Buildpacks, you can create Docker compatible images that you can run anywhere. +Spring Boot includes buildpack support directly for both Maven and Gradle. +This means you can just type a single command and quickly get a sensible image into your locally running Docker daemon. + +Refer to the individual plugin documentation on how to use buildpacks with {spring-boot-maven-plugin-docs}#build-image[Maven] and {spring-boot-gradle-plugin-docs}#build-image[Gradle]. + +NOTE: The https://github.com/paketo-buildpacks/spring-boot[Paketo Spring Boot buildpack] has also been updated to support the `layers.idx` file so any customization that is applied to it will be reflected in the image created by the buildpack. + +NOTE: In order to achieve reproducible builds and container image caching, Buildpacks can manipulate the application resources metadata (such as the file "last modified" information). +You should ensure that your application does not rely on that metadata at runtime. +Spring Boot can use that information when serving static resources, but this can be disabled with configprop:spring.web.resources.cache.use-last-modified[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/developing-auto-configuration.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/developing-auto-configuration.adoc new file mode 100644 index 0000000000..2ff0f0e16f --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/developing-auto-configuration.adoc @@ -0,0 +1,350 @@ +[[features.developing-auto-configuration]] +== Creating Your Own Auto-configuration +If you work in a company that develops shared libraries, or if you work on an open-source or commercial library, you might want to develop your own auto-configuration. +Auto-configuration classes can be bundled in external jars and still be picked-up by Spring Boot. + +Auto-configuration can be associated to a "`starter`" that provides the auto-configuration code as well as the typical libraries that you would use with it. +We first cover what you need to know to build your own auto-configuration and then we move on to the <>. + +TIP: A https://github.com/snicoll-demos/spring-boot-master-auto-configuration[demo project] is available to showcase how you can create a starter step-by-step. + + + +[[features.developing-auto-configuration.understanding-auto-configured-beans]] +=== Understanding Auto-configured Beans +Under the hood, auto-configuration is implemented with standard `@Configuration` classes. +Additional `@Conditional` annotations are used to constrain when the auto-configuration should apply. +Usually, auto-configuration classes use `@ConditionalOnClass` and `@ConditionalOnMissingBean` annotations. +This ensures that auto-configuration applies only when relevant classes are found and when you have not declared your own `@Configuration`. + +You can browse the source code of {spring-boot-autoconfigure-module-code}[`spring-boot-autoconfigure`] to see the `@Configuration` classes that Spring provides (see the {spring-boot-code}/spring-boot-project/spring-boot-autoconfigure/src/main/resources/META-INF/spring.factories[`META-INF/spring.factories`] file). + + + +[[features.developing-auto-configuration.locating-auto-configuration-candidates]] +=== Locating Auto-configuration Candidates +Spring Boot checks for the presence of a `META-INF/spring.factories` file within your published jar. +The file should list your configuration classes under the `EnableAutoConfiguration` key, as shown in the following example: + +[indent=0] +---- + org.springframework.boot.autoconfigure.EnableAutoConfiguration=\ + com.mycorp.libx.autoconfigure.LibXAutoConfiguration,\ + com.mycorp.libx.autoconfigure.LibXWebAutoConfiguration +---- + +NOTE: Auto-configurations must be loaded that way _only_. +Make sure that they are defined in a specific package space and that they are never the target of component scanning. +Furthermore, auto-configuration classes should not enable component scanning to find additional components. +Specific ``@Import``s should be used instead. + +You can use the {spring-boot-autoconfigure-module-code}/AutoConfigureAfter.java[`@AutoConfigureAfter`] or {spring-boot-autoconfigure-module-code}/AutoConfigureBefore.java[`@AutoConfigureBefore`] annotations if your configuration needs to be applied in a specific order. +For example, if you provide web-specific configuration, your class may need to be applied after `WebMvcAutoConfiguration`. + +If you want to order certain auto-configurations that should not have any direct knowledge of each other, you can also use `@AutoConfigureOrder`. +That annotation has the same semantic as the regular `@Order` annotation but provides a dedicated order for auto-configuration classes. + +As with standard `@Configuration` classes, the order in which auto-configuration classes are applied only affects the order in which their beans are defined. +The order in which those beans are subsequently created is unaffected and is determined by each bean's dependencies and any `@DependsOn` relationships. + + + +[[features.developing-auto-configuration.condition-annotations]] +=== Condition Annotations +You almost always want to include one or more `@Conditional` annotations on your auto-configuration class. +The `@ConditionalOnMissingBean` annotation is one common example that is used to allow developers to override auto-configuration if they are not happy with your defaults. + +Spring Boot includes a number of `@Conditional` annotations that you can reuse in your own code by annotating `@Configuration` classes or individual `@Bean` methods. +These annotations include: + +* <> +* <> +* <> +* <> +* <> +* <> + + + +[[features.developing-auto-configuration.condition-annotations.class-conditions]] +==== Class Conditions +The `@ConditionalOnClass` and `@ConditionalOnMissingClass` annotations let `@Configuration` classes be included based on the presence or absence of specific classes. +Due to the fact that annotation metadata is parsed by using https://asm.ow2.io/[ASM], you can use the `value` attribute to refer to the real class, even though that class might not actually appear on the running application classpath. +You can also use the `name` attribute if you prefer to specify the class name by using a `String` value. + +This mechanism does not apply the same way to `@Bean` methods where typically the return type is the target of the condition: before the condition on the method applies, the JVM will have loaded the class and potentially processed method references which will fail if the class is not present. + +To handle this scenario, a separate `@Configuration` class can be used to isolate the condition, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/creatingautoconfiguration/classconditions/MyAutoConfiguration.java[] +---- + +TIP: If you use `@ConditionalOnClass` or `@ConditionalOnMissingClass` as a part of a meta-annotation to compose your own composed annotations, you must use `name` as referring to the class in such a case is not handled. + + + +[[features.developing-auto-configuration.condition-annotations.bean-conditions]] +==== Bean Conditions +The `@ConditionalOnBean` and `@ConditionalOnMissingBean` annotations let a bean be included based on the presence or absence of specific beans. +You can use the `value` attribute to specify beans by type or `name` to specify beans by name. +The `search` attribute lets you limit the `ApplicationContext` hierarchy that should be considered when searching for beans. + +When placed on a `@Bean` method, the target type defaults to the return type of the method, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/creatingautoconfiguration/beanconditions/MyAutoConfiguration.java[] +---- + +In the preceding example, the `myService` bean is going to be created if no bean of type `MyService` is already contained in the `ApplicationContext`. + +TIP: You need to be very careful about the order in which bean definitions are added, as these conditions are evaluated based on what has been processed so far. +For this reason, we recommend using only `@ConditionalOnBean` and `@ConditionalOnMissingBean` annotations on auto-configuration classes (since these are guaranteed to load after any user-defined bean definitions have been added). + +NOTE: `@ConditionalOnBean` and `@ConditionalOnMissingBean` do not prevent `@Configuration` classes from being created. +The only difference between using these conditions at the class level and marking each contained `@Bean` method with the annotation is that the former prevents registration of the `@Configuration` class as a bean if the condition does not match. + +TIP: When declaring a `@Bean` method, provide as much type information as possible in the method's return type. +For example, if your bean's concrete class implements an interface the bean method's return type should be the concrete class and not the interface. +Providing as much type information as possible in `@Bean` methods is particularly important when using bean conditions as their evaluation can only rely upon to type information that's available in the method signature. + + + +[[features.developing-auto-configuration.condition-annotations.property-conditions]] +==== Property Conditions +The `@ConditionalOnProperty` annotation lets configuration be included based on a Spring Environment property. +Use the `prefix` and `name` attributes to specify the property that should be checked. +By default, any property that exists and is not equal to `false` is matched. +You can also create more advanced checks by using the `havingValue` and `matchIfMissing` attributes. + + + +[[features.developing-auto-configuration.condition-annotations.resource-conditions]] +==== Resource Conditions +The `@ConditionalOnResource` annotation lets configuration be included only when a specific resource is present. +Resources can be specified by using the usual Spring conventions, as shown in the following example: `file:/home/user/test.dat`. + + + +[[features.developing-auto-configuration.condition-annotations.web-application-conditions]] +==== Web Application Conditions +The `@ConditionalOnWebApplication` and `@ConditionalOnNotWebApplication` annotations let configuration be included depending on whether the application is a "`web application`". +A servlet-based web application is any application that uses a Spring `WebApplicationContext`, defines a `session` scope, or has a `ConfigurableWebEnvironment`. +A reactive web application is any application that uses a `ReactiveWebApplicationContext`, or has a `ConfigurableReactiveWebEnvironment`. + +The `@ConditionalOnWarDeployment` annotation lets configuration be included depending on whether the application is a traditional WAR application that is deployed to a container. +This condition will not match for applications that are run with an embedded server. + + + +[[features.developing-auto-configuration.condition-annotations.spel-conditions]] +==== SpEL Expression Conditions +The `@ConditionalOnExpression` annotation lets configuration be included based on the result of a {spring-framework-docs}/core.html#expressions[SpEL expression]. + + + +[[features.developing-auto-configuration.testing]] +=== Testing your Auto-configuration +An auto-configuration can be affected by many factors: user configuration (`@Bean` definition and `Environment` customization), condition evaluation (presence of a particular library), and others. +Concretely, each test should create a well defined `ApplicationContext` that represents a combination of those customizations. +`ApplicationContextRunner` provides a great way to achieve that. + +`ApplicationContextRunner` is usually defined as a field of the test class to gather the base, common configuration. +The following example makes sure that `UserServiceAutoConfiguration` is always invoked: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/UserServiceAutoConfigurationTests.java[tag=runner] +---- + +TIP: If multiple auto-configurations have to be defined, there is no need to order their declarations as they are invoked in the exact same order as when running the application. + +Each test can use the runner to represent a particular use case. +For instance, the sample below invokes a user configuration (`UserConfiguration`) and checks that the auto-configuration backs off properly. +Invoking `run` provides a callback context that can be used with `AssertJ`. + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/UserServiceAutoConfigurationTests.java[tag=test-user-config] +---- + +It is also possible to easily customize the `Environment`, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/UserServiceAutoConfigurationTests.java[tag=test-env] +---- + +The runner can also be used to display the `ConditionEvaluationReport`. +The report can be printed at `INFO` or `DEBUG` level. +The following example shows how to use the `ConditionEvaluationReportLoggingListener` to print the report in auto-configuration tests. + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/ConditionEvaluationReportTests.java[tag=*] +---- + + + +[[features.developing-auto-configuration.testing.simulating-a-web-context]] +==== Simulating a Web Context +If you need to test an auto-configuration that only operates in a Servlet or Reactive web application context, use the `WebApplicationContextRunner` or `ReactiveWebApplicationContextRunner` respectively. + + + +[[features.developing-auto-configuration.testing.overriding-classpath]] +==== Overriding the Classpath +It is also possible to test what happens when a particular class and/or package is not present at runtime. +Spring Boot ships with a `FilteredClassLoader` that can easily be used by the runner. +In the following example, we assert that if `UserService` is not present, the auto-configuration is properly disabled: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/UserServiceAutoConfigurationTests.java[tag=test-classloader] +---- + + + +[[features.developing-auto-configuration.custom-starter]] +=== Creating Your Own Starter +A typical Spring Boot starter contains code to auto-configure and customize the infrastructure of a given technology, let's call that "acme". +To make it easily extensible, a number of configuration keys in a dedicated namespace can be exposed to the environment. +Finally, a single "starter" dependency is provided to help users get started as easily as possible. + +Concretely, a custom starter can contain the following: + +* The `autoconfigure` module that contains the auto-configuration code for "acme". +* The `starter` module that provides a dependency to the `autoconfigure` module as well as "acme" and any additional dependencies that are typically useful. +In a nutshell, adding the starter should provide everything needed to start using that library. + +This separation in two modules is in no way necessary. +If "acme" has several flavours, options or optional features, then it is better to separate the auto-configuration as you can clearly express the fact some features are optional. +Besides, you have the ability to craft a starter that provides an opinion about those optional dependencies. +At the same time, others can rely only on the `autoconfigure` module and craft their own starter with different opinions. + +If the auto-configuration is relatively straightforward and does not have optional feature, merging the two modules in the starter is definitely an option. + + + +[[features.developing-auto-configuration.custom-starter.naming]] +==== Naming +You should make sure to provide a proper namespace for your starter. +Do not start your module names with `spring-boot`, even if you use a different Maven `groupId`. +We may offer official support for the thing you auto-configure in the future. + +As a rule of thumb, you should name a combined module after the starter. +For example, assume that you are creating a starter for "acme" and that you name the auto-configure module `acme-spring-boot` and the starter `acme-spring-boot-starter`. +If you only have one module that combines the two, name it `acme-spring-boot-starter`. + + + +[[features.developing-auto-configuration.custom-starter.configuration-keys]] +==== Configuration keys +If your starter provides configuration keys, use a unique namespace for them. +In particular, do not include your keys in the namespaces that Spring Boot uses (such as `server`, `management`, `spring`, and so on). +If you use the same namespace, we may modify these namespaces in the future in ways that break your modules. +As a rule of thumb, prefix all your keys with a namespace that you own (e.g. `acme`). + +Make sure that configuration keys are documented by adding field javadoc for each property, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/creatingautoconfiguration/configurationkeys/AcmeProperties.java[] +---- + +NOTE: You should only use plain text with `@ConfigurationProperties` field Javadoc, since they are not processed before being added to the JSON. + +Here are some rules we follow internally to make sure descriptions are consistent: + +* Do not start the description by "The" or "A". +* For `boolean` types, start the description with "Whether" or "Enable". +* For collection-based types, start the description with "Comma-separated list" +* Use `java.time.Duration` rather than `long` and describe the default unit if it differs from milliseconds, e.g. "If a duration suffix is not specified, seconds will be used". +* Do not provide the default value in the description unless it has to be determined at runtime. + +Make sure to <> so that IDE assistance is available for your keys as well. +You may want to review the generated metadata (`META-INF/spring-configuration-metadata.json`) to make sure your keys are properly documented. +Using your own starter in a compatible IDE is also a good idea to validate that quality of the metadata. + + + +[[features.developing-auto-configuration.custom-starter.autoconfigure-module]] +==== The "`autoconfigure`" Module +The `autoconfigure` module contains everything that is necessary to get started with the library. +It may also contain configuration key definitions (such as `@ConfigurationProperties`) and any callback interface that can be used to further customize how the components are initialized. + +TIP: You should mark the dependencies to the library as optional so that you can include the `autoconfigure` module in your projects more easily. +If you do it that way, the library is not provided and, by default, Spring Boot backs off. + +Spring Boot uses an annotation processor to collect the conditions on auto-configurations in a metadata file (`META-INF/spring-autoconfigure-metadata.properties`). +If that file is present, it is used to eagerly filter auto-configurations that do not match, which will improve startup time. +It is recommended to add the following dependency in a module that contains auto-configurations: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + org.springframework.boot + spring-boot-autoconfigure-processor + true + +---- + +If you have defined auto-configurations directly in your application, make sure to configure the `spring-boot-maven-plugin` to prevent the `repackage` goal from adding the dependency into the fat jar: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + + + + org.springframework.boot + spring-boot-maven-plugin + + + + org.springframework.boot + spring-boot-autoconfigure-processor + + + + + + + +---- + +With Gradle 4.5 and earlier, the dependency should be declared in the `compileOnly` configuration, as shown in the following example: + +[source,groovy,indent=0,subs="verbatim,quotes,attributes"] +---- + dependencies { + compileOnly "org.springframework.boot:spring-boot-autoconfigure-processor" + } +---- + +With Gradle 4.6 and later, the dependency should be declared in the `annotationProcessor` configuration, as shown in the following example: + +[source,groovy,indent=0,subs="verbatim,quotes,attributes"] +---- + dependencies { + annotationProcessor "org.springframework.boot:spring-boot-autoconfigure-processor" + } +---- + + + +[[features.developing-auto-configuration.custom-starter.starter-module]] +==== Starter Module +The starter is really an empty jar. +Its only purpose is to provide the necessary dependencies to work with the library. +You can think of it as an opinionated view of what is required to get started. + +Do not make assumptions about the project in which your starter is added. +If the library you are auto-configuring typically requires other starters, mention them as well. +Providing a proper set of _default_ dependencies may be hard if the number of optional dependencies is high, as you should avoid including dependencies that are unnecessary for a typical usage of the library. +In other words, you should not include optional dependencies. + +NOTE: Either way, your starter must reference the core Spring Boot starter (`spring-boot-starter`) directly or indirectly (i.e. no need to add it if your starter relies on another starter). +If a project is created with only your custom starter, Spring Boot's core features will be honoured by the presence of the core starter. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/developing-web-applications.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/developing-web-applications.adoc new file mode 100644 index 0000000000..37531be01f --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/developing-web-applications.adoc @@ -0,0 +1,891 @@ +[[features.developing-web-applications]] +== Developing Web Applications +Spring Boot is well suited for web application development. +You can create a self-contained HTTP server by using embedded Tomcat, Jetty, Undertow, or Netty. +Most web applications use the `spring-boot-starter-web` module to get up and running quickly. +You can also choose to build reactive web applications by using the `spring-boot-starter-webflux` module. + +If you have not yet developed a Spring Boot web application, you can follow the "Hello World!" example in the _<>_ section. + + + +[[features.developing-web-applications.spring-mvc]] +=== The "`Spring Web MVC Framework`" +The {spring-framework-docs}/web.html#mvc[Spring Web MVC framework] (often referred to as "`Spring MVC`") is a rich "`model view controller`" web framework. +Spring MVC lets you create special `@Controller` or `@RestController` beans to handle incoming HTTP requests. +Methods in your controller are mapped to HTTP by using `@RequestMapping` annotations. + +The following code shows a typical `@RestController` that serves JSON data: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/webapplications/servlet/MyRestController.java[] +---- + +Spring MVC is part of the core Spring Framework, and detailed information is available in the {spring-framework-docs}/web.html#mvc[reference documentation]. +There are also several guides that cover Spring MVC available at https://spring.io/guides. + + + +[[features.developing-web-applications.spring-mvc.auto-configuration]] +==== Spring MVC Auto-configuration +Spring Boot provides auto-configuration for Spring MVC that works well with most applications. + +The auto-configuration adds the following features on top of Spring's defaults: + +* Inclusion of `ContentNegotiatingViewResolver` and `BeanNameViewResolver` beans. +* Support for serving static resources, including support for WebJars (covered <>)). +* Automatic registration of `Converter`, `GenericConverter`, and `Formatter` beans. +* Support for `HttpMessageConverters` (covered <>). +* Automatic registration of `MessageCodesResolver` (covered <>). +* Static `index.html` support. +* Automatic use of a `ConfigurableWebBindingInitializer` bean (covered <>). + +If you want to keep those Spring Boot MVC customizations and make more {spring-framework-docs}/web.html#mvc[MVC customizations] (interceptors, formatters, view controllers, and other features), you can add your own `@Configuration` class of type `WebMvcConfigurer` but *without* `@EnableWebMvc`. + +If you want to provide custom instances of `RequestMappingHandlerMapping`, `RequestMappingHandlerAdapter`, or `ExceptionHandlerExceptionResolver`, and still keep the Spring Boot MVC customizations, you can declare a bean of type `WebMvcRegistrations` and use it to provide custom instances of those components. + +If you want to take complete control of Spring MVC, you can add your own `@Configuration` annotated with `@EnableWebMvc`, or alternatively add your own `@Configuration`-annotated `DelegatingWebMvcConfiguration` as described in the Javadoc of `@EnableWebMvc`. + +[NOTE] +==== +Spring MVC uses a different `ConversionService` to the one used to convert values from your `application.properties` or `application.yaml` file. +It means that `Period`, `Duration` and `DataSize` converters are not available and that `@DurationUnit` and `@DataSizeUnit` annotations will be ignored. + +If you want to customize the `ConversionService` used by Spring MVC, you can provide a `WebMvcConfigurer` bean with an `addFormatters` method. +From this method you can register any converter that you like, or you can delegate to the static methods available on `ApplicationConversionService`. +==== + + + +[[features.developing-web-applications.spring-mvc.message-converters]] +==== HttpMessageConverters +Spring MVC uses the `HttpMessageConverter` interface to convert HTTP requests and responses. +Sensible defaults are included out of the box. +For example, objects can be automatically converted to JSON (by using the Jackson library) or XML (by using the Jackson XML extension, if available, or by using JAXB if the Jackson XML extension is not available). +By default, strings are encoded in `UTF-8`. + +If you need to add or customize converters, you can use Spring Boot's `HttpMessageConverters` class, as shown in the following listing: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/webapplications/HttpMessageConvertersConfiguration.java[] +---- + +Any `HttpMessageConverter` bean that is present in the context is added to the list of converters. +You can also override default converters in the same way. + + + +[[features.developing-web-applications.spring-mvc.json]] +==== Custom JSON Serializers and Deserializers +If you use Jackson to serialize and deserialize JSON data, you might want to write your own `JsonSerializer` and `JsonDeserializer` classes. +Custom serializers are usually https://github.com/FasterXML/jackson-docs/wiki/JacksonHowToCustomSerializers[registered with Jackson through a module], but Spring Boot provides an alternative `@JsonComponent` annotation that makes it easier to directly register Spring Beans. + +You can use the `@JsonComponent` annotation directly on `JsonSerializer`, `JsonDeserializer` or `KeyDeserializer` implementations. +You can also use it on classes that contain serializers/deserializers as inner classes, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/webapplications/json/MyJsonComponent.java[] +---- + +All `@JsonComponent` beans in the `ApplicationContext` are automatically registered with Jackson. +Because `@JsonComponent` is meta-annotated with `@Component`, the usual component-scanning rules apply. + +Spring Boot also provides {spring-boot-module-code}/jackson/JsonObjectSerializer.java[`JsonObjectSerializer`] and {spring-boot-module-code}/jackson/JsonObjectDeserializer.java[`JsonObjectDeserializer`] base classes that provide useful alternatives to the standard Jackson versions when serializing objects. +See {spring-boot-module-api}/jackson/JsonObjectSerializer.html[`JsonObjectSerializer`] and {spring-boot-module-api}/jackson/JsonObjectDeserializer.html[`JsonObjectDeserializer`] in the Javadoc for details. + +The example above can be rewritten to use `JsonObjectSerializer`/`JsonObjectDeserializer` as follows: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/webapplications/json/object/MyJsonComponent.java[] +---- + + + +[[features.developing-web-applications.spring-mvc.message-codes]] +==== MessageCodesResolver +Spring MVC has a strategy for generating error codes for rendering error messages from binding errors: `MessageCodesResolver`. +If you set the configprop:spring.mvc.message-codes-resolver-format[] property `PREFIX_ERROR_CODE` or `POSTFIX_ERROR_CODE`, Spring Boot creates one for you (see the enumeration in {spring-framework-api}/validation/DefaultMessageCodesResolver.Format.html[`DefaultMessageCodesResolver.Format`]). + + + +[[features.developing-web-applications.spring-mvc.static-content]] +==== Static Content +By default, Spring Boot serves static content from a directory called `/static` (or `/public` or `/resources` or `/META-INF/resources`) in the classpath or from the root of the `ServletContext`. +It uses the `ResourceHttpRequestHandler` from Spring MVC so that you can modify that behavior by adding your own `WebMvcConfigurer` and overriding the `addResourceHandlers` method. + +In a stand-alone web application, the default servlet from the container is also enabled and acts as a fallback, serving content from the root of the `ServletContext` if Spring decides not to handle it. +Most of the time, this does not happen (unless you modify the default MVC configuration), because Spring can always handle requests through the `DispatcherServlet`. + +By default, resources are mapped on `+/**+`, but you can tune that with the configprop:spring.mvc.static-path-pattern[] property. +For instance, relocating all resources to `/resources/**` can be achieved as follows: + +[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] +---- + spring: + mvc: + static-path-pattern: "/resources/**" +---- + +You can also customize the static resource locations by using the configprop:spring.web.resources.static-locations[] property (replacing the default values with a list of directory locations). +The root Servlet context path, `"/"`, is automatically added as a location as well. + +In addition to the "`standard`" static resource locations mentioned earlier, a special case is made for https://www.webjars.org/[Webjars content]. +Any resources with a path in `+/webjars/**+` are served from jar files if they are packaged in the Webjars format. + +TIP: Do not use the `src/main/webapp` directory if your application is packaged as a jar. +Although this directory is a common standard, it works *only* with war packaging, and it is silently ignored by most build tools if you generate a jar. + +Spring Boot also supports the advanced resource handling features provided by Spring MVC, allowing use cases such as cache-busting static resources or using version agnostic URLs for Webjars. + +To use version agnostic URLs for Webjars, add the `webjars-locator-core` dependency. +Then declare your Webjar. +Using jQuery as an example, adding `"/webjars/jquery/jquery.min.js"` results in `"/webjars/jquery/x.y.z/jquery.min.js"` where `x.y.z` is the Webjar version. + +NOTE: If you use JBoss, you need to declare the `webjars-locator-jboss-vfs` dependency instead of the `webjars-locator-core`. +Otherwise, all Webjars resolve as a `404`. + +To use cache busting, the following configuration configures a cache busting solution for all static resources, effectively adding a content hash, such as ``, in URLs: + +[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] +---- + spring: + web: + resources: + chain: + strategy: + content: + enabled: true + paths: "/**" +---- + +NOTE: Links to resources are rewritten in templates at runtime, thanks to a `ResourceUrlEncodingFilter` that is auto-configured for Thymeleaf and FreeMarker. +You should manually declare this filter when using JSPs. +Other template engines are currently not automatically supported but can be with custom template macros/helpers and the use of the {spring-framework-api}/web/servlet/resource/ResourceUrlProvider.html[`ResourceUrlProvider`]. + +When loading resources dynamically with, for example, a JavaScript module loader, renaming files is not an option. +That is why other strategies are also supported and can be combined. +A "fixed" strategy adds a static version string in the URL without changing the file name, as shown in the following example: + +[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] +---- + spring: + web: + resources: + chain: + strategy: + content: + enabled: true + paths: "/**" + fixed: + enabled: true + paths: "/js/lib/" + version: "v12" +---- + +With this configuration, JavaScript modules located under `"/js/lib/"` use a fixed versioning strategy (`"/v12/js/lib/mymodule.js"`), while other resources still use the content one (``). + +See {spring-boot-autoconfigure-module-code}/web/ResourceProperties.java[`ResourceProperties`] for more supported options. + +[TIP] +==== +This feature has been thoroughly described in a dedicated https://spring.io/blog/2014/07/24/spring-framework-4-1-handling-static-web-resources[blog post] and in Spring Framework's {spring-framework-docs}/web.html#mvc-config-static-resources[reference documentation]. +==== + + + +[[features.developing-web-applications.spring-mvc.welcome-page]] +==== Welcome Page +Spring Boot supports both static and templated welcome pages. +It first looks for an `index.html` file in the configured static content locations. +If one is not found, it then looks for an `index` template. +If either is found, it is automatically used as the welcome page of the application. + + + +[[features.developing-web-applications.spring-mvc.content-negotiation]] +==== Path Matching and Content Negotiation +Spring MVC can map incoming HTTP requests to handlers by looking at the request path and matching it to the mappings defined in your application (for example, `@GetMapping` annotations on Controller methods). + +Spring Boot chooses to disable suffix pattern matching by default, which means that requests like `"GET /projects/spring-boot.json"` won't be matched to `@GetMapping("/projects/spring-boot")` mappings. +This is considered as a {spring-framework-docs}/web.html#mvc-ann-requestmapping-suffix-pattern-match[best practice for Spring MVC applications]. +This feature was mainly useful in the past for HTTP clients which did not send proper "Accept" request headers; we needed to make sure to send the correct Content Type to the client. +Nowadays, Content Negotiation is much more reliable. + +There are other ways to deal with HTTP clients that don't consistently send proper "Accept" request headers. +Instead of using suffix matching, we can use a query parameter to ensure that requests like `"GET /projects/spring-boot?format=json"` will be mapped to `@GetMapping("/projects/spring-boot")`: + +[source,yaml,indent=0,subs="verbatim,quotes,attributes",configblocks] +---- + spring: + mvc: + contentnegotiation: + favor-parameter: true +---- + +Or if you prefer to use a different parameter name: + +[source,properties,indent=0,subs="verbatim,quotes,attributes"] +---- + spring: + mvc: + contentnegotiation: + favor-parameter: true + parameter-name: "myparam" +---- + +Most standard media types are supported out-of-the-box, but you can also define new ones: + +[source,yaml,indent=0,subs="verbatim,quotes,attributes",configblocks] +---- + spring: + mvc: + contentnegotiation: + media-types: + markdown: "text/markdown" +---- + + + +Suffix pattern matching is deprecated and will be removed in a future release. +If you understand the caveats and would still like your application to use suffix pattern matching, the following configuration is required: + +[source,yaml,indent=0,subs="verbatim,quotes,attributes",configblocks] +---- + spring: + mvc: + contentnegotiation: + favor-path-extension: true + pathmatch: + use-suffix-pattern: true +---- + +Alternatively, rather than open all suffix patterns, it's more secure to only support registered suffix patterns: + +[source,yaml,indent=0,subs="verbatim,quotes,attributes",configblocks] +---- + spring: + mvc: + contentnegotiation: + favor-path-extension: true + pathmatch: + use-registered-suffix-pattern: true +---- + +As of Spring Framework 5.3, Spring MVC supports several implementation strategies for matching request paths to Controller handlers. +It was previously only supporting the `AntPathMatcher` strategy, but it now also offers `PathPatternParser`. +Spring Boot now provides a configuration property to choose and opt in the new strategy: + +[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] +---- + spring: + mvc: + pathmatch: + matching-strategy: "path-pattern-parser" +---- + +For more details on why you should consider this new implementation, please check out the +https://spring.io/blog/2020/06/30/url-matching-with-pathpattern-in-spring-mvc[dedicated blog post]. + +NOTE: `PathPatternParser` is an optimized implementation but restricts usage of +{spring-framework-docs}/web.html#mvc-ann-requestmapping-uri-templates[some path patterns variants] +and is incompatible with suffix pattern matching (configprop:spring.mvc.pathmatch.use-suffix-pattern[deprecated], +configprop:spring.mvc.pathmatch.use-registered-suffix-pattern[deprecated]) or mapping the `DispatcherServlet` +with a Servlet prefix (configprop:spring.mvc.servlet.path[]). + + + +[[features.developing-web-applications.spring-mvc.binding-initializer]] +==== ConfigurableWebBindingInitializer +Spring MVC uses a `WebBindingInitializer` to initialize a `WebDataBinder` for a particular request. +If you create your own `ConfigurableWebBindingInitializer` `@Bean`, Spring Boot automatically configures Spring MVC to use it. + + + +[[features.developing-web-applications.spring-mvc.template-engines]] +==== Template Engines +As well as REST web services, you can also use Spring MVC to serve dynamic HTML content. +Spring MVC supports a variety of templating technologies, including Thymeleaf, FreeMarker, and JSPs. +Also, many other templating engines include their own Spring MVC integrations. + +Spring Boot includes auto-configuration support for the following templating engines: + + * https://freemarker.apache.org/docs/[FreeMarker] + * https://docs.groovy-lang.org/docs/next/html/documentation/template-engines.html#_the_markuptemplateengine[Groovy] + * https://www.thymeleaf.org[Thymeleaf] + * https://mustache.github.io/[Mustache] + +TIP: If possible, JSPs should be avoided. +There are several <> when using them with embedded servlet containers. + +When you use one of these templating engines with the default configuration, your templates are picked up automatically from `src/main/resources/templates`. + +TIP: Depending on how you run your application, your IDE may order the classpath differently. +Running your application in the IDE from its main method results in a different ordering than when you run your application by using Maven or Gradle or from its packaged jar. +This can cause Spring Boot to fail to find the expected template. +If you have this problem, you can reorder the classpath in the IDE to place the module's classes and resources first. + + + +[[features.developing-web-applications.spring-mvc.error-handling]] +==== Error Handling +By default, Spring Boot provides an `/error` mapping that handles all errors in a sensible way, and it is registered as a "`global`" error page in the servlet container. +For machine clients, it produces a JSON response with details of the error, the HTTP status, and the exception message. +For browser clients, there is a "`whitelabel`" error view that renders the same data in HTML format (to customize it, add a `View` that resolves to `error`). + +There are a number of `server.error` properties that can be set if you want to customize the default error handling behavior. +See the <> section of the Appendix. + +To replace the default behavior completely, you can implement `ErrorController` and register a bean definition of that type or add a bean of type `ErrorAttributes` to use the existing mechanism but replace the contents. + +TIP: The `BasicErrorController` can be used as a base class for a custom `ErrorController`. +This is particularly useful if you want to add a handler for a new content type (the default is to handle `text/html` specifically and provide a fallback for everything else). +To do so, extend `BasicErrorController`, add a public method with a `@RequestMapping` that has a `produces` attribute, and create a bean of your new type. + +You can also define a class annotated with `@ControllerAdvice` to customize the JSON document to return for a particular controller and/or exception type, as shown in the following example: + +[source,java,indent=0,subs="verbatim,quotes,attributes"] +---- +include::{include-springbootfeatures}/webapplications/servlet/MyControllerAdvice.java[] +---- + +In the preceding example, if `YourException` is thrown by a controller defined in the same package as `AcmeController`, a JSON representation of the `CustomErrorType` POJO is used instead of the `ErrorAttributes` representation. + +In some cases, errors handled at the controller level are not recorded by the <>. +Applications can ensure that such exceptions are recorded with the request metrics by setting the handled exception as a request attribute: + +[source,java,indent=0,subs="verbatim,quotes,attributes"] +---- +include::{include-springbootfeatures}/webapplications/servlet/MyController.java[] +---- + + + +[[features.developing-web-applications.spring-mvc.error-handling.error-pages]] +===== Custom Error Pages +If you want to display a custom HTML error page for a given status code, you can add a file to an `/error` directory. +Error pages can either be static HTML (that is, added under any of the static resource directories) or be built by using templates. +The name of the file should be the exact status code or a series mask. + +For example, to map `404` to a static HTML file, your directory structure would be as follows: + +[source,indent=0,subs="verbatim,quotes,attributes"] +---- + src/ + +- main/ + +- java/ + | + + +- resources/ + +- public/ + +- error/ + | +- 404.html + +- +---- + +To map all `5xx` errors by using a FreeMarker template, your directory structure would be as follows: + +[source,indent=0,subs="verbatim,quotes,attributes"] +---- + src/ + +- main/ + +- java/ + | + + +- resources/ + +- templates/ + +- error/ + | +- 5xx.ftlh + +- +---- + +For more complex mappings, you can also add beans that implement the `ErrorViewResolver` interface, as shown in the following example: + +[source,java,indent=0,subs="verbatim,quotes,attributes"] +---- +include::{include-springbootfeatures}/webapplications/servlet/MyErrorViewResolver.java[] +---- + +You can also use regular Spring MVC features such as {spring-framework-docs}/web.html#mvc-exceptionhandlers[`@ExceptionHandler` methods] and {spring-framework-docs}/web.html#mvc-ann-controller-advice[`@ControllerAdvice`]. +The `ErrorController` then picks up any unhandled exceptions. + + + +[[features.developing-web-applications.spring-mvc.error-handling.error-pages-without-spring-mvc]] +===== Mapping Error Pages outside of Spring MVC +For applications that do not use Spring MVC, you can use the `ErrorPageRegistrar` interface to directly register `ErrorPages`. +This abstraction works directly with the underlying embedded servlet container and works even if you do not have a Spring MVC `DispatcherServlet`. + +[source,java,indent=0,subs="verbatim,quotes,attributes"] +---- +include::{include-springbootfeatures}/webapplications/servlet/ErrorPageConfiguration.java[] +---- + +NOTE: If you register an `ErrorPage` with a path that ends up being handled by a `Filter` (as is common with some non-Spring web frameworks, like Jersey and Wicket), then the `Filter` has to be explicitly registered as an `ERROR` dispatcher, as shown in the following example: + +[source,java,indent=0,subs="verbatim,quotes,attributes"] +---- +include::{include-springbootfeatures}/webapplications/servlet/ServletFilterConfiguration.java[] +---- + +Note that the default `FilterRegistrationBean` does not include the `ERROR` dispatcher type. + + + +[[features.developing-web-applications.spring-mvc.error-handling.in-a-war-deployment]] +===== Error handling in a war deployment +When deployed to a servlet container, Spring Boot uses its error page filter to forward a request with an error status to the appropriate error page. +This is necessary as the Servlet specification does not provide an API for registering error pages. +Depending on the container that you are deploying your war file to and the technologies that your application uses, some additional configuration may be required. + +The error page filter can only forward the request to the correct error page if the response has not already been committed. +By default, WebSphere Application Server 8.0 and later commits the response upon successful completion of a servlet's service method. +You should disable this behavior by setting `com.ibm.ws.webcontainer.invokeFlushAfterService` to `false`. + +If you are using Spring Security and want to access the principal in an error page, you must configure Spring Security's filter to be invoked on error dispatches. +To do so, set the `spring.security.filter.dispatcher-types` property to `async, error, forward, request`. + + + +[[features.developing-web-applications.spring-mvc.spring-hateoas]] +==== Spring HATEOAS +If you develop a RESTful API that makes use of hypermedia, Spring Boot provides auto-configuration for Spring HATEOAS that works well with most applications. +The auto-configuration replaces the need to use `@EnableHypermediaSupport` and registers a number of beans to ease building hypermedia-based applications, including a `LinkDiscoverers` (for client side support) and an `ObjectMapper` configured to correctly marshal responses into the desired representation. +The `ObjectMapper` is customized by setting the various `spring.jackson.*` properties or, if one exists, by a `Jackson2ObjectMapperBuilder` bean. + +You can take control of Spring HATEOAS's configuration by using `@EnableHypermediaSupport`. +Note that doing so disables the `ObjectMapper` customization described earlier. + + + +[[features.developing-web-applications.spring-mvc.cors]] +==== CORS Support +https://en.wikipedia.org/wiki/Cross-origin_resource_sharing[Cross-origin resource sharing] (CORS) is a https://www.w3.org/TR/cors/[W3C specification] implemented by https://caniuse.com/#feat=cors[most browsers] that lets you specify in a flexible way what kind of cross-domain requests are authorized., instead of using some less secure and less powerful approaches such as IFRAME or JSONP. + +As of version 4.2, Spring MVC {spring-framework-docs}/web.html#mvc-cors[supports CORS]. +Using {spring-framework-docs}/web.html#mvc-cors-controller[controller method CORS configuration] with {spring-framework-api}/web/bind/annotation/CrossOrigin.html[`@CrossOrigin`] annotations in your Spring Boot application does not require any specific configuration. +{spring-framework-docs}/web.html#mvc-cors-global[Global CORS configuration] can be defined by registering a `WebMvcConfigurer` bean with a customized `addCorsMappings(CorsRegistry)` method, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/webapplications/servlet/CorsConfiguration.java[] +---- + + + +[[features.developing-web-applications.spring-webflux]] +=== The "`Spring WebFlux Framework`" +Spring WebFlux is the new reactive web framework introduced in Spring Framework 5.0. +Unlike Spring MVC, it does not require the Servlet API, is fully asynchronous and non-blocking, and implements the https://www.reactive-streams.org/[Reactive Streams] specification through https://projectreactor.io/[the Reactor project]. + +Spring WebFlux comes in two flavors: functional and annotation-based. +The annotation-based one is quite close to the Spring MVC model, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/webapplications/webflux/MyRestController.java[] +---- + +"`WebFlux.fn`", the functional variant, separates the routing configuration from the actual handling of the requests, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/webapplications/webflux/fn/RoutingConfiguration.java[] +---- + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/webapplications/webflux/fn/UserHandler.java[] +---- + +WebFlux is part of the Spring Framework and detailed information is available in its {spring-framework-docs}/web-reactive.html#webflux-fn[reference documentation]. + +TIP: You can define as many `RouterFunction` beans as you like to modularize the definition of the router. +Beans can be ordered if you need to apply a precedence. + +To get started, add the `spring-boot-starter-webflux` module to your application. + +NOTE: Adding both `spring-boot-starter-web` and `spring-boot-starter-webflux` modules in your application results in Spring Boot auto-configuring Spring MVC, not WebFlux. +This behavior has been chosen because many Spring developers add `spring-boot-starter-webflux` to their Spring MVC application to use the reactive `WebClient`. +You can still enforce your choice by setting the chosen application type to `SpringApplication.setWebApplicationType(WebApplicationType.REACTIVE)`. + + + +[[features.developing-web-applications.spring-webflux.auto-configuration]] +==== Spring WebFlux Auto-configuration +Spring Boot provides auto-configuration for Spring WebFlux that works well with most applications. + +The auto-configuration adds the following features on top of Spring's defaults: + +* Configuring codecs for `HttpMessageReader` and `HttpMessageWriter` instances (described <>). +* Support for serving static resources, including support for WebJars (described <>). + +If you want to keep Spring Boot WebFlux features and you want to add additional {spring-framework-docs}/web-reactive.html#webflux-config[WebFlux configuration], you can add your own `@Configuration` class of type `WebFluxConfigurer` but *without* `@EnableWebFlux`. + +If you want to take complete control of Spring WebFlux, you can add your own `@Configuration` annotated with `@EnableWebFlux`. + + + +[[features.developing-web-applications.spring-webflux.httpcodecs]] +==== HTTP Codecs with HttpMessageReaders and HttpMessageWriters +Spring WebFlux uses the `HttpMessageReader` and `HttpMessageWriter` interfaces to convert HTTP requests and responses. +They are configured with `CodecConfigurer` to have sensible defaults by looking at the libraries available in your classpath. + +Spring Boot provides dedicated configuration properties for codecs, `+spring.codec.*+`. +It also applies further customization by using `CodecCustomizer` instances. +For example, `+spring.jackson.*+` configuration keys are applied to the Jackson codec. + +If you need to add or customize codecs, you can create a custom `CodecCustomizer` component, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/webapplications/webflux/CodecConfiguration.java[] +---- + +You can also leverage <>. + + + +[[features.developing-web-applications.spring-webflux.static-content]] +==== Static Content +By default, Spring Boot serves static content from a directory called `/static` (or `/public` or `/resources` or `/META-INF/resources`) in the classpath. +It uses the `ResourceWebHandler` from Spring WebFlux so that you can modify that behavior by adding your own `WebFluxConfigurer` and overriding the `addResourceHandlers` method. + +By default, resources are mapped on `+/**+`, but you can tune that by setting the configprop:spring.webflux.static-path-pattern[] property. +For instance, relocating all resources to `/resources/**` can be achieved as follows: + +[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] +---- + spring: + webflux: + static-path-pattern: "/resources/**" +---- + +You can also customize the static resource locations by using `spring.web.resources.static-locations`. +Doing so replaces the default values with a list of directory locations. +If you do so, the default welcome page detection switches to your custom locations. +So, if there is an `index.html` in any of your locations on startup, it is the home page of the application. + +In addition to the "`standard`" static resource locations listed earlier, a special case is made for https://www.webjars.org/[Webjars content]. +Any resources with a path in `+/webjars/**+` are served from jar files if they are packaged in the Webjars format. + +TIP: Spring WebFlux applications do not strictly depend on the Servlet API, so they cannot be deployed as war files and do not use the `src/main/webapp` directory. + + + +[[features.developing-web-applications.spring-webflux.welcome-page]] +==== Welcome Page +Spring Boot supports both static and templated welcome pages. +It first looks for an `index.html` file in the configured static content locations. +If one is not found, it then looks for an `index` template. +If either is found, it is automatically used as the welcome page of the application. + + + +[[features.developing-web-applications.spring-webflux.template-engines]] +==== Template Engines +As well as REST web services, you can also use Spring WebFlux to serve dynamic HTML content. +Spring WebFlux supports a variety of templating technologies, including Thymeleaf, FreeMarker, and Mustache. + +Spring Boot includes auto-configuration support for the following templating engines: + + * https://freemarker.apache.org/docs/[FreeMarker] + * https://www.thymeleaf.org[Thymeleaf] + * https://mustache.github.io/[Mustache] + +When you use one of these templating engines with the default configuration, your templates are picked up automatically from `src/main/resources/templates`. + + + +[[features.developing-web-applications.spring-webflux.error-handling]] +==== Error Handling +Spring Boot provides a `WebExceptionHandler` that handles all errors in a sensible way. +Its position in the processing order is immediately before the handlers provided by WebFlux, which are considered last. +For machine clients, it produces a JSON response with details of the error, the HTTP status, and the exception message. +For browser clients, there is a "`whitelabel`" error handler that renders the same data in HTML format. +You can also provide your own HTML templates to display errors (see the <>). + +The first step to customizing this feature often involves using the existing mechanism but replacing or augmenting the error contents. +For that, you can add a bean of type `ErrorAttributes`. + +To change the error handling behavior, you can implement `ErrorWebExceptionHandler` and register a bean definition of that type. +Because a `WebExceptionHandler` is quite low-level, Spring Boot also provides a convenient `AbstractErrorWebExceptionHandler` to let you handle errors in a WebFlux functional way, as shown in the following example: + +[source,java,indent=0,subs="verbatim,quotes,attributes"] +---- +include::{include-springbootfeatures}/webapplications/webflux/CustomErrorWebExceptionHandler.java[] +---- + +For a more complete picture, you can also subclass `DefaultErrorWebExceptionHandler` directly and override specific methods. + +In some cases, errors handled at the controller or handler function level are not recorded by the <>. +Applications can ensure that such exceptions are recorded with the request metrics by setting the handled exception as a request attribute: + +[source,java,indent=0,subs="verbatim,quotes,attributes"] +---- +include::{include-springbootfeatures}/webapplications/webflux/ExceptionHandlingController.java[] +---- + + + +[[features.developing-web-applications.spring-webflux.error-handling.error-pages]] +===== Custom Error Pages +If you want to display a custom HTML error page for a given status code, you can add a file to an `/error` directory. +Error pages can either be static HTML (that is, added under any of the static resource directories) or built with templates. +The name of the file should be the exact status code or a series mask. + +For example, to map `404` to a static HTML file, your directory structure would be as follows: + +[source,indent=0,subs="verbatim,quotes,attributes"] +---- + src/ + +- main/ + +- java/ + | + + +- resources/ + +- public/ + +- error/ + | +- 404.html + +- +---- + +To map all `5xx` errors by using a Mustache template, your directory structure would be as follows: + +[source,indent=0,subs="verbatim,quotes,attributes"] +---- + src/ + +- main/ + +- java/ + | + + +- resources/ + +- templates/ + +- error/ + | +- 5xx.mustache + +- +---- + + + +[[features.developing-web-applications.spring-webflux.web-filters]] +==== Web Filters +Spring WebFlux provides a `WebFilter` interface that can be implemented to filter HTTP request-response exchanges. +`WebFilter` beans found in the application context will be automatically used to filter each exchange. + +Where the order of the filters is important they can implement `Ordered` or be annotated with `@Order`. +Spring Boot auto-configuration may configure web filters for you. +When it does so, the orders shown in the following table will be used: + +|=== +| Web Filter | Order + +| `MetricsWebFilter` +| `Ordered.HIGHEST_PRECEDENCE + 1` + +| `WebFilterChainProxy` (Spring Security) +| `-100` + +| `HttpTraceWebFilter` +| `Ordered.LOWEST_PRECEDENCE - 10` +|=== + + + +[[features.developing-web-applications.jersey]] +=== JAX-RS and Jersey +If you prefer the JAX-RS programming model for REST endpoints, you can use one of the available implementations instead of Spring MVC. +https://jersey.github.io/[Jersey] and https://cxf.apache.org/[Apache CXF] work quite well out of the box. +CXF requires you to register its `Servlet` or `Filter` as a `@Bean` in your application context. +Jersey has some native Spring support, so we also provide auto-configuration support for it in Spring Boot, together with a starter. + +To get started with Jersey, include the `spring-boot-starter-jersey` as a dependency and then you need one `@Bean` of type `ResourceConfig` in which you register all the endpoints, as shown in the following example: + +[source,java,indent=0,subs="verbatim,quotes,attributes"] +---- +include::{include-springbootfeatures}/webapplications/jersey/JerseyConfig.java[] +---- + +WARNING: Jersey's support for scanning executable archives is rather limited. +For example, it cannot scan for endpoints in a package found in a <> or in `WEB-INF/classes` when running an executable war file. +To avoid this limitation, the `packages` method should not be used, and endpoints should be registered individually by using the `register` method, as shown in the preceding example. + +For more advanced customizations, you can also register an arbitrary number of beans that implement `ResourceConfigCustomizer`. + +All the registered endpoints should be `@Components` with HTTP resource annotations (`@GET` and others), as shown in the following example: + +[source,java,indent=0,subs="verbatim,quotes,attributes"] +---- +include::{include-springbootfeatures}/webapplications/jersey/Endpoint.java[] +---- + +Since the `Endpoint` is a Spring `@Component`, its lifecycle is managed by Spring and you can use the `@Autowired` annotation to inject dependencies and use the `@Value` annotation to inject external configuration. +By default, the Jersey servlet is registered and mapped to `/*`. +You can change the mapping by adding `@ApplicationPath` to your `ResourceConfig`. + +By default, Jersey is set up as a Servlet in a `@Bean` of type `ServletRegistrationBean` named `jerseyServletRegistration`. +By default, the servlet is initialized lazily, but you can customize that behavior by setting `spring.jersey.servlet.load-on-startup`. +You can disable or override that bean by creating one of your own with the same name. +You can also use a filter instead of a servlet by setting `spring.jersey.type=filter` (in which case, the `@Bean` to replace or override is `jerseyFilterRegistration`). +The filter has an `@Order`, which you can set with `spring.jersey.filter.order`. +Both the servlet and the filter registrations can be given init parameters by using `spring.jersey.init.*` to specify a map of properties. + + + +[[features.developing-web-applications.embedded-container]] +=== Embedded Servlet Container Support +Spring Boot includes support for embedded https://tomcat.apache.org/[Tomcat], https://www.eclipse.org/jetty/[Jetty], and https://github.com/undertow-io/undertow[Undertow] servers. +Most developers use the appropriate "`Starter`" to obtain a fully configured instance. +By default, the embedded server listens for HTTP requests on port `8080`. + + + +[[features.developing-web-applications.embedded-container.servlets-filters-listeners]] +==== Servlets, Filters, and listeners +When using an embedded servlet container, you can register servlets, filters, and all the listeners (such as `HttpSessionListener`) from the Servlet spec, either by using Spring beans or by scanning for Servlet components. + + + +[[features.developing-web-applications.embedded-container.servlets-filters-listeners.beans]] +===== Registering Servlets, Filters, and Listeners as Spring Beans +Any `Servlet`, `Filter`, or servlet `*Listener` instance that is a Spring bean is registered with the embedded container. +This can be particularly convenient if you want to refer to a value from your `application.properties` during configuration. + +By default, if the context contains only a single Servlet, it is mapped to `/`. +In the case of multiple servlet beans, the bean name is used as a path prefix. +Filters map to `+/*+`. + +If convention-based mapping is not flexible enough, you can use the `ServletRegistrationBean`, `FilterRegistrationBean`, and `ServletListenerRegistrationBean` classes for complete control. + +It is usually safe to leave Filter beans unordered. +If a specific order is required, you should annotate the `Filter` with `@Order` or make it implement `Ordered`. +You cannot configure the order of a `Filter` by annotating its bean method with `@Order`. +If you cannot change the `Filter` class to add `@Order` or implement `Ordered`, you must define a `FilterRegistrationBean` for the `Filter` and set the registration bean's order using the `setOrder(int)` method. +Avoid configuring a Filter that reads the request body at `Ordered.HIGHEST_PRECEDENCE`, since it might go against the character encoding configuration of your application. +If a Servlet filter wraps the request, it should be configured with an order that is less than or equal to `OrderedFilter.REQUEST_WRAPPER_FILTER_MAX_ORDER`. + +TIP: To see the order of every `Filter` in your application, enable debug level logging for the `web` <> (`logging.level.web=debug`). +Details of the registered filters, including their order and URL patterns, will then be logged at startup. + +WARNING: Take care when registering `Filter` beans since they are initialized very early in the application lifecycle. +If you need to register a `Filter` that interacts with other beans, consider using a {spring-boot-module-api}/web/servlet/DelegatingFilterProxyRegistrationBean.html[`DelegatingFilterProxyRegistrationBean`] instead. + + + +[[features.developing-web-applications.embedded-container.context-initializer]] +==== Servlet Context Initialization +Embedded servlet containers do not directly execute the Servlet 3.0+ `javax.servlet.ServletContainerInitializer` interface or Spring's `org.springframework.web.WebApplicationInitializer` interface. +This is an intentional design decision intended to reduce the risk that third party libraries designed to run inside a war may break Spring Boot applications. + +If you need to perform servlet context initialization in a Spring Boot application, you should register a bean that implements the `org.springframework.boot.web.servlet.ServletContextInitializer` interface. +The single `onStartup` method provides access to the `ServletContext` and, if necessary, can easily be used as an adapter to an existing `WebApplicationInitializer`. + + + +[[features.developing-web-applications.embedded-container.context-initializer.scanning]] +===== Scanning for Servlets, Filters, and listeners +When using an embedded container, automatic registration of classes annotated with `@WebServlet`, `@WebFilter`, and `@WebListener` can be enabled by using `@ServletComponentScan`. + +TIP: `@ServletComponentScan` has no effect in a standalone container, where the container's built-in discovery mechanisms are used instead. + + + +[[features.developing-web-applications.embedded-container.application-context]] +==== The ServletWebServerApplicationContext +Under the hood, Spring Boot uses a different type of `ApplicationContext` for embedded servlet container support. +The `ServletWebServerApplicationContext` is a special type of `WebApplicationContext` that bootstraps itself by searching for a single `ServletWebServerFactory` bean. +Usually a `TomcatServletWebServerFactory`, `JettyServletWebServerFactory`, or `UndertowServletWebServerFactory` has been auto-configured. + +NOTE: You usually do not need to be aware of these implementation classes. +Most applications are auto-configured, and the appropriate `ApplicationContext` and `ServletWebServerFactory` are created on your behalf. + + + +[[features.developing-web-applications.embedded-container.customizing]] +==== Customizing Embedded Servlet Containers +Common servlet container settings can be configured by using Spring `Environment` properties. +Usually, you would define the properties in your `application.properties` or `application.yaml` file. + +Common server settings include: + +* Network settings: Listen port for incoming HTTP requests (`server.port`), interface address to bind to `server.address`, and so on. +* Session settings: Whether the session is persistent (`server.servlet.session.persistent`), session timeout (`server.servlet.session.timeout`), location of session data (`server.servlet.session.store-dir`), and session-cookie configuration (`server.servlet.session.cookie.*`). +* Error management: Location of the error page (`server.error.path`) and so on. +* <> +* <> + +Spring Boot tries as much as possible to expose common settings, but this is not always possible. +For those cases, dedicated namespaces offer server-specific customizations (see `server.tomcat` and `server.undertow`). +For instance, <> can be configured with specific features of the embedded servlet container. + +TIP: See the {spring-boot-autoconfigure-module-code}/web/ServerProperties.java[`ServerProperties`] class for a complete list. + + + +[[features.developing-web-applications.embedded-container.customizing.programmatic]] +===== Programmatic Customization +If you need to programmatically configure your embedded servlet container, you can register a Spring bean that implements the `WebServerFactoryCustomizer` interface. +`WebServerFactoryCustomizer` provides access to the `ConfigurableServletWebServerFactory`, which includes numerous customization setter methods. +The following example shows programmatically setting the port: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/webapplications/embeddedservletcontainer/CustomizationBean.java[] +---- + +`TomcatServletWebServerFactory`, `JettyServletWebServerFactory` and `UndertowServletWebServerFactory` are dedicated variants of `ConfigurableServletWebServerFactory` that have additional customization setter methods for Tomcat, Jetty and Undertow respectively. +The following example shows how to customize `TomcatServletWebServerFactory` that provides access to Tomcat-specific configuration options: + +[source,java,indent=0,subs="verbatim,quotes,attributes"] +---- +include::{include-springbootfeatures}/webapplications/embeddedservletcontainer/TomcatServerCustomizer.java[] +---- + + + +[[features.developing-web-applications.embedded-container.customizing.direct]] +===== Customizing ConfigurableServletWebServerFactory Directly +For more advanced use cases that require you to extend from `ServletWebServerFactory`, you can expose a bean of such type yourself. + +Setters are provided for many configuration options. +Several protected method "`hooks`" are also provided should you need to do something more exotic. +See the {spring-boot-module-api}/web/servlet/server/ConfigurableServletWebServerFactory.html[source code documentation] for details. + +NOTE: Auto-configured customizers are still applied on your custom factory, so use that option carefully. + + + +[[features.developing-web-applications.embedded-container.jsp-limitations]] +==== JSP Limitations +When running a Spring Boot application that uses an embedded servlet container (and is packaged as an executable archive), there are some limitations in the JSP support. + +* With Jetty and Tomcat, it should work if you use war packaging. + An executable war will work when launched with `java -jar`, and will also be deployable to any standard container. + JSPs are not supported when using an executable jar. + +* Undertow does not support JSPs. + +* Creating a custom `error.jsp` page does not override the default view for <>. + <> should be used instead. + + + +[[features.developing-web-applications.reactive-server]] +=== Embedded Reactive Server Support +Spring Boot includes support for the following embedded reactive web servers: Reactor Netty, Tomcat, Jetty, and Undertow. +Most developers use the appropriate “Starter” to obtain a fully configured instance. +By default, the embedded server listens for HTTP requests on port 8080. + + + +[[features.developing-web-applications.reactive-server-resources-configuration]] +=== Reactive Server Resources Configuration +When auto-configuring a Reactor Netty or Jetty server, Spring Boot will create specific beans that will provide HTTP resources to the server instance: `ReactorResourceFactory` or `JettyResourceFactory`. + +By default, those resources will be also shared with the Reactor Netty and Jetty clients for optimal performances, given: + +* the same technology is used for server and client +* the client instance is built using the `WebClient.Builder` bean auto-configured by Spring Boot + +Developers can override the resource configuration for Jetty and Reactor Netty by providing a custom `ReactorResourceFactory` or `JettyResourceFactory` bean - this will be applied to both clients and servers. + +You can learn more about the resource configuration on the client side in the <>. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/email.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/email.adoc new file mode 100644 index 0000000000..b4fbe84ae2 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/email.adoc @@ -0,0 +1,32 @@ +[[features.email]] +== Sending Email +The Spring Framework provides an abstraction for sending email by using the `JavaMailSender` interface, and Spring Boot provides auto-configuration for it as well as a starter module. + +TIP: See the {spring-framework-docs}/integration.html#mail[reference documentation] for a detailed explanation of how you can use `JavaMailSender`. + +If `spring.mail.host` and the relevant libraries (as defined by `spring-boot-starter-mail`) are available, a default `JavaMailSender` is created if none exists. +The sender can be further customized by configuration items from the `spring.mail` namespace. +See {spring-boot-autoconfigure-module-code}/mail/MailProperties.java[`MailProperties`] for more details. + +In particular, certain default timeout values are infinite, and you may want to change that to avoid having a thread blocked by an unresponsive mail server, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + mail: + properties: + "[mail.smtp.connectiontimeout]": 5000 + "[mail.smtp.timeout]": 3000 + "[mail.smtp.writetimeout]": 5000 +---- + +It is also possible to configure a `JavaMailSender` with an existing `Session` from JNDI: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + mail: + jndi-name: "mail/Session" +---- + +When a `jndi-name` is set, it takes precedence over all other Session-related settings. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/external-config.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/external-config.adoc new file mode 100644 index 0000000000..39a15f0b83 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/external-config.adoc @@ -0,0 +1,1168 @@ +[[features.external-config]] +== Externalized Configuration +Spring Boot lets you externalize your configuration so that you can work with the same application code in different environments. +You can use a variety of external configuration sources, include Java properties files, YAML files, environment variables, and command-line arguments. + +Property values can be injected directly into your beans by using the `@Value` annotation, accessed through Spring's `Environment` abstraction, or be <> through `@ConfigurationProperties`. + +Spring Boot uses a very particular `PropertySource` order that is designed to allow sensible overriding of values. +Properties are considered in the following order (with values from lower items overriding earlier ones): + +. Default properties (specified by setting `SpringApplication.setDefaultProperties`). +. {spring-framework-api}/context/annotation/PropertySource.html[`@PropertySource`] annotations on your `@Configuration` classes. + Please note that such property sources are not added to the `Environment` until the application context is being refreshed. + This is too late to configure certain properties such as `+logging.*+` and `+spring.main.*+` which are read before refresh begins. +. Config data (such as `application.properties` files) +. A `RandomValuePropertySource` that has properties only in `+random.*+`. +. OS environment variables. +. Java System properties (`System.getProperties()`). +. JNDI attributes from `java:comp/env`. +. `ServletContext` init parameters. +. `ServletConfig` init parameters. +. Properties from `SPRING_APPLICATION_JSON` (inline JSON embedded in an environment variable or system property). +. Command line arguments. +. `properties` attribute on your tests. + Available on {spring-boot-test-module-api}/context/SpringBootTest.html[`@SpringBootTest`] and the <>. +. {spring-framework-api}/test/context/TestPropertySource.html[`@TestPropertySource`] annotations on your tests. +. <> in the `$HOME/.config/spring-boot` directory when devtools is active. + +Config data files are considered in the following order: + +. <> packaged inside your jar (`application.properties` and YAML variants). +. <> packaged inside your jar (`application-\{profile}.properties` and YAML variants). +. <> outside of your packaged jar (`application.properties` and YAML variants). +. <> outside of your packaged jar (`application-\{profile}.properties` and YAML variants). + +NOTE: It is recommended to stick with one format for your entire application. +If you have configuration files with both `.properties` and `.yml` format in the same location, `.properties` takes precedence. + +To provide a concrete example, suppose you develop a `@Component` that uses a `name` property, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/externalizedconfiguration/valueinjection/MyBean.java[] +---- + +On your application classpath (for example, inside your jar) you can have an `application.properties` file that provides a sensible default property value for `name`. +When running in a new environment, an `application.properties` file can be provided outside of your jar that overrides the `name`. +For one-off testing, you can launch with a specific command line switch (for example, `java -jar app.jar --name="Spring"`). + +TIP: The `env` and `configprops` endpoints can be useful in determining why a property has a particular value. +You can use these two endpoints to diagnose unexpected property values. +See the "<>" section for details. + + + +[[features.external-config.command-line-args]] +=== Accessing Command Line Properties +By default, `SpringApplication` converts any command line option arguments (that is, arguments starting with `--`, such as `--server.port=9000`) to a `property` and adds them to the Spring `Environment`. +As mentioned previously, command line properties always take precedence over file based property sources. + +If you do not want command line properties to be added to the `Environment`, you can disable them by using `SpringApplication.setAddCommandLineProperties(false)`. + + + +[[features.external-config.application-json]] +=== JSON Application Properties +Environment variables and system properties often have restrictions that mean some property names cannot be used. +To help with this, Spring Boot allows you to encode a block of properties into a single JSON structure. + +When your application starts, any `spring.application.json` or `SPRING_APPLICATION_JSON` properties will be parsed and added to the `Environment`. + +For example, the `SPRING_APPLICATION_JSON` property can be supplied on the command line in a UN{asterisk}X shell as an environment variable: + +[indent=0] +---- + $ SPRING_APPLICATION_JSON='{"acme":{"name":"test"}}' java -jar myapp.jar +---- + +In the preceding example, you end up with `acme.name=test` in the Spring `Environment`. + +The same JSON can also be provided as a system property: + +[indent=0] +---- + $ java -Dspring.application.json='{"acme":{"name":"test"}}' -jar myapp.jar +---- + +Or you could supply the JSON by using a command line argument: + +[indent=0] +---- + $ java -jar myapp.jar --spring.application.json='{"acme":{"name":"test"}}' +---- + +If you are deploying to a classic Application Server, you could also use a JNDI variable named `java:comp/env/spring.application.json`. + +NOTE: Although `null` values from the JSON will be added to the resulting property source, the `PropertySourcesPropertyResolver` treats `null` properties as missing values. +This means that the JSON cannot override properties from lower order property sources with a `null` value. + + + +[[features.external-config.files]] +=== External Application Properties [[features.external-config.files]] +Spring Boot will automatically find and load `application.properties` and `application.yaml` files from the following locations when your application starts: + +. The classpath root +. The classpath `/config` package +. The current directory +. The `/config` subdirectory in the current directory +. Immediate child directories of the `/config` subdirectory + +The list is ordered by precedence (with values from lower items overriding earlier ones). +Documents from the loaded files are added as `PropertySources` to the Spring `Environment`. + +If you do not like `application` as the configuration file name, you can switch to another file name by specifying a configprop:spring.config.name[] environment property. +You can also refer to an explicit location by using the `spring.config.location` environment property (which is a comma-separated list of directory locations or file paths). +The following example shows how to specify a different file name: + +[indent=0] +---- + $ java -jar myproject.jar --spring.config.name=myproject +---- + +The following example shows how to specify two locations: + +[indent=0] +---- + $ java -jar myproject.jar --spring.config.location=optional:classpath:/default.properties,optional:classpath:/override.properties +---- + +TIP: Use the prefix `optional:` if the <> and you don't mind if they don't exist. + +WARNING: `spring.config.name`, `spring.config.location`, and `spring.config.additional-location` are used very early to determine which files have to be loaded. +They must be defined as an environment property (typically an OS environment variable, a system property, or a command-line argument). + +If `spring.config.location` contains directories (as opposed to files), they must end in `/` or the system-dependent `File.separator`. +At runtime they will be appended with the names generated from `spring.config.name` before being loaded. +If `spring.config.location` contains files, they are used as-is. + +Whether specified directly or contained in a directory, file references must include a file extension in their name. +Typical extensions that are supported out-of-the-box are `.properties`, `.yaml`, and `.yml`. + +When multiple locations are specified, the later ones can override the values of earlier ones. + +Locations configured by using `spring.config.location` replace the default locations. +For example, if `spring.config.location` is configured with the value `optional:classpath:/custom-config/,optional:file:./custom-config/`, the complete set of locations considered is: + +. `optional:classpath:custom-config/` +. `optional:file:./custom-config/` + +If you prefer to add additional locations, rather than replacing them, you can use `spring.config.additional-location`. +Properties loaded from additional locations can override those in the default locations. +For example, if `spring.config.additional-location` is configured with the value `optional:classpath:/custom-config/,optional:file:./custom-config/`, the complete set of locations considered is: + +. `optional:classpath:/` +. `optional:classpath:/config/` +. `optional:file:./` +. `optional:file:./config/` +. `optional:file:./config/*/` +. `optional:classpath:custom-config/` +. `optional:file:./custom-config/` + +This search ordering lets you specify default values in one configuration file and then selectively override those values in another. +You can provide default values for your application in `application.properties` (or whatever other basename you choose with `spring.config.name`) in one of the default locations. +These default values can then be overridden at runtime with a different file located in one of the custom locations. + +NOTE: If you use environment variables rather than system properties, most operating systems disallow period-separated key names, but you can use underscores instead (for example, configprop:spring.config.name[format=envvar] instead of configprop:spring.config.name[]). +See <> for details. + +NOTE: If your application runs in a servlet container or application server, then JNDI properties (in `java:comp/env`) or servlet context initialization parameters can be used instead of, or as well as, environment variables or system properties. + + + +[[features.external-config.files.optional-prefix]] +==== Optional Locations +By default, when a specified config data location does not exist, Spring Boot will throw a `ConfigDataLocationNotFoundException` and your application will not start. + +If you want to specify a location, but you don't mind if it doesn't always exist, you can use the `optional:` prefix. +You can use this prefix with the `spring.config.location` and `spring.config.additional-location` properties, as well as with <> declarations. + +For example, a `spring.config.import` value of `optional:file:./myconfig.properties` allows your application to start, even if the `myconfig.properties` file is missing. + +If you want to ignore all `ConfigDataLocationNotFoundExceptions` and always continue to start your application, you can use the `spring.config.on-not-found` property. +Set the value to `ignore` using `SpringApplication.setDefaultProperties(...)` or with a system/environment variable. + + + +[[features.external-config.files.wildcard-locations]] +==== Wildcard Locations +If a config file location includes the `{asterisk}` character for the last path segment, it is considered a wildcard location. +Wildcards are expanded when the config is loaded so that immediate subdirectories are also checked. +Wildcard locations are particularly useful in an environment such as Kubernetes when there are multiple sources of config properties. + +For example, if you have some Redis configuration and some MySQL configuration, you might want to keep those two pieces of configuration separate, while requiring that both those are present in an `application.properties` file. +This might result in two separate `application.properties` files mounted at different locations such as `/config/redis/application.properties` and `/config/mysql/application.properties`. +In such a case, having a wildcard location of `config/*/`, will result in both files being processed. + +By default, Spring Boot includes `config/*/` in the default search locations. +It means that all subdirectories of the `/config` directory outside of your jar will be searched. + +You can use wildcard locations yourself with the `spring.config.location` and `spring.config.additional-location` properties. + +NOTE: A wildcard location must contain only one `{asterisk}` and end with `{asterisk}/` for search locations that are directories or `*/` for search locations that are files. +Locations with wildcards are sorted alphabetically based on the absolute path of the file names. + +TIP: Wildcard locations only work with external directories. +You cannot use a wildcard in a `classpath:` location. + + + +[[features.external-config.files.profile-specific]] +==== Profile Specific Files +As well as `application` property files, Spring Boot will also attempt to load profile-specific files using the naming convention `application-\{profile}`. +For example, if your application activates a profile named `prod` and uses YAML files, then both `application.yml` and `application-prod.yml` will be considered. + +Profile-specific properties are loaded from the same locations as standard `application.properties`, with profile-specific files always overriding the non-specific ones. +If several profiles are specified, a last-wins strategy applies. +For example, if profiles `prod,live` are specified by the configprop:spring.profiles.active[] property, values in `application-prod.properties` can be overridden by those in `application-live.properties`. + +The `Environment` has a set of default profiles (by default, `[default]`) that are used if no active profiles are set. +In other words, if no profiles are explicitly activated, then properties from `application-default` are considered. + +NOTE: Properties files are only ever loaded once. +If you've already directly <> a profile specific property files then it won't be imported a second time. + + + +[[features.external-config.files.importing]] +==== Importing Additional Data +Application properties may import further config data from other locations using the `spring.config.import` property. +Imports are processed as they are discovered, and are treated as additional documents inserted immediately below the one that declares the import. + +For example, you might have the following in your classpath `application.properties` file: + +[source,yaml,indent=0,configblocks] +---- + spring: + application: + name: "myapp" + config: + import: "optional:file:./dev.properties" +---- + +This will trigger the import of a `dev.properties` file in current directory (if such a file exists). +Values from the imported `dev.properties` will take precedence over the file that triggered the import. +In the above example, the `dev.properties` could redefine `spring.application.name` to a different value. +An import will only be imported once no matter how many times it is declared. +The order an import is defined inside a single document within the properties/yaml file doesn't matter. +For instance, the two examples below produce the same result: + +[source,yaml,indent=0,configblocks] +---- + spring: + config: + import: my.properties + my: + property: value +---- + +[source,yaml,indent=0,configblocks] +---- + my: + property: value + spring: + config: + import: my.properties +---- + +In both of the above examples, the values from the `my.properties` file will take precedence over the file that triggered its import. + +Several locations can be specified under a single `spring.config.import` key. +Locations will be processed in the order that they are defined, with later imports taking precedence. + +[TIP] +==== +Spring Boot includes pluggable API that allows various different location addresses to be supported. +By default you can import Java Properties, YAML and "`<>`". + +Third-party jars can offer support for additional technologies (there's no requirement for files to be local). +For example, you can imagine config data being from external stores such as Consul, Apache ZooKeeper or Netflix Archaius. + +If you want to support your own locations, see the `ConfigDataLocationResolver` and `ConfigDataLoader` classes in the `org.springframework.boot.context.config` package. +==== + + + +[[features.external-config.files.importing-extensionless]] +==== Importing Extensionless Files +Some cloud platforms cannot add a file extension to volume mounted files. +To import these extensionless files, you need to give Spring Boot a hint so that it knows how to load them. +You can do this by putting an extension hint in square brackets. + +For example, suppose you have a `/etc/config/myconfig` file that you wish to import as yaml. +You can import it from your `application.properties` using the following: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + config: + import: "file:/etc/config/myconfig[.yaml]" +---- + + + +[[features.external-config.files.configtree]] +==== Using Configuration Trees +When running applications on a cloud platform (such as Kubernetes) you often need to read config values that the platform supplies. +It's not uncommon to use environment variables for such purposes, but this can have drawbacks, especially if the value is supposed to be kept secret. + +As an alternative to environment variables, many cloud platforms now allow you to map configuration into mounted data volumes. +For example, Kubernetes can volume mount both https://kubernetes.io/docs/tasks/configure-pod-container/configure-pod-configmap/#populate-a-volume-with-data-stored-in-a-configmap[`ConfigMaps`] and https://kubernetes.io/docs/concepts/configuration/secret/#using-secrets-as-files-from-a-pod[`Secrets`]. + +There are two common volume mount patterns that can be use: + +. A single file contains a complete set of properties (usually written as YAML). +. Multiple files are written to a directory tree, with the filename becoming the '`key`' and the contents becoming the '`value`'. + +For the first case, you can import the YAML or Properties file directly using `spring.config.import` as described <>. +For the second case, you need to use the `configtree:` prefix so that Spring Boot knows it needs to expose all the files as properties. + +As an example, let's imagine that Kubernetes has mounted the following volume: + +[indent=0] +---- + etc/ + config/ + myapp/ + username + password +---- + +The contents of the `username` file would be a config value, and the contents of `password` would be a secret. + +To import these properties, you can add the following to your `application.properties` or `application.yaml` file: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + config: + import: "optional:configtree:/etc/config/" +---- + +You can then access or inject `myapp.username` and `myapp.password` properties from the `Environment` in the usual way. + +TIP: Configuration tree values can be bound to both string `String` and `byte[]` types depending on the contents expected. + +If you have multiple config trees to import from the same parent folder you can use a wildcard shortcut. +Any `configtree:` location that ends with `/*/` will import all immediate children as config trees. + +For example, given the following volume: + +[indent=0] +---- + etc/ + config/ + dbconfig/ + db/ + username + password + mqconfig/ + mq/ + username + password +---- + +You can use `configtree:/etc/config/*/` as the import location: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + config: + import: "optional:configtree:/etc/config/*/" +---- + +This will add `db.username`, `db.password`, `mq.username` and `mq.password` properties. + +NOTE: Directories loaded using a wildcard are sorted alphabetically. +If you need a different order, then you should list each location as a separate import + + +Configuration trees can also be used for Docker secrets. +When a Docker swarm service is granted access to a secret, the secret gets mounted into the container. +For example, if a secret named `db.password` is mounted at location `/run/secrets/`, you can make `db.password` available to the Spring environment using the following: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + config: + import: "optional:configtree:/run/secrets/" +---- + + + +[[features.external-config.files.property-placeholders]] +==== Property Placeholders +The values in `application.properties` and `application.yml` are filtered through the existing `Environment` when they are used, so you can refer back to previously defined values (for example, from System properties). +The standard `$\{name}` property-placeholder syntax can be used anywhere within a value. + +For example, the following file will set `app.description` to "`MyApp is a Spring Boot application`": + +[source,yaml,indent=0,configblocks] +---- + app: + name: "MyApp" + description: "${app.name} is a Spring Boot application" +---- + +TIP: You can also use this technique to create "`short`" variants of existing Spring Boot properties. +See the _<>_ how-to for details. + + + +[[features.external-config.files.multi-document]] +==== Working with Multi-Document Files +Spring Boot allows you to split a single physical file into multiple logical documents which are each added independently. +Documents are processed in order, from top to bottom. +Later documents can override the properties defined in earlier ones. + +For `application.yml` files, the standard YAML multi-document syntax is used. +Three consecutive hyphens represent the end of one document, and the start of the next. + +For example, the following file has two logical documents: + +[source,yaml,indent=0] +---- + spring.application.name: MyApp + --- + spring.config.activate.on-cloud-platform: kubernetes + spring.application.name: MyCloudApp +---- + +For `application.properties` files a special `#---` comment is used to mark the document splits: + +[source,properties,indent=0] +---- + spring.application.name=MyApp + #--- + spring.config.activate.on-cloud-platform=kubernetes + spring.application.name=MyCloudApp +---- + +NOTE: Property file separators must not have any leading whitespace and must have exactly three hyphen characters. +The lines immediately before and after the separator must not be comments. + +TIP: Multi-document property files are often used in conjunction with activation properties such as `spring.config.activate.on-profile`. +See the <> for details. + +WARNING: Multi-document property files cannot be loaded by using the `@PropertySource` or `@TestPropertySource` annotations. + + + +[[features.external-config.files.activation-properties]] +==== Activation Properties +It's sometimes useful to only activate a given get of properties when certain conditions are met. +For example, you might have properties that are only relevant when a specific profile is active. + +You can conditionally activate a properties document using `spring.config.activate.*`. + +The following activation properties are available: + +.activation properties +[cols="1,4"] +|=== +| Property | Note + +| `on-profile` +| A profile expression that must match for the document to be active. + +| `on-cloud-platform` +| The `CloudPlatform` that must be detected for the document to be active. +|=== + +For example, the following specifies that the second document is only active when running on Kubernetes, and only when either the "`prod`" or "`staging`" profiles are active: + +[source,yaml,indent=0,configblocks] +---- + myprop: + always-set + --- + spring: + config: + activate: + on-cloud-platform: "kubernetes" + on-profile: "prod | staging" + myotherprop: sometimes-set +---- + + + +[[features.external-config.encrypting]] +=== Encrypting Properties +Spring Boot does not provide any built in support for encrypting property values, however, it does provide the hook points necessary to modify values contained in the Spring `Environment`. +The `EnvironmentPostProcessor` interface allows you to manipulate the `Environment` before the application starts. +See <> for details. + +If you're looking for a secure way to store credentials and passwords, the https://cloud.spring.io/spring-cloud-vault/[Spring Cloud Vault] project provides support for storing externalized configuration in https://www.vaultproject.io/[HashiCorp Vault]. + + + +[[features.external-config.yaml]] +=== Working with YAML +https://yaml.org[YAML] is a superset of JSON and, as such, is a convenient format for specifying hierarchical configuration data. +The `SpringApplication` class automatically supports YAML as an alternative to properties whenever you have the https://bitbucket.org/asomov/snakeyaml[SnakeYAML] library on your classpath. + +NOTE: If you use "`Starters`", SnakeYAML is automatically provided by `spring-boot-starter`. + + + +[[features.external-config.yaml.mapping-to-properties]] +==== Mapping YAML to Properties +YAML documents need to be converted from their hierarchical format to a flat structure that can be used with the Spring `Environment`. +For example, consider the following YAML document: + +[source,yaml,indent=0] +---- + environments: + dev: + url: https://dev.example.com + name: Developer Setup + prod: + url: https://another.example.com + name: My Cool App +---- + +In order to access these properties from the `Environment`, they would be flattened as follows: + +[source,properties,indent=0] +---- + environments.dev.url=https://dev.example.com + environments.dev.name=Developer Setup + environments.prod.url=https://another.example.com + environments.prod.name=My Cool App +---- + +Likewise, YAML lists also need to be flattened. +They are represented as property keys with `[index]` dereferencers. +For example, consider the following YAML: + +[source,yaml,indent=0] +---- + my: + servers: + - dev.example.com + - another.example.com +---- + +The preceding example would be transformed into these properties: + +[source,properties,indent=0] +---- + my.servers[0]=dev.example.com + my.servers[1]=another.example.com +---- + +TIP: Properties that use the `[index]` notation can be bound to Java `List` or `Set` objects using Spring Boot's `Binder` class. +For more details see the "`<>`" section below. + +WARNING: YAML files cannot be loaded by using the `@PropertySource` or `@TestPropertySource` annotations. +So, in the case that you need to load values that way, you need to use a properties file. + + + +[[features.external-config.yaml.directly-loading]] +[[features.external-config.yaml.directly-loading]] +==== Directly Loading YAML +Spring Framework provides two convenient classes that can be used to load YAML documents. +The `YamlPropertiesFactoryBean` loads YAML as `Properties` and the `YamlMapFactoryBean` loads YAML as a `Map`. + +You can also use the `YamlPropertySourceLoader` class if you want to load YAML as a Spring `PropertySource`. + + + +[[features.external-config.random-values]] +=== Configuring Random Values +The `RandomValuePropertySource` is useful for injecting random values (for example, into secrets or test cases). +It can produce integers, longs, uuids, or strings, as shown in the following example: + +[source,yaml,indent=0,configblocks] +---- + my: + secret: "${random.value}" + number: "${random.int}" + bignumber: "${random.long}" + uuid: "${random.uuid}" + number-less-than-ten: "${random.int(10)}" + number-in-range: "${random.int[1024,65536]}" +---- + +The `+random.int*+` syntax is `OPEN value (,max) CLOSE` where the `OPEN,CLOSE` are any character and `value,max` are integers. +If `max` is provided, then `value` is the minimum value and `max` is the maximum value (exclusive). + + + +[[features.external-config.system-environment]] +=== Configuring System Environment Properties +Spring Boot supports setting a prefix for environment properties. +This is useful if the system environment is shared by multiple Spring Boot applications with different configuration requirements. +The prefix for system environment properties can be set directly on `SpringApplication`. + +For example, if you set the prefix to `input`, a property such as `remote.timeout` will also be resolved as `input.remote.timeout` in the system environment. + + + +[[features.external-config.typesafe-configuration-properties]] +=== Type-safe Configuration Properties +Using the `@Value("$\{property}")` annotation to inject configuration properties can sometimes be cumbersome, especially if you are working with multiple properties or your data is hierarchical in nature. +Spring Boot provides an alternative method of working with properties that lets strongly typed beans govern and validate the configuration of your application. + +TIP: See also the <>. + + + +[[features.external-config.typesafe-configuration-properties.java-bean-binding]] +==== JavaBean properties binding +It is possible to bind a bean declaring standard JavaBean properties as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/externalizedconfiguration/javabeanbinding/AcmeProperties.java[] +---- + +The preceding POJO defines the following properties: + +* `acme.enabled`, with a value of `false` by default. +* `acme.remote-address`, with a type that can be coerced from `String`. +* `acme.security.username`, with a nested "security" object whose name is determined by the name of the property. + In particular, the return type is not used at all there and could have been `SecurityProperties`. +* `acme.security.password`. +* `acme.security.roles`, with a collection of `String` that defaults to `USER`. + +NOTE: The properties that map to `@ConfigurationProperties` classes available in Spring Boot, which are configured via properties files, YAML files, environment variables etc., are public API but the accessors (getters/setters) of the class itself are not meant to be used directly. + +[NOTE] +==== +Such arrangement relies on a default empty constructor and getters and setters are usually mandatory, since binding is through standard Java Beans property descriptors, just like in Spring MVC. +A setter may be omitted in the following cases: + +* Maps, as long as they are initialized, need a getter but not necessarily a setter, since they can be mutated by the binder. +* Collections and arrays can be accessed either through an index (typically with YAML) or by using a single comma-separated value (properties). + In the latter case, a setter is mandatory. + We recommend to always add a setter for such types. + If you initialize a collection, make sure it is not immutable (as in the preceding example). +* If nested POJO properties are initialized (like the `Security` field in the preceding example), a setter is not required. + If you want the binder to create the instance on the fly by using its default constructor, you need a setter. + +Some people use Project Lombok to add getters and setters automatically. +Make sure that Lombok does not generate any particular constructor for such a type, as it is used automatically by the container to instantiate the object. + +Finally, only standard Java Bean properties are considered and binding on static properties is not supported. +==== + + + +[[features.external-config.typesafe-configuration-properties.constructor-binding]] +==== Constructor binding +The example in the previous section can be rewritten in an immutable fashion as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/externalizedconfiguration/constructorbinding/AcmeProperties.java[] +---- + +In this setup, the `@ConstructorBinding` annotation is used to indicate that constructor binding should be used. +This means that the binder will expect to find a constructor with the parameters that you wish to have bound. + +Nested members of a `@ConstructorBinding` class (such as `Security` in the example above) will also be bound via their constructor. + +Default values can be specified using `@DefaultValue` and the same conversion service will be applied to coerce the `String` value to the target type of a missing property. +By default, if no properties are bound to `Security`, the `AcmeProperties` instance will contain a `null` value for `security`. +If you wish you return a non-null instance of `Security` even when no properties are bound to it, you can use an empty `@DefaultValue` annotation to do so: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/externalizedconfiguration/constructorbinding/nonnull/AcmeProperties.java[tag=*] +---- + + +NOTE: To use constructor binding the class must be enabled using `@EnableConfigurationProperties` or configuration property scanning. +You cannot use constructor binding with beans that are created by the regular Spring mechanisms (e.g. `@Component` beans, beans created via `@Bean` methods or beans loaded using `@Import`) + +TIP: If you have more than one constructor for your class you can also use `@ConstructorBinding` directly on the constructor that should be bound. + +NOTE: The use of `java.util.Optional` with `@ConfigurationProperties` is not recommended as it is primarily intended for use as a return type. +As such, it is not well-suited to configuration property injection. +For consistency with properties of other types, if you do declare an `Optional` property and it has no value, `null` rather than an empty `Optional` will be bound. + + + +[[features.external-config.typesafe-configuration-properties.enabling-annotated-types]] +==== Enabling @ConfigurationProperties-annotated types +Spring Boot provides infrastructure to bind `@ConfigurationProperties` types and register them as beans. +You can either enable configuration properties on a class-by-class basis or enable configuration property scanning that works in a similar manner to component scanning. + +Sometimes, classes annotated with `@ConfigurationProperties` might not be suitable for scanning, for example, if you're developing your own auto-configuration or you want to enable them conditionally. +In these cases, specify the list of types to process using the `@EnableConfigurationProperties` annotation. +This can be done on any `@Configuration` class, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/externalizedconfiguration/enable/MyConfiguration.java[] +---- + +To use configuration property scanning, add the `@ConfigurationPropertiesScan` annotation to your application. +Typically, it is added to the main application class that is annotated with `@SpringBootApplication` but it can be added to any `@Configuration` class. +By default, scanning will occur from the package of the class that declares the annotation. +If you want to define specific packages to scan, you can do so as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/externalizedconfiguration/enable/MyApplication.java[] +---- + +[NOTE] +==== +When the `@ConfigurationProperties` bean is registered using configuration property scanning or via `@EnableConfigurationProperties`, the bean has a conventional name: `-`, where `` is the environment key prefix specified in the `@ConfigurationProperties` annotation and `` is the fully qualified name of the bean. +If the annotation does not provide any prefix, only the fully qualified name of the bean is used. + +The bean name in the example above is `acme-com.example.AcmeProperties`. +==== + +We recommend that `@ConfigurationProperties` only deal with the environment and, in particular, does not inject other beans from the context. +For corner cases, setter injection can be used or any of the `*Aware` interfaces provided by the framework (such as `EnvironmentAware` if you need access to the `Environment`). +If you still want to inject other beans using the constructor, the configuration properties bean must be annotated with `@Component` and use JavaBean-based property binding. + + + +[[features.external-config.typesafe-configuration-properties.using-annotated-types]] +==== Using @ConfigurationProperties-annotated types +This style of configuration works particularly well with the `SpringApplication` external YAML configuration, as shown in the following example: + +[source,yaml,indent=0] +---- + acme: + remote-address: 192.168.1.1 + security: + username: admin + roles: + - USER + - ADMIN +---- + +To work with `@ConfigurationProperties` beans, you can inject them in the same way as any other bean, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/externalizedconfiguration/use/MyService.java[] +---- + +TIP: Using `@ConfigurationProperties` also lets you generate metadata files that can be used by IDEs to offer auto-completion for your own keys. +See the <> for details. + + + +[[features.external-config.typesafe-configuration-properties.3rd-party-configuration]] +==== Third-party Configuration +As well as using `@ConfigurationProperties` to annotate a class, you can also use it on public `@Bean` methods. +Doing so can be particularly useful when you want to bind properties to third-party components that are outside of your control. + +To configure a bean from the `Environment` properties, add `@ConfigurationProperties` to its bean registration, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/externalizedconfiguration/ThirdPartyConfiguration.java[] +---- + +Any JavaBean property defined with the `another` prefix is mapped onto that `AnotherComponent` bean in manner similar to the preceding `AcmeProperties` example. + + + +[[features.external-config.typesafe-configuration-properties.relaxed-binding]] +==== Relaxed Binding +Spring Boot uses some relaxed rules for binding `Environment` properties to `@ConfigurationProperties` beans, so there does not need to be an exact match between the `Environment` property name and the bean property name. +Common examples where this is useful include dash-separated environment properties (for example, `context-path` binds to `contextPath`), and capitalized environment properties (for example, `PORT` binds to `port`). + +As an example, consider the following `@ConfigurationProperties` class: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/externalizedconfiguration/relaxed/OwnerProperties.java[] +---- + +With the preceding code, the following properties names can all be used: + +.relaxed binding +[cols="1,4"] +|=== +| Property | Note + +| `acme.my-project.person.first-name` +| Kebab case, which is recommended for use in `.properties` and `.yml` files. + +| `acme.myProject.person.firstName` +| Standard camel case syntax. + +| `acme.my_project.person.first_name` +| Underscore notation, which is an alternative format for use in `.properties` and `.yml` files. + +| `ACME_MYPROJECT_PERSON_FIRSTNAME` +| Upper case format, which is recommended when using system environment variables. +|=== + +NOTE: The `prefix` value for the annotation _must_ be in kebab case (lowercase and separated by `-`, such as `acme.my-project.person`). + +.relaxed binding rules per property source +[cols="2,4,4"] +|=== +| Property Source | Simple | List + +| Properties Files +| Camel case, kebab case, or underscore notation +| Standard list syntax using `[ ]` or comma-separated values + +| YAML Files +| Camel case, kebab case, or underscore notation +| Standard YAML list syntax or comma-separated values + +| Environment Variables +| Upper case format with underscore as the delimiter (see <>). +| Numeric values surrounded by underscores (see <>) + +| System properties +| Camel case, kebab case, or underscore notation +| Standard list syntax using `[ ]` or comma-separated values +|=== + +TIP: We recommend that, when possible, properties are stored in lower-case kebab format, such as `my.property-name=acme`. + + + +[[features.external-config.typesafe-configuration-properties.relaxed-binding.maps]] +===== Binding Maps +When binding to `Map` properties you may need to use a special bracket notation so that the original `key` value is preserved. +If the key is not surrounded by `[]`, any characters that are not alpha-numeric, `-` or `.` are removed. + +For example, consider binding the following properties to a `Map`: + + +[source,properties,indent=0,role="primary"] +.Properties +---- + acme.map.[/key1]=value1 + acme.map.[/key2]=value2 + acme.map./key3=value3 +---- + +[source,yaml,indent=0,role="secondary"] +.Yaml +---- + acme: + map: + "[/key1]": "value1" + "[/key2]": "value2" + "/key3": "value3" +---- + +NOTE: For YAML files, the brackets need to be surrounded by quotes for the keys to be parsed properly. + +The properties above will bind to a `Map` with `/key1`, `/key2` and `key3` as the keys in the map. +The slash has been removed from `key3` because it wasn't surrounded by square brackets. + +You may also occasionally need to use the bracket notation if your `key` contains a `.` and you are binding to non-scalar value. +For example, binding `a.b=c` to `Map` will return a Map with the entry `{"a"={"b"="c"}}` whereas `[a.b]=c` will return a Map with the entry `{"a.b"="c"}`. + + + +[[features.external-config.typesafe-configuration-properties.relaxed-binding.environment-variables]] +===== Binding from Environment Variables +Most operating systems impose strict rules around the names that can be used for environment variables. +For example, Linux shell variables can contain only letters (`a` to `z` or `A` to `Z`), numbers (`0` to `9`) or the underscore character (`_`). +By convention, Unix shell variables will also have their names in UPPERCASE. + +Spring Boot's relaxed binding rules are, as much as possible, designed to be compatible with these naming restrictions. + +To convert a property name in the canonical-form to an environment variable name you can follow these rules: + +* Replace dots (`.`) with underscores (`_`). +* Remove any dashes (`-`). +* Convert to uppercase. + +For example, the configuration property `spring.main.log-startup-info` would be an environment variable named `SPRING_MAIN_LOGSTARTUPINFO`. + +Environment variables can also be used when binding to object lists. +To bind to a `List`, the element number should be surrounded with underscores in the variable name. + +For example, the configuration property `my.acme[0].other` would use an environment variable named `MY_ACME_0_OTHER`. + + + +[[features.external-config.typesafe-configuration-properties.merging-complex-types]] +==== Merging Complex Types +When lists are configured in more than one place, overriding works by replacing the entire list. + +For example, assume a `MyPojo` object with `name` and `description` attributes that are `null` by default. +The following example exposes a list of `MyPojo` objects from `AcmeProperties`: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/externalizedconfiguration/merge/list/AcmeProperties.java[tag=*] +---- + +Consider the following configuration: + +[source,yaml,indent=0,configblocks] +---- + acme: + list: + - name: "my name" + description: "my description" + --- + spring: + config: + activate: + on-profile: "dev" + acme: + list: + - name: "my another name" +---- + +If the `dev` profile is not active, `AcmeProperties.list` contains one `MyPojo` entry, as previously defined. +If the `dev` profile is enabled, however, the `list` _still_ contains only one entry (with a name of `my another name` and a description of `null`). +This configuration _does not_ add a second `MyPojo` instance to the list, and it does not merge the items. + +When a `List` is specified in multiple profiles, the one with the highest priority (and only that one) is used. +Consider the following example: + +[source,yaml,indent=0,configblocks] +---- + acme: + list: + - name: "my name" + description: "my description" + - name: "another name" + description: "another description" + --- + spring: + config: + activate: + on-profile: "dev" + acme: + list: + - name: "my another name" +---- + +In the preceding example, if the `dev` profile is active, `AcmeProperties.list` contains _one_ `MyPojo` entry (with a name of `my another name` and a description of `null`). +For YAML, both comma-separated lists and YAML lists can be used for completely overriding the contents of the list. + +For `Map` properties, you can bind with property values drawn from multiple sources. +However, for the same property in multiple sources, the one with the highest priority is used. +The following example exposes a `Map` from `AcmeProperties`: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/externalizedconfiguration/merge/map/AcmeProperties.java[tag=*] +---- + +Consider the following configuration: + +[source,yaml,indent=0,configblocks] +---- + acme: + map: + key1: + name: "my name 1" + description: "my description 1" + --- + spring: + config: + activate: + on-profile: "dev" + acme: + map: + key1: + name: "dev name 1" + key2: + name: "dev name 2" + description: "dev description 2" +---- + +If the `dev` profile is not active, `AcmeProperties.map` contains one entry with key `key1` (with a name of `my name 1` and a description of `my description 1`). +If the `dev` profile is enabled, however, `map` contains two entries with keys `key1` (with a name of `dev name 1` and a description of `my description 1`) and `key2` (with a name of `dev name 2` and a description of `dev description 2`). + +NOTE: The preceding merging rules apply to properties from all property sources, and not just files. + + + +[[features.external-config.typesafe-configuration-properties.conversion]] +==== Properties Conversion +Spring Boot attempts to coerce the external application properties to the right type when it binds to the `@ConfigurationProperties` beans. +If you need custom type conversion, you can provide a `ConversionService` bean (with a bean named `conversionService`) or custom property editors (through a `CustomEditorConfigurer` bean) or custom `Converters` (with bean definitions annotated as `@ConfigurationPropertiesBinding`). + +NOTE: As this bean is requested very early during the application lifecycle, make sure to limit the dependencies that your `ConversionService` is using. +Typically, any dependency that you require may not be fully initialized at creation time. +You may want to rename your custom `ConversionService` if it is not required for configuration keys coercion and only rely on custom converters qualified with `@ConfigurationPropertiesBinding`. + + + +[[features.external-config.typesafe-configuration-properties.conversion.durations]] +===== Converting Durations +Spring Boot has dedicated support for expressing durations. +If you expose a `java.time.Duration` property, the following formats in application properties are available: + +* A regular `long` representation (using milliseconds as the default unit unless a `@DurationUnit` has been specified) +* The standard ISO-8601 format {java-api}/java/time/Duration.html#parse-java.lang.CharSequence-[used by `java.time.Duration`] +* A more readable format where the value and the unit are coupled (e.g. `10s` means 10 seconds) + +Consider the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/externalizedconfiguration/duration/javabeanbinding/AppSystemProperties.java[] +---- + +To specify a session timeout of 30 seconds, `30`, `PT30S` and `30s` are all equivalent. +A read timeout of 500ms can be specified in any of the following form: `500`, `PT0.5S` and `500ms`. + +You can also use any of the supported units. +These are: + +* `ns` for nanoseconds +* `us` for microseconds +* `ms` for milliseconds +* `s` for seconds +* `m` for minutes +* `h` for hours +* `d` for days + +The default unit is milliseconds and can be overridden using `@DurationUnit` as illustrated in the sample above. + +If you prefer to use constructor binding, the same properties can be exposed, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/externalizedconfiguration/duration/constructorbinding/AppSystemProperties.java[] +---- + + +TIP: If you are upgrading a `Long` property, make sure to define the unit (using `@DurationUnit`) if it isn't milliseconds. +Doing so gives a transparent upgrade path while supporting a much richer format. + + + +[[features.external-config.typesafe-configuration-properties.conversion.periods]] +===== Converting periods +In addition to durations, Spring Boot can also work with `java.time.Period` type. +The following formats can be used in application properties: + +* An regular `int` representation (using days as the default unit unless a `@PeriodUnit` has been specified) +* The standard ISO-8601 format {java-api}/java/time/Period.html#parse-java.lang.CharSequence-[used by `java.time.Period`] +* A simpler format where the value and the unit pairs are coupled (e.g. `1y3d` means 1 year and 3 days) + +The following units are supported with the simple format: + +* `y` for years +* `m` for months +* `w` for weeks +* `d` for days + +NOTE: The `java.time.Period` type never actually stores the number of weeks, it is a shortcut that means "`7 days`". + + + +[[features.external-config.typesafe-configuration-properties.conversion.data-sizes]] +===== Converting Data Sizes +Spring Framework has a `DataSize` value type that expresses a size in bytes. +If you expose a `DataSize` property, the following formats in application properties are available: + +* A regular `long` representation (using bytes as the default unit unless a `@DataSizeUnit` has been specified) +* A more readable format where the value and the unit are coupled (e.g. `10MB` means 10 megabytes) + +Consider the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/externalizedconfiguration/datasize/javabeanbinding/AppIoProperties.java[] +---- + +To specify a buffer size of 10 megabytes, `10` and `10MB` are equivalent. +A size threshold of 256 bytes can be specified as `256` or `256B`. + +You can also use any of the supported units. +These are: + +* `B` for bytes +* `KB` for kilobytes +* `MB` for megabytes +* `GB` for gigabytes +* `TB` for terabytes + +The default unit is bytes and can be overridden using `@DataSizeUnit` as illustrated in the sample above. + +If you prefer to use constructor binding, the same properties can be exposed, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/externalizedconfiguration/datasize/constructorbinding/AppIoProperties.java[] +---- + +TIP: If you are upgrading a `Long` property, make sure to define the unit (using `@DataSizeUnit`) if it isn't bytes. +Doing so gives a transparent upgrade path while supporting a much richer format. + + + +[[features.external-config.typesafe-configuration-properties.validation]] +==== @ConfigurationProperties Validation +Spring Boot attempts to validate `@ConfigurationProperties` classes whenever they are annotated with Spring's `@Validated` annotation. +You can use JSR-303 `javax.validation` constraint annotations directly on your configuration class. +To do so, ensure that a compliant JSR-303 implementation is on your classpath and then add constraint annotations to your fields, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/externalizedconfiguration/validate/AcmeProperties.java[] +---- + +TIP: You can also trigger validation by annotating the `@Bean` method that creates the configuration properties with `@Validated`. + +To ensure that validation is always triggered for nested properties, even when no properties are found, the associated field must be annotated with `@Valid`. +The following example builds on the preceding `AcmeProperties` example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/externalizedconfiguration/validate/nested/AcmeProperties.java[] +---- + +You can also add a custom Spring `Validator` by creating a bean definition called `configurationPropertiesValidator`. +The `@Bean` method should be declared `static`. +The configuration properties validator is created very early in the application's lifecycle, and declaring the `@Bean` method as static lets the bean be created without having to instantiate the `@Configuration` class. +Doing so avoids any problems that may be caused by early instantiation. + +TIP: The `spring-boot-actuator` module includes an endpoint that exposes all `@ConfigurationProperties` beans. +Point your web browser to `/actuator/configprops` or use the equivalent JMX endpoint. +See the "<>" section for details. + + + +[[features.external-config.typesafe-configuration-properties.vs-value-annotation]] +==== @ConfigurationProperties vs. @Value +The `@Value` annotation is a core container feature, and it does not provide the same features as type-safe configuration properties. +The following table summarizes the features that are supported by `@ConfigurationProperties` and `@Value`: + +[cols="4,2,2"] +|=== +| Feature |`@ConfigurationProperties` |`@Value` + +| <> +| Yes +| Limited (see <>) + +| <> +| Yes +| No + +| `SpEL` evaluation +| No +| Yes +|=== + +[[features.external-config.typesafe-configuration-properties.vs-value-annotation.note]] +NOTE: If you do want to use `@Value`, we recommend that you refer to property names using their canonical form (kebab-case using only lowercase letters). +This will allow Spring Boot to use the same logic as it does when relaxed binding `@ConfigurationProperties`. +For example, `@Value("{demo.item-price}")` will pick up `demo.item-price` and `demo.itemPrice` forms from the `application.properties` file, as well as `DEMO_ITEMPRICE` from the system environment. +If you used `@Value("{demo.itemPrice}")` instead, `demo.item-price` and `DEMO_ITEMPRICE` would not be considered. + +If you define a set of configuration keys for your own components, we recommend you group them in a POJO annotated with `@ConfigurationProperties`. +Doing so will provide you with structured, type-safe object that you can inject into your own beans. + +`SpEL` expressions from <> are not processed at time of parsing these files and populating the environment. +However, it is possible to write a `SpEL` expression in `@Value`. +If the value of a property from an application property file is a `SpEL` expression, it will be evaluated when consumed via `@Value`. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/graceful-shutdown.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/graceful-shutdown.adoc new file mode 100644 index 0000000000..fe14287883 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/graceful-shutdown.adoc @@ -0,0 +1,30 @@ +[[features.graceful-shutdown]] +== Graceful shutdown +Graceful shutdown is supported with all four embedded web servers (Jetty, Reactor Netty, Tomcat, and Undertow) and with both reactive and Servlet-based web applications. +It occurs as part of closing the application context and is performed in the earliest phase of stopping `SmartLifecycle` beans. +This stop processing uses a timeout which provides a grace period during which existing requests will be allowed to complete but no new requests will be permitted. +The exact way in which new requests are not permitted varies depending on the web server that is being used. +Jetty, Reactor Netty, and Tomcat will stop accepting requests at the network layer. +Undertow will accept requests but respond immediately with a service unavailable (503) response. + +NOTE: Graceful shutdown with Tomcat requires Tomcat 9.0.33 or later. + +To enable graceful shutdown, configure the configprop:server.shutdown[] property, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- +server: + shutdown: "graceful" +---- + +To configure the timeout period, configure the configprop:spring.lifecycle.timeout-per-shutdown-phase[] property, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- +spring: + lifecycle: + timeout-per-shutdown-phase: "20s" +---- + +IMPORTANT: Using graceful shutdown with your IDE may not work properly if it does not send a proper `SIGTERM` signal. +Refer to the documentation of your IDE for more details. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/hazelcast.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/hazelcast.adoc new file mode 100644 index 0000000000..f63b4db165 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/hazelcast.adoc @@ -0,0 +1,34 @@ +[[features.hazelcast]] +== Hazelcast +If https://hazelcast.com/[Hazelcast] is on the classpath and a suitable configuration is found, Spring Boot auto-configures a `HazelcastInstance` that you can inject in your application. + +Spring Boot first attempts to create a client by checking the following configuration options: + +* The presence of a `com.hazelcast.client.config.ClientConfig` bean. +* A configuration file defined by the configprop:spring.hazelcast.config[] property. +* The presence of the `hazelcast.client.config` system property. +* A `hazelcast-client.xml` in the working directory or at the root of the classpath. +* A `hazelcast-client.yaml` in the working directory or at the root of the classpath. + +NOTE: Spring Boot supports both Hazelcast 4 and Hazelcast 3. +If you downgrade to Hazelcast 3, `hazelcast-client` should be added to the classpath to configure a client. + +If a client can't be created, Spring Boot attempts to configure an embedded server. +If you define a `com.hazelcast.config.Config` bean, Spring Boot uses that. +If your configuration defines an instance name, Spring Boot tries to locate an existing instance rather than creating a new one. + +You could also specify the Hazelcast configuration file to use through configuration, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + hazelcast: + config: "classpath:config/my-hazelcast.xml" +---- + +Otherwise, Spring Boot tries to find the Hazelcast configuration from the default locations: `hazelcast.xml` in the working directory or at the root of the classpath, or a `.yaml` counterpart in the same locations. +We also check if the `hazelcast.config` system property is set. +See the https://docs.hazelcast.org/docs/latest/manual/html-single/[Hazelcast documentation] for more details. + +NOTE: Spring Boot also has <>. +If caching is enabled, the `HazelcastInstance` is automatically wrapped in a `CacheManager` implementation. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/internationalization.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/internationalization.adoc new file mode 100644 index 0000000000..5c46af625b --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/internationalization.adoc @@ -0,0 +1,22 @@ +[[features.internationalization]] +== Internationalization +Spring Boot supports localized messages so that your application can cater to users of different language preferences. +By default, Spring Boot looks for the presence of a `messages` resource bundle at the root of the classpath. + +NOTE: The auto-configuration applies when the default properties file for the configured resource bundle is available (i.e. `messages.properties` by default). +If your resource bundle contains only language-specific properties files, you are required to add the default. +If no properties file is found that matches any of the configured base names, there will be no auto-configured `MessageSource`. + +The basename of the resource bundle as well as several other attributes can be configured using the `spring.messages` namespace, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + messages: + basename: "messages,config.i18n.messages" + fallback-to-system-locale: false +---- + +TIP: `spring.messages.basename` supports comma-separated list of locations, either a package qualifier or a resource resolved from the classpath root. + +See {spring-boot-autoconfigure-module-code}/context/MessageSourceProperties.java[`MessageSourceProperties`] for more supported options. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/jmx.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/jmx.adoc new file mode 100644 index 0000000000..e0ac4ec3d1 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/jmx.adoc @@ -0,0 +1,10 @@ +[[features.jmx]] +== Monitoring and Management over JMX +Java Management Extensions (JMX) provide a standard mechanism to monitor and manage applications. +Spring Boot exposes the most suitable `MBeanServer` as a bean with an ID of `mbeanServer`. +Any of your beans that are annotated with Spring JMX annotations (`@ManagedResource`, `@ManagedAttribute`, or `@ManagedOperation`) are exposed to it. + +If your platform provides a standard `MBeanServer`, Spring Boot will use that and default to the VM `MBeanServer` if necessary. +If all that fails, a new `MBeanServer` will be created. + +See the {spring-boot-autoconfigure-module-code}/jmx/JmxAutoConfiguration.java[`JmxAutoConfiguration`] class for more details. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/json.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/json.adoc new file mode 100644 index 0000000000..e3f82ba9c8 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/json.adoc @@ -0,0 +1,34 @@ +[[features.json]] +== JSON +Spring Boot provides integration with three JSON mapping libraries: + +- Gson +- Jackson +- JSON-B + +Jackson is the preferred and default library. + + + +[[features.json.jackson]] +=== Jackson +Auto-configuration for Jackson is provided and Jackson is part of `spring-boot-starter-json`. +When Jackson is on the classpath an `ObjectMapper` bean is automatically configured. +Several configuration properties are provided for <>. + + + +[[features.json.gson]] +=== Gson +Auto-configuration for Gson is provided. +When Gson is on the classpath a `Gson` bean is automatically configured. +Several `+spring.gson.*+` configuration properties are provided for customizing the configuration. +To take more control, one or more `GsonBuilderCustomizer` beans can be used. + + + +[[features.json.json-b]] +=== JSON-B +Auto-configuration for JSON-B is provided. +When the JSON-B API and an implementation are on the classpath a `Jsonb` bean will be automatically configured. +The preferred JSON-B implementation is Apache Johnzon for which dependency management is provided. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/jta.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/jta.adoc new file mode 100644 index 0000000000..9edd71b7c5 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/jta.adoc @@ -0,0 +1,74 @@ +[[features.jta]] +== Distributed Transactions with JTA +Spring Boot supports distributed JTA transactions across multiple XA resources by using an https://www.atomikos.com/[Atomikos] embedded transaction manager. +JTA transactions are also supported when deploying to a suitable Java EE Application Server. + +When a JTA environment is detected, Spring's `JtaTransactionManager` is used to manage transactions. +Auto-configured JMS, DataSource, and JPA beans are upgraded to support XA transactions. +You can use standard Spring idioms, such as `@Transactional`, to participate in a distributed transaction. +If you are within a JTA environment and still want to use local transactions, you can set the configprop:spring.jta.enabled[] property to `false` to disable the JTA auto-configuration. + + + +[[features.jta.atomikos]] +=== Using an Atomikos Transaction Manager +https://www.atomikos.com/[Atomikos] is a popular open source transaction manager which can be embedded into your Spring Boot application. +You can use the `spring-boot-starter-jta-atomikos` starter to pull in the appropriate Atomikos libraries. +Spring Boot auto-configures Atomikos and ensures that appropriate `depends-on` settings are applied to your Spring beans for correct startup and shutdown ordering. + +By default, Atomikos transaction logs are written to a `transaction-logs` directory in your application's home directory (the directory in which your application jar file resides). +You can customize the location of this directory by setting a configprop:spring.jta.log-dir[] property in your `application.properties` file. +Properties starting with `spring.jta.atomikos.properties` can also be used to customize the Atomikos `UserTransactionServiceImp`. +See the {spring-boot-module-api}/jta/atomikos/AtomikosProperties.html[`AtomikosProperties` Javadoc] for complete details. + +NOTE: To ensure that multiple transaction managers can safely coordinate the same resource managers, each Atomikos instance must be configured with a unique ID. +By default, this ID is the IP address of the machine on which Atomikos is running. +To ensure uniqueness in production, you should configure the configprop:spring.jta.transaction-manager-id[] property with a different value for each instance of your application. + + + +[[features.jta.javaee]] +=== Using a Java EE Managed Transaction Manager +If you package your Spring Boot application as a `war` or `ear` file and deploy it to a Java EE application server, you can use your application server's built-in transaction manager. +Spring Boot tries to auto-configure a transaction manager by looking at common JNDI locations (`java:comp/UserTransaction`, `java:comp/TransactionManager`, and so on). +If you use a transaction service provided by your application server, you generally also want to ensure that all resources are managed by the server and exposed over JNDI. +Spring Boot tries to auto-configure JMS by looking for a `ConnectionFactory` at the JNDI path (`java:/JmsXA` or `java:/XAConnectionFactory`), and you can use the <> to configure your `DataSource`. + + + +[[features.jta.mixing-xa-and-non-xa-connections]] +=== Mixing XA and Non-XA JMS Connections +When using JTA, the primary JMS `ConnectionFactory` bean is XA-aware and participates in distributed transactions. +You can inject into your bean without needing to use any `@Qualifier`: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/jta/primary/MyBean.java[tag=*] +---- + +In some situations, you might want to process certain JMS messages by using a non-XA `ConnectionFactory`. +For example, your JMS processing logic might take longer than the XA timeout. + +If you want to use a non-XA `ConnectionFactory`, you can the `nonXaJmsConnectionFactory` bean: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/jta/nonxa/MyBean.java[tag=*] +---- + +For consistency, the `jmsConnectionFactory` bean is also provided by using the bean alias `xaJmsConnectionFactory`: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/jta/xa/MyBean.java[tag=*] +---- + + + +[[features.jta.supporting-alternative-embedded-transaction-manager]] +=== Supporting an Alternative Embedded Transaction Manager +The {spring-boot-module-code}/jms/XAConnectionFactoryWrapper.java[`XAConnectionFactoryWrapper`] and {spring-boot-module-code}/jdbc/XADataSourceWrapper.java[`XADataSourceWrapper`] interfaces can be used to support alternative embedded transaction managers. +The interfaces are responsible for wrapping `XAConnectionFactory` and `XADataSource` beans and exposing them as regular `ConnectionFactory` and `DataSource` beans, which transparently enroll in the distributed transaction. +DataSource and JMS auto-configuration use JTA variants, provided you have a `JtaTransactionManager` bean and appropriate XA wrapper beans registered within your `ApplicationContext`. + +The {spring-boot-module-code}/jta/atomikos/AtomikosXAConnectionFactoryWrapper.java[AtomikosXAConnectionFactoryWrapper] and {spring-boot-module-code}/jta/atomikos/AtomikosXADataSourceWrapper.java[AtomikosXADataSourceWrapper] provide good examples of how to write XA wrappers. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/kotlin.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/kotlin.adoc new file mode 100644 index 0000000000..fc50b47c1e --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/kotlin.adoc @@ -0,0 +1,173 @@ +[[features.kotlin]] +== Kotlin support +https://kotlinlang.org[Kotlin] is a statically-typed language targeting the JVM (and other platforms) which allows writing concise and elegant code while providing {kotlin-docs}java-interop.html[interoperability] with existing libraries written in Java. + +Spring Boot provides Kotlin support by leveraging the support in other Spring projects such as Spring Framework, Spring Data, and Reactor. +See the {spring-framework-docs}/languages.html#kotlin[Spring Framework Kotlin support documentation] for more information. + +The easiest way to start with Spring Boot and Kotlin is to follow https://spring.io/guides/tutorials/spring-boot-kotlin/[this comprehensive tutorial]. +You can create new Kotlin projects via https://start.spring.io/#!language=kotlin[start.spring.io]. +Feel free to join the #spring channel of https://slack.kotlinlang.org/[Kotlin Slack] or ask a question with the `spring` and `kotlin` tags on https://stackoverflow.com/questions/tagged/spring+kotlin[Stack Overflow] if you need support. + + + +[[features.kotlin.requirements]] +=== Requirements +Spring Boot supports Kotlin 1.3.x. +To use Kotlin, `org.jetbrains.kotlin:kotlin-stdlib` and `org.jetbrains.kotlin:kotlin-reflect` must be present on the classpath. +The `kotlin-stdlib` variants `kotlin-stdlib-jdk7` and `kotlin-stdlib-jdk8` can also be used. + +Since https://discuss.kotlinlang.org/t/classes-final-by-default/166[Kotlin classes are final by default], you are likely to want to configure {kotlin-docs}compiler-plugins.html#spring-support[kotlin-spring] plugin in order to automatically open Spring-annotated classes so that they can be proxied. + +https://github.com/FasterXML/jackson-module-kotlin[Jackson's Kotlin module] is required for serializing / deserializing JSON data in Kotlin. +It is automatically registered when found on the classpath. +A warning message is logged if Jackson and Kotlin are present but the Jackson Kotlin module is not. + +TIP: These dependencies and plugins are provided by default if one bootstraps a Kotlin project on https://start.spring.io/#!language=kotlin[start.spring.io]. + + + +[[features.kotlin.null-safety]] +=== Null-safety +One of Kotlin's key features is {kotlin-docs}null-safety.html[null-safety]. +It deals with `null` values at compile time rather than deferring the problem to runtime and encountering a `NullPointerException`. +This helps to eliminate a common source of bugs without paying the cost of wrappers like `Optional`. +Kotlin also allows using functional constructs with nullable values as described in this https://www.baeldung.com/kotlin-null-safety[comprehensive guide to null-safety in Kotlin]. + +Although Java does not allow one to express null-safety in its type system, Spring Framework, Spring Data, and Reactor now provide null-safety of their API via tooling-friendly annotations. +By default, types from Java APIs used in Kotlin are recognized as {kotlin-docs}java-interop.html#null-safety-and-platform-types[platform types] for which null-checks are relaxed. +{kotlin-docs}java-interop.html#jsr-305-support[Kotlin's support for JSR 305 annotations] combined with nullability annotations provide null-safety for the related Spring API in Kotlin. + +The JSR 305 checks can be configured by adding the `-Xjsr305` compiler flag with the following options: `-Xjsr305={strict|warn|ignore}`. +The default behavior is the same as `-Xjsr305=warn`. +The `strict` value is required to have null-safety taken in account in Kotlin types inferred from Spring API but should be used with the knowledge that Spring API nullability declaration could evolve even between minor releases and more checks may be added in the future). + +WARNING: Generic type arguments, varargs and array elements nullability are not yet supported. +See https://jira.spring.io/browse/SPR-15942[SPR-15942] for up-to-date information. +Also be aware that Spring Boot's own API is {github-issues}10712[not yet annotated]. + + + +[[features.kotlin.api]] +=== Kotlin API + + + +[[features.kotlin.api.?run-application]] +==== runApplication +Spring Boot provides an idiomatic way to run an application with `runApplication(*args)` as shown in the following example: + +[source,kotlin,indent=0] +---- + import org.springframework.boot.autoconfigure.SpringBootApplication + import org.springframework.boot.runApplication + + @SpringBootApplication + class MyApplication + + fun main(args: Array) { + runApplication(*args) + } +---- + +This is a drop-in replacement for `SpringApplication.run(MyApplication::class.java, *args)`. +It also allows customization of the application as shown in the following example: + +[source,kotlin,indent=0] +---- + runApplication(*args) { + setBannerMode(OFF) + } +---- + + + +[[features.kotlin.api.extensions]] +==== Extensions +Kotlin {kotlin-docs}extensions.html[extensions] provide the ability to extend existing classes with additional functionality. +The Spring Boot Kotlin API makes use of these extensions to add new Kotlin specific conveniences to existing APIs. + +`TestRestTemplate` extensions, similar to those provided by Spring Framework for `RestOperations` in Spring Framework, are provided. +Among other things, the extensions make it possible to take advantage of Kotlin reified type parameters. + + + +[[features.kotlin.dependency-management]] +=== Dependency management +In order to avoid mixing different versions of Kotlin dependencies on the classpath, Spring Boot imports the Kotlin BOM. + +With Maven, the Kotlin version can be customized via the `kotlin.version` property and plugin management is provided for `kotlin-maven-plugin`. +With Gradle, the Spring Boot plugin automatically aligns the `kotlin.version` with the version of the Kotlin plugin. + +Spring Boot also manages the version of Coroutines dependencies by importing the Kotlin Coroutines BOM. +The version can be customized via the `kotlin-coroutines.version` property. + +TIP: `org.jetbrains.kotlinx:kotlinx-coroutines-reactor` dependency is provided by default if one bootstraps a Kotlin project with at least one reactive dependency on https://start.spring.io/#!language=kotlin[start.spring.io]. + + + +[[features.kotlin.configuration-properties]] +=== @ConfigurationProperties +`@ConfigurationProperties` when used in combination with <> supports classes with immutable `val` properties as shown in the following example: + +[source,kotlin,indent=0] +---- +@ConstructorBinding +@ConfigurationProperties("example.kotlin") +data class KotlinExampleProperties( + val name: String, + val description: String, + val myService: MyService) { + + data class MyService( + val apiToken: String, + val uri: URI + ) +} +---- + +TIP: To generate <> using the annotation processor, {kotlin-docs}kapt.html[`kapt` should be configured] with the `spring-boot-configuration-processor` dependency. +Note that some features (such as detecting the default value or deprecated items) are not working due to limitations in the model kapt provides. + + + +[[features.kotlin.testing]] +=== Testing +While it is possible to use JUnit 4 to test Kotlin code, JUnit 5 is provided by default and is recommended. +JUnit 5 enables a test class to be instantiated once and reused for all of the class's tests. +This makes it possible to use `@BeforeAll` and `@AfterAll` annotations on non-static methods, which is a good fit for Kotlin. + +To mock Kotlin classes, https://mockk.io/[MockK] is recommended. +If you need the `Mockk` equivalent of the Mockito specific <>, you can use https://github.com/Ninja-Squad/springmockk[SpringMockK] which provides similar `@MockkBean` and `@SpykBean` annotations. + + + +[[features.kotlin.resources]] +=== Resources + + + +[[features.kotlin.resources.further-reading]] +==== Further reading +* {kotlin-docs}[Kotlin language reference] +* https://kotlinlang.slack.com/[Kotlin Slack] (with a dedicated #spring channel) +* https://stackoverflow.com/questions/tagged/spring+kotlin[Stackoverflow with `spring` and `kotlin` tags] +* https://try.kotlinlang.org/[Try Kotlin in your browser] +* https://blog.jetbrains.com/kotlin/[Kotlin blog] +* https://kotlin.link/[Awesome Kotlin] +* https://spring.io/guides/tutorials/spring-boot-kotlin/[Tutorial: building web applications with Spring Boot and Kotlin] +* https://spring.io/blog/2016/02/15/developing-spring-boot-applications-with-kotlin[Developing Spring Boot applications with Kotlin] +* https://spring.io/blog/2016/03/20/a-geospatial-messenger-with-kotlin-spring-boot-and-postgresql[A Geospatial Messenger with Kotlin, Spring Boot and PostgreSQL] +* https://spring.io/blog/2017/01/04/introducing-kotlin-support-in-spring-framework-5-0[Introducing Kotlin support in Spring Framework 5.0] +* https://spring.io/blog/2017/08/01/spring-framework-5-kotlin-apis-the-functional-way[Spring Framework 5 Kotlin APIs, the functional way] + + + +[[features.kotlin.resources.examples]] +==== Examples +* https://github.com/sdeleuze/spring-boot-kotlin-demo[spring-boot-kotlin-demo]: regular Spring Boot + Spring Data JPA project +* https://github.com/mixitconf/mixit[mixit]: Spring Boot 2 + WebFlux + Reactive Spring Data MongoDB +* https://github.com/sdeleuze/spring-kotlin-fullstack[spring-kotlin-fullstack]: WebFlux Kotlin fullstack example with Kotlin2js for frontend instead of JavaScript or TypeScript +* https://github.com/spring-petclinic/spring-petclinic-kotlin[spring-petclinic-kotlin]: Kotlin version of the Spring PetClinic Sample Application +* https://github.com/sdeleuze/spring-kotlin-deepdive[spring-kotlin-deepdive]: a step by step migration for Boot 1.0 + Java to Boot 2.0 + Kotlin +* https://github.com/sdeleuze/spring-boot-coroutines-demo[spring-boot-coroutines-demo]: Coroutines sample project diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/logging.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/logging.adoc new file mode 100644 index 0000000000..c6faa538bc --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/logging.adoc @@ -0,0 +1,481 @@ +[[features.logging]] +== Logging +Spring Boot uses https://commons.apache.org/logging[Commons Logging] for all internal logging but leaves the underlying log implementation open. +Default configurations are provided for {java-api}/java/util/logging/package-summary.html[Java Util Logging], https://logging.apache.org/log4j/2.x/[Log4J2], and https://logback.qos.ch/[Logback]. +In each case, loggers are pre-configured to use console output with optional file output also available. + +By default, if you use the "`Starters`", Logback is used for logging. +Appropriate Logback routing is also included to ensure that dependent libraries that use Java Util Logging, Commons Logging, Log4J, or SLF4J all work correctly. + +TIP: There are a lot of logging frameworks available for Java. +Do not worry if the above list seems confusing. +Generally, you do not need to change your logging dependencies and the Spring Boot defaults work just fine. + +TIP: When you deploy your application to a servlet container or application server, logging performed via the Java Util Logging API is not routed into your application's logs. +This prevents logging performed by the container or other applications that have been deployed to it from appearing in your application's logs. + + + +[[features.logging.log-format]] +=== Log Format +The default log output from Spring Boot resembles the following example: + +[indent=0] +---- +2019-03-05 10:57:51.112 INFO 45469 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet Engine: Apache Tomcat/7.0.52 +2019-03-05 10:57:51.253 INFO 45469 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext +2019-03-05 10:57:51.253 INFO 45469 --- [ost-startStop-1] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 1358 ms +2019-03-05 10:57:51.698 INFO 45469 --- [ost-startStop-1] o.s.b.c.e.ServletRegistrationBean : Mapping servlet: 'dispatcherServlet' to [/] +2019-03-05 10:57:51.702 INFO 45469 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean : Mapping filter: 'hiddenHttpMethodFilter' to: [/*] +---- + +The following items are output: + +* Date and Time: Millisecond precision and easily sortable. +* Log Level: `ERROR`, `WARN`, `INFO`, `DEBUG`, or `TRACE`. +* Process ID. +* A `---` separator to distinguish the start of actual log messages. +* Thread name: Enclosed in square brackets (may be truncated for console output). +* Logger name: This is usually the source class name (often abbreviated). +* The log message. + +NOTE: Logback does not have a `FATAL` level. +It is mapped to `ERROR`. + + + +[[features.logging.console-output]] +=== Console Output +The default log configuration echoes messages to the console as they are written. +By default, `ERROR`-level, `WARN`-level, and `INFO`-level messages are logged. +You can also enable a "`debug`" mode by starting your application with a `--debug` flag. + +[indent=0] +---- + $ java -jar myapp.jar --debug +---- + +NOTE: You can also specify `debug=true` in your `application.properties`. + +When the debug mode is enabled, a selection of core loggers (embedded container, Hibernate, and Spring Boot) are configured to output more information. +Enabling the debug mode does _not_ configure your application to log all messages with `DEBUG` level. + +Alternatively, you can enable a "`trace`" mode by starting your application with a `--trace` flag (or `trace=true` in your `application.properties`). +Doing so enables trace logging for a selection of core loggers (embedded container, Hibernate schema generation, and the whole Spring portfolio). + + + +[[features.logging.console-output.color-coded]] +==== Color-coded Output +If your terminal supports ANSI, color output is used to aid readability. +You can set `spring.output.ansi.enabled` to a {spring-boot-module-api}/ansi/AnsiOutput.Enabled.html[supported value] to override the auto-detection. + +Color coding is configured by using the `%clr` conversion word. +In its simplest form, the converter colors the output according to the log level, as shown in the following example: + +[source,indent=0] +---- +%clr(%5p) +---- + +The following table describes the mapping of log levels to colors: + +|=== +| Level | Color + +| `FATAL` +| Red + +| `ERROR` +| Red + +| `WARN` +| Yellow + +| `INFO` +| Green + +| `DEBUG` +| Green + +| `TRACE` +| Green +|=== + +Alternatively, you can specify the color or style that should be used by providing it as an option to the conversion. +For example, to make the text yellow, use the following setting: + +[source,indent=0] +---- +%clr(%d{yyyy-MM-dd HH:mm:ss.SSS}){yellow} +---- + +The following colors and styles are supported: + +* `blue` +* `cyan` +* `faint` +* `green` +* `magenta` +* `red` +* `yellow` + + + +[[features.logging.file-output]] +=== File Output +By default, Spring Boot logs only to the console and does not write log files. +If you want to write log files in addition to the console output, you need to set a configprop:logging.file.name[] or configprop:logging.file.path[] property (for example, in your `application.properties`). + +The following table shows how the `logging.*` properties can be used together: + +.Logging properties +[cols="1,1,1,4"] +|=== +| configprop:logging.file.name[] | configprop:logging.file.path[] | Example | Description + +| _(none)_ +| _(none)_ +| +| Console only logging. + +| Specific file +| _(none)_ +| `my.log` +| Writes to the specified log file. + Names can be an exact location or relative to the current directory. + +| _(none)_ +| Specific directory +| `/var/log` +| Writes `spring.log` to the specified directory. + Names can be an exact location or relative to the current directory. +|=== + +Log files rotate when they reach 10 MB and, as with console output, `ERROR`-level, `WARN`-level, and `INFO`-level messages are logged by default. + +TIP: Logging properties are independent of the actual logging infrastructure. +As a result, specific configuration keys (such as `logback.configurationFile` for Logback) are not managed by spring Boot. + + + +[[features.logging.file-rotation]] +=== File Rotation +If you are using the Logback, it's possible to fine-tune log rotation settings using your `application.properties` or `application.yaml` file. +For all other logging system, you'll need to configure rotation settings directly yourself (for example, if you use Log4J2 then you could add a `log4j.xml` file). + +The following rotation policy properties are supported: + +|=== +| Name | Description + +| configprop:logging.logback.rollingpolicy.file-name-pattern[] +| The filename pattern used to create log archives. + +| configprop:logging.logback.rollingpolicy.clean-history-on-start[] +| If log archive cleanup should occur when the application starts. + +| configprop:logging.logback.rollingpolicy.max-file-size[] +| The maximum size of log file before it's archived. + +| configprop:logging.logback.rollingpolicy.total-size-cap[] +| The maximum amount of size log archives can take before being deleted. + +| configprop:logging.logback.rollingpolicy.max-history[] +| The number of days to keep log archives (defaults to 7) +|=== + + + +[[features.logging.log-levels]] +=== Log Levels +All the supported logging systems can have the logger levels set in the Spring `Environment` (for example, in `application.properties`) by using `+logging.level.=+` where `level` is one of TRACE, DEBUG, INFO, WARN, ERROR, FATAL, or OFF. +The `root` logger can be configured by using `logging.level.root`. + +The following example shows potential logging settings in `application.properties`: + +[source,properties,indent=0,subs="verbatim,quotes,attributes",configprops,role="primary"] +.Properties +---- + logging.level.root=warn + logging.level.org.springframework.web=debug + logging.level.org.hibernate=error +---- + +[source,properties,indent=0,subs="verbatim,quotes,attributes",role="secondary"] +.Yaml +---- + logging: + level: + root: "warn" + org.springframework.web: "debug" + org.hibernate: "error" +---- + +It's also possible to set logging levels using environment variables. +For example, `LOGGING_LEVEL_ORG_SPRINGFRAMEWORK_WEB=DEBUG` will set `org.springframework.web` to `DEBUG`. + +NOTE: The above approach will only work for package level logging. +Since relaxed binding always converts environment variables to lowercase, it's not possible to configure logging for an individual class in this way. +If you need to configure logging for a class, you can use <> variable. + + + +[[features.logging.log-groups]] +=== Log Groups +It's often useful to be able to group related loggers together so that they can all be configured at the same time. +For example, you might commonly change the logging levels for _all_ Tomcat related loggers, but you can't easily remember top level packages. + +To help with this, Spring Boot allows you to define logging groups in your Spring `Environment`. +For example, here's how you could define a "`tomcat`" group by adding it to your `application.properties`: + +[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] +---- + logging: + group: + tomcat: "org.apache.catalina,org.apache.coyote,org.apache.tomcat" +---- + +Once defined, you can change the level for all the loggers in the group with a single line: + +[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] +---- + logging: + level: + tomcat: "trace" +---- + +Spring Boot includes the following pre-defined logging groups that can be used out-of-the-box: + +[cols="1,4"] +|=== +| Name | Loggers + +| web +| `org.springframework.core.codec`, `org.springframework.http`, `org.springframework.web`, `org.springframework.boot.actuate.endpoint.web`, `org.springframework.boot.web.servlet.ServletContextInitializerBeans` + +| sql +| `org.springframework.jdbc.core`, `org.hibernate.SQL`, `org.jooq.tools.LoggerListener` +|=== + + + +[[features.logging.shutdown-hook]] +=== Using a Log Shutdown Hook +In order to release logging resources when your application terminates, a shutdown hook that will trigger log system cleanup when the JVM exits is provided. +This shutdown hook is registered automatically unless your application is deployed as a war file. +If your application has complex context hierarchies the shutdown hook may not meet your needs. +If it does not, disable the shutdown hook and investigate the options provided directly by the underlying logging system. +For example, Logback offers http://logback.qos.ch/manual/loggingSeparation.html[context selectors] which allow each Logger to be created in its own context. +You can use the configprop:logging.register-shutdown-hook[] property to disable the shutdown hook. +Setting it to `false` will disable the registration. +You can set the property in your `application.properties` or `application.yaml` file: + +[source,yaml,indent=0,configprops,configblocks] +---- + logging: + register-shutdown-hook: false +---- + + + +[[features.logging.custom-log-configuration]] +=== Custom Log Configuration +The various logging systems can be activated by including the appropriate libraries on the classpath and can be further customized by providing a suitable configuration file in the root of the classpath or in a location specified by the following Spring `Environment` property: configprop:logging.config[]. + +You can force Spring Boot to use a particular logging system by using the `org.springframework.boot.logging.LoggingSystem` system property. +The value should be the fully qualified class name of a `LoggingSystem` implementation. +You can also disable Spring Boot's logging configuration entirely by using a value of `none`. + +NOTE: Since logging is initialized *before* the `ApplicationContext` is created, it is not possible to control logging from `@PropertySources` in Spring `@Configuration` files. +The only way to change the logging system or disable it entirely is via System properties. + +Depending on your logging system, the following files are loaded: + +|=== +| Logging System | Customization + +| Logback +| `logback-spring.xml`, `logback-spring.groovy`, `logback.xml`, or `logback.groovy` + +| Log4j2 +| `log4j2-spring.xml` or `log4j2.xml` + +| JDK (Java Util Logging) +| `logging.properties` +|=== + +NOTE: When possible, we recommend that you use the `-spring` variants for your logging configuration (for example, `logback-spring.xml` rather than `logback.xml`). +If you use standard configuration locations, Spring cannot completely control log initialization. + +WARNING: There are known classloading issues with Java Util Logging that cause problems when running from an 'executable jar'. +We recommend that you avoid it when running from an 'executable jar' if at all possible. + +To help with the customization, some other properties are transferred from the Spring `Environment` to System properties, as described in the following table: + +|=== +| Spring Environment | System Property | Comments + +| configprop:logging.exception-conversion-word[] +| `LOG_EXCEPTION_CONVERSION_WORD` +| The conversion word used when logging exceptions. + +| configprop:logging.file.name[] +| `LOG_FILE` +| If defined, it is used in the default log configuration. + +| configprop:logging.file.path[] +| `LOG_PATH` +| If defined, it is used in the default log configuration. + +| configprop:logging.pattern.console[] +| `CONSOLE_LOG_PATTERN` +| The log pattern to use on the console (stdout). + +| configprop:logging.pattern.dateformat[] +| `LOG_DATEFORMAT_PATTERN` +| Appender pattern for log date format. + +| configprop:logging.charset.console[] +| `CONSOLE_LOG_CHARSET` +| The charset to use for console logging. + +| configprop:logging.pattern.file[] +| `FILE_LOG_PATTERN` +| The log pattern to use in a file (if `LOG_FILE` is enabled). + +| configprop:logging.charset.file[] +| `FILE_LOG_CHARSET` +| The charset to use for file logging (if `LOG_FILE` is enabled). + +| configprop:logging.pattern.level[] +| `LOG_LEVEL_PATTERN` +| The format to use when rendering the log level (default `%5p`). + +| `PID` +| `PID` +| The current process ID (discovered if possible and when not already defined as an OS environment variable). +|=== + +If you're using Logback, the following properties are also transferred: + +|=== +| Spring Environment | System Property | Comments + +| configprop:logging.logback.rollingpolicy.file-name-pattern[] +| `LOGBACK_ROLLINGPOLICY_FILE_NAME_PATTERN` +| Pattern for rolled-over log file names (default `$\{LOG_FILE}.%d\{yyyy-MM-dd}.%i.gz`). + +| configprop:logging.logback.rollingpolicy.clean-history-on-start[] +| `LOGBACK_ROLLINGPOLICY_CLEAN_HISTORY_ON_START` +| Whether to clean the archive log files on startup. + +| configprop:logging.logback.rollingpolicy.max-file-size[] +| `LOGBACK_ROLLINGPOLICY_MAX_FILE_SIZE` +| Maximum log file size. + +| configprop:logging.logback.rollingpolicy.total-size-cap[] +| `LOGBACK_ROLLINGPOLICY_TOTAL_SIZE_CAP` +| Total size of log backups to be kept. + +| configprop:logging.logback.rollingpolicy.max-history[] +| `LOGBACK_ROLLINGPOLICY_MAX_HISTORY` +| Maximum number of archive log files to keep. +|=== + + +All the supported logging systems can consult System properties when parsing their configuration files. +See the default configurations in `spring-boot.jar` for examples: + +* {spring-boot-code}/spring-boot-project/spring-boot/src/main/resources/org/springframework/boot/logging/logback/defaults.xml[Logback] +* {spring-boot-code}/spring-boot-project/spring-boot/src/main/resources/org/springframework/boot/logging/log4j2/log4j2.xml[Log4j 2] +* {spring-boot-code}/spring-boot-project/spring-boot/src/main/resources/org/springframework/boot/logging/java/logging-file.properties[Java Util logging] + +[TIP] +==== +If you want to use a placeholder in a logging property, you should use <> and not the syntax of the underlying framework. +Notably, if you use Logback, you should use `:` as the delimiter between a property name and its default value and not use `:-`. +==== + +[TIP] +==== +You can add MDC and other ad-hoc content to log lines by overriding only the `LOG_LEVEL_PATTERN` (or `logging.pattern.level` with Logback). +For example, if you use `logging.pattern.level=user:%X\{user} %5p`, then the default log format contains an MDC entry for "user", if it exists, as shown in the following example. + +[indent=0] +---- + 2019-08-30 12:30:04.031 user:someone INFO 22174 --- [ nio-8080-exec-0] demo.Controller + Handling authenticated request +---- +==== + + + +[[features.logging.logback-extensions]] +=== Logback Extensions +Spring Boot includes a number of extensions to Logback that can help with advanced configuration. +You can use these extensions in your `logback-spring.xml` configuration file. + +NOTE: Because the standard `logback.xml` configuration file is loaded too early, you cannot use extensions in it. +You need to either use `logback-spring.xml` or define a configprop:logging.config[] property. + +WARNING: The extensions cannot be used with Logback's https://logback.qos.ch/manual/configuration.html#autoScan[configuration scanning]. +If you attempt to do so, making changes to the configuration file results in an error similar to one of the following being logged: + +[indent=0] +---- + ERROR in ch.qos.logback.core.joran.spi.Interpreter@4:71 - no applicable action for [springProperty], current ElementPath is [[configuration][springProperty]] + ERROR in ch.qos.logback.core.joran.spi.Interpreter@4:71 - no applicable action for [springProfile], current ElementPath is [[configuration][springProfile]] +---- + + + +[[features.logging.logback-extensions.profile-specific]] +==== Profile-specific Configuration +The `` tag lets you optionally include or exclude sections of configuration based on the active Spring profiles. +Profile sections are supported anywhere within the `` element. +Use the `name` attribute to specify which profile accepts the configuration. +The `` tag can contain a profile name (for example `staging`) or a profile expression. +A profile expression allows for more complicated profile logic to be expressed, for example `production & (eu-central | eu-west)`. +Check the {spring-framework-docs}/core.html#beans-definition-profiles-java[reference guide] for more details. +The following listing shows three sample profiles: + +[source,xml,indent=0] +---- + + + + + + + + + + + +---- + + + +[[features.logging.logback-extensions.environment-properties]] +==== Environment Properties +The `` tag lets you expose properties from the Spring `Environment` for use within Logback. +Doing so can be useful if you want to access values from your `application.properties` file in your Logback configuration. +The tag works in a similar way to Logback's standard `` tag. +However, rather than specifying a direct `value`, you specify the `source` of the property (from the `Environment`). +If you need to store the property somewhere other than in `local` scope, you can use the `scope` attribute. +If you need a fallback value (in case the property is not set in the `Environment`), you can use the `defaultValue` attribute. +The following example shows how to expose properties for use within Logback: + +[source,xml,indent=0] +---- + + + ${fluentHost} + ... + +---- + +NOTE: The `source` must be specified in kebab case (such as `my.property-name`). +However, properties can be added to the `Environment` by using the relaxed rules. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/messaging.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/messaging.adoc new file mode 100644 index 0000000000..e092c8cfe1 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/messaging.adoc @@ -0,0 +1,492 @@ +[[features.messaging]] +== Messaging +The Spring Framework provides extensive support for integrating with messaging systems, from simplified use of the JMS API using `JmsTemplate` to a complete infrastructure to receive messages asynchronously. +Spring AMQP provides a similar feature set for the Advanced Message Queuing Protocol. +Spring Boot also provides auto-configuration options for `RabbitTemplate` and RabbitMQ. +Spring WebSocket natively includes support for STOMP messaging, and Spring Boot has support for that through starters and a small amount of auto-configuration. +Spring Boot also has support for Apache Kafka. + + + +[[features.messaging.jms]] +=== JMS +The `javax.jms.ConnectionFactory` interface provides a standard method of creating a `javax.jms.Connection` for interacting with a JMS broker. +Although Spring needs a `ConnectionFactory` to work with JMS, you generally need not use it directly yourself and can instead rely on higher level messaging abstractions. +(See the {spring-framework-docs}/integration.html#jms[relevant section] of the Spring Framework reference documentation for details.) +Spring Boot also auto-configures the necessary infrastructure to send and receive messages. + + + +[[features.messaging.jms.activemq]] +==== ActiveMQ Support +When https://activemq.apache.org/[ActiveMQ] is available on the classpath, Spring Boot can also configure a `ConnectionFactory`. +If the broker is present, an embedded broker is automatically started and configured (provided no broker URL is specified through configuration). + +NOTE: If you use `spring-boot-starter-activemq`, the necessary dependencies to connect or embed an ActiveMQ instance are provided, as is the Spring infrastructure to integrate with JMS. + +ActiveMQ configuration is controlled by external configuration properties in `+spring.activemq.*+`. +For example, you might declare the following section in `application.properties`: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + activemq: + broker-url: "tcp://192.168.1.210:9876" + user: "admin" + password: "secret" +---- + +By default, a `CachingConnectionFactory` wraps the native `ConnectionFactory` with sensible settings that you can control by external configuration properties in `+spring.jms.*+`: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + jms: + cache: + session-cache-size: 5 +---- + +If you'd rather use native pooling, you can do so by adding a dependency to `org.messaginghub:pooled-jms` and configuring the `JmsPoolConnectionFactory` accordingly, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + activemq: + pool: + enabled: true + max-connections: 50 +---- + +TIP: See {spring-boot-autoconfigure-module-code}/jms/activemq/ActiveMQProperties.java[`ActiveMQProperties`] for more of the supported options. +You can also register an arbitrary number of beans that implement `ActiveMQConnectionFactoryCustomizer` for more advanced customizations. + +By default, ActiveMQ creates a destination if it does not yet exist so that destinations are resolved against their provided names. + + + +[[features.messaging.jms.artemis]] +==== ActiveMQ Artemis Support +Spring Boot can auto-configure a `ConnectionFactory` when it detects that https://activemq.apache.org/components/artemis/[ActiveMQ Artemis] is available on the classpath. +If the broker is present, an embedded broker is automatically started and configured (unless the mode property has been explicitly set). +The supported modes are `embedded` (to make explicit that an embedded broker is required and that an error should occur if the broker is not available on the classpath) and `native` (to connect to a broker using the `netty` transport protocol). +When the latter is configured, Spring Boot configures a `ConnectionFactory` that connects to a broker running on the local machine with the default settings. + +NOTE: If you use `spring-boot-starter-artemis`, the necessary dependencies to connect to an existing ActiveMQ Artemis instance are provided, as well as the Spring infrastructure to integrate with JMS. +Adding `org.apache.activemq:artemis-jms-server` to your application lets you use embedded mode. + +ActiveMQ Artemis configuration is controlled by external configuration properties in `+spring.artemis.*+`. +For example, you might declare the following section in `application.properties`: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + artemis: + mode: native + broker-url: "tcp://192.168.1.210:9876" + user: "admin" + password: "secret" +---- + +When embedding the broker, you can choose if you want to enable persistence and list the destinations that should be made available. +These can be specified as a comma-separated list to create them with the default options, or you can define bean(s) of type `org.apache.activemq.artemis.jms.server.config.JMSQueueConfiguration` or `org.apache.activemq.artemis.jms.server.config.TopicConfiguration`, for advanced queue and topic configurations, respectively. + +By default, a `CachingConnectionFactory` wraps the native `ConnectionFactory` with sensible settings that you can control by external configuration properties in `+spring.jms.*+`: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + jms: + cache: + session-cache-size: 5 +---- + +If you'd rather use native pooling, you can do so by adding a dependency to `org.messaginghub:pooled-jms` and configuring the `JmsPoolConnectionFactory` accordingly, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + artemis: + pool: + enabled: true + max-connections: 50 +---- + +See {spring-boot-autoconfigure-module-code}/jms/artemis/ArtemisProperties.java[`ArtemisProperties`] for more supported options. + +No JNDI lookup is involved, and destinations are resolved against their names, using either the `name` attribute in the Artemis configuration or the names provided through configuration. + + + +[[features.messaging.jms.jndi]] +==== Using a JNDI ConnectionFactory +If you are running your application in an application server, Spring Boot tries to locate a JMS `ConnectionFactory` by using JNDI. +By default, the `java:/JmsXA` and `java:/XAConnectionFactory` location are checked. +You can use the configprop:spring.jms.jndi-name[] property if you need to specify an alternative location, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + jms: + jndi-name: "java:/MyConnectionFactory" +---- + + + +[[features.messaging.jms.sending]] +==== Sending a Message +Spring's `JmsTemplate` is auto-configured, and you can autowire it directly into your own beans, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/messaging/jms/template/MyBean.java[] +---- + +NOTE: {spring-framework-api}/jms/core/JmsMessagingTemplate.html[`JmsMessagingTemplate`] can be injected in a similar manner. +If a `DestinationResolver` or a `MessageConverter` bean is defined, it is associated automatically to the auto-configured `JmsTemplate`. + + + +[[features.messaging.jms.receiving]] +==== Receiving a Message +When the JMS infrastructure is present, any bean can be annotated with `@JmsListener` to create a listener endpoint. +If no `JmsListenerContainerFactory` has been defined, a default one is configured automatically. +If a `DestinationResolver`, a `MessageConverter`, or a `javax.jms.ExceptionListener` beans are defined, they are associated automatically with the default factory. + +By default, the default factory is transactional. +If you run in an infrastructure where a `JtaTransactionManager` is present, it is associated to the listener container by default. +If not, the `sessionTransacted` flag is enabled. +In that latter scenario, you can associate your local data store transaction to the processing of an incoming message by adding `@Transactional` on your listener method (or a delegate thereof). +This ensures that the incoming message is acknowledged, once the local transaction has completed. +This also includes sending response messages that have been performed on the same JMS session. + +The following component creates a listener endpoint on the `someQueue` destination: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/messaging/jms/receiving/MyBean.java[] +---- + +TIP: See {spring-framework-api}/jms/annotation/EnableJms.html[the Javadoc of `@EnableJms`] for more details. + +If you need to create more `JmsListenerContainerFactory` instances or if you want to override the default, Spring Boot provides a `DefaultJmsListenerContainerFactoryConfigurer` that you can use to initialize a `DefaultJmsListenerContainerFactory` with the same settings as the one that is auto-configured. + +For instance, the following example exposes another factory that uses a specific `MessageConverter`: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/messaging/jms/receiving/custom/JmsConfiguration.java[] +---- + +Then you can use the factory in any `@JmsListener`-annotated method as follows: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/messaging/jms/receiving/custom/MyBean.java[] +---- + + + +[[features.messaging.amqp]] +=== AMQP +The Advanced Message Queuing Protocol (AMQP) is a platform-neutral, wire-level protocol for message-oriented middleware. +The Spring AMQP project applies core Spring concepts to the development of AMQP-based messaging solutions. +Spring Boot offers several conveniences for working with AMQP through RabbitMQ, including the `spring-boot-starter-amqp` "`Starter`". + + + +[[features.messaging.amqp.rabbitmq]] +==== RabbitMQ support +https://www.rabbitmq.com/[RabbitMQ] is a lightweight, reliable, scalable, and portable message broker based on the AMQP protocol. +Spring uses `RabbitMQ` to communicate through the AMQP protocol. + +RabbitMQ configuration is controlled by external configuration properties in `+spring.rabbitmq.*+`. +For example, you might declare the following section in `application.properties`: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + rabbitmq: + host: "localhost" + port: 5672 + username: "admin" + password: "secret" +---- + +Alternatively, you could configure the same connection using the `addresses` attribute: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + rabbitmq: + addresses: "amqp://admin:secret@localhost" +---- + +NOTE: When specifying addresses that way, the `host` and `port` properties are ignored. +If the address uses the `amqps` protocol, SSL support is enabled automatically. + +See {spring-boot-autoconfigure-module-code}/amqp/RabbitProperties.java[`RabbitProperties`] for more of the supported property-based configuration options. +To configure lower-level details of the RabbitMQ `ConnectionFactory` that is used by Spring AMQP, define a `ConnectionFactoryCustomizer` bean. + +If a `ConnectionNameStrategy` bean exists in the context, it will be automatically used to name connections created by the auto-configured `CachingConnectionFactory`. + +TIP: See https://spring.io/blog/2010/06/14/understanding-amqp-the-protocol-used-by-rabbitmq/[Understanding AMQP, the protocol used by RabbitMQ] for more details. + + + +[[features.messaging.amqp.sending]] +==== Sending a Message +Spring's `AmqpTemplate` and `AmqpAdmin` are auto-configured, and you can autowire them directly into your own beans, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/messaging/amqp/sending/MyBean.java[] +---- + +NOTE: {spring-amqp-api}/rabbit/core/RabbitMessagingTemplate.html[`RabbitMessagingTemplate`] can be injected in a similar manner. +If a `MessageConverter` bean is defined, it is associated automatically to the auto-configured `AmqpTemplate`. + +If necessary, any `org.springframework.amqp.core.Queue` that is defined as a bean is automatically used to declare a corresponding queue on the RabbitMQ instance. + +To retry operations, you can enable retries on the `AmqpTemplate` (for example, in the event that the broker connection is lost): + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + rabbitmq: + template: + retry: + enabled: true + initial-interval: "2s" +---- + +Retries are disabled by default. +You can also customize the `RetryTemplate` programmatically by declaring a `RabbitRetryTemplateCustomizer` bean. + +If you need to create more `RabbitTemplate` instances or if you want to override the default, Spring Boot provides a `RabbitTemplateConfigurer` bean that you can use to initialize a `RabbitTemplate` with the same settings as the factories used by the auto-configuration. + + + +[[features.messaging.amqp.receiving]] +==== Receiving a Message +When the Rabbit infrastructure is present, any bean can be annotated with `@RabbitListener` to create a listener endpoint. +If no `RabbitListenerContainerFactory` has been defined, a default `SimpleRabbitListenerContainerFactory` is automatically configured and you can switch to a direct container using the configprop:spring.rabbitmq.listener.type[] property. +If a `MessageConverter` or a `MessageRecoverer` bean is defined, it is automatically associated with the default factory. + +The following sample component creates a listener endpoint on the `someQueue` queue: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/messaging/amqp/receiving/MyBean.java[] +---- + +TIP: See {spring-amqp-api}/rabbit/annotation/EnableRabbit.html[the Javadoc of `@EnableRabbit`] for more details. + +If you need to create more `RabbitListenerContainerFactory` instances or if you want to override the default, Spring Boot provides a `SimpleRabbitListenerContainerFactoryConfigurer` and a `DirectRabbitListenerContainerFactoryConfigurer` that you can use to initialize a `SimpleRabbitListenerContainerFactory` and a `DirectRabbitListenerContainerFactory` with the same settings as the factories used by the auto-configuration. + +TIP: It does not matter which container type you chose. +Those two beans are exposed by the auto-configuration. + +For instance, the following configuration class exposes another factory that uses a specific `MessageConverter`: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/messaging/amqp/receiving/custom/RabbitConfiguration.java[] +---- + +Then you can use the factory in any `@RabbitListener`-annotated method, as follows: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/messaging/amqp/receiving/custom/MyBean.java[] +---- + +You can enable retries to handle situations where your listener throws an exception. +By default, `RejectAndDontRequeueRecoverer` is used, but you can define a `MessageRecoverer` of your own. +When retries are exhausted, the message is rejected and either dropped or routed to a dead-letter exchange if the broker is configured to do so. +By default, retries are disabled. +You can also customize the `RetryTemplate` programmatically by declaring a `RabbitRetryTemplateCustomizer` bean. + +IMPORTANT: By default, if retries are disabled and the listener throws an exception, the delivery is retried indefinitely. +You can modify this behavior in two ways: Set the `defaultRequeueRejected` property to `false` so that zero re-deliveries are attempted or throw an `AmqpRejectAndDontRequeueException` to signal the message should be rejected. +The latter is the mechanism used when retries are enabled and the maximum number of delivery attempts is reached. + + + +[[features.messaging.kafka]] +=== Apache Kafka Support +https://kafka.apache.org/[Apache Kafka] is supported by providing auto-configuration of the `spring-kafka` project. + +Kafka configuration is controlled by external configuration properties in `spring.kafka.*`. +For example, you might declare the following section in `application.properties`: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + kafka: + bootstrap-servers: "localhost:9092" + consumer: + group-id: "myGroup" +---- + +TIP: To create a topic on startup, add a bean of type `NewTopic`. +If the topic already exists, the bean is ignored. + +See {spring-boot-autoconfigure-module-code}/kafka/KafkaProperties.java[`KafkaProperties`] for more supported options. + + + +[[features.messaging.kafka.sending]] +==== Sending a Message +Spring's `KafkaTemplate` is auto-configured, and you can autowire it directly in your own beans, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/messaging/kafka/sending/MyBean.java[] +---- + +NOTE: If the property configprop:spring.kafka.producer.transaction-id-prefix[] is defined, a `KafkaTransactionManager` is automatically configured. +Also, if a `RecordMessageConverter` bean is defined, it is automatically associated to the auto-configured `KafkaTemplate`. + + + +[[features.messaging.kafka.receiving]] +==== Receiving a Message +When the Apache Kafka infrastructure is present, any bean can be annotated with `@KafkaListener` to create a listener endpoint. +If no `KafkaListenerContainerFactory` has been defined, a default one is automatically configured with keys defined in `spring.kafka.listener.*`. + +The following component creates a listener endpoint on the `someTopic` topic: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/messaging/kafka/receiving/MyBean.java[] +---- + +If a `KafkaTransactionManager` bean is defined, it is automatically associated to the container factory. +Similarly, if a `RecordFilterStrategy`, `ErrorHandler`, `AfterRollbackProcessor` or `ConsumerAwareRebalanceListener` bean is defined, it is automatically associated to the default factory. + +Depending on the listener type, a `RecordMessageConverter` or `BatchMessageConverter` bean is associated to the default factory. +If only a `RecordMessageConverter` bean is present for a batch listener, it is wrapped in a `BatchMessageConverter`. + +TIP: A custom `ChainedKafkaTransactionManager` must be marked `@Primary` as it usually references the auto-configured `KafkaTransactionManager` bean. + + + +[[features.messaging.kafka.streams]] +==== Kafka Streams +Spring for Apache Kafka provides a factory bean to create a `StreamsBuilder` object and manage the lifecycle of its streams. +Spring Boot auto-configures the required `KafkaStreamsConfiguration` bean as long as `kafka-streams` is on the classpath and Kafka Streams is enabled via the `@EnableKafkaStreams` annotation. + +Enabling Kafka Streams means that the application id and bootstrap servers must be set. +The former can be configured using `spring.kafka.streams.application-id`, defaulting to `spring.application.name` if not set. +The latter can be set globally or specifically overridden only for streams. + +Several additional properties are available using dedicated properties; other arbitrary Kafka properties can be set using the `spring.kafka.streams.properties` namespace. +See also <> for more information. + +To use the factory bean, wire `StreamsBuilder` into your `@Bean` as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/messaging/KafkaStreamsConfiguration.java[] +---- + +By default, the streams managed by the `StreamBuilder` object it creates are started automatically. +You can customize this behaviour using the configprop:spring.kafka.streams.auto-startup[] property. + + + +[[features.messaging.kafka.additional-properties]] +==== Additional Kafka Properties +The properties supported by auto configuration are shown in <>. +Note that, for the most part, these properties (hyphenated or camelCase) map directly to the Apache Kafka dotted properties. +Refer to the Apache Kafka documentation for details. + +The first few of these properties apply to all components (producers, consumers, admins, and streams) but can be specified at the component level if you wish to use different values. +Apache Kafka designates properties with an importance of HIGH, MEDIUM, or LOW. +Spring Boot auto-configuration supports all HIGH importance properties, some selected MEDIUM and LOW properties, and any properties that do not have a default value. + +Only a subset of the properties supported by Kafka are available directly through the `KafkaProperties` class. +If you wish to configure the producer or consumer with additional properties that are not directly supported, use the following properties: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + kafka: + properties: + "[prop.one]": "first" + admin: + properties: + "[prop.two]": "second" + consumer: + properties: + "[prop.three]": "third" + producer: + properties: + "[prop.four]": "fourth" + streams: + properties: + "[prop.five]": "fifth" +---- + +This sets the common `prop.one` Kafka property to `first` (applies to producers, consumers and admins), the `prop.two` admin property to `second`, the `prop.three` consumer property to `third`, the `prop.four` producer property to `fourth` and the `prop.five` streams property to `fifth`. + +You can also configure the Spring Kafka `JsonDeserializer` as follows: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + kafka: + consumer: + value-deserializer: "org.springframework.kafka.support.serializer.JsonDeserializer" + properties: + "[spring.json.value.default.type]": "com.example.Invoice" + "[spring.json.trusted.packages]": "com.example,org.acme" +---- + +Similarly, you can disable the `JsonSerializer` default behavior of sending type information in headers: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + kafka: + producer: + value-serializer: "org.springframework.kafka.support.serializer.JsonSerializer" + properties: + "[spring.json.add.type.headers]": false +---- + +IMPORTANT: Properties set in this way override any configuration item that Spring Boot explicitly supports. + + + +[[features.messaging.kafka.embedded]] +==== Testing with Embedded Kafka +Spring for Apache Kafka provides a convenient way to test projects with an embedded Apache Kafka broker. +To use this feature, annotate a test class with `@EmbeddedKafka` from the `spring-kafka-test` module. +For more information, please see the Spring for Apache Kafka {spring-kafka-docs}#embedded-kafka-annotation[reference manual]. + +To make Spring Boot auto-configuration work with the aforementioned embedded Apache Kafka broker, you need to remap a system property for embedded broker addresses (populated by the `EmbeddedKafkaBroker`) into the Spring Boot configuration property for Apache Kafka. +There are several ways to do that: + +* Provide a system property to map embedded broker addresses into configprop:spring.kafka.bootstrap-servers[] in the test class: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/messaging/kafka/test/property/MyTest.java[tag=*] +---- + +* Configure a property name on the `@EmbeddedKafka` annotation: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/messaging/kafka/test/annotation/MyTest.java[] +---- + +* Use a placeholder in configuration properties: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + kafka: + bootstrap-servers: "${spring.embedded.kafka.brokers}" +---- diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/nosql.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/nosql.adoc new file mode 100644 index 0000000000..899c68e17e --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/nosql.adoc @@ -0,0 +1,644 @@ +[[features.nosql]] +== Working with NoSQL Technologies +Spring Data provides additional projects that help you access a variety of NoSQL technologies, including: + +* {spring-data-mongodb}[MongoDB] +* {spring-data-neo4j}[Neo4J] +* {spring-data-elasticsearch}[Elasticsearch] +* {spring-data-redis}[Redis] +* {spring-data-gemfire}[GemFire] or {spring-data-geode}[Geode] +* {spring-data-cassandra}[Cassandra] +* {spring-data-couchbase}[Couchbase] +* {spring-data-ldap}[LDAP] + +Spring Boot provides auto-configuration for Redis, MongoDB, Neo4j, Elasticsearch, Solr Cassandra, Couchbase, and LDAP. +You can make use of the other projects, but you must configure them yourself. +Refer to the appropriate reference documentation at {spring-data}. + + + +[[features.nosql.redis]] +=== Redis +https://redis.io/[Redis] is a cache, message broker, and richly-featured key-value store. +Spring Boot offers basic auto-configuration for the https://github.com/lettuce-io/lettuce-core/[Lettuce] and https://github.com/xetorthio/jedis/[Jedis] client libraries and the abstractions on top of them provided by https://github.com/spring-projects/spring-data-redis[Spring Data Redis]. + +There is a `spring-boot-starter-data-redis` "`Starter`" for collecting the dependencies in a convenient way. +By default, it uses https://github.com/lettuce-io/lettuce-core/[Lettuce]. +That starter handles both traditional and reactive applications. + +TIP: We also provide a `spring-boot-starter-data-redis-reactive` "`Starter`" for consistency with the other stores with reactive support. + + + +[[features.nosql.redis.connecting]] +==== Connecting to Redis +You can inject an auto-configured `RedisConnectionFactory`, `StringRedisTemplate`, or vanilla `RedisTemplate` instance as you would any other Spring Bean. +By default, the instance tries to connect to a Redis server at `localhost:6379`. +The following listing shows an example of such a bean: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/nosql/redis/MyBean.java[] +---- + +TIP: You can also register an arbitrary number of beans that implement `LettuceClientConfigurationBuilderCustomizer` for more advanced customizations. +If you use Jedis, `JedisClientConfigurationBuilderCustomizer` is also available. + +If you add your own `@Bean` of any of the auto-configured types, it replaces the default (except in the case of `RedisTemplate`, when the exclusion is based on the bean name, `redisTemplate`, not its type). +By default, if `commons-pool2` is on the classpath, you get a pooled connection factory. + + + +[[features.nosql.mongodb]] +=== MongoDB +https://www.mongodb.com/[MongoDB] is an open-source NoSQL document database that uses a JSON-like schema instead of traditional table-based relational data. +Spring Boot offers several conveniences for working with MongoDB, including the `spring-boot-starter-data-mongodb` and `spring-boot-starter-data-mongodb-reactive` "`Starters`". + + + +[[features.nosql.mongodb.connecting]] +==== Connecting to a MongoDB Database +To access MongoDB databases, you can inject an auto-configured `org.springframework.data.mongodb.MongoDatabaseFactory`. +By default, the instance tries to connect to a MongoDB server at `mongodb://localhost/test`. +The following example shows how to connect to a MongoDB database: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/nosql/mongodb/databasefactory/MyBean.java[] +---- + +If you have defined your own `MongoClient`, it will be used to auto-configure a suitable `MongoDatabaseFactory`. + +The auto-configured `MongoClient` is created using a `MongoClientSettings` bean. +If you have defined your own `MongoClientSettings`, it will be used without modification and the `spring.data.mongodb` properties will be ignored. +Otherwise a `MongoClientSettings` will be auto-configured and will have the `spring.data.mongodb` properties applied to it. +In either case, you can declare one or more `MongoClientSettingsBuilderCustomizer` beans to fine-tune the `MongoClientSettings` configuration. +Each will be called in order with the `MongoClientSettings.Builder` that is used to build the `MongoClientSettings`. + +You can set the configprop:spring.data.mongodb.uri[] property to change the URL and configure additional settings such as the _replica set_, as shown in the following example: + +[source,properties,indent=0,configprops] +---- + spring.data.mongodb.uri=mongodb://user:secret@mongo1.example.com:12345,mongo2.example.com:23456/test +---- + +Alternatively, you can specify connection details using discrete properties. +For example, you might declare the following settings in your `application.properties`: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + data: + mongodb: + host: "mongoserver.example.com" + port: 27017 + database: "test" + username: "user" + password: "secret" +---- + +TIP: If `spring.data.mongodb.port` is not specified, the default of `27017` is used. +You could delete this line from the example shown earlier. + +TIP: If you do not use Spring Data MongoDB, you can inject a `MongoClient` bean instead of using `MongoDatabaseFactory`. +If you want to take complete control of establishing the MongoDB connection, you can also declare your own `MongoDatabaseFactory` or `MongoClient` bean. + +NOTE: If you are using the reactive driver, Netty is required for SSL. +The auto-configuration configures this factory automatically if Netty is available and the factory to use hasn't been customized already. + + + +[[features.nosql.mongodb.template]] +==== MongoTemplate +{spring-data-mongodb}[Spring Data MongoDB] provides a {spring-data-mongodb-api}/core/MongoTemplate.html[`MongoTemplate`] class that is very similar in its design to Spring's `JdbcTemplate`. +As with `JdbcTemplate`, Spring Boot auto-configures a bean for you to inject the template, as follows: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/nosql/mongodb/template/MyBean.java[] +---- + +See the {spring-data-mongodb-api}/core/MongoOperations.html[`MongoOperations` Javadoc] for complete details. + + + +[[features.nosql.mongodb.repositories]] +[[features.nosql.mongodb.repositories]] +==== Spring Data MongoDB Repositories +Spring Data includes repository support for MongoDB. +As with the JPA repositories discussed earlier, the basic principle is that queries are constructed automatically, based on method names. + +In fact, both Spring Data JPA and Spring Data MongoDB share the same common infrastructure. +You could take the JPA example from earlier and, assuming that `City` is now a MongoDB data class rather than a JPA `@Entity`, it works in the same way, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/nosql/mongodb/data/CityRepository.java[] +---- + +TIP: You can customize document scanning locations by using the `@EntityScan` annotation. + +TIP: For complete details of Spring Data MongoDB, including its rich object mapping technologies, refer to its {spring-data-mongodb}[reference documentation]. + + + +[[features.nosql.mongodb.embedded]] +==== Embedded Mongo +Spring Boot offers auto-configuration for https://github.com/flapdoodle-oss/de.flapdoodle.embed.mongo[Embedded Mongo]. +To use it in your Spring Boot application, add a dependency on `de.flapdoodle.embed:de.flapdoodle.embed.mongo`. + +The port that Mongo listens on can be configured by setting the configprop:spring.data.mongodb.port[] property. +To use a randomly allocated free port, use a value of 0. +The `MongoClient` created by `MongoAutoConfiguration` is automatically configured to use the randomly allocated port. + +NOTE: If you do not configure a custom port, the embedded support uses a random port (rather than 27017) by default. + +If you have SLF4J on the classpath, the output produced by Mongo is automatically routed to a logger named `org.springframework.boot.autoconfigure.mongo.embedded.EmbeddedMongo`. + +You can declare your own `IMongodConfig` and `IRuntimeConfig` beans to take control of the Mongo instance's configuration and logging routing. +The download configuration can be customized by declaring a `DownloadConfigBuilderCustomizer` bean. + + + +[[features.nosql.neo4j]] +=== Neo4j +https://neo4j.com/[Neo4j] is an open-source NoSQL graph database that uses a rich data model of nodes connected by first class relationships, which is better suited for connected big data than traditional RDBMS approaches. +Spring Boot offers several conveniences for working with Neo4j, including the `spring-boot-starter-data-neo4j` "`Starter`". + + + +[[features.nosql.neo4j.connecting]] +==== Connecting to a Neo4j Database +To access a Neo4j server, you can inject an auto-configured `org.neo4j.driver.Driver`. +By default, the instance tries to connect to a Neo4j server at `localhost:7687` using the Bolt protocol. +The following example shows how to inject a Neo4j `Driver` that gives you access, amongst other things, to a `Session`: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/nosql/neo4j/driver/MyBean.java[] +---- + +You can configure various aspects of the driver using `spring.neo4j.*` properties. +The following example shows how to configure the uri and credentials to use: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + neo4j: + uri: "bolt://my-server:7687" + authentication: + username: "neo4j" + password: "secret" +---- + +The auto-configured `Driver` is created using `ConfigBuilder`. +To fine-tune its configuration, declare one or more `ConfigBuilderCustomizer` beans. +Each will be called in order with the `ConfigBuilder` that is used to build the `Driver`. + + + +[[features.nosql.neo4j.repositories]] +==== Spring Data Neo4j Repositories +Spring Data includes repository support for Neo4j. +For complete details of Spring Data Neo4j, refer to the {spring-data-neo4j-docs}[reference documentation]. + +Spring Data Neo4j shares the common infrastructure with Spring Data JPA as many other Spring Data modules do. +You could take the JPA example from earlier and define `City` as Spring Data Neo4j `@Node` rather than JPA `@Entity` and the repository abstraction works in the same way, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/nosql/neo4j/data/CityRepository.java[] +---- + +The `spring-boot-starter-data-neo4j` "`Starter`" enables the repository support as well as transaction management. +Spring Boot supports both classic and reactive Neo4j repositories, using the `Neo4jTemplate` or `ReactiveNeo4jTemplate` beans. +When Project Reactor is available on the classpath, the reactive style is also auto-configured. + +You can customize the locations to look for repositories and entities by using `@EnableNeo4jRepositories` and `@EntityScan` respectively on a `@Configuration`-bean. + +[NOTE] +==== +In an application using the reactive style, a `ReactiveTransactionManager` is not auto-configured. +To enable transaction management, the following bean must be defined in your configuration: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/nosql/Neo4jReactiveTransactionManagerConfiguration.java[] +---- +==== + + + +[[features.nosql.solr]] +=== Solr +https://lucene.apache.org/solr/[Apache Solr] is a search engine. +Spring Boot offers basic auto-configuration for the Solr 5 client library. + + + +[[features.nosql.solr.connecting]] +==== Connecting to Solr +You can inject an auto-configured `SolrClient` instance as you would any other Spring bean. +By default, the instance tries to connect to a server at `http://localhost:8983/solr`. +The following example shows how to inject a Solr bean: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/nosql/solr/client/MyBean.java[] +---- + +If you add your own `@Bean` of type `SolrClient`, it replaces the default. + + + +[[features.nosql.elasticsearch]] +=== Elasticsearch +https://www.elastic.co/products/elasticsearch[Elasticsearch] is an open source, distributed, RESTful search and analytics engine. +Spring Boot offers basic auto-configuration for Elasticsearch. + +Spring Boot supports several clients: + +* The official Java "Low Level" and "High Level" REST clients +* The `ReactiveElasticsearchClient` provided by Spring Data Elasticsearch + +Spring Boot provides a dedicated "`Starter`", `spring-boot-starter-data-elasticsearch`. + + + +[[features.nosql.elasticsearch.connecting-using-rest]] +==== Connecting to Elasticsearch using REST clients +Elasticsearch ships https://www.elastic.co/guide/en/elasticsearch/client/java-rest/current/index.html[two different REST clients] that you can use to query a cluster: the "Low Level" client and the "High Level" client. +Spring Boot provides support for the "High Level" client, which ships with `org.elasticsearch.client:elasticsearch-rest-high-level-client`. + +If you have this dependency on the classpath, Spring Boot will auto-configure and register a `RestHighLevelClient` bean that by default targets `http://localhost:9200`. +You can further tune how `RestHighLevelClient` is configured, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + elasticsearch: + rest: + uris: "https://search.example.com:9200" + read-timeout: "10s" + username: "user" + password: "secret" +---- + +You can also register an arbitrary number of beans that implement `RestClientBuilderCustomizer` for more advanced customizations. +To take full control over the registration, define a `RestClientBuilder` bean. + +TIP: If your application needs access to a "Low Level" `RestClient`, you can get it by calling `client.getLowLevelClient()` on the auto-configured `RestHighLevelClient`. + +Additionally, if `elasticsearch-rest-client-sniffer` is on the classpath, a `Sniffer` is auto-configured to automatically discover nodes from a running Elasticsearch cluster and set them to the `RestHighLevelClient` bean. +You can further tune how `Sniffer` is configured, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + elasticsearch: + rest: + sniffer: + interval: 10m + delay-after-failure: 30s +---- + + + +[[features.nosql.elasticsearch.connecting-using-reactive-rest]] +==== Connecting to Elasticsearch using Reactive REST clients +{spring-data-elasticsearch}[Spring Data Elasticsearch] ships `ReactiveElasticsearchClient` for querying Elasticsearch instances in a reactive fashion. +It is built on top of WebFlux's `WebClient`, so both `spring-boot-starter-elasticsearch` and `spring-boot-starter-webflux` dependencies are useful to enable this support. + +By default, Spring Boot will auto-configure and register a `ReactiveElasticsearchClient` +bean that targets `http://localhost:9200`. +You can further tune how it is configured, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + data: + elasticsearch: + client: + reactive: + endpoints: "search.example.com:9200" + use-ssl: true + socket-timeout: "10s" + username: "user" + password: "secret" +---- + +If the configuration properties are not enough and you'd like to fully control the client +configuration, you can register a custom `ClientConfiguration` bean. + + + +[[features.nosql.elasticsearch.connecting-using-spring-data]] +==== Connecting to Elasticsearch by Using Spring Data +To connect to Elasticsearch, a `RestHighLevelClient` bean must be defined, +auto-configured by Spring Boot or manually provided by the application (see previous sections). +With this configuration in place, an +`ElasticsearchRestTemplate` can be injected like any other Spring bean, +as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/nosql/elasticsearch/template/MyBean.java[] +---- + +In the presence of `spring-data-elasticsearch` and the required dependencies for using a `WebClient` (typically `spring-boot-starter-webflux`), Spring Boot can also auto-configure a <> and a `ReactiveElasticsearchTemplate` as beans. +They are the reactive equivalent of the other REST clients. + + + +[[features.nosql.elasticsearch.repositories]] +==== Spring Data Elasticsearch Repositories +Spring Data includes repository support for Elasticsearch. +As with the JPA repositories discussed earlier, the basic principle is that queries are constructed for you automatically based on method names. + +In fact, both Spring Data JPA and Spring Data Elasticsearch share the same common infrastructure. +You could take the JPA example from earlier and, assuming that `City` is now an Elasticsearch `@Document` class rather than a JPA `@Entity`, it works in the same way. + +TIP: For complete details of Spring Data Elasticsearch, refer to the {spring-data-elasticsearch-docs}[reference documentation]. + +Spring Boot supports both classic and reactive Elasticsearch repositories, using the `ElasticsearchRestTemplate` or `ReactiveElasticsearchTemplate` beans. +Most likely those beans are auto-configured by Spring Boot given the required dependencies are present. + +If you wish to use your own template for backing the Elasticsearch repositories, you can add your own `ElasticsearchRestTemplate` or `ElasticsearchOperations` `@Bean`, as long as it is named `"elasticsearchTemplate"`. +Same applies to `ReactiveElasticsearchTemplate` and `ReactiveElasticsearchOperations`, with the bean name `"reactiveElasticsearchTemplate"`. + +You can choose to disable the repositories support with the following property: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + data: + elasticsearch: + repositories: + enabled: false +---- + + + +[[features.nosql.cassandra]] +=== Cassandra +https://cassandra.apache.org/[Cassandra] is an open source, distributed database management system designed to handle large amounts of data across many commodity servers. +Spring Boot offers auto-configuration for Cassandra and the abstractions on top of it provided by https://github.com/spring-projects/spring-data-cassandra[Spring Data Cassandra]. +There is a `spring-boot-starter-data-cassandra` "`Starter`" for collecting the dependencies in a convenient way. + + + +[[features.nosql.cassandra.connecting]] +==== Connecting to Cassandra +You can inject an auto-configured `CassandraTemplate` or a Cassandra `CqlSession` instance as you would with any other Spring Bean. +The `spring.data.cassandra.*` properties can be used to customize the connection. +Generally, you provide `keyspace-name` and `contact-points` as well the local datacenter name, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + data: + cassandra: + keyspace-name: "mykeyspace" + contact-points: "cassandrahost1:9042,cassandrahost2:9042" + local-datacenter: "datacenter1" +---- + +If the port is the same for all your contact points you can use a shortcut and only specify the host names, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + data: + cassandra: + keyspace-name: "mykeyspace" + contact-points: "cassandrahost1,cassandrahost2" + local-datacenter: "datacenter1" +---- + +TIP: Those two examples are identical as the port default to `9042`. +If you need to configure the port, use `spring.data.cassandra.port`. + +[NOTE] +==== +The Cassandra driver has its own configuration infrastructure that loads an `application.conf` at the root of the classpath. + +Spring Boot does not look for such a file by default but can load one using `spring.data.cassandra.config`. +If a property is both present in `+spring.data.cassandra.*+` and the configuration file, the value in `+spring.data.cassandra.*+` takes precedence. + +For more advanced driver customizations, you can register an arbitrary number of beans that implement `DriverConfigLoaderBuilderCustomizer`. +The `CqlSession` can be customized with a bean of type `CqlSessionBuilderCustomizer`. +==== + +NOTE: If you're using `CqlSessionBuilder` to create multiple `CqlSession` beans, keep in mind the builder is mutable so make sure to inject a fresh copy for each session. + +The following code listing shows how to inject a Cassandra bean: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/nosql/cassandra/template/MyBean.java[] +---- + +If you add your own `@Bean` of type `CassandraTemplate`, it replaces the default. + + + +[[features.nosql.cassandra.repositories]] +==== Spring Data Cassandra Repositories +Spring Data includes basic repository support for Cassandra. +Currently, this is more limited than the JPA repositories discussed earlier and needs to annotate finder methods with `@Query`. + +TIP: For complete details of Spring Data Cassandra, refer to the https://docs.spring.io/spring-data/cassandra/docs/[reference documentation]. + + + +[[features.nosql.couchbase]] +=== Couchbase +https://www.couchbase.com/[Couchbase] is an open-source, distributed, multi-model NoSQL document-oriented database that is optimized for interactive applications. +Spring Boot offers auto-configuration for Couchbase and the abstractions on top of it provided by https://github.com/spring-projects/spring-data-couchbase[Spring Data Couchbase]. +There are `spring-boot-starter-data-couchbase` and `spring-boot-starter-data-couchbase-reactive` "`Starters`" for collecting the dependencies in a convenient way. + + + +[[features.nosql.couchbase.connecting]] +==== Connecting to Couchbase +You can get a `Cluster` by adding the Couchbase SDK and some configuration. +The `spring.couchbase.*` properties can be used to customize the connection. +Generally, you provide the https://github.com/couchbaselabs/sdk-rfcs/blob/master/rfc/0011-connection-string.md[connection string], username, and password, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + couchbase: + connection-string: "couchbase://192.168.1.123" + username: "user" + password: "secret" +---- + +It is also possible to customize some of the `ClusterEnvironment` settings. +For instance, the following configuration changes the timeout to use to open a new `Bucket` and enables SSL support: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + couchbase: + env: + timeouts: + connect: "3s" + ssl: + key-store: "/location/of/keystore.jks" + key-store-password: "secret" +---- + +TIP: Check the `spring.couchbase.env.*` properties for more details. +To take more control, one or more `ClusterEnvironmentBuilderCustomizer` beans can be used. + + + +[[features.nosql.couchbase.repositories]] +==== Spring Data Couchbase Repositories +Spring Data includes repository support for Couchbase. +For complete details of Spring Data Couchbase, refer to the {spring-data-couchbase-docs}[reference documentation]. + +You can inject an auto-configured `CouchbaseTemplate` instance as you would with any other Spring Bean, provided a `CouchbaseClientFactory` bean is available. +This happens when a `Cluster` is available, as described above, and a bucket name has been specified: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + data: + couchbase: + bucket-name: "my-bucket" +---- + +The following examples shows how to inject a `CouchbaseTemplate` bean: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/nosql/couchbase/template/MyBean.java[] +---- + +There are a few beans that you can define in your own configuration to override those provided by the auto-configuration: + +* A `CouchbaseMappingContext` `@Bean` with a name of `couchbaseMappingContext`. +* A `CustomConversions` `@Bean` with a name of `couchbaseCustomConversions`. +* A `CouchbaseTemplate` `@Bean` with a name of `couchbaseTemplate`. + +To avoid hard-coding those names in your own config, you can reuse `BeanNames` provided by Spring Data Couchbase. +For instance, you can customize the converters to use, as follows: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/nosql/couchbase/CouchbaseConversionsConfiguration.java[] +---- + + + +[[features.nosql.ldap]] +=== LDAP +https://en.wikipedia.org/wiki/Lightweight_Directory_Access_Protocol[LDAP] (Lightweight Directory Access Protocol) is an open, vendor-neutral, industry standard application protocol for accessing and maintaining distributed directory information services over an IP network. +Spring Boot offers auto-configuration for any compliant LDAP server as well as support for the embedded in-memory LDAP server from https://ldap.com/unboundid-ldap-sdk-for-java/[UnboundID]. + +LDAP abstractions are provided by https://github.com/spring-projects/spring-data-ldap[Spring Data LDAP]. +There is a `spring-boot-starter-data-ldap` "`Starter`" for collecting the dependencies in a convenient way. + + + +[[features.nosql.ldap.connecting]] +==== Connecting to an LDAP Server +To connect to an LDAP server, make sure you declare a dependency on the `spring-boot-starter-data-ldap` "`Starter`" or `spring-ldap-core` and then declare the URLs of your server in your application.properties, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + ldap: + urls: "ldap://myserver:1235" + username: "admin" + password: "secret" +---- + +If you need to customize connection settings, you can use the `spring.ldap.base` and `spring.ldap.base-environment` properties. + +An `LdapContextSource` is auto-configured based on these settings. +If a `DirContextAuthenticationStrategy` bean is available, it is associated to the auto-configured `LdapContextSource`. +If you need to customize it, for instance to use a `PooledContextSource`, you can still inject the auto-configured `LdapContextSource`. +Make sure to flag your customized `ContextSource` as `@Primary` so that the auto-configured `LdapTemplate` uses it. + + + +[[features.nosql.ldap.repositories]] +==== Spring Data LDAP Repositories +Spring Data includes repository support for LDAP. +For complete details of Spring Data LDAP, refer to the https://docs.spring.io/spring-data/ldap/docs/1.0.x/reference/html/[reference documentation]. + +You can also inject an auto-configured `LdapTemplate` instance as you would with any other Spring Bean, as shown in the following example: + + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/nosql/ldap/template/MyBean.java[] +---- + + + +[[features.nosql.ldap.embedded]] +==== Embedded In-memory LDAP Server +For testing purposes, Spring Boot supports auto-configuration of an in-memory LDAP server from https://ldap.com/unboundid-ldap-sdk-for-java/[UnboundID]. +To configure the server, add a dependency to `com.unboundid:unboundid-ldapsdk` and declare a configprop:spring.ldap.embedded.base-dn[] property, as follows: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + ldap: + embedded: + base-dn: "dc=spring,dc=io" +---- + +[NOTE] +==== +It is possible to define multiple base-dn values, however, since distinguished names usually contain commas, they must be defined using the correct notation. + +In yaml files, you can use the yaml list notation. In properties files, you must include the index as part of the property name: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring.ldap.embedded.base-dn: + - dc=spring,dc=io + - dc=pivotal,dc=io +---- +==== + +By default, the server starts on a random port and triggers the regular LDAP support. +There is no need to specify a configprop:spring.ldap.urls[] property. + +If there is a `schema.ldif` file on your classpath, it is used to initialize the server. +If you want to load the initialization script from a different resource, you can also use the configprop:spring.ldap.embedded.ldif[] property. + +By default, a standard schema is used to validate `LDIF` files. +You can turn off validation altogether by setting the configprop:spring.ldap.embedded.validation.enabled[] property. +If you have custom attributes, you can use configprop:spring.ldap.embedded.validation.schema[] to define your custom attribute types or object classes. + + + +[[features.nosql.influxdb]] +=== InfluxDB +https://www.influxdata.com/[InfluxDB] is an open-source time series database optimized for fast, high-availability storage and retrieval of time series data in fields such as operations monitoring, application metrics, Internet-of-Things sensor data, and real-time analytics. + + + +[[features.nosql.influxdb.connecting]] +==== Connecting to InfluxDB +Spring Boot auto-configures an `InfluxDB` instance, provided the `influxdb-java` client is on the classpath and the URL of the database is set, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + influx: + url: "https://172.0.0.1:8086" +---- + +If the connection to InfluxDB requires a user and password, you can set the `spring.influx.user` and `spring.influx.password` properties accordingly. + +InfluxDB relies on OkHttp. +If you need to tune the http client `InfluxDB` uses behind the scenes, you can register an `InfluxDbOkHttpClientBuilderProvider` bean. + +If you need more control over the configuration, consider registering an `InfluxDbCustomizer` bean. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/profiles.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/profiles.adoc new file mode 100644 index 0000000000..66dbe79234 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/profiles.adoc @@ -0,0 +1,75 @@ +[[features.profiles]] +== Profiles +Spring Profiles provide a way to segregate parts of your application configuration and make it be available only in certain environments. +Any `@Component`, `@Configuration` or `@ConfigurationProperties` can be marked with `@Profile` to limit when it is loaded, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/profiles/ProductionConfiguration.java[] +---- + +NOTE: If `@ConfigurationProperties` beans are registered via `@EnableConfigurationProperties` instead of automatic scanning, the `@Profile` annotation needs to be specified on the `@Configuration` class that has the `@EnableConfigurationProperties` annotation. +In the case where `@ConfigurationProperties` are scanned, `@Profile` can be specified on the `@ConfigurationProperties` class itself. + +You can use a configprop:spring.profiles.active[] `Environment` property to specify which profiles are active. +You can specify the property in any of the ways described earlier in this chapter. +For example, you could include it in your `application.properties`, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + profiles: + active: "dev,hsqldb" +---- + +You could also specify it on the command line by using the following switch: `--spring.profiles.active=dev,hsqldb`. + + + +[[features.profiles.adding-active-profiles]] +=== Adding Active Profiles +The configprop:spring.profiles.active[] property follows the same ordering rules as other properties: The highest `PropertySource` wins. +This means that you can specify active profiles in `application.properties` and then *replace* them by using the command line switch. + +Sometimes, it is useful to have properties that *add* to the active profiles rather than replace them. +The `SpringApplication` entry point has a Java API for setting additional profiles (that is, on top of those activated by the configprop:spring.profiles.active[] property). +See the `setAdditionalProfiles()` method in {spring-boot-module-api}/SpringApplication.html[SpringApplication]. +Profile groups, which are described in the <> can also be used to add active profiles if a given profile is active. + + + +[[features.profiles.groups]] +=== Profile Groups +Occasionally the profiles that you define and use in your application are too fine-grained and become cumbersome to use. +For example, you might have `proddb` and `prodmq` profiles that you use to enable database and messaging features independently. + +To help with this, Spring Boot lets you define profile groups. +A profile group allows you to define a logical name for a related group of profiles. + +For example, we can create a `production` group that consists of our `proddb` and `prodmq` profiles. + +[source,yaml,indent=0,configblocks] +---- + spring: + profiles: + group: + production: + - "proddb" + - "prodmq" +---- + +Our application can now be started using `--spring.profiles.active=production` to active the `production`, `proddb` and `prodmq` profiles in one hit. + + + +[[features.profiles.programmatically-setting-profiles]] +=== Programmatically Setting Profiles +You can programmatically set active profiles by calling `SpringApplication.setAdditionalProfiles(...)` before your application runs. +It is also possible to activate profiles by using Spring's `ConfigurableEnvironment` interface. + + + +[[features.profiles.profile-specific-configuration-files]] +=== Profile-specific Configuration Files +Profile-specific variants of both `application.properties` (or `application.yml`) and files referenced through `@ConfigurationProperties` are considered as files and loaded. +See "<>" for details. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/quartz.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/quartz.adoc new file mode 100644 index 0000000000..91cbc08f33 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/quartz.adoc @@ -0,0 +1,56 @@ +[[features.quartz]] +== Quartz Scheduler +Spring Boot offers several conveniences for working with the https://www.quartz-scheduler.org/[Quartz scheduler], including the `spring-boot-starter-quartz` "`Starter`". +If Quartz is available, a `Scheduler` is auto-configured (through the `SchedulerFactoryBean` abstraction). + +Beans of the following types are automatically picked up and associated with the `Scheduler`: + +* `JobDetail`: defines a particular Job. + `JobDetail` instances can be built with the `JobBuilder` API. +* `Calendar`. +* `Trigger`: defines when a particular job is triggered. + +By default, an in-memory `JobStore` is used. +However, it is possible to configure a JDBC-based store if a `DataSource` bean is available in your application and if the configprop:spring.quartz.job-store-type[] property is configured accordingly, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + quartz: + job-store-type: "jdbc" +---- + +When the JDBC store is used, the schema can be initialized on startup, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + quartz: + jdbc: + initialize-schema: "always" +---- + +WARNING: By default, the database is detected and initialized by using the standard scripts provided with the Quartz library. +These scripts drop existing tables, deleting all triggers on every restart. +It is also possible to provide a custom script by setting the configprop:spring.quartz.jdbc.schema[] property. + +To have Quartz use a `DataSource` other than the application's main `DataSource`, declare a `DataSource` bean, annotating its `@Bean` method with `@QuartzDataSource`. +Doing so ensures that the Quartz-specific `DataSource` is used by both the `SchedulerFactoryBean` and for schema initialization. +Similarly, to have Quartz use a `TransactionManager` other than the application's main `TransactionManager` declare a `TransactionManager` bean, annotating its `@Bean` method with `@QuartzTransactionManager`. + +By default, jobs created by configuration will not overwrite already registered jobs that have been read from a persistent job store. +To enable overwriting existing job definitions set the configprop:spring.quartz.overwrite-existing-jobs[] property. + +Quartz Scheduler configuration can be customized using `spring.quartz` properties and `SchedulerFactoryBeanCustomizer` beans, which allow programmatic `SchedulerFactoryBean` customization. +Advanced Quartz configuration properties can be customized using `spring.quartz.properties.*`. + +NOTE: In particular, an `Executor` bean is not associated with the scheduler as Quartz offers a way to configure the scheduler via `spring.quartz.properties`. +If you need to customize the task executor, consider implementing `SchedulerFactoryBeanCustomizer`. + +Jobs can define setters to inject data map properties. +Regular beans can also be injected in a similar manner, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/quartz/SampleJob.java[] +---- diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/resttemplate.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/resttemplate.adoc new file mode 100644 index 0000000000..00b69a58a7 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/resttemplate.adoc @@ -0,0 +1,47 @@ +[[features.resttemplate]] +== Calling REST Services with RestTemplate +If you need to call remote REST services from your application, you can use the Spring Framework's {spring-framework-api}/web/client/RestTemplate.html[`RestTemplate`] class. +Since `RestTemplate` instances often need to be customized before being used, Spring Boot does not provide any single auto-configured `RestTemplate` bean. +It does, however, auto-configure a `RestTemplateBuilder`, which can be used to create `RestTemplate` instances when needed. +The auto-configured `RestTemplateBuilder` ensures that sensible `HttpMessageConverters` are applied to `RestTemplate` instances. + +The following code shows a typical example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/resttemplate/MyService.java[] +---- + +TIP: `RestTemplateBuilder` includes a number of useful methods that can be used to quickly configure a `RestTemplate`. +For example, to add BASIC auth support, you can use `builder.basicAuthentication("user", "password").build()`. + + + +[[features.resttemplate.customization]] +=== RestTemplate Customization +There are three main approaches to `RestTemplate` customization, depending on how broadly you want the customizations to apply. + +To make the scope of any customizations as narrow as possible, inject the auto-configured `RestTemplateBuilder` and then call its methods as required. +Each method call returns a new `RestTemplateBuilder` instance, so the customizations only affect this use of the builder. + +To make an application-wide, additive customization, use a `RestTemplateCustomizer` bean. +All such beans are automatically registered with the auto-configured `RestTemplateBuilder` and are applied to any templates that are built with it. + +The following example shows a customizer that configures the use of a proxy for all hosts except `192.168.0.5`: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/resttemplate/RestTemplateProxyCustomizer.java[] +---- + +Finally, you can also create your own `RestTemplateBuilder` bean. +To prevent switching off the auto-configuration of a `RestTemplateBuilder` and prevent any `RestTemplateCustomizer` beans from being used, make sure to configure your custom instance with a `RestTemplateBuilderConfigurer`. +The following example exposes a `RestTemplateBuilder` with what Spring Boot would auto-configure, except that custom connect and read timeouts are also specified: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/resttemplate/RestTemplateBuilderConfiguration.java[] +---- + +The most extreme (and rarely used) option is to create your own `RestTemplateBuilder` bean without using a configurer. +Doing so switches off the auto-configuration of a `RestTemplateBuilder` and prevents any `RestTemplateCustomizer` beans from being used. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/rsocket.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/rsocket.adoc new file mode 100644 index 0000000000..238ac662c7 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/rsocket.adoc @@ -0,0 +1,86 @@ +[[features.rsocket]] +== RSocket +https://rsocket.io[RSocket] is a binary protocol for use on byte stream transports. +It enables symmetric interaction models via async message passing over a single connection. + + +The `spring-messaging` module of the Spring Framework provides support for RSocket requesters and responders, both on the client and on the server side. +See the {spring-framework-docs}/web-reactive.html#rsocket-spring[RSocket section] of the Spring Framework reference for more details, including an overview of the RSocket protocol. + + + +[[features.rsocket.strategies-auto-configuration]] +=== RSocket Strategies Auto-configuration +Spring Boot auto-configures an `RSocketStrategies` bean that provides all the required infrastructure for encoding and decoding RSocket payloads. +By default, the auto-configuration will try to configure the following (in order): + +. https://cbor.io/[CBOR] codecs with Jackson +. JSON codecs with Jackson + +The `spring-boot-starter-rsocket` starter provides both dependencies. +Check out the <> to know more about customization possibilities. + +Developers can customize the `RSocketStrategies` component by creating beans that implement the `RSocketStrategiesCustomizer` interface. +Note that their `@Order` is important, as it determines the order of codecs. + + + +[[features.rsocket.server-auto-configuration]] +=== RSocket server Auto-configuration +Spring Boot provides RSocket server auto-configuration. +The required dependencies are provided by the `spring-boot-starter-rsocket`. + +Spring Boot allows exposing RSocket over WebSocket from a WebFlux server, or standing up an independent RSocket server. +This depends on the type of application and its configuration. + +For WebFlux application (i.e. of type `WebApplicationType.REACTIVE`), the RSocket server will be plugged into the Web Server only if the following properties match: + +[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] +---- + spring: + rsocket: + server: + mapping-path: "/rsocket" + transport: "websocket" +---- + +WARNING: Plugging RSocket into a web server is only supported with Reactor Netty, as RSocket itself is built with that library. + +Alternatively, an RSocket TCP or websocket server is started as an independent, embedded server. +Besides the dependency requirements, the only required configuration is to define a port for that server: + +[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] +---- + spring: + rsocket: + server: + port: 9898 +---- + + + +[[features.rsocket.messaging]] +=== Spring Messaging RSocket support +Spring Boot will auto-configure the Spring Messaging infrastructure for RSocket. + +This means that Spring Boot will create a `RSocketMessageHandler` bean that will handle RSocket requests to your application. + + + +[[features.rsocket.requester]] +=== Calling RSocket Services with RSocketRequester +Once the `RSocket` channel is established between server and client, any party can send or receive requests to the other. + +As a server, you can get injected with an `RSocketRequester` instance on any handler method of an RSocket `@Controller`. +As a client, you need to configure and establish an RSocket connection first. +Spring Boot auto-configures an `RSocketRequester.Builder` for such cases with the expected codecs. + +The `RSocketRequester.Builder` instance is a prototype bean, meaning each injection point will provide you with a new instance . +This is done on purpose since this builder is stateful and you shouldn't create requesters with different setups using the same instance. + +The following code shows a typical example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/rsocket/MyService.java[] +---- diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/security.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/security.adoc new file mode 100644 index 0000000000..a5828846ec --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/security.adoc @@ -0,0 +1,313 @@ +[[features.security]] +== Security +If {spring-security}[Spring Security] is on the classpath, then web applications are secured by default. +Spring Boot relies on Spring Security’s content-negotiation strategy to determine whether to use `httpBasic` or `formLogin`. +To add method-level security to a web application, you can also add `@EnableGlobalMethodSecurity` with your desired settings. +Additional information can be found in the {spring-security-docs}#jc-method[Spring Security Reference Guide]. + +The default `UserDetailsService` has a single user. +The user name is `user`, and the password is random and is printed at INFO level when the application starts, as shown in the following example: + +[indent=0] +---- + Using generated security password: 78fa095d-3f4c-48b1-ad50-e24c31d5cf35 +---- + +NOTE: If you fine-tune your logging configuration, ensure that the `org.springframework.boot.autoconfigure.security` category is set to log `INFO`-level messages. +Otherwise, the default password is not printed. + +You can change the username and password by providing a `spring.security.user.name` and `spring.security.user.password`. + +The basic features you get by default in a web application are: + +* A `UserDetailsService` (or `ReactiveUserDetailsService` in case of a WebFlux application) bean with in-memory store and a single user with a generated password (see {spring-boot-module-api}/autoconfigure/security/SecurityProperties.User.html[`SecurityProperties.User`] for the properties of the user). +* Form-based login or HTTP Basic security (depending on the `Accept` header in the request) for the entire application (including actuator endpoints if actuator is on the classpath). +* A `DefaultAuthenticationEventPublisher` for publishing authentication events. + +You can provide a different `AuthenticationEventPublisher` by adding a bean for it. + + + +[[features.security.spring-mvc]] +=== MVC Security +The default security configuration is implemented in `SecurityAutoConfiguration` and `UserDetailsServiceAutoConfiguration`. +`SecurityAutoConfiguration` imports `SpringBootWebSecurityConfiguration` for web security and `UserDetailsServiceAutoConfiguration` configures authentication, which is also relevant in non-web applications. +To switch off the default web application security configuration completely or to combine multiple Spring Security components such as OAuth2 Client and Resource Server, add a bean of type `SecurityFilterChain` (doing so does not disable the `UserDetailsService` configuration or Actuator's security). + +To also switch off the `UserDetailsService` configuration, you can add a bean of type `UserDetailsService`, `AuthenticationProvider`, or `AuthenticationManager`. + +Access rules can be overridden by adding a custom `SecurityFilterChain` or `WebSecurityConfigurerAdapter` bean. +Spring Boot provides convenience methods that can be used to override access rules for actuator endpoints and static resources. +`EndpointRequest` can be used to create a `RequestMatcher` that is based on the configprop:management.endpoints.web.base-path[] property. +`PathRequest` can be used to create a `RequestMatcher` for resources in commonly used locations. + + + +[[features.security.spring-webflux]] +=== WebFlux Security +Similar to Spring MVC applications, you can secure your WebFlux applications by adding the `spring-boot-starter-security` dependency. +The default security configuration is implemented in `ReactiveSecurityAutoConfiguration` and `UserDetailsServiceAutoConfiguration`. +`ReactiveSecurityAutoConfiguration` imports `WebFluxSecurityConfiguration` for web security and `UserDetailsServiceAutoConfiguration` configures authentication, which is also relevant in non-web applications. +To switch off the default web application security configuration completely, you can add a bean of type `WebFilterChainProxy` (doing so does not disable the `UserDetailsService` configuration or Actuator's security). + +To also switch off the `UserDetailsService` configuration, you can add a bean of type `ReactiveUserDetailsService` or `ReactiveAuthenticationManager`. + +Access rules and the use of multiple Spring Security components such as OAuth 2 Client and Resource Server can be configured by adding a custom `SecurityWebFilterChain` bean. +Spring Boot provides convenience methods that can be used to override access rules for actuator endpoints and static resources. +`EndpointRequest` can be used to create a `ServerWebExchangeMatcher` that is based on the configprop:management.endpoints.web.base-path[] property. + +`PathRequest` can be used to create a `ServerWebExchangeMatcher` for resources in commonly used locations. + +For example, you can customize your security configuration by adding something like: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/security/CustomWebFluxSecurityConfiguration.java[] +---- + + + +[[features.security.oauth2]] +=== OAuth2 +https://oauth.net/2/[OAuth2] is a widely used authorization framework that is supported by Spring. + + + +[[features.security.oauth2.client]] +==== Client +If you have `spring-security-oauth2-client` on your classpath, you can take advantage of some auto-configuration to set up an OAuth2/Open ID Connect clients. +This configuration makes use of the properties under `OAuth2ClientProperties`. +The same properties are applicable to both servlet and reactive applications. + +You can register multiple OAuth2 clients and providers under the `spring.security.oauth2.client` prefix, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + security: + oauth2: + client: + registration: + my-client-1: + client-id: "abcd" + client-secret: "password" + client-name: "Client for user scope" + provider: "my-oauth-provider" + scope: "user" + redirect-uri: "https://my-redirect-uri.com" + client-authentication-method: "basic" + authorization-grant-type: "authorization-code" + + my-client-2: + client-id: "abcd" + client-secret: "password" + client-name: "Client for email scope" + provider: "my-oauth-provider" + scope: "email" + redirect-uri: "https://my-redirect-uri.com" + client-authentication-method: "basic" + authorization-grant-type: "authorization_code" + + provider: + my-oauth-provider: + authorization-uri: "https://my-auth-server/oauth/authorize" + token-uri: "https://my-auth-server/oauth/token" + user-info-uri: "https://my-auth-server/userinfo" + user-info-authentication-method: "header" + jwk-set-uri: "https://my-auth-server/token_keys" + user-name-attribute: "name" +---- + +For OpenID Connect providers that support https://openid.net/specs/openid-connect-discovery-1_0.html[OpenID Connect discovery], the configuration can be further simplified. +The provider needs to be configured with an `issuer-uri` which is the URI that the it asserts as its Issuer Identifier. +For example, if the `issuer-uri` provided is "https://example.com", then an `OpenID Provider Configuration Request` will be made to "https://example.com/.well-known/openid-configuration". +The result is expected to be an `OpenID Provider Configuration Response`. +The following example shows how an OpenID Connect Provider can be configured with the `issuer-uri`: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + security: + oauth2: + client: + provider: + oidc-provider: + issuer-uri: "https://dev-123456.oktapreview.com/oauth2/default/" +---- + +By default, Spring Security's `OAuth2LoginAuthenticationFilter` only processes URLs matching `/login/oauth2/code/*`. +If you want to customize the `redirect-uri` to use a different pattern, you need to provide configuration to process that custom pattern. +For example, for servlet applications, you can add your own `SecurityFilterChain` that resembles the following: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/security/OAuthClientConfiguration.java[] +---- + +TIP: Spring Boot auto-configures an `InMemoryOAuth2AuthorizedClientService` which is used by Spring Security for the management of client registrations. +The `InMemoryOAuth2AuthorizedClientService` has limited capabilities and we recommend using it only for development environments. +For production environments, consider using a `JdbcOAuth2AuthorizedClientService` or creating your own implementation of `OAuth2AuthorizedClientService`. + + + +[[features.security.oauth2.client.common-providers]] +===== OAuth2 client registration for common providers +For common OAuth2 and OpenID providers, including Google, Github, Facebook, and Okta, we provide a set of provider defaults (`google`, `github`, `facebook`, and `okta`, respectively). + +If you do not need to customize these providers, you can set the `provider` attribute to the one for which you need to infer defaults. +Also, if the key for the client registration matches a default supported provider, Spring Boot infers that as well. + +In other words, the two configurations in the following example use the Google provider: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + security: + oauth2: + client: + registration: + my-client: + client-id: "abcd" + client-secret: "password" + provider: "google" + google: + client-id: "abcd" + client-secret: "password" +---- + + + +[[features.security.oauth2.server]] +==== Resource Server +If you have `spring-security-oauth2-resource-server` on your classpath, Spring Boot can set up an OAuth2 Resource Server. +For JWT configuration, a JWK Set URI or OIDC Issuer URI needs to be specified, as shown in the following examples: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + security: + oauth2: + resourceserver: + jwt: + jwk-set-uri: "https://example.com/oauth2/default/v1/keys" +---- + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + security: + oauth2: + resourceserver: + jwt: + issuer-uri: "https://dev-123456.oktapreview.com/oauth2/default/" +---- + +NOTE: If the authorization server does not support a JWK Set URI, you can configure the resource server with the Public Key used for verifying the signature of the JWT. +This can be done using the configprop:spring.security.oauth2.resourceserver.jwt.public-key-location[] property, where the value needs to point to a file containing the public key in the PEM-encoded x509 format. + +The same properties are applicable for both servlet and reactive applications. + +Alternatively, you can define your own `JwtDecoder` bean for servlet applications or a `ReactiveJwtDecoder` for reactive applications. + +In cases where opaque tokens are used instead of JWTs, you can configure the following properties to validate tokens via introspection: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + security: + oauth2: + resourceserver: + opaquetoken: + introspection-uri: "https://example.com/check-token" + client-id: "my-client-id" + client-secret: "my-client-secret" +---- + +Again, the same properties are applicable for both servlet and reactive applications. + +Alternatively, you can define your own `OpaqueTokenIntrospector` bean for servlet applications or a `ReactiveOpaqueTokenIntrospector` for reactive applications. + + + +[[features.security.oauth2.authorization-server]] +==== Authorization Server +Currently, Spring Security does not provide support for implementing an OAuth 2.0 Authorization Server. +However, this functionality is available from the {spring-security-oauth2}[Spring Security OAuth] project, which will eventually be superseded by Spring Security completely. +Until then, you can use the `spring-security-oauth2-autoconfigure` module to easily set up an OAuth 2.0 authorization server; see its https://docs.spring.io/spring-security-oauth2-boot/[documentation] for instructions. + + + +[[features.security.saml2]] +=== SAML 2.0 + + + +[[features.security.saml2.relying-party]] +==== Relying Party +If you have `spring-security-saml2-service-provider` on your classpath, you can take advantage of some auto-configuration to set up a SAML 2.0 Relying Party. +This configuration makes use of the properties under `Saml2RelyingPartyProperties`. + +A relying party registration represents a paired configuration between an Identity Provider, IDP, and a Service Provider, SP. +You can register multiple relying parties under the `spring.security.saml2.relyingparty` prefix, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + security: + saml2: + relyingparty: + registration: + my-relying-party1: + signing: + credentials: + - private-key-location: "path-to-private-key" + certificate-location: "path-to-certificate" + decryption: + credentials: + - private-key-location: "path-to-private-key" + certificate-location: "path-to-certificate" + identityprovider: + verification: + credentials: + - certificate-location: "path-to-verification-cert" + entity-id: "remote-idp-entity-id1" + sso-url: "https://remoteidp1.sso.url" + my-relying-party2: + signing: + credentials: + - private-key-location: "path-to-private-key" + certificate-location: "path-to-certificate" + decryption: + credentials: + - private-key-location: "path-to-private-key" + certificate-location: "path-to-certificate" + identityprovider: + verification: + credentials: + - certificate-location: "path-to-other-verification-cert" + entity-id: "remote-idp-entity-id2" + sso-url: "https://remoteidp2.sso.url" +---- + + + +[[features.security.actuator]] +=== Actuator Security +For security purposes, all actuators other than `/health` are disabled by default. +The configprop:management.endpoints.web.exposure.include[] property can be used to enable the actuators. + +If Spring Security is on the classpath and no other `WebSecurityConfigurerAdapter` or `SecurityFilterChain` bean is present, all actuators other than `/health` are secured by Spring Boot auto-configuration. +If you define a custom `WebSecurityConfigurerAdapter` or `SecurityFilterChain` bean, Spring Boot auto-configuration will back off and you will be in full control of actuator access rules. + +NOTE: Before setting the `management.endpoints.web.exposure.include`, ensure that the exposed actuators do not contain sensitive information and/or are secured by placing them behind a firewall or by something like Spring Security. + + + +[[features.security.actuator.csrf]] +==== Cross Site Request Forgery Protection +Since Spring Boot relies on Spring Security's defaults, CSRF protection is turned on by default. +This means that the actuator endpoints that require a `POST` (shutdown and loggers endpoints), `PUT` or `DELETE` will get a 403 forbidden error when the default security configuration is in use. + +NOTE: We recommend disabling CSRF protection completely only if you are creating a service that is used by non-browser clients. + +Additional information about CSRF protection can be found in the {spring-security-docs}#csrf[Spring Security Reference Guide]. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/spring-application.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/spring-application.adoc new file mode 100644 index 0000000000..b7aa2ab159 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/spring-application.adoc @@ -0,0 +1,420 @@ +[[features.spring-application]] +== SpringApplication +The `SpringApplication` class provides a convenient way to bootstrap a Spring application that is started from a `main()` method. +In many situations, you can delegate to the static `SpringApplication.run` method, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/springapplication/main/run/MyApplication.java[] +---- + +When your application starts, you should see something similar to the following output: + +[indent=0,subs="attributes"] +---- + . ____ _ __ _ _ + /\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \ +( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \ + \\/ ___)| |_)| | | | | || (_| | ) ) ) ) + ' |____| .__|_| |_|_| |_\__, | / / / / + =========|_|==============|___/=/_/_/_/ + :: Spring Boot :: v{spring-boot-version} + +2021-02-03 10:33:25.224 INFO 17321 --- [ main] o.s.b.d.s.s.SpringAppplicationExample : Starting SpringAppplicationExample using Java 1.8.0_232 on mycomputer with PID 17321 (/apps/myjar.jar started by pwebb) +2021-02-03 10:33:25.226 INFO 17900 --- [ main] o.s.b.d.s.s.SpringAppplicationExample : No active profile set, falling back to default profiles: default +2021-02-03 10:33:26.046 INFO 17321 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http) +2021-02-03 10:33:26.054 INFO 17900 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat] +2021-02-03 10:33:26.055 INFO 17900 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/9.0.41] +2021-02-03 10:33:26.097 INFO 17900 --- [ main] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext +2021-02-03 10:33:26.097 INFO 17900 --- [ main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 821 ms +2021-02-03 10:33:26.144 INFO 17900 --- [ main] s.tomcat.SampleTomcatApplication : ServletContext initialized +2021-02-03 10:33:26.376 INFO 17900 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path '' +2021-02-03 10:33:26.384 INFO 17900 --- [ main] o.s.b.d.s.s.SpringAppplicationExample : Started SampleTomcatApplication in 1.514 seconds (JVM running for 1.823) +---- + + + +By default, `INFO` logging messages are shown, including some relevant startup details, such as the user that launched the application. +If you need a log level other than `INFO`, you can set it, as described in <>. +The application version is determined using the implementation version from the main application class's package. +Startup information logging can be turned off by setting `spring.main.log-startup-info` to `false`. +This will also turn off logging of the application's active profiles. + +TIP: To add additional logging during startup, you can override `logStartupInfo(boolean)` in a subclass of `SpringApplication`. + + + +[[features.spring-application.startup-failure]] +=== Startup Failure +If your application fails to start, registered `FailureAnalyzers` get a chance to provide a dedicated error message and a concrete action to fix the problem. +For instance, if you start a web application on port `8080` and that port is already in use, you should see something similar to the following message: + +[indent=0] +---- + *************************** + APPLICATION FAILED TO START + *************************** + + Description: + + Embedded servlet container failed to start. Port 8080 was already in use. + + Action: + + Identify and stop the process that's listening on port 8080 or configure this application to listen on another port. +---- + +NOTE: Spring Boot provides numerous `FailureAnalyzer` implementations, and you can <>. + +If no failure analyzers are able to handle the exception, you can still display the full conditions report to better understand what went wrong. +To do so, you need to <> or <> for `org.springframework.boot.autoconfigure.logging.ConditionEvaluationReportLoggingListener`. + +For instance, if you are running your application by using `java -jar`, you can enable the `debug` property as follows: + +[indent=0,subs="attributes"] +---- + $ java -jar myproject-0.0.1-SNAPSHOT.jar --debug +---- + + + +[[features.spring-application.lazy-initialization]] +=== Lazy Initialization +`SpringApplication` allows an application to be initialized lazily. +When lazy initialization is enabled, beans are created as they are needed rather than during application startup. +As a result, enabling lazy initialization can reduce the time that it takes your application to start. +In a web application, enabling lazy initialization will result in many web-related beans not being initialized until an HTTP request is received. + +A downside of lazy initialization is that it can delay the discovery of a problem with the application. +If a misconfigured bean is initialized lazily, a failure will no longer occur during startup and the problem will only become apparent when the bean is initialized. +Care must also be taken to ensure that the JVM has sufficient memory to accommodate all of the application's beans and not just those that are initialized during startup. +For these reasons, lazy initialization is not enabled by default and it is recommended that fine-tuning of the JVM's heap size is done before enabling lazy initialization. + +Lazy initialization can be enabled programmatically using the `lazyInitialization` method on `SpringApplicationBuilder` or the `setLazyInitialization` method on `SpringApplication`. +Alternatively, it can be enabled using the configprop:spring.main.lazy-initialization[] property as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + main: + lazy-initialization: true +---- + +TIP: If you want to disable lazy initialization for certain beans while using lazy initialization for the rest of the application, you can explicitly set their lazy attribute to false using the `@Lazy(false)` annotation. + + + +[[features.spring-application.banner]] +=== Customizing the Banner +The banner that is printed on start up can be changed by adding a `banner.txt` file to your classpath or by setting the configprop:spring.banner.location[] property to the location of such a file. +If the file has an encoding other than UTF-8, you can set `spring.banner.charset`. +In addition to a text file, you can also add a `banner.gif`, `banner.jpg`, or `banner.png` image file to your classpath or set the configprop:spring.banner.image.location[] property. +Images are converted into an ASCII art representation and printed above any text banner. + +Inside your `banner.txt` file, you can use any of the following placeholders: + +.Banner variables +|=== +| Variable | Description + +| `${application.version}` +| The version number of your application, as declared in `MANIFEST.MF`. + For example, `Implementation-Version: 1.0` is printed as `1.0`. + +| `${application.formatted-version}` +| The version number of your application, as declared in `MANIFEST.MF` and formatted for display (surrounded with brackets and prefixed with `v`). + For example `(v1.0)`. + +| `${spring-boot.version}` +| The Spring Boot version that you are using. + For example `{spring-boot-version}`. + +| `${spring-boot.formatted-version}` +| The Spring Boot version that you are using, formatted for display (surrounded with brackets and prefixed with `v`). + For example `(v{spring-boot-version})`. + +| `${Ansi.NAME}` (or `${AnsiColor.NAME}`, `${AnsiBackground.NAME}`, `${AnsiStyle.NAME}`) +| Where `NAME` is the name of an ANSI escape code. + See {spring-boot-module-code}/ansi/AnsiPropertySource.java[`AnsiPropertySource`] for details. + +| `${application.title}` +| The title of your application, as declared in `MANIFEST.MF`. + For example `Implementation-Title: MyApp` is printed as `MyApp`. +|=== + +TIP: The `SpringApplication.setBanner(...)` method can be used if you want to generate a banner programmatically. +Use the `org.springframework.boot.Banner` interface and implement your own `printBanner()` method. + +You can also use the configprop:spring.main.banner-mode[] property to determine if the banner has to be printed on `System.out` (`console`), sent to the configured logger (`log`), or not produced at all (`off`). + +The printed banner is registered as a singleton bean under the following name: `springBootBanner`. + +[NOTE] +==== +The `${application.version}` and `${application.formatted-version}` properties are only available if you are using Spring Boot launchers. +The values won't be resolved if you are running an unpacked jar and starting it with `java -cp `. + +This is why we recommend that you always launch unpacked jars using `java org.springframework.boot.loader.JarLauncher`. +This will initialize the `application.*` banner variables before building the classpath and launching your app. +==== + + + +[[features.spring-application.customizing-spring-application]] +=== Customizing SpringApplication +If the `SpringApplication` defaults are not to your taste, you can instead create a local instance and customize it. +For example, to turn off the banner, you could write: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/springapplication/main/custom/MyApplication.java[] +---- + +NOTE: The constructor arguments passed to `SpringApplication` are configuration sources for Spring beans. +In most cases, these are references to `@Configuration` classes, but they could also be references to XML configuration or to packages that should be scanned. + +It is also possible to configure the `SpringApplication` by using an `application.properties` file. +See _<>_ for details. + +For a complete list of the configuration options, see the {spring-boot-module-api}/SpringApplication.html[`SpringApplication` Javadoc]. + + + +[[features.spring-application.fluent-builder-api]] +=== Fluent Builder API +If you need to build an `ApplicationContext` hierarchy (multiple contexts with a parent/child relationship) or if you prefer using a "`fluent`" builder API, you can use the `SpringApplicationBuilder`. + +The `SpringApplicationBuilder` lets you chain together multiple method calls and includes `parent` and `child` methods that let you create a hierarchy, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/springapplication/SpringApplicationBuilderExample.java[tag=*] +---- + +NOTE: There are some restrictions when creating an `ApplicationContext` hierarchy. +For example, Web components *must* be contained within the child context, and the same `Environment` is used for both parent and child contexts. +See the {spring-boot-module-api}/builder/SpringApplicationBuilder.html[`SpringApplicationBuilder` Javadoc] for full details. + + + +[[features.spring-application.application-availability]] +=== Application Availability +When deployed on platforms, applications can provide information about their availability to the platform using infrastructure such as https://kubernetes.io/docs/tasks/configure-pod-container/configure-liveness-readiness-startup-probes/[Kubernetes Probes]. +Spring Boot includes out-of-the box support for the commonly used "`liveness`" and "`readiness`" availability states. +If you are using Spring Boot's "`actuator`" support then these states are exposed as health endpoint groups. + +In addition, you can also obtain availability states by injecting the `ApplicationAvailability` interface into your own beans. + + + +[[features.spring-application.application-availability.liveness]] +==== Liveness State +The "`Liveness`" state of an application tells whether its internal state allows it to work correctly, or recover by itself if it's currently failing. +A broken "`Liveness`" state means that the application is in a state that it cannot recover from, and the infrastructure should restart the application. + +NOTE: In general, the "Liveness" state should not be based on external checks, such as <>. +If it did, a failing external system (a database, a Web API, an external cache) would trigger massive restarts and cascading failures across the platform. + +The internal state of Spring Boot applications is mostly represented by the Spring `ApplicationContext`. +If the application context has started successfully, Spring Boot assumes that the application is in a valid state. +An application is considered live as soon as the context has been refreshed, see <>. + + + +[[features.spring-application.application-availability.readiness]] +==== Readiness State +The "`Readiness`" state of an application tells whether the application is ready to handle traffic. +A failing "`Readiness`" state tells the platform that it should not route traffic to the application for now. +This typically happens during startup, while `CommandLineRunner` and `ApplicationRunner` components are being processed, or at any time if the application decides that it's too busy for additional traffic. + +An application is considered ready as soon as application and command-line runners have been called, see <>. + +TIP: Tasks expected to run during startup should be executed by `CommandLineRunner` and `ApplicationRunner` components instead of using Spring component lifecycle callbacks such as `@PostConstruct`. + + + +[[features.spring-application.application-availability.managing]] +==== Managing the Application Availability State +Application components can retrieve the current availability state at any time, by injecting the `ApplicationAvailability` interface and calling methods on it. +More often, applications will want to listen to state updates or update the state of the application. + +For example, we can export the "Readiness" state of the application to a file so that a Kubernetes "exec Probe" can look at this file: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/springapplication/availability/ReadinessStateExporter.java[] +---- + +We can also update the state of the application, when the application breaks and cannot recover: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/springapplication/availability/LocalCacheVerifier.java[] +---- + +Spring Boot provides <>. +You can get more guidance about <>. + + + +[[features.spring-application.application-events-and-listeners]] +=== Application Events and Listeners +In addition to the usual Spring Framework events, such as {spring-framework-api}/context/event/ContextRefreshedEvent.html[`ContextRefreshedEvent`], a `SpringApplication` sends some additional application events. + +[NOTE] +==== +Some events are actually triggered before the `ApplicationContext` is created, so you cannot register a listener on those as a `@Bean`. +You can register them with the `SpringApplication.addListeners(...)` method or the `SpringApplicationBuilder.listeners(...)` method. + +If you want those listeners to be registered automatically, regardless of the way the application is created, you can add a `META-INF/spring.factories` file to your project and reference your listener(s) by using the `org.springframework.context.ApplicationListener` key, as shown in the following example: + +[indent=0] +---- + org.springframework.context.ApplicationListener=com.example.project.MyListener +---- + +==== + +Application events are sent in the following order, as your application runs: + +. An `ApplicationStartingEvent` is sent at the start of a run but before any processing, except for the registration of listeners and initializers. +. An `ApplicationEnvironmentPreparedEvent` is sent when the `Environment` to be used in the context is known but before the context is created. +. An `ApplicationContextInitializedEvent` is sent when the `ApplicationContext` is prepared and ApplicationContextInitializers have been called but before any bean definitions are loaded. +. An `ApplicationPreparedEvent` is sent just before the refresh is started but after bean definitions have been loaded. +. An `ApplicationStartedEvent` is sent after the context has been refreshed but before any application and command-line runners have been called. +. An `AvailabilityChangeEvent` is sent right after with `LivenessState.CORRECT` to indicate that the application is considered as live. +. An `ApplicationReadyEvent` is sent after any <> have been called. +. An `AvailabilityChangeEvent` is sent right after with `ReadinessState.ACCEPTING_TRAFFIC` to indicate that the application is ready to service requests. +. An `ApplicationFailedEvent` is sent if there is an exception on startup. + +The above list only includes ``SpringApplicationEvent``s that are tied to a `SpringApplication`. +In addition to these, the following events are also published after `ApplicationPreparedEvent` and before `ApplicationStartedEvent`: + +- A `WebServerInitializedEvent` is sent after the `WebServer` is ready. + `ServletWebServerInitializedEvent` and `ReactiveWebServerInitializedEvent` are the servlet and reactive variants respectively. +- A `ContextRefreshedEvent` is sent when an `ApplicationContext` is refreshed. + +TIP: You often need not use application events, but it can be handy to know that they exist. +Internally, Spring Boot uses events to handle a variety of tasks. + +NOTE: Event listeners should not run potentially lengthy tasks as they execute in the same thread by default. +Consider using <> instead. + +Application events are sent by using Spring Framework's event publishing mechanism. +Part of this mechanism ensures that an event published to the listeners in a child context is also published to the listeners in any ancestor contexts. +As a result of this, if your application uses a hierarchy of `SpringApplication` instances, a listener may receive multiple instances of the same type of application event. + +To allow your listener to distinguish between an event for its context and an event for a descendant context, it should request that its application context is injected and then compare the injected context with the context of the event. +The context can be injected by implementing `ApplicationContextAware` or, if the listener is a bean, by using `@Autowired`. + + + +[[features.spring-application.web-environment]] +=== Web Environment +A `SpringApplication` attempts to create the right type of `ApplicationContext` on your behalf. +The algorithm used to determine a `WebApplicationType` is the following: + +* If Spring MVC is present, an `AnnotationConfigServletWebServerApplicationContext` is used +* If Spring MVC is not present and Spring WebFlux is present, an `AnnotationConfigReactiveWebServerApplicationContext` is used +* Otherwise, `AnnotationConfigApplicationContext` is used + +This means that if you are using Spring MVC and the new `WebClient` from Spring WebFlux in the same application, Spring MVC will be used by default. +You can override that easily by calling `setWebApplicationType(WebApplicationType)`. + +It is also possible to take complete control of the `ApplicationContext` type that is used by calling `setApplicationContextClass(...)`. + +TIP: It is often desirable to call `setWebApplicationType(WebApplicationType.NONE)` when using `SpringApplication` within a JUnit test. + + + +[[features.spring-application.application-arguments]] +=== Accessing Application Arguments +If you need to access the application arguments that were passed to `SpringApplication.run(...)`, you can inject a `org.springframework.boot.ApplicationArguments` bean. +The `ApplicationArguments` interface provides access to both the raw `String[]` arguments as well as parsed `option` and `non-option` arguments, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/springapplication/ApplicationArgumentsExample.java[] +---- + +TIP: Spring Boot also registers a `CommandLinePropertySource` with the Spring `Environment`. +This lets you also inject single application arguments by using the `@Value` annotation. + + + +[[features.spring-application.command-line-runner]] +=== Using the ApplicationRunner or CommandLineRunner +If you need to run some specific code once the `SpringApplication` has started, you can implement the `ApplicationRunner` or `CommandLineRunner` interfaces. +Both interfaces work in the same way and offer a single `run` method, which is called just before `SpringApplication.run(...)` completes. + +NOTE: This contract is well suited for tasks that should run after application startup but before it starts accepting traffic. + + +The `CommandLineRunner` interfaces provides access to application arguments as a string array, whereas the `ApplicationRunner` uses the `ApplicationArguments` interface discussed earlier. +The following example shows a `CommandLineRunner` with a `run` method: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/springapplication/CommandLineRunnerExample.java[] +---- + +If several `CommandLineRunner` or `ApplicationRunner` beans are defined that must be called in a specific order, you can additionally implement the `org.springframework.core.Ordered` interface or use the `org.springframework.core.annotation.Order` annotation. + + + +[[features.spring-application.application-exit]] +=== Application Exit +Each `SpringApplication` registers a shutdown hook with the JVM to ensure that the `ApplicationContext` closes gracefully on exit. +All the standard Spring lifecycle callbacks (such as the `DisposableBean` interface or the `@PreDestroy` annotation) can be used. + +In addition, beans may implement the `org.springframework.boot.ExitCodeGenerator` interface if they wish to return a specific exit code when `SpringApplication.exit()` is called. +This exit code can then be passed to `System.exit()` to return it as a status code, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/springapplication/exitcode/MyApplication.java[] +---- + +Also, the `ExitCodeGenerator` interface may be implemented by exceptions. +When such an exception is encountered, Spring Boot returns the exit code provided by the implemented `getExitCode()` method. + + + +[[features.spring-application.admin]] +=== Admin Features +It is possible to enable admin-related features for the application by specifying the configprop:spring.application.admin.enabled[] property. +This exposes the {spring-boot-module-code}/admin/SpringApplicationAdminMXBean.java[`SpringApplicationAdminMXBean`] on the platform `MBeanServer`. +You could use this feature to administer your Spring Boot application remotely. +This feature could also be useful for any service wrapper implementation. + +TIP: If you want to know on which HTTP port the application is running, get the property with a key of `local.server.port`. + + + +[[features.spring-application.startup-tracking]] +=== Application Startup tracking +During the application startup, the `SpringApplication` and the `ApplicationContext` perform many tasks related to the application lifecycle, +the beans lifecycle or even processing application events. +With {spring-framework-api}/core/metrics/ApplicationStartup.html[`ApplicationStartup`], Spring Framework {spring-framework-docs}/core.html#context-functionality-startup[allows you to track the application startup sequence with ``StartupStep``s]. +This data can be collected for profiling purposes, or just to have a better understanding of an application startup process. + +You can choose an `ApplicationStartup` implementation when setting up the `SpringApplication` instance. +For example, to use the `BufferingApplicationStartup`, you could write: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/springapplication/startup/MyApplication.java[tag=*] +---- + +The first available implementation, `FlightRecorderApplicationStartup` is provided by Spring Framework. +It adds Spring-specific startup events to a Java Flight Recorder session and is meant for profiling applications and correlating their Spring context lifecycle with JVM events (such as allocations, GCs, class loading...). +Once configured, you can record data by running the application with the Flight Recorder enabled: + +[source,bash,indent=0] +---- + $ java -XX:StartFlightRecording:filename=recording.jfr,duration=10s -jar demo.jar +---- + +Spring Boot ships with the `BufferingApplicationStartup` variant; this implementation is meant for buffering the startup steps and draining them into an external metrics system. +Applications can ask for the bean of type `BufferingApplicationStartup` in any component. +Additionally, Spring Boot Actuator will {spring-boot-actuator-restapi-docs}/#startup[expose a `startup` endpoint to expose this information as a JSON document]. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/spring-integration.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/spring-integration.adoc new file mode 100644 index 0000000000..b8633f294b --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/spring-integration.adoc @@ -0,0 +1,50 @@ +[[features.spring-integration]] +== Spring Integration +Spring Boot offers several conveniences for working with {spring-integration}[Spring Integration], including the `spring-boot-starter-integration` "`Starter`". +Spring Integration provides abstractions over messaging and also other transports such as HTTP, TCP, and others. +If Spring Integration is available on your classpath, it is initialized through the `@EnableIntegration` annotation. + +Spring Integration polling logic relies <>. + +Spring Boot also configures some features that are triggered by the presence of additional Spring Integration modules. +If `spring-integration-jmx` is also on the classpath, message processing statistics are published over JMX. +If `spring-integration-jdbc` is available, the default database schema can be created on startup, as shown in the following line: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + integration: + jdbc: + initialize-schema: "always" +---- + +If `spring-integration-rsocket` is available, developers can configure an RSocket server using `"spring.rsocket.server.*"` properties and let it use `IntegrationRSocketEndpoint` or `RSocketOutboundGateway` components to handle incoming RSocket messages. +This infrastructure can handle Spring Integration RSocket channel adapters and `@MessageMapping` handlers (given `"spring.integration.rsocket.server.message-mapping-enabled"` is configured). + +Spring Boot can also auto-configure an `ClientRSocketConnector` using configuration properties: + +[source,yaml,indent=0,configprops,configblocks] +---- + # Connecting to a RSocket server over TCP + spring: + integration: + rsocket: + client: + host: "example.org" + port: 9898 +---- + +[source,yaml,indent=0,configprops,configblocks] +---- + # Connecting to a RSocket Server over WebSocket + spring: + integration: + rsocket: + client: + uri: "ws://example.org" +---- + +See the {spring-boot-autoconfigure-module-code}/integration/IntegrationAutoConfiguration.java[`IntegrationAutoConfiguration`] and {spring-boot-autoconfigure-module-code}/integration/IntegrationProperties.java[`IntegrationProperties`] classes for more details. + +By default, if a Micrometer `meterRegistry` bean is present, Spring Integration metrics will be managed by Micrometer. +If you wish to use legacy Spring Integration metrics, add a `DefaultMetricsFactory` bean to the application context. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/spring-session.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/spring-session.adoc new file mode 100644 index 0000000000..7723d4de58 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/spring-session.adoc @@ -0,0 +1,50 @@ +[[features.spring-session]] +== Spring Session +Spring Boot provides {spring-session}[Spring Session] auto-configuration for a wide range of data stores. +When building a Servlet web application, the following stores can be auto-configured: + +* JDBC +* Redis +* Hazelcast +* MongoDB + +The Servlet auto-configuration replaces the need to use `@Enable*HttpSession`. + +When building a reactive web application, the following stores can be auto-configured: + +* Redis +* MongoDB + +The reactive auto-configuration replaces the need to use `@Enable*WebSession`. + +If a single Spring Session module is present on the classpath, Spring Boot uses that store implementation automatically. +If you have more than one implementation, you must choose the {spring-boot-autoconfigure-module-code}/session/StoreType.java[`StoreType`] that you wish to use to store the sessions. +For instance, to use JDBC as the back-end store, you can configure your application as follows: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + session: + store-type: "jdbc" +---- + +TIP: You can disable Spring Session by setting the `store-type` to `none`. + +Each store has specific additional settings. +For instance, it is possible to customize the name of the table for the JDBC store, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + session: + jdbc: + table-name: "SESSIONS" +---- + +For setting the timeout of the session you can use the configprop:spring.session.timeout[] property. +If that property is not set with a Servlet web application, the auto-configuration falls back to the value of configprop:server.servlet.session.timeout[]. + + +You can take control over Spring Session's configuration using `@Enable*HttpSession` (Servlet) or `@Enable*WebSession` (Reactive). +This will cause the auto-configuration to back off. +Spring Session can then be configured using the annotation's attributes rather than the previously described configuration properties. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/sql.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/sql.adoc new file mode 100644 index 0000000000..6f7108f3e0 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/sql.adoc @@ -0,0 +1,500 @@ +[[features.sql]] +== Working with SQL Databases +The {spring-framework}[Spring Framework] provides extensive support for working with SQL databases, from direct JDBC access using `JdbcTemplate` to complete "`object relational mapping`" technologies such as Hibernate. +{spring-data}[Spring Data] provides an additional level of functionality: creating `Repository` implementations directly from interfaces and using conventions to generate queries from your method names. + + + +[[features.sql.datasource]] +=== Configure a DataSource +Java's `javax.sql.DataSource` interface provides a standard method of working with database connections. +Traditionally, a 'DataSource' uses a `URL` along with some credentials to establish a database connection. + +TIP: See <> for more advanced examples, typically to take full control over the configuration of the DataSource. + + + +[[features.sql.datasource.embedded]] +==== Embedded Database Support +It is often convenient to develop applications by using an in-memory embedded database. +Obviously, in-memory databases do not provide persistent storage. +You need to populate your database when your application starts and be prepared to throw away data when your application ends. + +TIP: The "`How-to`" section includes a <>. + +Spring Boot can auto-configure embedded https://www.h2database.com[H2], http://hsqldb.org/[HSQL], and https://db.apache.org/derby/[Derby] databases. +You need not provide any connection URLs. +You need only include a build dependency to the embedded database that you want to use. +If there are multiple embedded databases on the classpath, set the configprop:spring.datasource.embedded-database-connection[] configuration property to control which one is used. +Setting the property to `none` disables auto-configuration of an embedded database. + +[NOTE] +==== +If you are using this feature in your tests, you may notice that the same database is reused by your whole test suite regardless of the number of application contexts that you use. +If you want to make sure that each context has a separate embedded database, you should set `spring.datasource.generate-unique-name` to `true`. +==== + +For example, the typical POM dependencies would be as follows: + +[source,xml,indent=0] +---- + + org.springframework.boot + spring-boot-starter-data-jpa + + + org.hsqldb + hsqldb + runtime + +---- + +NOTE: You need a dependency on `spring-jdbc` for an embedded database to be auto-configured. +In this example, it is pulled in transitively through `spring-boot-starter-data-jpa`. + +TIP: If, for whatever reason, you do configure the connection URL for an embedded database, take care to ensure that the database's automatic shutdown is disabled. +If you use H2, you should use `DB_CLOSE_ON_EXIT=FALSE` to do so. +If you use HSQLDB, you should ensure that `shutdown=true` is not used. +Disabling the database's automatic shutdown lets Spring Boot control when the database is closed, thereby ensuring that it happens once access to the database is no longer needed. + + + +[[features.sql.datasource.production]] +==== Connection to a Production Database +Production database connections can also be auto-configured by using a pooling `DataSource`. + + + +[[features.sql.datasource.configuration]] +==== DataSource Configuration +DataSource configuration is controlled by external configuration properties in `+spring.datasource.*+`. +For example, you might declare the following section in `application.properties`: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + datasource: + url: "jdbc:mysql://localhost/test" + username: "dbuser" + password: "dbpass" +---- + +NOTE: You should at least specify the URL by setting the configprop:spring.datasource.url[] property. +Otherwise, Spring Boot tries to auto-configure an embedded database. + +TIP: Spring Boot can deduce the JDBC driver class for most databases from the URL. +If you need to specify a specific class, you can use the configprop:spring.datasource.driver-class-name[] property. + +NOTE: For a pooling `DataSource` to be created, we need to be able to verify that a valid `Driver` class is available, so we check for that before doing anything. +In other words, if you set `spring.datasource.driver-class-name=com.mysql.jdbc.Driver`, then that class has to be loadable. + +See {spring-boot-autoconfigure-module-code}/jdbc/DataSourceProperties.java[`DataSourceProperties`] for more of the supported options. +These are the standard options that work regardless of <>. +It is also possible to fine-tune implementation-specific settings by using their respective prefix (`+spring.datasource.hikari.*+`, `+spring.datasource.tomcat.*+`, `+spring.datasource.dbcp2.*+`, and `+spring.datasource.oracleucp.*+`). +Refer to the documentation of the connection pool implementation you are using for more details. + +For instance, if you use the {tomcat-docs}/jdbc-pool.html#Common_Attributes[Tomcat connection pool], you could customize many additional settings, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + datasource: + tomcat: + max-wait: 10000 + max-active: 50 + test-on-borrow: true +---- + +This will set the pool to wait 10000 ms before throwing an exception if no connection is available, limit the maximum number of connections to 50 and validate the connection before borrowing it from the pool. + + + +[[features.sql.datasource.connection-pool]] +==== Supported Connection Pools +Spring Boot uses the following algorithm for choosing a specific implementation: + +. We prefer https://github.com/brettwooldridge/HikariCP[HikariCP] for its performance and concurrency. +If HikariCP is available, we always choose it. +. Otherwise, if the Tomcat pooling `DataSource` is available, we use it. +. Otherwise, if https://commons.apache.org/proper/commons-dbcp/[Commons DBCP2] is available, we use it. +. If none of HikariCP, Tomcat, and DBCP2 are available and if Oracle UCP is available, we use it. + +NOTE: If you use the `spring-boot-starter-jdbc` or `spring-boot-starter-data-jpa` "`starters`", you automatically get a dependency to `HikariCP`. + +You can bypass that algorithm completely and specify the connection pool to use by setting the configprop:spring.datasource.type[] property. +This is especially important if you run your application in a Tomcat container, as `tomcat-jdbc` is provided by default. + +Additional connection pools can always be configured manually, using `DataSourceBuilder`. +If you define your own `DataSource` bean, auto-configuration does not occur. +The following connection pools are supported by `DataSourceBuilder`: + +* HikariCP +* Tomcat pooling `Datasource` +* Commons DBCP2 +* Oracle UCP & `OracleDataSource` +* Spring Framework's `SimpleDriverDataSource` +* H2 `JdbcDataSource` +* PostgreSQL `PGSimpleDataSource` + + + +[[features.sql.datasource.jndi]] +==== Connection to a JNDI DataSource +If you deploy your Spring Boot application to an Application Server, you might want to configure and manage your DataSource by using your Application Server's built-in features and access it by using JNDI. + +The configprop:spring.datasource.jndi-name[] property can be used as an alternative to the configprop:spring.datasource.url[], configprop:spring.datasource.username[], and configprop:spring.datasource.password[] properties to access the `DataSource` from a specific JNDI location. +For example, the following section in `application.properties` shows how you can access a JBoss AS defined `DataSource`: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + datasource: + jndi-name: "java:jboss/datasources/customers" +---- + + + +[[features.sql.jdbc-template]] +=== Using JdbcTemplate +Spring's `JdbcTemplate` and `NamedParameterJdbcTemplate` classes are auto-configured, and you can `@Autowire` them directly into your own beans, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/sql/jdbctemplate/MyBean.java[] +---- + +You can customize some properties of the template by using the `spring.jdbc.template.*` properties, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + jdbc: + template: + max-rows: 500 +---- + +NOTE: The `NamedParameterJdbcTemplate` reuses the same `JdbcTemplate` instance behind the scenes. +If more than one `JdbcTemplate` is defined and no primary candidate exists, the `NamedParameterJdbcTemplate` is not auto-configured. + + + +[[features.sql.jpa-and-spring-data]] +=== JPA and Spring Data JPA +The Java Persistence API is a standard technology that lets you "`map`" objects to relational databases. +The `spring-boot-starter-data-jpa` POM provides a quick way to get started. +It provides the following key dependencies: + +* Hibernate: One of the most popular JPA implementations. +* Spring Data JPA: Helps you to implement JPA-based repositories. +* Spring ORM: Core ORM support from the Spring Framework. + +TIP: We do not go into too many details of JPA or {spring-data}[Spring Data] here. +You can follow the https://spring.io/guides/gs/accessing-data-jpa/["`Accessing Data with JPA`"] guide from https://spring.io and read the {spring-data-jpa}[Spring Data JPA] and https://hibernate.org/orm/documentation/[Hibernate] reference documentation. + + + +[[features.sql.jpa-and-spring-data.entity-classes]] +==== Entity Classes +Traditionally, JPA "`Entity`" classes are specified in a `persistence.xml` file. +With Spring Boot, this file is not necessary and "`Entity Scanning`" is used instead. +By default, all packages below your main configuration class (the one annotated with `@EnableAutoConfiguration` or `@SpringBootApplication`) are searched. + +Any classes annotated with `@Entity`, `@Embeddable`, or `@MappedSuperclass` are considered. +A typical entity class resembles the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/sql/jpa/City.java[] +---- + +TIP: You can customize entity scanning locations by using the `@EntityScan` annotation. +See the "`<>`" how-to. + + + +[[features.sql.jpa-and-spring-data.repositories]] +==== Spring Data JPA Repositories +{spring-data-jpa}[Spring Data JPA] repositories are interfaces that you can define to access data. +JPA queries are created automatically from your method names. +For example, a `CityRepository` interface might declare a `findAllByState(String state)` method to find all the cities in a given state. + +For more complex queries, you can annotate your method with Spring Data's {spring-data-jpa-api}/repository/Query.html[`Query`] annotation. + +Spring Data repositories usually extend from the {spring-data-commons-api}/repository/Repository.html[`Repository`] or {spring-data-commons-api}/repository/CrudRepository.html[`CrudRepository`] interfaces. +If you use auto-configuration, repositories are searched from the package containing your main configuration class (the one annotated with `@EnableAutoConfiguration` or `@SpringBootApplication`) down. + +The following example shows a typical Spring Data repository interface definition: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/sql/jpa/CityRepository.java[] +---- + +Spring Data JPA repositories support three different modes of bootstrapping: default, deferred, and lazy. +To enable deferred or lazy bootstrapping, set the configprop:spring.data.jpa.repositories.bootstrap-mode[] property to `deferred` or `lazy` respectively. +When using deferred or lazy bootstrapping, the auto-configured `EntityManagerFactoryBuilder` will use the context's `AsyncTaskExecutor`, if any, as the bootstrap executor. +If more than one exists, the one named `applicationTaskExecutor` will be used. + +[NOTE] +==== +When using deferred or lazy bootstrapping, make sure to defer any access to the JPA infrastructure after the application context bootstrap phase. +You can use `SmartInitializingSingleton` to invoke any initialization that requires the JPA infrastructure. +For JPA components (such as converters) that are created as Spring beans, use `ObjectProvider` to delay the resolution of dependencies, if any. +==== + +TIP: We have barely scratched the surface of Spring Data JPA. +For complete details, see the {spring-data-jdbc-docs}[Spring Data JPA reference documentation]. + + + +[[features.sql.jpa-and-spring-data.creating-and-dropping]] +==== Creating and Dropping JPA Databases +By default, JPA databases are automatically created *only* if you use an embedded database (H2, HSQL, or Derby). +You can explicitly configure JPA settings by using `+spring.jpa.*+` properties. +For example, to create and drop tables you can add the following line to your `application.properties`: + +[indent=0] +---- + spring.jpa.hibernate.ddl-auto=create-drop +---- + +NOTE: Hibernate's own internal property name for this (if you happen to remember it better) is `hibernate.hbm2ddl.auto`. +You can set it, along with other Hibernate native properties, by using `+spring.jpa.properties.*+` (the prefix is stripped before adding them to the entity manager). +The following line shows an example of setting JPA properties for Hibernate: + +[indent=0] +---- + spring.jpa.properties.hibernate.globally_quoted_identifiers=true +---- + +The line in the preceding example passes a value of `true` for the `hibernate.globally_quoted_identifiers` property to the Hibernate entity manager. + +By default, the DDL execution (or validation) is deferred until the `ApplicationContext` has started. +There is also a `spring.jpa.generate-ddl` flag, but it is not used if Hibernate auto-configuration is active, because the `ddl-auto` settings are more fine-grained. + + + +[[features.sql.jpa-and-spring-data.open-entity-manager-in-view]] +==== Open EntityManager in View +If you are running a web application, Spring Boot by default registers {spring-framework-api}/orm/jpa/support/OpenEntityManagerInViewInterceptor.html[`OpenEntityManagerInViewInterceptor`] to apply the "`Open EntityManager in View`" pattern, to allow for lazy loading in web views. +If you do not want this behavior, you should set `spring.jpa.open-in-view` to `false` in your `application.properties`. + + + +[[features.sql.jdbc]] +=== Spring Data JDBC +Spring Data includes repository support for JDBC and will automatically generate SQL for the methods on `CrudRepository`. +For more advanced queries, a `@Query` annotation is provided. + +Spring Boot will auto-configure Spring Data's JDBC repositories when the necessary dependencies are on the classpath. +They can be added to your project with a single dependency on `spring-boot-starter-data-jdbc`. +If necessary, you can take control of Spring Data JDBC's configuration by adding the `@EnableJdbcRepositories` annotation or a `JdbcConfiguration` subclass to your application. + +TIP: For complete details of Spring Data JDBC, please refer to the {spring-data-jdbc-docs}[reference documentation]. + + + +[[features.sql.h2-web-console]] +=== Using H2's Web Console +The https://www.h2database.com[H2 database] provides a https://www.h2database.com/html/quickstart.html#h2_console[browser-based console] that Spring Boot can auto-configure for you. +The console is auto-configured when the following conditions are met: + +* You are developing a servlet-based web application. +* `com.h2database:h2` is on the classpath. +* You are using <>. + +TIP: If you are not using Spring Boot's developer tools but would still like to make use of H2's console, you can configure the configprop:spring.h2.console.enabled[] property with a value of `true`. + +NOTE: The H2 console is only intended for use during development, so you should take care to ensure that `spring.h2.console.enabled` is not set to `true` in production. + + + +[[features.sql.h2-web-console.custom-path]] +==== Changing the H2 Console's Path +By default, the console is available at `/h2-console`. +You can customize the console's path by using the configprop:spring.h2.console.path[] property. + + + +[[features.sql.jooq]] +=== Using jOOQ +jOOQ Object Oriented Querying (https://www.jooq.org/[jOOQ]) is a popular product from https://www.datageekery.com/[Data Geekery] which generates Java code from your database and lets you build type-safe SQL queries through its fluent API. +Both the commercial and open source editions can be used with Spring Boot. + + + +[[features.sql.jooq.codegen]] +==== Code Generation +In order to use jOOQ type-safe queries, you need to generate Java classes from your database schema. +You can follow the instructions in the {jooq-docs}/#jooq-in-7-steps-step3[jOOQ user manual]. +If you use the `jooq-codegen-maven` plugin and you also use the `spring-boot-starter-parent` "`parent POM`", you can safely omit the plugin's `` tag. +You can also use Spring Boot-defined version variables (such as `h2.version`) to declare the plugin's database dependency. +The following listing shows an example: + +[source,xml,indent=0] +---- + + org.jooq + jooq-codegen-maven + + ... + + + + com.h2database + h2 + ${h2.version} + + + + + org.h2.Driver + jdbc:h2:~/yourdatabase + + + ... + + + +---- + + + +[[features.sql.jooq.dslcontext]] +==== Using DSLContext +The fluent API offered by jOOQ is initiated through the `org.jooq.DSLContext` interface. +Spring Boot auto-configures a `DSLContext` as a Spring Bean and connects it to your application `DataSource`. +To use the `DSLContext`, you can inject it, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/sql/jooq/JooqExample.java[tag=!method] +---- + +TIP: The jOOQ manual tends to use a variable named `create` to hold the `DSLContext`. + +You can then use the `DSLContext` to construct your queries, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/sql/jooq/JooqExample.java[tag=method] +---- + + + +[[features.sql.jooq.sqldialect]] +==== jOOQ SQL Dialect +Unless the configprop:spring.jooq.sql-dialect[] property has been configured, Spring Boot determines the SQL dialect to use for your datasource. +If Spring Boot could not detect the dialect, it uses `DEFAULT`. + +NOTE: Spring Boot can only auto-configure dialects supported by the open source version of jOOQ. + + + +[[features.sql.jooq.customizing]] +==== Customizing jOOQ +More advanced customizations can be achieved by defining your own `DefaultConfigurationCustomizer` bean that will be invoked prior to creating the `org.jooq.Configuration` `@Bean`. +This takes precedence to anything that is applied by the auto-configuration. + +You can also create your own `org.jooq.Configuration` `@Bean` if you want to take complete control of the jOOQ configuration. + + + +[[features.sql.r2dbc]] +=== Using R2DBC +The Reactive Relational Database Connectivity (https://r2dbc.io[R2DBC]) project brings reactive programming APIs to relational databases. +R2DBC's `io.r2dbc.spi.Connection` provides a standard method of working with non-blocking database connections. +Connections are provided via a `ConnectionFactory`, similar to a `DataSource` with jdbc. + +`ConnectionFactory` configuration is controlled by external configuration properties in `+spring.r2dbc.*+`. +For example, you might declare the following section in `application.properties`: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + r2dbc: + url: "r2dbc:postgresql://localhost/test" + username: "dbuser" + password: "dbpass" +---- + +TIP: You do not need to specify a driver class name, since Spring Boot obtains the driver from R2DBC's Connection Factory discovery. + +NOTE: At least the url should be provided. +Information specified in the URL takes precedence over individual properties, i.e. `name`, `username`, `password` and pooling options. + +TIP: The "`How-to`" section includes a <>. + +To customize the connections created by a `ConnectionFactory`, i.e., set specific parameters that you do not want (or cannot) configure in your central database configuration, you can use a `ConnectionFactoryOptionsBuilderCustomizer` `@Bean`. +The following example shows how to manually override the database port while the rest of the options is taken from the application configuration: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/sql/r2dbc/CustomizeR2dbcPortConfiguration.java[tag=*] +---- + +The following examples show how to set some PostgreSQL connection options: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/sql/r2dbc/CustomizeR2dbcPostgresOptionsConfiguration.java[tag=*] +---- + +When a `ConnectionFactory` bean is available, the regular JDBC `DataSource` auto-configuration backs off. +If you want to retain the JDBC `DataSource` auto-configuration, and are comfortable with the risk of using the blocking JDBC API in a reactive application, add `@Import(DataSourceAutoConfiguration.class)` on a `@Configuration` class in your application to re-enable it. + + + +[[features.sql.r2dbc.embedded]] +==== Embedded Database Support +Similarly to <>, Spring Boot can automatically configure an embedded database for reactive usage. +You need not provide any connection URLs. +You need only include a build dependency to the embedded database that you want to use, as shown in the following example: + +[source,xml,indent=0] +---- + + io.r2dbc + r2dbc-h2 + runtime + +---- + +[NOTE] +==== +If you are using this feature in your tests, you may notice that the same database is reused by your whole test suite regardless of the number of application contexts that you use. +If you want to make sure that each context has a separate embedded database, you should set `spring.r2dbc.generate-unique-name` to `true`. +==== + + + +[[features.sql.r2dbc.using-database-client]] +==== Using DatabaseClient +A `DatabaseClient` bean is auto-configured, and you can `@Autowire` it directly into your own beans, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/sql/r2dbc/databaseclient/MyBean.java[tag=*] +---- + + + +[[features.sql.r2dbc.repositories]] +==== Spring Data R2DBC Repositories +https://spring.io/projects/spring-data-r2dbc[Spring Data R2DBC] repositories are interfaces that you can define to access data. +Queries are created automatically from your method names. +For example, a `CityRepository` interface might declare a `findAllByState(String state)` method to find all the cities in a given state. + +For more complex queries, you can annotate your method with Spring Data's {spring-data-r2dbc-api}/repository/Query.html[`Query`] annotation. + +Spring Data repositories usually extend from the {spring-data-commons-api}/repository/Repository.html[`Repository`] or {spring-data-commons-api}/repository/CrudRepository.html[`CrudRepository`] interfaces. +If you use auto-configuration, repositories are searched from the package containing your main configuration class (the one annotated with `@EnableAutoConfiguration` or `@SpringBootApplication`) down. + +The following example shows a typical Spring Data repository interface definition: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/sql/r2dbc/CityRepository.java[tag=*] +---- + +TIP: We have barely scratched the surface of Spring Data R2DBC. For complete details, see the {spring-data-r2dbc-docs}[Spring Data R2DBC reference documentation]. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/task-execution-and-scheduling.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/task-execution-and-scheduling.adoc new file mode 100644 index 0000000000..307c491260 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/task-execution-and-scheduling.adoc @@ -0,0 +1,43 @@ +[[features.task-execution-and-scheduling]] +== Task Execution and Scheduling +In the absence of an `Executor` bean in the context, Spring Boot auto-configures a `ThreadPoolTaskExecutor` with sensible defaults that can be automatically associated to asynchronous task execution (`@EnableAsync`) and Spring MVC asynchronous request processing. + +[TIP] +==== +If you have defined a custom `Executor` in the context, regular task execution (i.e. `@EnableAsync`) will use it transparently but the Spring MVC support will not be configured as it requires an `AsyncTaskExecutor` implementation (named `applicationTaskExecutor`). +Depending on your target arrangement, you could change your `Executor` into a `ThreadPoolTaskExecutor` or define both a `ThreadPoolTaskExecutor` and an `AsyncConfigurer` wrapping your custom `Executor`. + +The auto-configured `TaskExecutorBuilder` allows you to easily create instances that reproduce what the auto-configuration does by default. +==== + +The thread pool uses 8 core threads that can grow and shrink according to the load. +Those default settings can be fine-tuned using the `spring.task.execution` namespace, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + task: + execution: + pool: + max-size: 16 + queue-capacity: 100 + keep-alive: "10s" +---- + +This changes the thread pool to use a bounded queue so that when the queue is full (100 tasks), the thread pool increases to maximum 16 threads. +Shrinking of the pool is more aggressive as threads are reclaimed when they are idle for 10 seconds (rather than 60 seconds by default). + +A `ThreadPoolTaskScheduler` can also be auto-configured if need to be associated to scheduled task execution (e.g. `@EnableScheduling`). +The thread pool uses one thread by default and its settings can be fine-tuned using the `spring.task.scheduling` namespace, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + task: + scheduling: + thread-name-prefix: "scheduling-" + pool: + size: 2 +---- + +Both a `TaskExecutorBuilder` bean and a `TaskSchedulerBuilder` bean are made available in the context if a custom executor or scheduler needs to be created. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/testing.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/testing.adoc new file mode 100644 index 0000000000..5458a5f630 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/testing.adoc @@ -0,0 +1,958 @@ +[[features.testing]] +== Testing +Spring Boot provides a number of utilities and annotations to help when testing your application. +Test support is provided by two modules: `spring-boot-test` contains core items, and `spring-boot-test-autoconfigure` supports auto-configuration for tests. + +Most developers use the `spring-boot-starter-test` "`Starter`", which imports both Spring Boot test modules as well as JUnit Jupiter, AssertJ, Hamcrest, and a number of other useful libraries. + +[TIP] +==== +If you have tests that use JUnit 4, JUnit 5's vintage engine can be used to run them. +To use the vintage engine, add a dependency on `junit-vintage-engine`, as shown in the following example: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + org.junit.vintage + junit-vintage-engine + test + + + org.hamcrest + hamcrest-core + + + +---- +==== + +`hamcrest-core` is excluded in favor of `org.hamcrest:hamcrest` that is part of `spring-boot-starter-test`. + + + +[[features.testing.test-scope-dependencies]] +=== Test Scope Dependencies +The `spring-boot-starter-test` "`Starter`" (in the `test` `scope`) contains the following provided libraries: + +* https://junit.org/junit5/[JUnit 5]: The de-facto standard for unit testing Java applications. +* {spring-framework-docs}/testing.html#integration-testing[Spring Test] & Spring Boot Test: Utilities and integration test support for Spring Boot applications. +* https://assertj.github.io/doc/[AssertJ]: A fluent assertion library. +* https://github.com/hamcrest/JavaHamcrest[Hamcrest]: A library of matcher objects (also known as constraints or predicates). +* https://site.mockito.org/[Mockito]: A Java mocking framework. +* https://github.com/skyscreamer/JSONassert[JSONassert]: An assertion library for JSON. +* https://github.com/jayway/JsonPath[JsonPath]: XPath for JSON. + +We generally find these common libraries to be useful when writing tests. +If these libraries do not suit your needs, you can add additional test dependencies of your own. + + + +[[features.testing.spring-applications]] +=== Testing Spring Applications +One of the major advantages of dependency injection is that it should make your code easier to unit test. +You can instantiate objects by using the `new` operator without even involving Spring. +You can also use _mock objects_ instead of real dependencies. + +Often, you need to move beyond unit testing and start integration testing (with a Spring `ApplicationContext`). +It is useful to be able to perform integration testing without requiring deployment of your application or needing to connect to other infrastructure. + +The Spring Framework includes a dedicated test module for such integration testing. +You can declare a dependency directly to `org.springframework:spring-test` or use the `spring-boot-starter-test` "`Starter`" to pull it in transitively. + +If you have not used the `spring-test` module before, you should start by reading the {spring-framework-docs}/testing.html#testing[relevant section] of the Spring Framework reference documentation. + + + +[[features.testing.spring-boot-applications]] +=== Testing Spring Boot Applications +A Spring Boot application is a Spring `ApplicationContext`, so nothing very special has to be done to test it beyond what you would normally do with a vanilla Spring context. + +NOTE: External properties, logging, and other features of Spring Boot are installed in the context by default only if you use `SpringApplication` to create it. + +Spring Boot provides a `@SpringBootTest` annotation, which can be used as an alternative to the standard `spring-test` `@ContextConfiguration` annotation when you need Spring Boot features. +The annotation works by <>. +In addition to `@SpringBootTest` a number of other annotations are also provided for <> of an application. + +TIP: If you are using JUnit 4, don't forget to also add `@RunWith(SpringRunner.class)` to your test, otherwise the annotations will be ignored. +If you are using JUnit 5, there's no need to add the equivalent `@ExtendWith(SpringExtension.class)` as `@SpringBootTest` and the other `@…Test` annotations are already annotated with it. + +By default, `@SpringBootTest` will not start a server. +You can use the `webEnvironment` attribute of `@SpringBootTest` to further refine how your tests run: + +* `MOCK`(Default) : Loads a web `ApplicationContext` and provides a mock web environment. + Embedded servers are not started when using this annotation. + If a web environment is not available on your classpath, this mode transparently falls back to creating a regular non-web `ApplicationContext`. + It can be used in conjunction with <> for mock-based testing of your web application. +* `RANDOM_PORT`: Loads a `WebServerApplicationContext` and provides a real web environment. + Embedded servers are started and listen on a random port. +* `DEFINED_PORT`: Loads a `WebServerApplicationContext` and provides a real web environment. + Embedded servers are started and listen on a defined port (from your `application.properties`) or on the default port of `8080`. +* `NONE`: Loads an `ApplicationContext` by using `SpringApplication` but does not provide _any_ web environment (mock or otherwise). + +NOTE: If your test is `@Transactional`, it rolls back the transaction at the end of each test method by default. +However, as using this arrangement with either `RANDOM_PORT` or `DEFINED_PORT` implicitly provides a real servlet environment, the HTTP client and server run in separate threads and, thus, in separate transactions. +Any transaction initiated on the server does not roll back in this case. + +NOTE: `@SpringBootTest` with `webEnvironment = WebEnvironment.RANDOM_PORT` will also start the management server on a separate random port if your application uses a different port for the management server. + + + +[[features.testing.spring-boot-applications.detecting-web-app-type]] +==== Detecting Web Application Type +If Spring MVC is available, a regular MVC-based application context is configured. +If you have only Spring WebFlux, we'll detect that and configure a WebFlux-based application context instead. + +If both are present, Spring MVC takes precedence. +If you want to test a reactive web application in this scenario, you must set the configprop:spring.main.web-application-type[] property: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/detection/MyWebFluxTests.java[] +---- + + + +[[features.testing.spring-boot-applications.detecting-configuration]] +==== Detecting Test Configuration +If you are familiar with the Spring Test Framework, you may be used to using `@ContextConfiguration(classes=...)` in order to specify which Spring `@Configuration` to load. +Alternatively, you might have often used nested `@Configuration` classes within your test. + +When testing Spring Boot applications, this is often not required. +Spring Boot's `@*Test` annotations search for your primary configuration automatically whenever you do not explicitly define one. + +The search algorithm works up from the package that contains the test until it finds a class annotated with `@SpringBootApplication` or `@SpringBootConfiguration`. +As long as you <> in a sensible way, your main configuration is usually found. + +[NOTE] +==== +If you use a <>, you should avoid adding configuration settings that are specific to a particular area on the <>. + +The underlying component scan configuration of `@SpringBootApplication` defines exclude filters that are used to make sure slicing works as expected. +If you are using an explicit `@ComponentScan` directive on your `@SpringBootApplication`-annotated class, be aware that those filters will be disabled. +If you are using slicing, you should define them again. +==== + +If you want to customize the primary configuration, you can use a nested `@TestConfiguration` class. +Unlike a nested `@Configuration` class, which would be used instead of your application's primary configuration, a nested `@TestConfiguration` class is used in addition to your application's primary configuration. + +NOTE: Spring's test framework caches application contexts between tests. +Therefore, as long as your tests share the same configuration (no matter how it is discovered), the potentially time-consuming process of loading the context happens only once. + + + +[[features.testing.spring-boot-applications.excluding-configuration]] +==== Excluding Test Configuration +If your application uses component scanning (for example, if you use `@SpringBootApplication` or `@ComponentScan`), you may find top-level configuration classes that you created only for specific tests accidentally get picked up everywhere. + +As we <>, `@TestConfiguration` can be used on an inner class of a test to customize the primary configuration. +When placed on a top-level class, `@TestConfiguration` indicates that classes in `src/test/java` should not be picked up by scanning. +You can then import that class explicitly where it is required, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/excluding/MyTests.java[] +---- + +NOTE: If you directly use `@ComponentScan` (that is, not through `@SpringBootApplication`) you need to register the `TypeExcludeFilter` with it. +See {spring-boot-module-api}/context/TypeExcludeFilter.html[the Javadoc] for details. + + + +[[features.testing.spring-boot-applications.using-application-arguments]] +==== Using Application Arguments +If your application expects <>, you can +have `@SpringBootTest` inject them using the `args` attribute. + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/ApplicationArgumentTests.java[] +---- + + + +[[features.testing.spring-boot-applications.with-mock-environment]] +==== Testing with a mock environment +By default, `@SpringBootTest` does not start the server. +If you have web endpoints that you want to test against this mock environment, you can additionally configure {spring-framework-docs}/testing.html#spring-mvc-test-framework[`MockMvc`] as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/MockMvcTests.java[] +---- + +TIP: If you want to focus only on the web layer and not start a complete `ApplicationContext`, consider <>. + +Alternatively, you can configure a {spring-framework-docs}/testing.html#webtestclient-tests[`WebTestClient`] as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/MockWebTestClientTests.java[] +---- + +[TIP] +==== +Testing within a mocked environment is usually faster than running with a full Servlet container. +However, since mocking occurs at the Spring MVC layer, code that relies on lower-level Servlet container behavior cannot be directly tested with MockMvc. + +For example, Spring Boot's error handling is based on the "`error page`" support provided by the Servlet container. +This means that, whilst you can test your MVC layer throws and handles exceptions as expected, you cannot directly test that a specific <> is rendered. +If you need to test these lower-level concerns, you can start a fully running server as described in the next section. +==== + + + +[[features.testing.spring-boot-applications.with-running-server]] +==== Testing with a running server +If you need to start a full running server, we recommend that you use random ports. +If you use `@SpringBootTest(webEnvironment=WebEnvironment.RANDOM_PORT)`, an available port is picked at random each time your test runs. + +The `@LocalServerPort` annotation can be used to <> into your test. +For convenience, tests that need to make REST calls to the started server can additionally `@Autowire` a {spring-framework-docs}/testing.html#webtestclient-tests[`WebTestClient`], which resolves relative links to the running server and comes with a dedicated API for verifying responses, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/RandomPortWebTestClientTests.java[] +---- + +This setup requires `spring-webflux` on the classpath. +If you can't or won't add webflux, Spring Boot also provides a `TestRestTemplate` facility: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/RandomPortTestRestTemplateTests.java[] +---- + + + +[[features.testing.spring-boot-applications.customizing-web-test-client]] +==== Customizing WebTestClient +To customize the `WebTestClient` bean, configure a `WebTestClientBuilderCustomizer` bean. +Any such beans are called with the `WebTestClient.Builder` that is used to create the `WebTestClient`. + + + +[[features.testing.spring-boot-applications.jmx]] +==== Using JMX +As the test context framework caches context, JMX is disabled by default to prevent identical components to register on the same domain. +If such test needs access to an `MBeanServer`, consider marking it dirty as well: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/jmx/SampleJmxTests.java[] +---- + + + +[[features.testing.spring-boot-applications.metrics]] +==== Using Metrics +Regardless of your classpath, meter registries, except the in-memory backed, are not auto-configured when using `@SpringBootTest`. + +If you need to export metrics to a different backend as part of an integration test, annotate it with `@AutoConfigureMetrics`. + + + +[[features.testing.spring-boot-applications.mocking-beans]] +==== Mocking and Spying Beans +When running tests, it is sometimes necessary to mock certain components within your application context. +For example, you may have a facade over some remote service that is unavailable during development. +Mocking can also be useful when you want to simulate failures that might be hard to trigger in a real environment. + +Spring Boot includes a `@MockBean` annotation that can be used to define a Mockito mock for a bean inside your `ApplicationContext`. +You can use the annotation to add new beans or replace a single existing bean definition. +The annotation can be used directly on test classes, on fields within your test, or on `@Configuration` classes and fields. +When used on a field, the instance of the created mock is also injected. +Mock beans are automatically reset after each test method. + +[NOTE] +==== +If your test uses one of Spring Boot's test annotations (such as `@SpringBootTest`), this feature is automatically enabled. +To use this feature with a different arrangement, listeners must be explicitly added, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/mocking/listener/MyTests.java[] +---- + +==== + +The following example replaces an existing `RemoteService` bean with a mock implementation: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/mocking/MyTests.java[] +---- + +NOTE: `@MockBean` cannot be used to mock the behavior of a bean that's exercised during application context refresh. +By the time the test is executed, the application context refresh has completed and it is too late to configure the mocked behavior. +We recommend using a `@Bean` method to create and configure the mock in this situation. + +Additionally, you can use `@SpyBean` to wrap any existing bean with a Mockito `spy`. +See the {spring-boot-test-module-api}/mock/mockito/SpyBean.html[Javadoc] for full details. + +NOTE: CGLib proxies, such as those created for scoped beans, declare the proxied methods as `final`. +This stops Mockito from functioning correctly as it cannot mock or spy on `final` methods in its default configuration. +If you want to mock or spy on such a bean, configure Mockito to use its inline mock maker by adding `org.mockito:mockito-inline` to your application's test dependencies. +This allows Mockito to mock and spy on `final` methods. + +NOTE: While Spring's test framework caches application contexts between tests and reuses a context for tests sharing the same configuration, the use of `@MockBean` or `@SpyBean` influences the cache key, which will most likely increase the number of contexts. + +TIP: If you are using `@SpyBean` to spy on a bean with `@Cacheable` methods that refer to parameters by name, your application must be compiled with `-parameters`. +This ensures that the parameter names are available to the caching infrastructure once the bean has been spied upon. + +TIP: When you are using `@SpyBean` to spy on a bean that is proxied by Spring, you may need to remove Spring's proxy in some situations, for example when setting expectations using `given` or `when`. +Use `AopTestUtils.getTargetObject(yourProxiedSpy)` to do so. + + + +[[features.testing.spring-boot-applications.autoconfigured-tests]] +==== Auto-configured Tests +Spring Boot's auto-configuration system works well for applications but can sometimes be a little too much for tests. +It often helps to load only the parts of the configuration that are required to test a "`slice`" of your application. +For example, you might want to test that Spring MVC controllers are mapping URLs correctly, and you do not want to involve database calls in those tests, or you might want to test JPA entities, and you are not interested in the web layer when those tests run. + +The `spring-boot-test-autoconfigure` module includes a number of annotations that can be used to automatically configure such "`slices`". +Each of them works in a similar way, providing a `@...Test` annotation that loads the `ApplicationContext` and one or more `@AutoConfigure...` annotations that can be used to customize auto-configuration settings. + +NOTE: Each slice restricts component scan to appropriate components and loads a very restricted set of auto-configuration classes. +If you need to exclude one of them, most `@...Test` annotations provide an `excludeAutoConfiguration` attribute. +Alternatively, you can use `@ImportAutoConfiguration#exclude`. + +NOTE: Including multiple "`slices`" by using several `@...Test` annotations in one test is not supported. +If you need multiple "`slices`", pick one of the `@...Test` annotations and include the `@AutoConfigure...` annotations of the other "`slices`" by hand. + +TIP: It is also possible to use the `@AutoConfigure...` annotations with the standard `@SpringBootTest` annotation. +You can use this combination if you are not interested in "`slicing`" your application but you want some of the auto-configured test beans. + + + +[[features.testing.spring-boot-applications.json-tests]] +==== Auto-configured JSON Tests +To test that object JSON serialization and deserialization is working as expected, you can use the `@JsonTest` annotation. +`@JsonTest` auto-configures the available supported JSON mapper, which can be one of the following libraries: + +* Jackson `ObjectMapper`, any `@JsonComponent` beans and any Jackson ``Module``s +* `Gson` +* `Jsonb` + +TIP: A list of the auto-configurations that are enabled by `@JsonTest` can be <>. + +If you need to configure elements of the auto-configuration, you can use the `@AutoConfigureJsonTesters` annotation. + +Spring Boot includes AssertJ-based helpers that work with the JSONAssert and JsonPath libraries to check that JSON appears as expected. +The `JacksonTester`, `GsonTester`, `JsonbTester`, and `BasicJsonTester` classes can be used for Jackson, Gson, Jsonb, and Strings respectively. +Any helper fields on the test class can be `@Autowired` when using `@JsonTest`. +The following example shows a test class for Jackson: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/json/MyJsonTests.java[] +---- + +NOTE: JSON helper classes can also be used directly in standard unit tests. +To do so, call the `initFields` method of the helper in your `@Before` method if you do not use `@JsonTest`. + +If you're using Spring Boot's AssertJ-based helpers to assert on a number value at a given JSON path, you might not be able to use `isEqualTo` depending on the type. +Instead, you can use AssertJ's `satisfies` to assert that the value matches the given condition. +For instance, the following example asserts that the actual number is a float value close to `0.15` within an offset of `0.01`. + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/json/AssertJ.java[tag=*] +---- + + + +[[features.testing.spring-boot-applications.spring-mvc-tests]] +==== Auto-configured Spring MVC Tests +To test whether Spring MVC controllers are working as expected, use the `@WebMvcTest` annotation. +`@WebMvcTest` auto-configures the Spring MVC infrastructure and limits scanned beans to `@Controller`, `@ControllerAdvice`, `@JsonComponent`, `Converter`, `GenericConverter`, `Filter`, `HandlerInterceptor`, `WebMvcConfigurer`, and `HandlerMethodArgumentResolver`. +Regular `@Component` and `@ConfigurationProperties` beans are not scanned when the `@WebMvcTest` annotation is used. +`@EnableConfigurationProperties` can be used to include `@ConfigurationProperties` beans. + +TIP: A list of the auto-configuration settings that are enabled by `@WebMvcTest` can be <>. + +TIP: If you need to register extra components, such as the Jackson `Module`, you can import additional configuration classes by using `@Import` on your test. + +Often, `@WebMvcTest` is limited to a single controller and is used in combination with `@MockBean` to provide mock implementations for required collaborators. + +`@WebMvcTest` also auto-configures `MockMvc`. +Mock MVC offers a powerful way to quickly test MVC controllers without needing to start a full HTTP server. + +TIP: You can also auto-configure `MockMvc` in a non-`@WebMvcTest` (such as `@SpringBootTest`) by annotating it with `@AutoConfigureMockMvc`. +The following example uses `MockMvc`: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/mvc/MyControllerTests.java[] +---- + +TIP: If you need to configure elements of the auto-configuration (for example, when servlet filters should be applied) you can use attributes in the `@AutoConfigureMockMvc` annotation. + +If you use HtmlUnit or Selenium, auto-configuration also provides an HtmlUnit `WebClient` bean and/or a Selenium `WebDriver` bean. +The following example uses HtmlUnit: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/mvc/MyHtmlUnitTests.java[] +---- + +NOTE: By default, Spring Boot puts `WebDriver` beans in a special "`scope`" to ensure that the driver exits after each test and that a new instance is injected. +If you do not want this behavior, you can add `@Scope("singleton")` to your `WebDriver` `@Bean` definition. + +WARNING: The `webDriver` scope created by Spring Boot will replace any user defined scope of the same name. +If you define your own `webDriver` scope you may find it stops working when you use `@WebMvcTest`. + +If you have Spring Security on the classpath, `@WebMvcTest` will also scan `WebSecurityConfigurer` beans. +Instead of disabling security completely for such tests, you can use Spring Security's test support. +More details on how to use Spring Security's `MockMvc` support can be found in this _<>_ how-to section. + +TIP: Sometimes writing Spring MVC tests is not enough; Spring Boot can help you run <>. + + + +[[features.testing.spring-boot-applications.spring-webflux-tests]] +==== Auto-configured Spring WebFlux Tests +To test that {spring-framework-docs}/web-reactive.html[Spring WebFlux] controllers are working as expected, you can use the `@WebFluxTest` annotation. +`@WebFluxTest` auto-configures the Spring WebFlux infrastructure and limits scanned beans to `@Controller`, `@ControllerAdvice`, `@JsonComponent`, `Converter`, `GenericConverter`, `WebFilter`, and `WebFluxConfigurer`. +Regular `@Component` and `@ConfigurationProperties` beans are not scanned when the `@WebFluxTest` annotation is used. +`@EnableConfigurationProperties` can be used to include `@ConfigurationProperties` beans. + +TIP: A list of the auto-configurations that are enabled by `@WebFluxTest` can be <>. + +TIP: If you need to register extra components, such as Jackson `Module`, you can import additional configuration classes using `@Import` on your test. + +Often, `@WebFluxTest` is limited to a single controller and used in combination with the `@MockBean` annotation to provide mock implementations for required collaborators. + +`@WebFluxTest` also auto-configures {spring-framework-docs}/testing.html#webtestclient[`WebTestClient`], which offers a powerful way to quickly test WebFlux controllers without needing to start a full HTTP server. + +TIP: You can also auto-configure `WebTestClient` in a non-`@WebFluxTest` (such as `@SpringBootTest`) by annotating it with `@AutoConfigureWebTestClient`. +The following example shows a class that uses both `@WebFluxTest` and a `WebTestClient`: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/webflux/MyControllerTests.java[] +---- + +TIP: This setup is only supported by WebFlux applications as using `WebTestClient` in a mocked web application only works with WebFlux at the moment. + +NOTE: `@WebFluxTest` cannot detect routes registered via the functional web framework. +For testing `RouterFunction` beans in the context, consider importing your `RouterFunction` yourself via `@Import` or using `@SpringBootTest`. + +NOTE: `@WebFluxTest` cannot detect custom security configuration registered via a `@Bean` of type `SecurityWebFilterChain`. +To include that in your test, you will need to import the configuration that registers the bean via `@Import` or use `@SpringBootTest`. + +TIP: Sometimes writing Spring WebFlux tests is not enough; Spring Boot can help you run <>. + + + +[[features.testing.spring-boot-applications.autoconfigured-spring-data-cassandra]] +==== Auto-configured Data Cassandra Tests +You can use `@DataCassandraTest` to test Cassandra applications. +By default, it configures a `CassandraTemplate`, scans for `@Table` classes, and configures Spring Data Cassandra repositories. +Regular `@Component` and `@ConfigurationProperties` beans are not scanned when the `@DataCassandraTest` annotation is used. +`@EnableConfigurationProperties` can be used to include `@ConfigurationProperties` beans. +(For more about using Cassandra with Spring Boot, see "<>", earlier in this chapter.) + +TIP: A list of the auto-configuration settings that are enabled by `@DataCassandraTest` can be <>. + +The following example shows a typical setup for using Cassandra tests in Spring Boot: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/data/cassandra/MyDataCassandraTests.java[] +---- + + + +[[features.testing.spring-boot-applications.autoconfigured-spring-data-jpa]] +==== Auto-configured Data JPA Tests +You can use the `@DataJpaTest` annotation to test JPA applications. +By default, it scans for `@Entity` classes and configures Spring Data JPA repositories. +If an embedded database is available on the classpath, it configures one as well. +SQL queries are logged by default by setting the `spring.jpa.show-sql` property to `true`. +This can be disabled using the `showSql()` attribute of the annotation. + +Regular `@Component` and `@ConfigurationProperties` beans are not scanned when the `@DataJpaTest` annotation is used. +`@EnableConfigurationProperties` can be used to include `@ConfigurationProperties` beans. + +TIP: A list of the auto-configuration settings that are enabled by `@DataJpaTest` can be <>. + +By default, data JPA tests are transactional and roll back at the end of each test. +See the {spring-framework-docs}/testing.html#testcontext-tx-enabling-transactions[relevant section] in the Spring Framework Reference Documentation for more details. +If that is not what you want, you can disable transaction management for a test or for the whole class as follows: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/data/jpa/MyNonTransactionalTests.java[] +---- + +Data JPA tests may also inject a {spring-boot-test-autoconfigure-module-code}/orm/jpa/TestEntityManager.java[`TestEntityManager`] bean, which provides an alternative to the standard JPA `EntityManager` that is specifically designed for tests. +If you want to use `TestEntityManager` outside of `@DataJpaTest` instances, you can also use the `@AutoConfigureTestEntityManager` annotation. +A `JdbcTemplate` is also available if you need that. +The following example shows the `@DataJpaTest` annotation in use: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/data/jpa/MyRepositoryTests.java[] +---- + +In-memory embedded databases generally work well for tests, since they are fast and do not require any installation. +If, however, you prefer to run tests against a real database you can use the `@AutoConfigureTestDatabase` annotation, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/data/jpa/db/MyRepositoryTests.java[] +---- + + + +[[features.testing.spring-boot-applications.autoconfigured-jdbc]] +==== Auto-configured JDBC Tests +`@JdbcTest` is similar to `@DataJpaTest` but is for tests that only require a `DataSource` and do not use Spring Data JDBC. +By default, it configures an in-memory embedded database and a `JdbcTemplate`. +Regular `@Component` and `@ConfigurationProperties` beans are not scanned when the `@JdbcTest` annotation is used. +`@EnableConfigurationProperties` can be used to include `@ConfigurationProperties` beans. + +TIP: A list of the auto-configurations that are enabled by `@JdbcTest` can be <>. + +By default, JDBC tests are transactional and roll back at the end of each test. +See the {spring-framework-docs}/testing.html#testcontext-tx-enabling-transactions[relevant section] in the Spring Framework Reference Documentation for more details. +If that is not what you want, you can disable transaction management for a test or for the whole class, as follows: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/data/jdbc/MyTransactionalTests.java[] +---- + +If you prefer your test to run against a real database, you can use the `@AutoConfigureTestDatabase` annotation in the same way as for `DataJpaTest`. +(See "<>".) + + + +[[features.testing.spring-boot-applications.autoconfigured-spring-data-jdbc]] +==== Auto-configured Data JDBC Tests +`@DataJdbcTest` is similar to `@JdbcTest` but is for tests that use Spring Data JDBC repositories. +By default, it configures an in-memory embedded database, a `JdbcTemplate`, and Spring Data JDBC repositories. +Regular `@Component` and `@ConfigurationProperties` beans are not scanned when the `@DataJdbcTest` annotation is used. +`@EnableConfigurationProperties` can be used to include `@ConfigurationProperties` beans. + +TIP: A list of the auto-configurations that are enabled by `@DataJdbcTest` can be <>. + +By default, Data JDBC tests are transactional and roll back at the end of each test. +See the {spring-framework-docs}/testing.html#testcontext-tx-enabling-transactions[relevant section] in the Spring Framework Reference Documentation for more details. +If that is not what you want, you can disable transaction management for a test or for the whole test class as <>. + +If you prefer your test to run against a real database, you can use the `@AutoConfigureTestDatabase` annotation in the same way as for `DataJpaTest`. +(See "<>".) + + + +[[features.testing.spring-boot-applications.autoconfigured-jooq]] +==== Auto-configured jOOQ Tests +You can use `@JooqTest` in a similar fashion as `@JdbcTest` but for jOOQ-related tests. +As jOOQ relies heavily on a Java-based schema that corresponds with the database schema, the existing `DataSource` is used. +If you want to replace it with an in-memory database, you can use `@AutoConfigureTestDatabase` to override those settings. +(For more about using jOOQ with Spring Boot, see "<>", earlier in this chapter.) +Regular `@Component` and `@ConfigurationProperties` beans are not scanned when the `@JooqTest` annotation is used. +`@EnableConfigurationProperties` can be used to include `@ConfigurationProperties` beans. + +TIP: A list of the auto-configurations that are enabled by `@JooqTest` can be <>. + +`@JooqTest` configures a `DSLContext`. +The following example shows the `@JooqTest` annotation in use: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/jooq/MyJooqTests.java[] +---- + +JOOQ tests are transactional and roll back at the end of each test by default. +If that is not what you want, you can disable transaction management for a test or for the whole test class as <>. + + + +[[features.testing.spring-boot-applications.autoconfigured-spring-data-mongodb]] +==== Auto-configured Data MongoDB Tests +You can use `@DataMongoTest` to test MongoDB applications. +By default, it configures an in-memory embedded MongoDB (if available), configures a `MongoTemplate`, scans for `@Document` classes, and configures Spring Data MongoDB repositories. +Regular `@Component` and `@ConfigurationProperties` beans are not scanned when the `@DataMongoTest` annotation is used. +`@EnableConfigurationProperties` can be used to include `@ConfigurationProperties` beans. +(For more about using MongoDB with Spring Boot, see "<>", earlier in this chapter.) + +TIP: A list of the auto-configuration settings that are enabled by `@DataMongoTest` can be <>. + +The following class shows the `@DataMongoTest` annotation in use: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/data/mongodb/MyDataMongoDbTests.java[] +---- + +In-memory embedded MongoDB generally works well for tests, since it is fast and does not require any developer installation. +If, however, you prefer to run tests against a real MongoDB server, you should exclude the embedded MongoDB auto-configuration, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/data/mongodb/db/MyDataMongoDbTests.java[] +---- + + + +[[features.testing.spring-boot-applications.autoconfigured-spring-data-neo4j]] +==== Auto-configured Data Neo4j Tests +You can use `@DataNeo4jTest` to test Neo4j applications. +By default, it scans for `@Node` classes, and configures Spring Data Neo4j repositories. +Regular `@Component` and `@ConfigurationProperties` beans are not scanned when the `@DataNeo4jTest` annotation is used. +`@EnableConfigurationProperties` can be used to include `@ConfigurationProperties` beans. +(For more about using Neo4J with Spring Boot, see "<>", earlier in this chapter.) + +TIP: A list of the auto-configuration settings that are enabled by `@DataNeo4jTest` can be <>. + +The following example shows a typical setup for using Neo4J tests in Spring Boot: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/data/neo4j/MyDataNeo4jTests.java[] +---- + +By default, Data Neo4j tests are transactional and roll back at the end of each test. +See the {spring-framework-docs}/testing.html#testcontext-tx-enabling-transactions[relevant section] in the Spring Framework Reference Documentation for more details. +If that is not what you want, you can disable transaction management for a test or for the whole class, as follows: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/data/neo4j/tx/MyDataNeo4jTests.java[] +---- + +NOTE: Transactional tests are not supported with reactive access. +If you are using this style, you must configure `@DataNeo4jTest` tests as described above. + + + +[[features.testing.spring-boot-applications.autoconfigured-spring-data-redis]] +==== Auto-configured Data Redis Tests +You can use `@DataRedisTest` to test Redis applications. +By default, it scans for `@RedisHash` classes and configures Spring Data Redis repositories. +Regular `@Component` and `@ConfigurationProperties` beans are not scanned when the `@DataRedisTest` annotation is used. +`@EnableConfigurationProperties` can be used to include `@ConfigurationProperties` beans. +(For more about using Redis with Spring Boot, see "<>", earlier in this chapter.) + +TIP: A list of the auto-configuration settings that are enabled by `@DataRedisTest` can be <>. + +The following example shows the `@DataRedisTest` annotation in use: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/data/redis/MyDataRedisTests.java[] +---- + + + +[[features.testing.spring-boot-applications.autoconfigured-spring-data-ldap]] +==== Auto-configured Data LDAP Tests +You can use `@DataLdapTest` to test LDAP applications. +By default, it configures an in-memory embedded LDAP (if available), configures an `LdapTemplate`, scans for `@Entry` classes, and configures Spring Data LDAP repositories. +Regular `@Component` and `@ConfigurationProperties` beans are not scanned when the `@DataLdapTest` annotation is used. +`@EnableConfigurationProperties` can be used to include `@ConfigurationProperties` beans. +(For more about using LDAP with Spring Boot, see "<>", earlier in this chapter.) + +TIP: A list of the auto-configuration settings that are enabled by `@DataLdapTest` can be <>. + +The following example shows the `@DataLdapTest` annotation in use: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/data/ldap/MyDataLdapTests.java[] +---- + +In-memory embedded LDAP generally works well for tests, since it is fast and does not require any developer installation. +If, however, you prefer to run tests against a real LDAP server, you should exclude the embedded LDAP auto-configuration, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/data/ldap/server/MyDataLdapTests.java[] +---- + + + +[[features.testing.spring-boot-applications.autoconfigured-rest-client]] +==== Auto-configured REST Clients +You can use the `@RestClientTest` annotation to test REST clients. +By default, it auto-configures Jackson, GSON, and Jsonb support, configures a `RestTemplateBuilder`, and adds support for `MockRestServiceServer`. +Regular `@Component` and `@ConfigurationProperties` beans are not scanned when the `@RestClientTest` annotation is used. +`@EnableConfigurationProperties` can be used to include `@ConfigurationProperties` beans. + +TIP: A list of the auto-configuration settings that are enabled by `@RestClientTest` can be <>. + +The specific beans that you want to test should be specified by using the `value` or `components` attribute of `@RestClientTest`, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/restclient/MyRestClientTests.java[] +---- + + + +[[features.testing.spring-boot-applications.autoconfigured-spring-restdocs]] +==== Auto-configured Spring REST Docs Tests +You can use the `@AutoConfigureRestDocs` annotation to use {spring-restdocs}[Spring REST Docs] in your tests with Mock MVC, REST Assured, or WebTestClient. +It removes the need for the JUnit extension in Spring REST Docs. + +`@AutoConfigureRestDocs` can be used to override the default output directory (`target/generated-snippets` if you are using Maven or `build/generated-snippets` if you are using Gradle). +It can also be used to configure the host, scheme, and port that appears in any documented URIs. + + + +[[features.testing.spring-boot-applications.autoconfigured-spring-restdocs.with-mock-mvc]] +===== Auto-configured Spring REST Docs Tests with Mock MVC +`@AutoConfigureRestDocs` customizes the `MockMvc` bean to use Spring REST Docs when testing Servlet-based web applications. +You can inject it by using `@Autowired` and use it in your tests as you normally would when using Mock MVC and Spring REST Docs, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/restdocs/mvc/UserDocumentationTests.java[] +---- + +If you require more control over Spring REST Docs configuration than offered by the attributes of `@AutoConfigureRestDocs`, you can use a `RestDocsMockMvcConfigurationCustomizer` bean, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/restdocs/mvc/CustomizationConfiguration.java[] +---- + +If you want to make use of Spring REST Docs support for a parameterized output directory, you can create a `RestDocumentationResultHandler` bean. +The auto-configuration calls `alwaysDo` with this result handler, thereby causing each `MockMvc` call to automatically generate the default snippets. +The following example shows a `RestDocumentationResultHandler` being defined: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/restdocs/mvc/ResultHandlerConfiguration.java[] +---- + + + +[[features.testing.spring-boot-applications.autoconfigured-spring-restdocs.with-web-test-client]] +===== Auto-configured Spring REST Docs Tests with WebTestClient +`@AutoConfigureRestDocs` can also be used with `WebTestClient` when testing reactive web applications. +You can inject it by using `@Autowired` and use it in your tests as you normally would when using `@WebFluxTest` and Spring REST Docs, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/restdocs/webclient/UsersDocumentationTests.java[] +---- + +If you require more control over Spring REST Docs configuration than offered by the attributes of `@AutoConfigureRestDocs`, you can use a `RestDocsWebTestClientConfigurationCustomizer` bean, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/restdocs/webclient/AdvancedRestDocsConfiguration.java[] +---- + + + +[[features.testing.spring-boot-applications.autoconfigured-spring-restdocs.with-rest-assured]] +===== Auto-configured Spring REST Docs Tests with REST Assured +`@AutoConfigureRestDocs` makes a `RequestSpecification` bean, preconfigured to use Spring REST Docs, available to your tests. +You can inject it by using `@Autowired` and use it in your tests as you normally would when using REST Assured and Spring REST Docs, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/restdocs/restassured/UserDocumentationTests.java[] +---- + +If you require more control over Spring REST Docs configuration than offered by the attributes of `@AutoConfigureRestDocs`, a `RestDocsRestAssuredConfigurationCustomizer` bean can be used, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/restdocs/restassured/AdvancedRestDocsConfiguration.java[] +---- + + + +[[features.testing.spring-boot-applications.autoconfigured-webservices]] +==== Auto-configured Spring Web Services Tests +You can use `@WebServiceClientTest` to test applications that use call web services using the Spring Web Services project. +By default, it configures a mock `WebServiceServer` bean and automatically customizes your `WebServiceTemplateBuilder`. +(For more about using Web Services with Spring Boot, see "<>", earlier in this chapter.) + + +TIP: A list of the auto-configuration settings that are enabled by `@WebServiceClientTest` can be <>. + +The following example shows the `@WebServiceClientTest` annotation in use: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/webservices/MyWebServiceClientTests.java[] +---- + + + +[[features.testing.spring-boot-applications.additional-autoconfiguration-and-slicing]] +==== Additional Auto-configuration and Slicing +Each slice provides one or more `@AutoConfigure...` annotations that namely defines the auto-configurations that should be included as part of a slice. +Additional auto-configurations can be added on a test-by-test basis by creating a custom `@AutoConfigure...` annotation or by adding `@ImportAutoConfiguration` to the test as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/slicing/ExampleJdbcTests.java[] +---- + +NOTE: Make sure to not use the regular `@Import` annotation to import auto-configurations as they are handled in a specific way by Spring Boot. + +Alternatively, additional auto-configurations can be added for any use of a slice annotation by registering them in `META-INF/spring.factories` as shown in the following example: + +[indent=0] +---- + org.springframework.boot.test.autoconfigure.jdbc.JdbcTest=com.example.IntegrationAutoConfiguration +---- + +TIP: A slice or `@AutoConfigure...` annotation can be customized this way as long as it is meta-annotated with `@ImportAutoConfiguration`. + + + +[[features.testing.spring-boot-applications.user-configuration-and-slicing]] +==== User Configuration and Slicing +If you <> in a sensible way, your `@SpringBootApplication` class is <> as the configuration of your tests. + +It then becomes important not to litter the application's main class with configuration settings that are specific to a particular area of its functionality. + +Assume that you are using Spring Batch and you rely on the auto-configuration for it. +You could define your `@SpringBootApplication` as follows: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/slicing/SampleApplication.java[] +---- + +Because this class is the source configuration for the test, any slice test actually tries to start Spring Batch, which is definitely not what you want to do. +A recommended approach is to move that area-specific configuration to a separate `@Configuration` class at the same level as your application, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/slicing/BatchConfiguration.java[] +---- + +NOTE: Depending on the complexity of your application, you may either have a single `@Configuration` class for your customizations or one class per domain area. +The latter approach lets you enable it in one of your tests, if necessary, with the `@Import` annotation. + +Test slices exclude `@Configuration` classes from scanning. +For example, for a `@WebMvcTest`, the following configuration will not include the given `WebMvcConfigurer` bean in the application context loaded by the test slice: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/slicing/WebConfiguration.java[] +---- + +The configuration below will, however, cause the custom `WebMvcConfigurer` to be loaded by the test slice. + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/slicing/TestWebMvcConfigurer.java[] +---- + +Another source of confusion is classpath scanning. +Assume that, while you structured your code in a sensible way, you need to scan an additional package. +Your application may resemble the following code: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/applications/slicing/scan/SampleApplication.java[] +---- + +Doing so effectively overrides the default component scan directive with the side effect of scanning those two packages regardless of the slice that you chose. +For instance, a `@DataJpaTest` seems to suddenly scan components and user configurations of your application. +Again, moving the custom directive to a separate class is a good way to fix this issue. + +TIP: If this is not an option for you, you can create a `@SpringBootConfiguration` somewhere in the hierarchy of your test so that it is used instead. +Alternatively, you can specify a source for your test, which disables the behavior of finding a default one. + + + +[[features.testing.spring-boot-applications.spock]] +==== Using Spock to Test Spring Boot Applications +If you wish to use Spock to test a Spring Boot application, you should add a dependency on Spock's `spock-spring` module to your application's build. +`spock-spring` integrates Spring's test framework into Spock. +See https://spockframework.org/spock/docs/2.0-M4/modules.html#_spring_module[the documentation for Spock's Spring module] for further details. + +NOTE: As of Spring Boot 2.5.x and its support for Groovy 3.x you have two options to make use of Spock: +Either use the latest Spock 2.0 milestone or release that is compatible with Groovy 3.x or stick with Spock 1.3 and downgrade Spring Boot's Groovy version to 2.5.x. + + + +[[features.testing.utilities]] +=== Test Utilities +A few test utility classes that are generally useful when testing your application are packaged as part of `spring-boot`. + + + +[[features.testing.utilities.config-data-application-context-initializer]] +==== ConfigDataApplicationContextInitializer +`ConfigDataApplicationContextInitializer` is an `ApplicationContextInitializer` that you can apply to your tests to load Spring Boot `application.properties` files. +You can use it when you do not need the full set of features provided by `@SpringBootTest`, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/utils/MyConfigFileTests.java[] +---- + +NOTE: Using `ConfigDataApplicationContextInitializer` alone does not provide support for `@Value("${...}")` injection. +Its only job is to ensure that `application.properties` files are loaded into Spring's `Environment`. +For `@Value` support, you need to either additionally configure a `PropertySourcesPlaceholderConfigurer` or use `@SpringBootTest`, which auto-configures one for you. + + + +[[features.testing.utilities.test-property-values]] +==== TestPropertyValues +`TestPropertyValues` lets you quickly add properties to a `ConfigurableEnvironment` or `ConfigurableApplicationContext`. +You can call it with `key=value` strings, as follows: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/utils/MyEnvironmentTests.java[tag=*] +---- + + + +[[features.testing.utilities.output-capture]] +==== OutputCapture +`OutputCapture` is a JUnit `Extension` that you can use to capture `System.out` and `System.err` output. +To use add `@ExtendWith(OutputCaptureExtension.class)` and inject `CapturedOutput` as an argument to your test class constructor or test method as follows: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/OutputCaptureTests.java[] +---- + + + +[[features.testing.utilities.test-rest-template]] +==== TestRestTemplate +`TestRestTemplate` is a convenience alternative to Spring's `RestTemplate` that is useful in integration tests. +You can get a vanilla template or one that sends Basic HTTP authentication (with a username and password). +In either case, the template behaves in a test-friendly way by not throwing exceptions on server-side errors. + +TIP: Spring Framework 5.0 provides a new `WebTestClient` that works for <> and both <>. +It provides a fluent API for assertions, unlike `TestRestTemplate`. + +It is recommended, but not mandatory, to use the Apache HTTP Client (version 4.3.2 or better). +If you have that on your classpath, the `TestRestTemplate` responds by configuring the client appropriately. +If you do use Apache's HTTP client, some additional test-friendly features are enabled: + +* Redirects are not followed (so you can assert the response location). +* Cookies are ignored (so the template is stateless). + +`TestRestTemplate` can be instantiated directly in your integration tests, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/utils/testresttemplate/MyTest.java[] +---- + +Alternatively, if you use the `@SpringBootTest` annotation with `WebEnvironment.RANDOM_PORT` or `WebEnvironment.DEFINED_PORT`, you can inject a fully configured `TestRestTemplate` and start using it. +If necessary, additional customizations can be applied through the `RestTemplateBuilder` bean. +Any URLs that do not specify a host and port automatically connect to the embedded server, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/testing/webclient/SampleWebClientTests.java[] +---- diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/validation.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/validation.adoc new file mode 100644 index 0000000000..5281aaf696 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/validation.adoc @@ -0,0 +1,12 @@ +[[features.validation]] +== Validation +The method validation feature supported by Bean Validation 1.1 is automatically enabled as long as a JSR-303 implementation (such as Hibernate validator) is on the classpath. +This lets bean methods be annotated with `javax.validation` constraints on their parameters and/or on their return value. +Target classes with such annotated methods need to be annotated with the `@Validated` annotation at the type level for their methods to be searched for inline constraint annotations. + +For instance, the following service triggers the validation of the first argument, making sure its size is between 8 and 10: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/validation/MyBean.java[] +---- diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/webclient.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/webclient.adoc new file mode 100644 index 0000000000..2b4fb3c9a6 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/webclient.adoc @@ -0,0 +1,47 @@ +[[features.webclient]] +== Calling REST Services with WebClient +If you have Spring WebFlux on your classpath, you can also choose to use `WebClient` to call remote REST services. +Compared to `RestTemplate`, this client has a more functional feel and is fully reactive. +You can learn more about the `WebClient` in the dedicated {spring-framework-docs}/web-reactive.html#webflux-client[section in the Spring Framework docs]. + +Spring Boot creates and pre-configures a `WebClient.Builder` for you; it is strongly advised to inject it in your components and use it to create `WebClient` instances. +Spring Boot is configuring that builder to share HTTP resources, reflect codecs setup in the same fashion as the server ones (see <>), and more. + +The following code shows a typical example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/webclient/MyService.java[] +---- + + + +[[features.webclient.runtime]] +=== WebClient Runtime +Spring Boot will auto-detect which `ClientHttpConnector` to use to drive `WebClient`, depending on the libraries available on the application classpath. +For now, Reactor Netty and Jetty RS client are supported. + +The `spring-boot-starter-webflux` starter depends on `io.projectreactor.netty:reactor-netty` by default, which brings both server and client implementations. +If you choose to use Jetty as a reactive server instead, you should add a dependency on the Jetty Reactive HTTP client library, `org.eclipse.jetty:jetty-reactive-httpclient`. +Using the same technology for server and client has it advantages, as it will automatically share HTTP resources between client and server. + +Developers can override the resource configuration for Jetty and Reactor Netty by providing a custom `ReactorResourceFactory` or `JettyResourceFactory` bean - this will be applied to both clients and servers. + +If you wish to override that choice for the client, you can define your own `ClientHttpConnector` bean and have full control over the client configuration. + +You can learn more about the {spring-framework-docs}/web-reactive.html#webflux-client-builder[`WebClient` configuration options in the Spring Framework reference documentation]. + + + +[[features.webclient.customization]] +=== WebClient Customization +There are three main approaches to `WebClient` customization, depending on how broadly you want the customizations to apply. + +To make the scope of any customizations as narrow as possible, inject the auto-configured `WebClient.Builder` and then call its methods as required. +`WebClient.Builder` instances are stateful: Any change on the builder is reflected in all clients subsequently created with it. +If you want to create several clients with the same builder, you can also consider cloning the builder with `WebClient.Builder other = builder.clone();`. + +To make an application-wide, additive customization to all `WebClient.Builder` instances, you can declare `WebClientCustomizer` beans and change the `WebClient.Builder` locally at the point of injection. + +Finally, you can fall back to the original API and use `WebClient.create()`. +In that case, no auto-configuration or `WebClientCustomizer` is applied. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/webservices.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/webservices.adoc new file mode 100644 index 0000000000..6690da5f7b --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/webservices.adoc @@ -0,0 +1,39 @@ +[[features.webservices]] +== Web Services +Spring Boot provides Web Services auto-configuration so that all you must do is define your `Endpoints`. + +The {spring-webservices-docs}[Spring Web Services features] can be easily accessed with the `spring-boot-starter-webservices` module. + +`SimpleWsdl11Definition` and `SimpleXsdSchema` beans can be automatically created for your WSDLs and XSDs respectively. +To do so, configure their location, as shown in the following example: + + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + webservices: + wsdl-locations: "classpath:/wsdl" +---- + + + +[[features.webservices.template]] +=== Calling Web Services with WebServiceTemplate +If you need to call remote Web services from your application, you can use the {spring-webservices-docs}#client-web-service-template[`WebServiceTemplate`] class. +Since `WebServiceTemplate` instances often need to be customized before being used, Spring Boot does not provide any single auto-configured `WebServiceTemplate` bean. +It does, however, auto-configure a `WebServiceTemplateBuilder`, which can be used to create `WebServiceTemplate` instances when needed. + +The following code shows a typical example: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/webservices/MyService.java[] +---- + +By default, `WebServiceTemplateBuilder` detects a suitable HTTP-based `WebServiceMessageSender` using the available HTTP client libraries on the classpath. +You can also customize read and connection timeouts as follows: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/webservices/MyWebServiceTemplateConfiguration.java[] +---- diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/websockets.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/websockets.adoc new file mode 100644 index 0000000000..28952f2894 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/websockets.adoc @@ -0,0 +1,16 @@ +[[features.websockets]] +== WebSockets +Spring Boot provides WebSockets auto-configuration for embedded Tomcat, Jetty, and Undertow. +If you deploy a war file to a standalone container, Spring Boot assumes that the container is responsible for the configuration of its WebSocket support. + +Spring Framework provides {spring-framework-docs}/web.html#websocket[rich WebSocket support] for MVC web applications that can be easily accessed through the `spring-boot-starter-websocket` module. + +WebSocket support is also available for {spring-framework-docs}/web-reactive.html#webflux-websocket[reactive web applications] and requires to include the WebSocket API alongside `spring-boot-starter-webflux`: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + javax.websocket + javax.websocket-api + +---- diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/whats-next.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/whats-next.adoc new file mode 100644 index 0000000000..f08953adde --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/whats-next.adoc @@ -0,0 +1,6 @@ +[[features.whats-next]] +== What to Read Next +If you want to learn more about any of the classes discussed in this section, you can check out the {spring-boot-api}/[Spring Boot API documentation] or you can browse the {spring-boot-code}[source code directly]. +If you have specific questions, take a look at the <> section. + +If you are comfortable with Spring Boot's core features, you can continue on and read about <>. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/getting-started.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/getting-started.adoc index 2eb87b56eb..57ea7dbd2d 100644 --- a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/getting-started.adoc +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/getting-started.adoc @@ -2,6 +2,8 @@ = Getting Started include::attributes.adoc[] + + If you are getting started with Spring Boot, or "`Spring`" in general, start by reading this section. It answers the basic "`what?`", "`how?`" and "`why?`" questions. It includes an introduction to Spring Boot, along with installation instructions. @@ -9,684 +11,13 @@ We then walk you through building your first Spring Boot application, discussing -[[getting-started.introducing-spring-boot]] -== Introducing Spring Boot -Spring Boot helps you to create stand-alone, production-grade Spring-based Applications that you can run. -We take an opinionated view of the Spring platform and third-party libraries, so that you can get started with minimum fuss. -Most Spring Boot applications need very little Spring configuration. +include::getting-started/introducing-spring-boot.adoc[] -You can use Spring Boot to create Java applications that can be started by using `java -jar` or more traditional war deployments. -We also provide a command line tool that runs "`spring scripts`". +include::getting-started/system-requirements.adoc[] -Our primary goals are: +include::getting-started/installing.adoc[] -* Provide a radically faster and widely accessible getting-started experience for all Spring development. -* Be opinionated out of the box but get out of the way quickly as requirements start to diverge from the defaults. -* Provide a range of non-functional features that are common to large classes of projects (such as embedded servers, security, metrics, health checks, and externalized configuration). -* Absolutely no code generation and no requirement for XML configuration. +include::getting-started/first-application.adoc[] +include::getting-started/whats-next.adoc[] - -[[getting-started.system-requirements]] -== System Requirements -Spring Boot {spring-boot-version} requires https://www.java.com[Java 8] and is compatible up to Java 16 (included). -{spring-framework-docs}/[Spring Framework {spring-framework-version}] or above is also required. - -Explicit build support is provided for the following build tools: - -|=== -| Build Tool | Version - -| Maven -| 3.5+ - -| Gradle -| 6.8.x and 7.x -|=== - - - -[[getting-started.system-requirements.servlet-containers]] -=== Servlet Containers -Spring Boot supports the following embedded servlet containers: - -|=== -| Name | Servlet Version - -| Tomcat 9.0 -| 4.0 - -| Jetty 9.4 -| 3.1 - -| Jetty 10.0 -| 4.0 - -| Undertow 2.0 -| 4.0 -|=== - -You can also deploy Spring Boot applications to any Servlet 3.1+ compatible container. - - - -[[getting-started.installing]] -== Installing Spring Boot -Spring Boot can be used with "`classic`" Java development tools or installed as a command line tool. -Either way, you need https://www.java.com[Java SDK v1.8] or higher. -Before you begin, you should check your current Java installation by using the following command: - -[indent=0] ----- - $ java -version ----- - -If you are new to Java development or if you want to experiment with Spring Boot, you might want to try the <> (Command Line Interface) first. -Otherwise, read on for "`classic`" installation instructions. - - - -[[getting-started.installing.java]] -=== Installation Instructions for the Java Developer -You can use Spring Boot in the same way as any standard Java library. -To do so, include the appropriate `+spring-boot-*.jar+` files on your classpath. -Spring Boot does not require any special tools integration, so you can use any IDE or text editor. -Also, there is nothing special about a Spring Boot application, so you can run and debug a Spring Boot application as you would any other Java program. - -Although you _could_ copy Spring Boot jars, we generally recommend that you use a build tool that supports dependency management (such as Maven or Gradle). - - - -[[getting-started.installing.java.maven]] -==== Maven Installation -Spring Boot is compatible with Apache Maven 3.3 or above. -If you do not already have Maven installed, you can follow the instructions at https://maven.apache.org. - -TIP: On many operating systems, Maven can be installed with a package manager. -If you use OSX Homebrew, try `brew install maven`. -Ubuntu users can run `sudo apt-get install maven`. -Windows users with https://chocolatey.org/[Chocolatey] can run `choco install maven` from an elevated (administrator) prompt. - -Spring Boot dependencies use the `org.springframework.boot` `groupId`. -Typically, your Maven POM file inherits from the `spring-boot-starter-parent` project and declares dependencies to one or more <>. -Spring Boot also provides an optional <> to create executable jars. - -More details on getting started with Spring Boot and Maven can be found in the {spring-boot-maven-plugin-docs}#getting-started[Getting Started section] of the Maven plugin's reference guide. - - - -[[getting-started.installing.java.gradle]] -==== Gradle Installation -Spring Boot is compatible with Gradle 6.8 and 7.x. -If you do not already have Gradle installed, you can follow the instructions at https://gradle.org. - -Spring Boot dependencies can be declared by using the `org.springframework.boot` `group`. -Typically, your project declares dependencies to one or more <>. -Spring Boot provides a useful <> that can be used to simplify dependency declarations and to create executable jars. - -.Gradle Wrapper -**** -The Gradle Wrapper provides a nice way of "`obtaining`" Gradle when you need to build a project. -It is a small script and library that you commit alongside your code to bootstrap the build process. -See {gradle-docs}/gradle_wrapper.html for details. -**** - -More details on getting started with Spring Boot and Gradle can be found in the {spring-boot-gradle-plugin-docs}#getting-started[Getting Started section] of the Gradle plugin's reference guide. - - - -[[getting-started.installing.cli]] -=== Installing the Spring Boot CLI -The Spring Boot CLI (Command Line Interface) is a command line tool that you can use to quickly prototype with Spring. -It lets you run https://groovy-lang.org/[Groovy] scripts, which means that you have a familiar Java-like syntax without so much boilerplate code. - -You do not need to use the CLI to work with Spring Boot, but it is definitely the quickest way to get a Spring application off the ground. - - - -[[getting-started.installing.cli.manual-installation]] -==== Manual Installation -You can download the Spring CLI distribution from the Spring software repository: - -* https://repo.spring.io/{spring-boot-artifactory-repo}/org/springframework/boot/spring-boot-cli/{spring-boot-version}/spring-boot-cli-{spring-boot-version}-bin.zip[spring-boot-cli-{spring-boot-version}-bin.zip] -* https://repo.spring.io/{spring-boot-artifactory-repo}/org/springframework/boot/spring-boot-cli/{spring-boot-version}/spring-boot-cli-{spring-boot-version}-bin.tar.gz[spring-boot-cli-{spring-boot-version}-bin.tar.gz] - -Cutting edge -https://repo.spring.io/snapshot/org/springframework/boot/spring-boot-cli/[snapshot distributions] are also available. - -Once downloaded, follow the {github-raw}/spring-boot-project/spring-boot-cli/src/main/content/INSTALL.txt[INSTALL.txt] instructions from the unpacked archive. -In summary, there is a `spring` script (`spring.bat` for Windows) in a `bin/` directory in the `.zip` file. -Alternatively, you can use `java -jar` with the `.jar` file (the script helps you to be sure that the classpath is set correctly). - - - -[[getting-started.installing.cli.sdkman]] -==== Installation with SDKMAN! -SDKMAN! (The Software Development Kit Manager) can be used for managing multiple versions of various binary SDKs, including Groovy and the Spring Boot CLI. -Get SDKMAN! from https://sdkman.io and install Spring Boot by using the following commands: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - $ sdk install springboot - $ spring --version - Spring Boot v{spring-boot-version} ----- - -If you develop features for the CLI and want access to the version you built, use the following commands: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - $ sdk install springboot dev /path/to/spring-boot/spring-boot-cli/target/spring-boot-cli-{spring-boot-version}-bin/spring-{spring-boot-version}/ - $ sdk default springboot dev - $ spring --version - Spring CLI v{spring-boot-version} ----- - -The preceding instructions install a local instance of `spring` called the `dev` instance. -It points at your target build location, so every time you rebuild Spring Boot, `spring` is up-to-date. - -You can see it by running the following command: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - $ sdk ls springboot - - ================================================================================ - Available Springboot Versions - ================================================================================ - > + dev - * {spring-boot-version} - - ================================================================================ - + - local version - * - installed - > - currently in use - ================================================================================ ----- - - - -[[getting-started.installing.cli.homebrew]] -==== OSX Homebrew Installation -If you are on a Mac and use https://brew.sh/[Homebrew], you can install the Spring Boot CLI by using the following commands: - -[indent=0] ----- - $ brew tap spring-io/tap - $ brew install spring-boot ----- - -Homebrew installs `spring` to `/usr/local/bin`. - -NOTE: If you do not see the formula, your installation of brew might be out-of-date. -In that case, run `brew update` and try again. - - - -[[getting-started.installing.cli.macports]] -==== MacPorts Installation -If you are on a Mac and use https://www.macports.org/[MacPorts], you can install the Spring Boot CLI by using the following command: - -[indent=0] ----- - $ sudo port install spring-boot-cli ----- - - - -[[getting-started.installing.cli.completion]] -==== Command-line Completion -The Spring Boot CLI includes scripts that provide command completion for the https://en.wikipedia.org/wiki/Bash_%28Unix_shell%29[BASH] and https://en.wikipedia.org/wiki/Z_shell[zsh] shells. -You can `source` the script (also named `spring`) in any shell or put it in your personal or system-wide bash completion initialization. -On a Debian system, the system-wide scripts are in `/shell-completion/bash` and all scripts in that directory are executed when a new shell starts. -For example, to run the script manually if you have installed by using SDKMAN!, use the following commands: - -[indent=0] ----- - $ . ~/.sdkman/candidates/springboot/current/shell-completion/bash/spring - $ spring - grab help jar run test version ----- - -NOTE: If you install the Spring Boot CLI by using Homebrew or MacPorts, the command-line completion scripts are automatically registered with your shell. - - - -[[getting-started.installing.cli.scoop]] -==== Windows Scoop Installation -If you are on a Windows and use https://scoop.sh/[Scoop], you can install the Spring Boot CLI by using the following commands: - -[indent=0] ----- - > scoop bucket add extras - > scoop install springboot ----- - -Scoop installs `spring` to `~/scoop/apps/springboot/current/bin`. - -NOTE: If you do not see the app manifest, your installation of scoop might be out-of-date. -In that case, run `scoop update` and try again. - - - -[[getting-started.installing.cli.quick-start]] -==== Quick-start Spring CLI Example -You can use the following web application to test your installation. -To start, create a file called `app.groovy`, as follows: - -[source,groovy,indent=0,subs="verbatim,quotes,attributes"] ----- - @RestController - class ThisWillActuallyRun { - - @RequestMapping("/") - String home() { - "Hello World!" - } - - } ----- - -Then run it from a shell, as follows: - -[indent=0] ----- - $ spring run app.groovy ----- - -NOTE: The first run of your application is slow, as dependencies are downloaded. -Subsequent runs are much quicker. - -Open `http://localhost:8080` in your favorite web browser. -You should see the following output: - -[indent=0] ----- - Hello World! ----- - - - -[[getting-started.installing.upgrading]] -=== Upgrading from an Earlier Version of Spring Boot -If you are upgrading from the `1.x` release of Spring Boot, check the {github-wiki}/Spring-Boot-2.0-Migration-Guide["`migration guide`" on the project wiki] that provides detailed upgrade instructions. -Check also the {github-wiki}["`release notes`"] for a list of "`new and noteworthy`" features for each release. - -When upgrading to a new feature release, some properties may have been renamed or removed. -Spring Boot provides a way to analyze your application's environment and print diagnostics at startup, but also temporarily migrate properties at runtime for you. -To enable that feature, add the following dependency to your project: - -[source,xml,indent=0] ----- - - org.springframework.boot - spring-boot-properties-migrator - runtime - ----- - -WARNING: Properties that are added late to the environment, such as when using `@PropertySource`, will not be taken into account. - -NOTE: Once you're done with the migration, please make sure to remove this module from your project's dependencies. - -To upgrade an existing CLI installation, use the appropriate package manager command (for example, `brew upgrade`). -If you manually installed the CLI, follow the <>, remembering to update your `PATH` environment variable to remove any older references. - - - -[[getting-started.first-application]] -== Developing Your First Spring Boot Application -This section describes how to develop a small "`Hello World!`" web application that highlights some of Spring Boot's key features. -We use Maven to build this project, since most IDEs support it. - -[TIP] -==== -The https://spring.io[spring.io] web site contains many "`Getting Started`" https://spring.io/guides[guides] that use Spring Boot. -If you need to solve a specific problem, check there first. - -You can shortcut the steps below by going to https://start.spring.io and choosing the "Web" starter from the dependencies searcher. -Doing so generates a new project structure so that you can <>. -Check the https://github.com/spring-io/start.spring.io/blob/main/USING.adoc[start.spring.io user guide] for more details. -==== - -Before we begin, open a terminal and run the following commands to ensure that you have valid versions of Java and Maven installed: - -[indent=0] ----- - $ java -version - java version "1.8.0_102" - Java(TM) SE Runtime Environment (build 1.8.0_102-b14) - Java HotSpot(TM) 64-Bit Server VM (build 25.102-b14, mixed mode) ----- - -[indent=0] ----- - $ mvn -v - Apache Maven 3.5.4 (1edded0938998edf8bf061f1ceb3cfdeccf443fe; 2018-06-17T14:33:14-04:00) - Maven home: /usr/local/Cellar/maven/3.3.9/libexec - Java version: 1.8.0_102, vendor: Oracle Corporation ----- - -NOTE: This sample needs to be created in its own directory. -Subsequent instructions assume that you have created a suitable directory and that it is your current directory. - - - -[[getting-started.first-application.pom]] -=== Creating the POM -We need to start by creating a Maven `pom.xml` file. -The `pom.xml` is the recipe that is used to build your project. -Open your favorite text editor and add the following: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - - 4.0.0 - - com.example - myproject - 0.0.1-SNAPSHOT - - - org.springframework.boot - spring-boot-starter-parent - {spring-boot-version} - - - - - - - - - - - - - - - - -ifeval::["{spring-boot-artifactory-repo}" != "release"] - - - - spring-snapshots - https://repo.spring.io/snapshot - true - - - spring-milestones - https://repo.spring.io/milestone - - - - - spring-snapshots - https://repo.spring.io/snapshot - - - spring-milestones - https://repo.spring.io/milestone - - -endif::[] - ----- - -The preceding listing should give you a working build. -You can test it by running `mvn package` (for now, you can ignore the "`jar will be empty - no content was marked for inclusion!`" warning). - -NOTE: At this point, you could import the project into an IDE (most modern Java IDEs include built-in support for Maven). -For simplicity, we continue to use a plain text editor for this example. - - - -[[getting-started.first-application.dependencies]] -=== Adding Classpath Dependencies -Spring Boot provides a number of "`Starters`" that let you add jars to your classpath. -Our applications for smoke tests use the `spring-boot-starter-parent` in the `parent` section of the POM. -The `spring-boot-starter-parent` is a special starter that provides useful Maven defaults. -It also provides a <> section so that you can omit `version` tags for "`blessed`" dependencies. - -Other "`Starters`" provide dependencies that you are likely to need when developing a specific type of application. -Since we are developing a web application, we add a `spring-boot-starter-web` dependency. -Before that, we can look at what we currently have by running the following command: - -[indent=0] ----- - $ mvn dependency:tree - - [INFO] com.example:myproject:jar:0.0.1-SNAPSHOT ----- - -The `mvn dependency:tree` command prints a tree representation of your project dependencies. -You can see that `spring-boot-starter-parent` provides no dependencies by itself. -To add the necessary dependencies, edit your `pom.xml` and add the `spring-boot-starter-web` dependency immediately below the `parent` section: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - - org.springframework.boot - spring-boot-starter-web - - ----- - -If you run `mvn dependency:tree` again, you see that there are now a number of additional dependencies, including the Tomcat web server and Spring Boot itself. - - - -[[getting-started.first-application.code]] -=== Writing the Code -To finish our application, we need to create a single Java file. -By default, Maven compiles sources from `src/main/java`, so you need to create that directory structure and then add a file named `src/main/java/Example.java` to contain the following code: - -[source,java,pending-extract=true,indent=0] ----- - import org.springframework.boot.*; - import org.springframework.boot.autoconfigure.*; - import org.springframework.web.bind.annotation.*; - - @RestController - @EnableAutoConfiguration - public class Example { - - @RequestMapping("/") - String home() { - return "Hello World!"; - } - - public static void main(String[] args) { - SpringApplication.run(Example.class, args); - } - - } ----- - -Although there is not much code here, quite a lot is going on. -We step through the important parts in the next few sections. - - - -[[getting-started.first-application.code.mvc-annotations]] -==== The @RestController and @RequestMapping Annotations -The first annotation on our `Example` class is `@RestController`. -This is known as a _stereotype_ annotation. -It provides hints for people reading the code and for Spring that the class plays a specific role. -In this case, our class is a web `@Controller`, so Spring considers it when handling incoming web requests. - -The `@RequestMapping` annotation provides "`routing`" information. -It tells Spring that any HTTP request with the `/` path should be mapped to the `home` method. -The `@RestController` annotation tells Spring to render the resulting string directly back to the caller. - -TIP: The `@RestController` and `@RequestMapping` annotations are Spring MVC annotations (they are not specific to Spring Boot). -See the {spring-framework-docs}/web.html#mvc[MVC section] in the Spring Reference Documentation for more details. - - - -[[getting-started.first-application.code.enable-auto-configuration]] -==== The @EnableAutoConfiguration Annotation -The second class-level annotation is `@EnableAutoConfiguration`. -This annotation tells Spring Boot to "`guess`" how you want to configure Spring, based on the jar dependencies that you have added. -Since `spring-boot-starter-web` added Tomcat and Spring MVC, the auto-configuration assumes that you are developing a web application and sets up Spring accordingly. - -.Starters and Auto-configuration -**** -Auto-configuration is designed to work well with "`Starters`", but the two concepts are not directly tied. -You are free to pick and choose jar dependencies outside of the starters. -Spring Boot still does its best to auto-configure your application. -**** - - - -[[getting-started.first-application.code.main-method]] -==== The "`main`" Method -The final part of our application is the `main` method. -This is a standard method that follows the Java convention for an application entry point. -Our main method delegates to Spring Boot's `SpringApplication` class by calling `run`. -`SpringApplication` bootstraps our application, starting Spring, which, in turn, starts the auto-configured Tomcat web server. -We need to pass `Example.class` as an argument to the `run` method to tell `SpringApplication` which is the primary Spring component. -The `args` array is also passed through to expose any command-line arguments. - - - -[[getting-started.first-application.run]] -=== Running the Example -At this point, your application should work. -Since you used the `spring-boot-starter-parent` POM, you have a useful `run` goal that you can use to start the application. -Type `mvn spring-boot:run` from the root project directory to start the application. -You should see output similar to the following: - -[indent=0,subs="attributes"] ----- - $ mvn spring-boot:run - - . ____ _ __ _ _ - /\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \ - ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \ - \\/ ___)| |_)| | | | | || (_| | ) ) ) ) - ' |____| .__|_| |_|_| |_\__, | / / / / - =========|_|==============|___/=/_/_/_/ - :: Spring Boot :: (v{spring-boot-version}) - ....... . . . - ....... . . . (log output here) - ....... . . . - ........ Started Example in 2.222 seconds (JVM running for 6.514) ----- - -If you open a web browser to `http://localhost:8080`, you should see the following output: - -[indent=0] ----- - Hello World! ----- - -To gracefully exit the application, press `ctrl-c`. - - - -[[getting-started.first-application.executable-jar]] -=== Creating an Executable Jar -We finish our example by creating a completely self-contained executable jar file that we could run in production. -Executable jars (sometimes called "`fat jars`") are archives containing your compiled classes along with all of the jar dependencies that your code needs to run. - -.Executable jars and Java -**** -Java does not provide a standard way to load nested jar files (jar files that are themselves contained within a jar). -This can be problematic if you are looking to distribute a self-contained application. - -To solve this problem, many developers use "`uber`" jars. -An uber jar packages all the classes from all the application's dependencies into a single archive. -The problem with this approach is that it becomes hard to see which libraries are in your application. -It can also be problematic if the same filename is used (but with different content) in multiple jars. - -Spring Boot takes a <> and lets you actually nest jars directly. -**** - -To create an executable jar, we need to add the `spring-boot-maven-plugin` to our `pom.xml`. -To do so, insert the following lines just below the `dependencies` section: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - - - org.springframework.boot - spring-boot-maven-plugin - - - ----- - -NOTE: The `spring-boot-starter-parent` POM includes `` configuration to bind the `repackage` goal. -If you do not use the parent POM, you need to declare this configuration yourself. -See the {spring-boot-maven-plugin-docs}#getting-started[plugin documentation] for details. - -Save your `pom.xml` and run `mvn package` from the command line, as follows: - -[indent=0,subs="attributes"] ----- - $ mvn package - - [INFO] Scanning for projects... - [INFO] - [INFO] ------------------------------------------------------------------------ - [INFO] Building myproject 0.0.1-SNAPSHOT - [INFO] ------------------------------------------------------------------------ - [INFO] .... .. - [INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ myproject --- - [INFO] Building jar: /Users/developer/example/spring-boot-example/target/myproject-0.0.1-SNAPSHOT.jar - [INFO] - [INFO] --- spring-boot-maven-plugin:{spring-boot-version}:repackage (default) @ myproject --- - [INFO] ------------------------------------------------------------------------ - [INFO] BUILD SUCCESS - [INFO] ------------------------------------------------------------------------ ----- - -If you look in the `target` directory, you should see `myproject-0.0.1-SNAPSHOT.jar`. -The file should be around 10 MB in size. -If you want to peek inside, you can use `jar tvf`, as follows: - -[indent=0] ----- - $ jar tvf target/myproject-0.0.1-SNAPSHOT.jar ----- - -You should also see a much smaller file named `myproject-0.0.1-SNAPSHOT.jar.original` in the `target` directory. -This is the original jar file that Maven created before it was repackaged by Spring Boot. - -To run that application, use the `java -jar` command, as follows: - -[indent=0,subs="attributes"] ----- - $ java -jar target/myproject-0.0.1-SNAPSHOT.jar - - . ____ _ __ _ _ - /\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \ - ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \ - \\/ ___)| |_)| | | | | || (_| | ) ) ) ) - ' |____| .__|_| |_|_| |_\__, | / / / / - =========|_|==============|___/=/_/_/_/ - :: Spring Boot :: (v{spring-boot-version}) - ....... . . . - ....... . . . (log output here) - ....... . . . - ........ Started Example in 2.536 seconds (JVM running for 2.864) ----- - -As before, to exit the application, press `ctrl-c`. - - - -[[getting-started.whats=next]] -== What to Read Next -Hopefully, this section provided some of the Spring Boot basics and got you on your way to writing your own applications. -If you are a task-oriented type of developer, you might want to jump over to https://spring.io and check out some of the https://spring.io/guides/[getting started] guides that solve specific "`How do I do that with Spring?`" problems. -We also have Spring Boot-specific "`<>`" reference documentation. - -Otherwise, the next logical step is to read _<>_. -If you are really impatient, you could also jump ahead and read about _<>_. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/getting-started/first-application.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/getting-started/first-application.adoc new file mode 100644 index 0000000000..039cc5bb7f --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/getting-started/first-application.adoc @@ -0,0 +1,345 @@ +[[getting-started.first-application]] +== Developing Your First Spring Boot Application +This section describes how to develop a small "`Hello World!`" web application that highlights some of Spring Boot's key features. +We use Maven to build this project, since most IDEs support it. + +[TIP] +==== +The https://spring.io[spring.io] web site contains many "`Getting Started`" https://spring.io/guides[guides] that use Spring Boot. +If you need to solve a specific problem, check there first. + +You can shortcut the steps below by going to https://start.spring.io and choosing the "Web" starter from the dependencies searcher. +Doing so generates a new project structure so that you can <>. +Check the https://github.com/spring-io/start.spring.io/blob/main/USING.adoc[start.spring.io user guide] for more details. +==== + +Before we begin, open a terminal and run the following commands to ensure that you have valid versions of Java and Maven installed: + +[indent=0] +---- + $ java -version + java version "1.8.0_102" + Java(TM) SE Runtime Environment (build 1.8.0_102-b14) + Java HotSpot(TM) 64-Bit Server VM (build 25.102-b14, mixed mode) +---- + +[indent=0] +---- + $ mvn -v + Apache Maven 3.5.4 (1edded0938998edf8bf061f1ceb3cfdeccf443fe; 2018-06-17T14:33:14-04:00) + Maven home: /usr/local/Cellar/maven/3.3.9/libexec + Java version: 1.8.0_102, vendor: Oracle Corporation +---- + +NOTE: This sample needs to be created in its own directory. +Subsequent instructions assume that you have created a suitable directory and that it is your current directory. + + + +[[getting-started.first-application.pom]] +=== Creating the POM +We need to start by creating a Maven `pom.xml` file. +The `pom.xml` is the recipe that is used to build your project. +Open your favorite text editor and add the following: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + + 4.0.0 + + com.example + myproject + 0.0.1-SNAPSHOT + + + org.springframework.boot + spring-boot-starter-parent + {spring-boot-version} + + + + + + + + + + + + + + + + +ifeval::["{spring-boot-artifactory-repo}" != "release"] + + + + spring-snapshots + https://repo.spring.io/snapshot + true + + + spring-milestones + https://repo.spring.io/milestone + + + + + spring-snapshots + https://repo.spring.io/snapshot + + + spring-milestones + https://repo.spring.io/milestone + + +endif::[] + +---- + +The preceding listing should give you a working build. +You can test it by running `mvn package` (for now, you can ignore the "`jar will be empty - no content was marked for inclusion!`" warning). + +NOTE: At this point, you could import the project into an IDE (most modern Java IDEs include built-in support for Maven). +For simplicity, we continue to use a plain text editor for this example. + + + +[[getting-started.first-application.dependencies]] +=== Adding Classpath Dependencies +Spring Boot provides a number of "`Starters`" that let you add jars to your classpath. +Our applications for smoke tests use the `spring-boot-starter-parent` in the `parent` section of the POM. +The `spring-boot-starter-parent` is a special starter that provides useful Maven defaults. +It also provides a <> section so that you can omit `version` tags for "`blessed`" dependencies. + +Other "`Starters`" provide dependencies that you are likely to need when developing a specific type of application. +Since we are developing a web application, we add a `spring-boot-starter-web` dependency. +Before that, we can look at what we currently have by running the following command: + +[indent=0] +---- + $ mvn dependency:tree + + [INFO] com.example:myproject:jar:0.0.1-SNAPSHOT +---- + +The `mvn dependency:tree` command prints a tree representation of your project dependencies. +You can see that `spring-boot-starter-parent` provides no dependencies by itself. +To add the necessary dependencies, edit your `pom.xml` and add the `spring-boot-starter-web` dependency immediately below the `parent` section: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + + org.springframework.boot + spring-boot-starter-web + + +---- + +If you run `mvn dependency:tree` again, you see that there are now a number of additional dependencies, including the Tomcat web server and Spring Boot itself. + + + +[[getting-started.first-application.code]] +=== Writing the Code +To finish our application, we need to create a single Java file. +By default, Maven compiles sources from `src/main/java`, so you need to create that directory structure and then add a file named `src/main/java/Example.java` to contain the following code: + +[source,java,pending-extract=true,indent=0] +---- + import org.springframework.boot.*; + import org.springframework.boot.autoconfigure.*; + import org.springframework.web.bind.annotation.*; + + @RestController + @EnableAutoConfiguration + public class Example { + + @RequestMapping("/") + String home() { + return "Hello World!"; + } + + public static void main(String[] args) { + SpringApplication.run(Example.class, args); + } + + } +---- + +Although there is not much code here, quite a lot is going on. +We step through the important parts in the next few sections. + + + +[[getting-started.first-application.code.mvc-annotations]] +==== The @RestController and @RequestMapping Annotations +The first annotation on our `Example` class is `@RestController`. +This is known as a _stereotype_ annotation. +It provides hints for people reading the code and for Spring that the class plays a specific role. +In this case, our class is a web `@Controller`, so Spring considers it when handling incoming web requests. + +The `@RequestMapping` annotation provides "`routing`" information. +It tells Spring that any HTTP request with the `/` path should be mapped to the `home` method. +The `@RestController` annotation tells Spring to render the resulting string directly back to the caller. + +TIP: The `@RestController` and `@RequestMapping` annotations are Spring MVC annotations (they are not specific to Spring Boot). +See the {spring-framework-docs}/web.html#mvc[MVC section] in the Spring Reference Documentation for more details. + + + +[[getting-started.first-application.code.enable-auto-configuration]] +==== The @EnableAutoConfiguration Annotation +The second class-level annotation is `@EnableAutoConfiguration`. +This annotation tells Spring Boot to "`guess`" how you want to configure Spring, based on the jar dependencies that you have added. +Since `spring-boot-starter-web` added Tomcat and Spring MVC, the auto-configuration assumes that you are developing a web application and sets up Spring accordingly. + +.Starters and Auto-configuration +**** +Auto-configuration is designed to work well with "`Starters`", but the two concepts are not directly tied. +You are free to pick and choose jar dependencies outside of the starters. +Spring Boot still does its best to auto-configure your application. +**** + + + +[[getting-started.first-application.code.main-method]] +==== The "`main`" Method +The final part of our application is the `main` method. +This is a standard method that follows the Java convention for an application entry point. +Our main method delegates to Spring Boot's `SpringApplication` class by calling `run`. +`SpringApplication` bootstraps our application, starting Spring, which, in turn, starts the auto-configured Tomcat web server. +We need to pass `Example.class` as an argument to the `run` method to tell `SpringApplication` which is the primary Spring component. +The `args` array is also passed through to expose any command-line arguments. + + + +[[getting-started.first-application.run]] +=== Running the Example +At this point, your application should work. +Since you used the `spring-boot-starter-parent` POM, you have a useful `run` goal that you can use to start the application. +Type `mvn spring-boot:run` from the root project directory to start the application. +You should see output similar to the following: + +[indent=0,subs="attributes"] +---- + $ mvn spring-boot:run + + . ____ _ __ _ _ + /\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \ + ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \ + \\/ ___)| |_)| | | | | || (_| | ) ) ) ) + ' |____| .__|_| |_|_| |_\__, | / / / / + =========|_|==============|___/=/_/_/_/ + :: Spring Boot :: (v{spring-boot-version}) + ....... . . . + ....... . . . (log output here) + ....... . . . + ........ Started Example in 2.222 seconds (JVM running for 6.514) +---- + +If you open a web browser to `http://localhost:8080`, you should see the following output: + +[indent=0] +---- + Hello World! +---- + +To gracefully exit the application, press `ctrl-c`. + + + +[[getting-started.first-application.executable-jar]] +=== Creating an Executable Jar +We finish our example by creating a completely self-contained executable jar file that we could run in production. +Executable jars (sometimes called "`fat jars`") are archives containing your compiled classes along with all of the jar dependencies that your code needs to run. + +.Executable jars and Java +**** +Java does not provide a standard way to load nested jar files (jar files that are themselves contained within a jar). +This can be problematic if you are looking to distribute a self-contained application. + +To solve this problem, many developers use "`uber`" jars. +An uber jar packages all the classes from all the application's dependencies into a single archive. +The problem with this approach is that it becomes hard to see which libraries are in your application. +It can also be problematic if the same filename is used (but with different content) in multiple jars. + +Spring Boot takes a <> and lets you actually nest jars directly. +**** + +To create an executable jar, we need to add the `spring-boot-maven-plugin` to our `pom.xml`. +To do so, insert the following lines just below the `dependencies` section: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + + + org.springframework.boot + spring-boot-maven-plugin + + + +---- + +NOTE: The `spring-boot-starter-parent` POM includes `` configuration to bind the `repackage` goal. +If you do not use the parent POM, you need to declare this configuration yourself. +See the {spring-boot-maven-plugin-docs}#getting-started[plugin documentation] for details. + +Save your `pom.xml` and run `mvn package` from the command line, as follows: + +[indent=0,subs="attributes"] +---- + $ mvn package + + [INFO] Scanning for projects... + [INFO] + [INFO] ------------------------------------------------------------------------ + [INFO] Building myproject 0.0.1-SNAPSHOT + [INFO] ------------------------------------------------------------------------ + [INFO] .... .. + [INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ myproject --- + [INFO] Building jar: /Users/developer/example/spring-boot-example/target/myproject-0.0.1-SNAPSHOT.jar + [INFO] + [INFO] --- spring-boot-maven-plugin:{spring-boot-version}:repackage (default) @ myproject --- + [INFO] ------------------------------------------------------------------------ + [INFO] BUILD SUCCESS + [INFO] ------------------------------------------------------------------------ +---- + +If you look in the `target` directory, you should see `myproject-0.0.1-SNAPSHOT.jar`. +The file should be around 10 MB in size. +If you want to peek inside, you can use `jar tvf`, as follows: + +[indent=0] +---- + $ jar tvf target/myproject-0.0.1-SNAPSHOT.jar +---- + +You should also see a much smaller file named `myproject-0.0.1-SNAPSHOT.jar.original` in the `target` directory. +This is the original jar file that Maven created before it was repackaged by Spring Boot. + +To run that application, use the `java -jar` command, as follows: + +[indent=0,subs="attributes"] +---- + $ java -jar target/myproject-0.0.1-SNAPSHOT.jar + + . ____ _ __ _ _ + /\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \ + ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \ + \\/ ___)| |_)| | | | | || (_| | ) ) ) ) + ' |____| .__|_| |_|_| |_\__, | / / / / + =========|_|==============|___/=/_/_/_/ + :: Spring Boot :: (v{spring-boot-version}) + ....... . . . + ....... . . . (log output here) + ....... . . . + ........ Started Example in 2.536 seconds (JVM running for 2.864) +---- + +As before, to exit the application, press `ctrl-c`. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/getting-started/installing.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/getting-started/installing.adoc new file mode 100644 index 0000000000..5a6752e06a --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/getting-started/installing.adoc @@ -0,0 +1,261 @@ +[[getting-started.installing]] +== Installing Spring Boot +Spring Boot can be used with "`classic`" Java development tools or installed as a command line tool. +Either way, you need https://www.java.com[Java SDK v1.8] or higher. +Before you begin, you should check your current Java installation by using the following command: + +[indent=0] +---- + $ java -version +---- + +If you are new to Java development or if you want to experiment with Spring Boot, you might want to try the <> (Command Line Interface) first. +Otherwise, read on for "`classic`" installation instructions. + + + +[[getting-started.installing.java]] +=== Installation Instructions for the Java Developer +You can use Spring Boot in the same way as any standard Java library. +To do so, include the appropriate `+spring-boot-*.jar+` files on your classpath. +Spring Boot does not require any special tools integration, so you can use any IDE or text editor. +Also, there is nothing special about a Spring Boot application, so you can run and debug a Spring Boot application as you would any other Java program. + +Although you _could_ copy Spring Boot jars, we generally recommend that you use a build tool that supports dependency management (such as Maven or Gradle). + + + +[[getting-started.installing.java.maven]] +==== Maven Installation +Spring Boot is compatible with Apache Maven 3.3 or above. +If you do not already have Maven installed, you can follow the instructions at https://maven.apache.org. + +TIP: On many operating systems, Maven can be installed with a package manager. +If you use OSX Homebrew, try `brew install maven`. +Ubuntu users can run `sudo apt-get install maven`. +Windows users with https://chocolatey.org/[Chocolatey] can run `choco install maven` from an elevated (administrator) prompt. + +Spring Boot dependencies use the `org.springframework.boot` `groupId`. +Typically, your Maven POM file inherits from the `spring-boot-starter-parent` project and declares dependencies to one or more <>. +Spring Boot also provides an optional <> to create executable jars. + +More details on getting started with Spring Boot and Maven can be found in the {spring-boot-maven-plugin-docs}#getting-started[Getting Started section] of the Maven plugin's reference guide. + + + +[[getting-started.installing.java.gradle]] +==== Gradle Installation +Spring Boot is compatible with Gradle 6.8 and 7.x. +If you do not already have Gradle installed, you can follow the instructions at https://gradle.org. + +Spring Boot dependencies can be declared by using the `org.springframework.boot` `group`. +Typically, your project declares dependencies to one or more <>. +Spring Boot provides a useful <> that can be used to simplify dependency declarations and to create executable jars. + +.Gradle Wrapper +**** +The Gradle Wrapper provides a nice way of "`obtaining`" Gradle when you need to build a project. +It is a small script and library that you commit alongside your code to bootstrap the build process. +See {gradle-docs}/gradle_wrapper.html for details. +**** + +More details on getting started with Spring Boot and Gradle can be found in the {spring-boot-gradle-plugin-docs}#getting-started[Getting Started section] of the Gradle plugin's reference guide. + + + +[[getting-started.installing.cli]] +=== Installing the Spring Boot CLI +The Spring Boot CLI (Command Line Interface) is a command line tool that you can use to quickly prototype with Spring. +It lets you run https://groovy-lang.org/[Groovy] scripts, which means that you have a familiar Java-like syntax without so much boilerplate code. + +You do not need to use the CLI to work with Spring Boot, but it is definitely the quickest way to get a Spring application off the ground. + + + +[[getting-started.installing.cli.manual-installation]] +==== Manual Installation +You can download the Spring CLI distribution from the Spring software repository: + +* https://repo.spring.io/{spring-boot-artifactory-repo}/org/springframework/boot/spring-boot-cli/{spring-boot-version}/spring-boot-cli-{spring-boot-version}-bin.zip[spring-boot-cli-{spring-boot-version}-bin.zip] +* https://repo.spring.io/{spring-boot-artifactory-repo}/org/springframework/boot/spring-boot-cli/{spring-boot-version}/spring-boot-cli-{spring-boot-version}-bin.tar.gz[spring-boot-cli-{spring-boot-version}-bin.tar.gz] + +Cutting edge +https://repo.spring.io/snapshot/org/springframework/boot/spring-boot-cli/[snapshot distributions] are also available. + +Once downloaded, follow the {github-raw}/spring-boot-project/spring-boot-cli/src/main/content/INSTALL.txt[INSTALL.txt] instructions from the unpacked archive. +In summary, there is a `spring` script (`spring.bat` for Windows) in a `bin/` directory in the `.zip` file. +Alternatively, you can use `java -jar` with the `.jar` file (the script helps you to be sure that the classpath is set correctly). + + + +[[getting-started.installing.cli.sdkman]] +==== Installation with SDKMAN! +SDKMAN! (The Software Development Kit Manager) can be used for managing multiple versions of various binary SDKs, including Groovy and the Spring Boot CLI. +Get SDKMAN! from https://sdkman.io and install Spring Boot by using the following commands: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + $ sdk install springboot + $ spring --version + Spring Boot v{spring-boot-version} +---- + +If you develop features for the CLI and want access to the version you built, use the following commands: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + $ sdk install springboot dev /path/to/spring-boot/spring-boot-cli/target/spring-boot-cli-{spring-boot-version}-bin/spring-{spring-boot-version}/ + $ sdk default springboot dev + $ spring --version + Spring CLI v{spring-boot-version} +---- + +The preceding instructions install a local instance of `spring` called the `dev` instance. +It points at your target build location, so every time you rebuild Spring Boot, `spring` is up-to-date. + +You can see it by running the following command: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + $ sdk ls springboot + + ================================================================================ + Available Springboot Versions + ================================================================================ + > + dev + * {spring-boot-version} + + ================================================================================ + + - local version + * - installed + > - currently in use + ================================================================================ +---- + + + +[[getting-started.installing.cli.homebrew]] +==== OSX Homebrew Installation +If you are on a Mac and use https://brew.sh/[Homebrew], you can install the Spring Boot CLI by using the following commands: + +[indent=0] +---- + $ brew tap spring-io/tap + $ brew install spring-boot +---- + +Homebrew installs `spring` to `/usr/local/bin`. + +NOTE: If you do not see the formula, your installation of brew might be out-of-date. +In that case, run `brew update` and try again. + + + +[[getting-started.installing.cli.macports]] +==== MacPorts Installation +If you are on a Mac and use https://www.macports.org/[MacPorts], you can install the Spring Boot CLI by using the following command: + +[indent=0] +---- + $ sudo port install spring-boot-cli +---- + + + +[[getting-started.installing.cli.completion]] +==== Command-line Completion +The Spring Boot CLI includes scripts that provide command completion for the https://en.wikipedia.org/wiki/Bash_%28Unix_shell%29[BASH] and https://en.wikipedia.org/wiki/Z_shell[zsh] shells. +You can `source` the script (also named `spring`) in any shell or put it in your personal or system-wide bash completion initialization. +On a Debian system, the system-wide scripts are in `/shell-completion/bash` and all scripts in that directory are executed when a new shell starts. +For example, to run the script manually if you have installed by using SDKMAN!, use the following commands: + +[indent=0] +---- + $ . ~/.sdkman/candidates/springboot/current/shell-completion/bash/spring + $ spring + grab help jar run test version +---- + +NOTE: If you install the Spring Boot CLI by using Homebrew or MacPorts, the command-line completion scripts are automatically registered with your shell. + + + +[[getting-started.installing.cli.scoop]] +==== Windows Scoop Installation +If you are on a Windows and use https://scoop.sh/[Scoop], you can install the Spring Boot CLI by using the following commands: + +[indent=0] +---- + > scoop bucket add extras + > scoop install springboot +---- + +Scoop installs `spring` to `~/scoop/apps/springboot/current/bin`. + +NOTE: If you do not see the app manifest, your installation of scoop might be out-of-date. +In that case, run `scoop update` and try again. + + + +[[getting-started.installing.cli.quick-start]] +==== Quick-start Spring CLI Example +You can use the following web application to test your installation. +To start, create a file called `app.groovy`, as follows: + +[source,groovy,indent=0,subs="verbatim,quotes,attributes"] +---- + @RestController + class ThisWillActuallyRun { + + @RequestMapping("/") + String home() { + "Hello World!" + } + + } +---- + +Then run it from a shell, as follows: + +[indent=0] +---- + $ spring run app.groovy +---- + +NOTE: The first run of your application is slow, as dependencies are downloaded. +Subsequent runs are much quicker. + +Open `http://localhost:8080` in your favorite web browser. +You should see the following output: + +[indent=0] +---- + Hello World! +---- + + + +[[getting-started.installing.upgrading]] +=== Upgrading from an Earlier Version of Spring Boot +If you are upgrading from the `1.x` release of Spring Boot, check the {github-wiki}/Spring-Boot-2.0-Migration-Guide["`migration guide`" on the project wiki] that provides detailed upgrade instructions. +Check also the {github-wiki}["`release notes`"] for a list of "`new and noteworthy`" features for each release. + +When upgrading to a new feature release, some properties may have been renamed or removed. +Spring Boot provides a way to analyze your application's environment and print diagnostics at startup, but also temporarily migrate properties at runtime for you. +To enable that feature, add the following dependency to your project: + +[source,xml,indent=0] +---- + + org.springframework.boot + spring-boot-properties-migrator + runtime + +---- + +WARNING: Properties that are added late to the environment, such as when using `@PropertySource`, will not be taken into account. + +NOTE: Once you're done with the migration, please make sure to remove this module from your project's dependencies. + +To upgrade an existing CLI installation, use the appropriate package manager command (for example, `brew upgrade`). +If you manually installed the CLI, follow the <>, remembering to update your `PATH` environment variable to remove any older references. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/getting-started/introducing-spring-boot.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/getting-started/introducing-spring-boot.adoc new file mode 100644 index 0000000000..2f61664def --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/getting-started/introducing-spring-boot.adoc @@ -0,0 +1,15 @@ +[[getting-started.introducing-spring-boot]] +== Introducing Spring Boot +Spring Boot helps you to create stand-alone, production-grade Spring-based Applications that you can run. +We take an opinionated view of the Spring platform and third-party libraries, so that you can get started with minimum fuss. +Most Spring Boot applications need very little Spring configuration. + +You can use Spring Boot to create Java applications that can be started by using `java -jar` or more traditional war deployments. +We also provide a command line tool that runs "`spring scripts`". + +Our primary goals are: + +* Provide a radically faster and widely accessible getting-started experience for all Spring development. +* Be opinionated out of the box but get out of the way quickly as requirements start to diverge from the defaults. +* Provide a range of non-functional features that are common to large classes of projects (such as embedded servers, security, metrics, health checks, and externalized configuration). +* Absolutely no code generation and no requirement for XML configuration. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/getting-started/system-requirements.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/getting-started/system-requirements.adoc new file mode 100644 index 0000000000..7050189502 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/getting-started/system-requirements.adoc @@ -0,0 +1,40 @@ +[[getting-started.system-requirements]] +== System Requirements +Spring Boot {spring-boot-version} requires https://www.java.com[Java 8] and is compatible up to Java 16 (included). +{spring-framework-docs}/[Spring Framework {spring-framework-version}] or above is also required. + +Explicit build support is provided for the following build tools: + +|=== +| Build Tool | Version + +| Maven +| 3.5+ + +| Gradle +| 6.8.x and 7.x +|=== + + + +[[getting-started.system-requirements.servlet-containers]] +=== Servlet Containers +Spring Boot supports the following embedded servlet containers: + +|=== +| Name | Servlet Version + +| Tomcat 9.0 +| 4.0 + +| Jetty 9.4 +| 3.1 + +| Jetty 10.0 +| 4.0 + +| Undertow 2.0 +| 4.0 +|=== + +You can also deploy Spring Boot applications to any Servlet 3.1+ compatible container. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/getting-started/whats-next.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/getting-started/whats-next.adoc new file mode 100644 index 0000000000..556f98c613 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/getting-started/whats-next.adoc @@ -0,0 +1,8 @@ +[[getting-started.whats-next]] +== What to Read Next +Hopefully, this section provided some of the Spring Boot basics and got you on your way to writing your own applications. +If you are a task-oriented type of developer, you might want to jump over to https://spring.io and check out some of the https://spring.io/guides/[getting started] guides that solve specific "`How do I do that with Spring?`" problems. +We also have Spring Boot-specific "`<>`" reference documentation. + +Otherwise, the next logical step is to read _<>_. +If you are really impatient, you could also jump ahead and read about _<>_. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto.adoc index 72b14a1e42..24deb2d22a 100644 --- a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto.adoc +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto.adoc @@ -2,6 +2,8 @@ = "`How-to`" Guides include::attributes.adoc[] + + This section provides answers to some common '`how do I do that...`' questions that often arise when using Spring Boot. Its coverage is not exhaustive, but it does cover quite a lot. @@ -13,3023 +15,40 @@ If you want to add a '`how-to`', send us a {spring-boot-code}[pull request]. -[[howto.application]] -== Spring Boot Application -This section includes topics relating directly to Spring Boot applications. +include::howto/application.adoc[] +include::howto/properties-and-configuration.adoc[] +include::howto/webserver.adoc[] -[[howto.application.failure-analyzer]] -=== Create Your Own FailureAnalyzer -{spring-boot-module-api}/diagnostics/FailureAnalyzer.html[`FailureAnalyzer`] is a great way to intercept an exception on startup and turn it into a human-readable message, wrapped in a {spring-boot-module-api}/diagnostics/FailureAnalysis.html[`FailureAnalysis`]. -Spring Boot provides such an analyzer for application-context-related exceptions, JSR-303 validations, and more. -You can also create your own. +include::howto/spring-mvc.adoc[] -`AbstractFailureAnalyzer` is a convenient extension of `FailureAnalyzer` that checks the presence of a specified exception type in the exception to handle. -You can extend from that so that your implementation gets a chance to handle the exception only when it is actually present. -If, for whatever reason, you cannot handle the exception, return `null` to give another implementation a chance to handle the exception. +include::howto/testing-with-spring-security.adoc[] -`FailureAnalyzer` implementations must be registered in `META-INF/spring.factories`. -The following example registers `ProjectConstraintViolationFailureAnalyzer`: +include::howto/jersey.adoc[] -[source,properties,indent=0] ----- - org.springframework.boot.diagnostics.FailureAnalyzer=\ - com.example.ProjectConstraintViolationFailureAnalyzer ----- +include::howto/http-clients.adoc[] -NOTE: If you need access to the `BeanFactory` or the `Environment`, your `FailureAnalyzer` can implement `BeanFactoryAware` or `EnvironmentAware` respectively. +include::howto/logging.adoc[] +include::howto/data-access.adoc[] +include::howto/data-initialization.adoc[] -[[howto.application.troubleshoot-auto-configuration]] -=== Troubleshoot Auto-configuration -The Spring Boot auto-configuration tries its best to "`do the right thing`", but sometimes things fail, and it can be hard to tell why. +include::howto/messaging.adoc[] -There is a really useful `ConditionEvaluationReport` available in any Spring Boot `ApplicationContext`. -You can see it if you enable `DEBUG` logging output. -If you use the `spring-boot-actuator` (see <>), there is also a `conditions` endpoint that renders the report in JSON. -Use that endpoint to debug the application and see what features have been added (and which have not been added) by Spring Boot at runtime. +include::howto/batch.adoc[] -Many more questions can be answered by looking at the source code and the Javadoc. -When reading the code, remember the following rules of thumb: +include::howto/actuator.adoc[] -* Look for classes called `+*AutoConfiguration+` and read their sources. - Pay special attention to the `+@Conditional*+` annotations to find out what features they enable and when. - Add `--debug` to the command line or a System property `-Ddebug` to get a log on the console of all the auto-configuration decisions that were made in your app. - In a running application with actuator enabled, look at the `conditions` endpoint (`/actuator/conditions` or the JMX equivalent) for the same information. -* Look for classes that are `@ConfigurationProperties` (such as {spring-boot-autoconfigure-module-code}/web/ServerProperties.java[`ServerProperties`]) and read from there the available external configuration options. - The `@ConfigurationProperties` annotation has a `name` attribute that acts as a prefix to external properties. - Thus, `ServerProperties` has `prefix="server"` and its configuration properties are `server.port`, `server.address`, and others. - In a running application with actuator enabled, look at the `configprops` endpoint. -* Look for uses of the `bind` method on the `Binder` to pull configuration values explicitly out of the `Environment` in a relaxed manner. - It is often used with a prefix. -* Look for `@Value` annotations that bind directly to the `Environment`. -* Look for `@ConditionalOnExpression` annotations that switch features on and off in response to SpEL expressions, normally evaluated with placeholders resolved from the `Environment`. +include::howto/security.adoc[] +include::howto/hotswapping.adoc[] +include::howto/build.adoc[] -[[howto.application.customize-the-environment-or-application-context]] -=== Customize the Environment or ApplicationContext Before It Starts -A `SpringApplication` has `ApplicationListeners` and `ApplicationContextInitializers` that are used to apply customizations to the context or environment. -Spring Boot loads a number of such customizations for use internally from `META-INF/spring.factories`. -There is more than one way to register additional customizations: +include::howto/traditional-deployment.adoc[] -* Programmatically, per application, by calling the `addListeners` and `addInitializers` methods on `SpringApplication` before you run it. -* Declaratively, per application, by setting the `context.initializer.classes` or `context.listener.classes` properties. -* Declaratively, for all applications, by adding a `META-INF/spring.factories` and packaging a jar file that the applications all use as a library. +include::howto/jedis-instead-of-lettuce.adoc[] -The `SpringApplication` sends some special `ApplicationEvents` to the listeners (some even before the context is created) and then registers the listeners for events published by the `ApplicationContext` as well. -See "`<>`" in the '`Spring Boot features`' section for a complete list. - -It is also possible to customize the `Environment` before the application context is refreshed by using `EnvironmentPostProcessor`. -Each implementation should be registered in `META-INF/spring.factories`, as shown in the following example: - -[indent=0] ----- - org.springframework.boot.env.EnvironmentPostProcessor=com.example.YourEnvironmentPostProcessor ----- - -The implementation can load arbitrary files and add them to the `Environment`. -For instance, the following example loads a YAML configuration file from the classpath: - -[source,java,indent=0] ----- -include::{include-howto}/springbootapplication/MyEnvironmentPostProcessor.java[tag=*] ----- - -TIP: The `Environment` has already been prepared with all the usual property sources that Spring Boot loads by default. -It is therefore possible to get the location of the file from the environment. -The preceding example adds the `custom-resource` property source at the end of the list so that a key defined in any of the usual other locations takes precedence. -A custom implementation may define another order. - -CAUTION: While using `@PropertySource` on your `@SpringBootApplication` may seem to be a convenient way to load a custom resource in the `Environment`, we do not recommend it. -Such property sources are not added to the `Environment` until the application context is being refreshed. -This is too late to configure certain properties such as `+logging.*+` and `+spring.main.*+` which are read before refresh begins. - - - -[[howto.application.context-hierarchy]] -=== Build an ApplicationContext Hierarchy (Adding a Parent or Root Context) -You can use the `ApplicationBuilder` class to create parent/child `ApplicationContext` hierarchies. -See "`<>`" in the '`Spring Boot features`' section for more information. - - - -[[howto.application.non-web-application]] -=== Create a Non-web Application -Not all Spring applications have to be web applications (or web services). -If you want to execute some code in a `main` method but also bootstrap a Spring application to set up the infrastructure to use, you can use the `SpringApplication` features of Spring Boot. -A `SpringApplication` changes its `ApplicationContext` class, depending on whether it thinks it needs a web application or not. -The first thing you can do to help it is to leave server-related dependencies (e.g. servlet API) off the classpath. -If you cannot do that (for example, you run two applications from the same code base) then you can explicitly call `setWebApplicationType(WebApplicationType.NONE)` on your `SpringApplication` instance or set the `applicationContextClass` property (through the Java API or with external properties). -Application code that you want to run as your business logic can be implemented as a `CommandLineRunner` and dropped into the context as a `@Bean` definition. - - - -[[howto.properties-and-configuration]] -== Properties and Configuration -This section includes topics about setting and reading properties and configuration settings and their interaction with Spring Boot applications. - - - -[[howto.properties-and-configuration.expand-properties]] -=== Automatically Expand Properties at Build Time -Rather than hardcoding some properties that are also specified in your project's build configuration, you can automatically expand them by instead using the existing build configuration. -This is possible in both Maven and Gradle. - - - -[[howto.properties-and-configuration.expand-properties.maven]] -==== Automatic Property Expansion Using Maven -You can automatically expand properties from the Maven project by using resource filtering. -If you use the `spring-boot-starter-parent`, you can then refer to your Maven '`project properties`' with `@..@` placeholders, as shown in the following example: - -[source,yaml,indent=0,configblocks] ----- - app: - encoding: "@project.build.sourceEncoding@" - java: - version: "@java.version@" ----- - -NOTE: Only production configuration is filtered that way (in other words, no filtering is applied on `src/test/resources`). - -TIP: If you enable the `addResources` flag, the `spring-boot:run` goal can add `src/main/resources` directly to the classpath (for hot reloading purposes). -Doing so circumvents the resource filtering and this feature. -Instead, you can use the `exec:java` goal or customize the plugin's configuration. -See the {spring-boot-maven-plugin-docs}#getting-started[plugin usage page] for more details. - -If you do not use the starter parent, you need to include the following element inside the `` element of your `pom.xml`: - -[source,xml,indent=0] ----- - - - src/main/resources - true - - ----- - -You also need to include the following element inside ``: - -[source,xml,indent=0] ----- - - org.apache.maven.plugins - maven-resources-plugin - 2.7 - - - @ - - false - - ----- - -NOTE: The `useDefaultDelimiters` property is important if you use standard Spring placeholders (such as `$\{placeholder}`) in your configuration. -If that property is not set to `false`, these may be expanded by the build. - - - -[[howto.properties-and-configuration.expand-properties.gradle]] -==== Automatic Property Expansion Using Gradle -You can automatically expand properties from the Gradle project by configuring the Java plugin's `processResources` task to do so, as shown in the following example: - -[source,groovy,indent=0] ----- - processResources { - expand(project.properties) - } ----- - -You can then refer to your Gradle project's properties by using placeholders, as shown in the following example: - -[source,yaml,indent=0,configblocks] ----- - app: - name: "${name}" - description: "${description}" ----- - -NOTE: Gradle's `expand` method uses Groovy's `SimpleTemplateEngine`, which transforms `${..}` tokens. -The `${..}` style conflicts with Spring's own property placeholder mechanism. -To use Spring property placeholders together with automatic expansion, escape the Spring property placeholders as follows: `\${..}`. - - - -[[howto.properties-and-configuration.externalize-configuration]] -=== Externalize the Configuration of SpringApplication -A `SpringApplication` has bean properties (mainly setters), so you can use its Java API as you create the application to modify its behavior. -Alternatively, you can externalize the configuration by setting properties in `+spring.main.*+`. -For example, in `application.properties`, you might have the following settings: - -[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] ----- - spring: - main: - web-application-type: "none" - banner-mode: "off" ----- - -Then the Spring Boot banner is not printed on startup, and the application is not starting an embedded web server. - -Properties defined in external configuration override the values specified with the Java API, with the notable exception of the sources used to create the `ApplicationContext`. -Consider the following application: - -[source,java,pending-extract=true,indent=0] ----- - new SpringApplicationBuilder() - .bannerMode(Banner.Mode.OFF) - .sources(demo.MyApp.class) - .run(args); ----- - -Now consider the following configuration: - -[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] ----- - spring: - main: - sources: "com.acme.Config,com.acme.ExtraConfig" - banner-mode: "console" ----- - -The actual application _now_ shows the banner (as overridden by configuration) and uses three sources for the `ApplicationContext` (in the following order): `demo.MyApp`, `com.acme.Config`, and `com.acme.ExtraConfig`. - - - -[[howto.properties-and-configuration.external-properties-location]] -=== Change the Location of External Properties of an Application -By default, properties from different sources are added to the Spring `Environment` in a defined order (see "`<>`" in the '`Spring Boot features`' section for the exact order). - -You can also provide the following System properties (or environment variables) to change the behavior: - -* configprop:spring.config.name[] (configprop:spring.config.name[format=envvar]): Defaults to `application` as the root of the file name. -* configprop:spring.config.location[] (configprop:spring.config.location[format=envvar]): The file to load (such as a classpath resource or a URL). - A separate `Environment` property source is set up for this document and it can be overridden by system properties, environment variables, or the command line. - -No matter what you set in the environment, Spring Boot always loads `application.properties` as described above. -By default, if YAML is used, then files with the '`.yml`' extension are also added to the list. - -Spring Boot logs the configuration files that are loaded at the `DEBUG` level and the candidates it has not found at `TRACE` level. - -See {spring-boot-module-code}/context/config/ConfigFileApplicationListener.java[`ConfigFileApplicationListener`] for more detail. - - - -[[howto.properties-and-configuration.short-command-line-arguments]] -=== Use '`Short`' Command Line Arguments -Some people like to use (for example) `--port=9000` instead of `--server.port=9000` to set configuration properties on the command line. -You can enable this behavior by using placeholders in `application.properties`, as shown in the following example: - -[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] ----- - server: - port: "${port:8080}" ----- - -TIP: If you inherit from the `spring-boot-starter-parent` POM, the default filter token of the `maven-resources-plugins` has been changed from `+${*}+` to `@` (that is, `@maven.token@` instead of `${maven.token}`) to prevent conflicts with Spring-style placeholders. -If you have enabled Maven filtering for the `application.properties` directly, you may want to also change the default filter token to use https://maven.apache.org/plugins/maven-resources-plugin/resources-mojo.html#delimiters[other delimiters]. - -NOTE: In this specific case, the port binding works in a PaaS environment such as Heroku or Cloud Foundry. -In those two platforms, the `PORT` environment variable is set automatically and Spring can bind to capitalized synonyms for `Environment` properties. - - - -[[howto.properties-and-configuration.yaml]] -=== Use YAML for External Properties -YAML is a superset of JSON and, as such, is a convenient syntax for storing external properties in a hierarchical format, as shown in the following example: - -[source,yaml,indent=0,subs="verbatim,quotes,attributes"] ----- - spring: - application: - name: "cruncher" - datasource: - driver-class-name: "com.mysql.jdbc.Driver" - url: "jdbc:mysql://localhost/test" - server: - port: 9000 ----- - -Create a file called `application.yml` and put it in the root of your classpath. -Then add `snakeyaml` to your dependencies (Maven coordinates `org.yaml:snakeyaml`, already included if you use the `spring-boot-starter`). -A YAML file is parsed to a Java `Map` (like a JSON object), and Spring Boot flattens the map so that it is one level deep and has period-separated keys, as many people are used to with `Properties` files in Java. - -The preceding example YAML corresponds to the following `application.properties` file: - -[source,properties,indent=0,subs="verbatim,quotes,attributes",configprops] ----- - spring.application.name=cruncher - spring.datasource.driver-class-name=com.mysql.jdbc.Driver - spring.datasource.url=jdbc:mysql://localhost/test - server.port=9000 ----- - -See "`<>`" in the '`Spring Boot features`' section for more information about YAML. - - - -[[howto.properties-and-configuration.set-active-spring-profiles]] -=== Set the Active Spring Profiles -The Spring `Environment` has an API for this, but you would normally set a System property (configprop:spring.profiles.active[]) or an OS environment variable (configprop:spring.profiles.active[format=envvar]). -Also, you can launch your application with a `-D` argument (remember to put it before the main class or jar archive), as follows: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - $ java -jar -Dspring.profiles.active=production demo-0.0.1-SNAPSHOT.jar ----- - -In Spring Boot, you can also set the active profile in `application.properties`, as shown in the following example: - -[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] ----- - spring: - profiles: - active: "production" ----- - -A value set this way is replaced by the System property or environment variable setting but not by the `SpringApplicationBuilder.profiles()` method. -Thus, the latter Java API can be used to augment the profiles without changing the defaults. - -See "`<>`" in the "`Spring Boot features`" section for more information. - - - -[[howto.properties-and-configuration.change-configuration-depending-on-the-environment]] -=== Change Configuration Depending on the Environment -Spring Boot supports multi-document YAML and Properties files (see <> for details) which can be activated conditionally based on the active profiles. - -If a document contains a `spring.config.activate.on-profile` key, then the profiles value (a comma-separated list of profiles or a profile expression) is fed into the Spring `Environment.acceptsProfiles()` method. -If the profile expression matches then that document is included in the final merge (otherwise, it is not), as shown in the following example: - -[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] ----- - server: - port: 9000 - --- - spring: - config: - activate: - on-profile: "development" - server: - port: 9001 - --- - spring: - config: - activate: - on-profile: "production" - server: - port: 0 ----- - -In the preceding example, the default port is 9000. -However, if the Spring profile called '`development`' is active, then the port is 9001. -If '`production`' is active, then the port is 0. - -NOTE: The documents are merged in the order in which they are encountered. -Later values override earlier values. - - - -[[howto.properties-and-configuration.discover-build-in-options-for-external-properties]] -=== Discover Built-in Options for External Properties -Spring Boot binds external properties from `application.properties` (or `.yml` files and other places) into an application at runtime. -There is not (and technically cannot be) an exhaustive list of all supported properties in a single location, because contributions can come from additional jar files on your classpath. - -A running application with the Actuator features has a `configprops` endpoint that shows all the bound and bindable properties available through `@ConfigurationProperties`. - -The appendix includes an <> example with a list of the most common properties supported by Spring Boot. -The definitive list comes from searching the source code for `@ConfigurationProperties` and `@Value` annotations as well as the occasional use of `Binder`. -For more about the exact ordering of loading properties, see "<>". - - - -[[howto.webserver]] -== Embedded Web Servers -Each Spring Boot web application includes an embedded web server. -This feature leads to a number of how-to questions, including how to change the embedded server and how to configure the embedded server. -This section answers those questions. - - - -[[howto.webserver.use-another]] -=== Use Another Web Server -Many Spring Boot starters include default embedded containers. - -* For servlet stack applications, the `spring-boot-starter-web` includes Tomcat by including `spring-boot-starter-tomcat`, but you can use `spring-boot-starter-jetty` or `spring-boot-starter-undertow` instead. -* For reactive stack applications, the `spring-boot-starter-webflux` includes Reactor Netty by including `spring-boot-starter-reactor-netty`, but you can use `spring-boot-starter-tomcat`, `spring-boot-starter-jetty`, or `spring-boot-starter-undertow` instead. - -When switching to a different HTTP server, you need to swap the default dependencies for those that you need instead. -To help with this process, Spring Boot provides a separate starter for each of the supported HTTP servers. - -The following Maven example shows how to exclude Tomcat and include Jetty for Spring MVC: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - 3.1.0 - - - org.springframework.boot - spring-boot-starter-web - - - - org.springframework.boot - spring-boot-starter-tomcat - - - - - - org.springframework.boot - spring-boot-starter-jetty - ----- - -NOTE: The version of the Servlet API has been overridden as, unlike Tomcat 9 and Undertow 2, Jetty 9.4 does not support Servlet 4.0. -If you wish to use Jetty 10, which does support Servlet 4.0, override the `jetty.version` property rather than the `servlet-api.version` property. - -The following Gradle example shows how to use Undertow in place of Reactor Netty for Spring WebFlux: - -[source,groovy,indent=0,subs="verbatim,quotes,attributes"] ----- - configurations.all { - resolutionStrategy.dependencySubstitution.all { dependency -> - if (dependency.requested instanceof ModuleComponentSelector && dependency.requested.module == 'spring-boot-starter-reactor-netty') { - dependency.useTarget("org.springframework.boot:spring-boot-starter-undertow:$dependency.requested.version", 'Use Undertow instead of Reactor Netty') - } - } - } - - dependencies { - compile 'org.springframework.boot:spring-boot-starter-webflux' - // ... - } ----- - -NOTE: `spring-boot-starter-reactor-netty` is required to use the `WebClient` class, so you may need to keep a dependency on Netty even when you need to include a different HTTP server. - - - -[[howto.webserver.disable]] -=== Disabling the Web Server -If your classpath contains the necessary bits to start a web server, Spring Boot will automatically start it. -To disable this behavior configure the `WebApplicationType` in your `application.properties`, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - main: - web-application-type: "none" ----- - - - -[[howto.webserver.change-port]] -=== Change the HTTP Port -In a standalone application, the main HTTP port defaults to `8080` but can be set with configprop:server.port[] (for example, in `application.properties` or as a System property). -Thanks to relaxed binding of `Environment` values, you can also use configprop:server.port[format=envvar] (for example, as an OS environment variable). - -To switch off the HTTP endpoints completely but still create a `WebApplicationContext`, use `server.port=-1` (doing so is sometimes useful for testing). - -For more details, see "`<>`" in the '`Spring Boot Features`' section, or the {spring-boot-autoconfigure-module-code}/web/ServerProperties.java[`ServerProperties`] source code. - - - -[[howto.webserver.use-random-port]] -=== Use a Random Unassigned HTTP Port -To scan for a free port (using OS natives to prevent clashes) use `server.port=0`. - - - -[[howto.webserver.discover-port]] -=== Discover the HTTP Port at Runtime -You can access the port the server is running on from log output or from the `WebServerApplicationContext` through its `WebServer`. -The best way to get that and be sure it has been initialized is to add a `@Bean` of type `ApplicationListener` and pull the container out of the event when it is published. - -Tests that use `@SpringBootTest(webEnvironment=WebEnvironment.RANDOM_PORT)` can also inject the actual port into a field by using the `@LocalServerPort` annotation, as shown in the following example: - -[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] ----- - @SpringBootTest(webEnvironment=WebEnvironment.RANDOM_PORT) - public class MyWebIntegrationTests { - - @LocalServerPort - int port; - - // ... - - } ----- - -[NOTE] -==== -`@LocalServerPort` is a meta-annotation for `@Value("${local.server.port}")`. -Do not try to inject the port in a regular application. -As we just saw, the value is set only after the container has been initialized. -Contrary to a test, application code callbacks are processed early (before the value is actually available). -==== - - - -[[howto.webserver.enable-response-compression]] -=== Enable HTTP Response Compression -HTTP response compression is supported by Jetty, Tomcat, and Undertow. -It can be enabled in `application.properties`, as follows: - -[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] ----- - server: - compression: - enabled: true ----- - -By default, responses must be at least 2048 bytes in length for compression to be performed. -You can configure this behavior by setting the configprop:server.compression.min-response-size[] property. - -By default, responses are compressed only if their content type is one of the following: - -* `text/html` -* `text/xml` -* `text/plain` -* `text/css` -* `text/javascript` -* `application/javascript` -* `application/json` -* `application/xml` - -You can configure this behavior by setting the configprop:server.compression.mime-types[] property. - - - -[[howto.webserver.configure-ssl]] -=== Configure SSL -SSL can be configured declaratively by setting the various `+server.ssl.*+` properties, typically in `application.properties` or `application.yml`. -The following example shows setting SSL properties in `application.properties`: - -[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] ----- - server: - port: 8443 - ssl: - key-store: "classpath:keystore.jks" - key-store-password: "secret" - key-password: "another-secret" ----- - -See {spring-boot-module-code}/web/server/Ssl.java[`Ssl`] for details of all of the supported properties. - -Using configuration such as the preceding example means the application no longer supports a plain HTTP connector at port 8080. -Spring Boot does not support the configuration of both an HTTP connector and an HTTPS connector through `application.properties`. -If you want to have both, you need to configure one of them programmatically. -We recommend using `application.properties` to configure HTTPS, as the HTTP connector is the easier of the two to configure programmatically. - - - -[[howto.webserver.configure-http2]] -=== Configure HTTP/2 -You can enable HTTP/2 support in your Spring Boot application with the configprop:server.http2.enabled[] configuration property. -Both `h2` (HTTP/2 over TLS) and `h2c` (HTTP/2 over TCP) are supported. -To use `h2`, SSL must also be enabled. -When SSL is not enabled, `h2c` will be used. -The details of the `h2` support depend on the chosen web server and the application environment, since that protocol is not supported out-of-the-box by all JDK 8 releases. - - - -[[howto.webserver.configure-http2.tomcat]] -==== HTTP/2 with Tomcat -Spring Boot ships by default with Tomcat 9.0.x which supports `h2c` out of the box and `h2` out of the box when using JDK 9 or later. -Alternatively, `h2` can be used on JDK 8 if the `libtcnative` library and its dependencies are installed on the host operating system. - -The library directory must be made available, if not already, to the JVM library path. -You can do so with a JVM argument such as `-Djava.library.path=/usr/local/opt/tomcat-native/lib`. -More on this in the https://tomcat.apache.org/tomcat-9.0-doc/apr.html[official Tomcat documentation]. - -Starting Tomcat 9.0.x on JDK 8 with HTTP/2 and SSL enabled but without that native support logs the following error: - -[indent=0,subs="attributes"] ----- - ERROR 8787 --- [ main] o.a.coyote.http11.Http11NioProtocol : The upgrade handler [org.apache.coyote.http2.Http2Protocol] for [h2] only supports upgrade via ALPN but has been configured for the ["https-jsse-nio-8443"] connector that does not support ALPN. ----- - -This error is not fatal, and the application still starts with HTTP/1.1 SSL support. - - - -[[howto.webserver.configure-http2.jetty]] -==== HTTP/2 with Jetty -For HTTP/2 support, Jetty requires the additional `org.eclipse.jetty.http2:http2-server` dependency. -To use `h2c` no other dependencies are required. -To use `h2`, you also need to choose one of the following dependencies, depending on your deployment: - -* `org.eclipse.jetty:jetty-alpn-java-server` for applications running on JDK9+ -* `org.eclipse.jetty:jetty-alpn-openjdk8-server` for applications running on JDK8u252+ -* `org.eclipse.jetty:jetty-alpn-conscrypt-server` and the https://www.conscrypt.org/[Conscrypt library] with no JDK requirement - - - -[[howto.webserver.configure-http2.netty]] -==== HTTP/2 with Reactor Netty -The `spring-boot-webflux-starter` is using by default Reactor Netty as a server. -Reactor Netty supports `h2c` using JDK 8 or later with no additional dependencies. -Reactor Netty supports `h2` using the JDK support with JDK 9 or later. -For JDK 8 environments, or for optimal runtime performance, this server also supports `h2` with native libraries. -To enable that, your application needs to have an additional dependency. - -Spring Boot manages the version for the `io.netty:netty-tcnative-boringssl-static` "uber jar", containing native libraries for all platforms. -Developers can choose to import only the required dependencies using a classifier (see https://netty.io/wiki/forked-tomcat-native.html[the Netty official documentation]). - - - -[[howto.webserver.configure-http2.undertow]] -==== HTTP/2 with Undertow -As of Undertow 1.4.0+, both `h2` and `h2c` are supported on JDK 8 without any additional dependencies. - - - -[[howto.webserver.configure]] -=== Configure the Web Server -Generally, you should first consider using one of the many available configuration keys and customize your web server by adding new entries in your `application.properties` (or `application.yml`, or environment, etc. see "`<>`"). -The `server.{asterisk}` namespace is quite useful here, and it includes namespaces like `server.tomcat.{asterisk}`, `server.jetty.{asterisk}` and others, for server-specific features. -See the list of <>. - -The previous sections covered already many common use cases, such as compression, SSL or HTTP/2. -However, if a configuration key doesn't exist for your use case, you should then look at {spring-boot-module-api}/web/server/WebServerFactoryCustomizer.html[`WebServerFactoryCustomizer`]. -You can declare such a component and get access to the server factory relevant to your choice: you should select the variant for the chosen Server (Tomcat, Jetty, Reactor Netty, Undertow) and the chosen web stack (Servlet or Reactive). - -The example below is for Tomcat with the `spring-boot-starter-web` (Servlet stack): - -[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] ----- - @Component - public class MyTomcatWebServerCustomizer - implements WebServerFactoryCustomizer { - - @Override - public void customize(TomcatServletWebServerFactory factory) { - // customize the factory here - } - } ----- - -NOTE: Spring Boot uses that infrastructure internally to auto-configure the server. -Auto-configured `WebServerFactoryCustomizer` beans have an order of `0` and will be processed before any user-defined customizers, unless it has an explicit order that states otherwise. - -Once you've got access to a `WebServerFactory` using the customizer, you can use it to configure specific parts, like connectors, server resources, or the server itself - all using server-specific APIs. - -In addition Spring Boot provides: - -[[howto-configure-webserver-customizers]] -[cols="1,2,2", options="header"] -|=== -| Server | Servlet stack | Reactive stack - -| Tomcat -| `TomcatServletWebServerFactory` -| `TomcatReactiveWebServerFactory` - -| Jetty -| `JettyServletWebServerFactory` -| `JettyReactiveWebServerFactory` - -| Undertow -| `UndertowServletWebServerFactory` -| `UndertowReactiveWebServerFactory` - -| Reactor -| N/A -| `NettyReactiveWebServerFactory` -|=== - -As a last resort, you can also declare your own `WebServerFactory` bean, which will override the one provided by Spring Boot. -When you do so, auto-configured customizers are still applied on your custom factory, so use that option carefully. - - - -[[howto.webserver.add-servlet-filter-listener]] -=== Add a Servlet, Filter, or Listener to an Application -In a servlet stack application, i.e. with the `spring-boot-starter-web`, there are two ways to add `Servlet`, `Filter`, `ServletContextListener`, and the other listeners supported by the Servlet API to your application: - -* <> -* <> - - - -[[howto.webserver.add-servlet-filter-listener.spring-bean]] -==== Add a Servlet, Filter, or Listener by Using a Spring Bean -To add a `Servlet`, `Filter`, or Servlet `*Listener` by using a Spring bean, you must provide a `@Bean` definition for it. -Doing so can be very useful when you want to inject configuration or dependencies. -However, you must be very careful that they do not cause eager initialization of too many other beans, because they have to be installed in the container very early in the application lifecycle. -(For example, it is not a good idea to have them depend on your `DataSource` or JPA configuration.) -You can work around such restrictions by initializing the beans lazily when first used instead of on initialization. - -In the case of `Filters` and `Servlets`, you can also add mappings and init parameters by adding a `FilterRegistrationBean` or a `ServletRegistrationBean` instead of or in addition to the underlying component. - -[NOTE] -==== -If no `dispatcherType` is specified on a filter registration, `REQUEST` is used. -This aligns with the Servlet Specification's default dispatcher type. -==== - -Like any other Spring bean, you can define the order of Servlet filter beans; please make sure to check the "`<>`" section. - - - -[[howto.webserver.add-servlet-filter-listener.spring-bean.disable]] -===== Disable Registration of a Servlet or Filter -As <>, any `Servlet` or `Filter` beans are registered with the servlet container automatically. -To disable registration of a particular `Filter` or `Servlet` bean, create a registration bean for it and mark it as disabled, as shown in the following example: - -[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] ----- - @Bean - public FilterRegistrationBean registration(MyFilter filter) { - FilterRegistrationBean registration = new FilterRegistrationBean(filter); - registration.setEnabled(false); - return registration; - } ----- - - - -[[howto.webserver.add-servlet-filter-listener.using-scanning]] -==== Add Servlets, Filters, and Listeners by Using Classpath Scanning -`@WebServlet`, `@WebFilter`, and `@WebListener` annotated classes can be automatically registered with an embedded servlet container by annotating a `@Configuration` class with `@ServletComponentScan` and specifying the package(s) containing the components that you want to register. -By default, `@ServletComponentScan` scans from the package of the annotated class. - - - -[[howto.webserver.configure-access-logs]] -=== Configure Access Logging -Access logs can be configured for Tomcat, Undertow, and Jetty through their respective namespaces. - -For instance, the following settings log access on Tomcat with a {tomcat-docs}/config/valve.html#Access_Logging[custom pattern]. - -[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] ----- - server: - tomcat: - basedir: "my-tomcat" - accesslog: - enabled: true - pattern: "%t %a %r %s (%D ms)" ----- - -NOTE: The default location for logs is a `logs` directory relative to the Tomcat base directory. -By default, the `logs` directory is a temporary directory, so you may want to fix Tomcat's base directory or use an absolute path for the logs. -In the preceding example, the logs are available in `my-tomcat/logs` relative to the working directory of the application. - -Access logging for Undertow can be configured in a similar fashion, as shown in the following example: - -[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] ----- - server: - undertow: - accesslog: - enabled: true - pattern: "%t %a %r %s (%D ms)" ----- - -Logs are stored in a `logs` directory relative to the working directory of the application. -You can customize this location by setting the configprop:server.undertow.accesslog.dir[] property. - -Finally, access logging for Jetty can also be configured as follows: - -[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] ----- - server: - jetty: - accesslog: - enabled: true - filename: "/var/log/jetty-access.log" ----- - -By default, logs are redirected to `System.err`. -For more details, see the Jetty documentation. - - - -[[howto.webserver.use-behind-a-proxy-server]] -=== Running Behind a Front-end Proxy Server -If your application is running behind a proxy, a load-balancer or in the cloud, the request information (like the host, port, scheme...) might change along the way. -Your application may be running on `10.10.10.10:8080`, but HTTP clients should only see `example.org`. - -https://tools.ietf.org/html/rfc7239[RFC7239 "Forwarded Headers"] defines the `Forwarded` HTTP header; proxies can use this header to provide information about the original request. -You can configure your application to read those headers and automatically use that information when creating links and sending them to clients in HTTP 302 responses, JSON documents or HTML pages. -There are also non-standard headers, like `X-Forwarded-Host`, `X-Forwarded-Port`, `X-Forwarded-Proto`, `X-Forwarded-Ssl`, and `X-Forwarded-Prefix`. - -If the proxy adds the commonly used `X-Forwarded-For` and `X-Forwarded-Proto` headers, setting `server.forward-headers-strategy` to `NATIVE` is enough to support those. -With this option, the Web servers themselves natively support this feature; you can check their specific documentation to learn about specific behavior. - -If this is not enough, Spring Framework provides a {spring-framework-docs}/web.html#filters-forwarded-headers[ForwardedHeaderFilter]. -You can register it as a Servlet Filter in your application by setting `server.forward-headers-strategy` is set to `FRAMEWORK`. - -TIP: If you are using Tomcat and terminating SSL at the proxy, configprop:server.tomcat.redirect-context-root[] should be set to `false`. -This allows the `X-Forwarded-Proto` header to be honored before any redirects are performed. - -NOTE: If your application runs in Cloud Foundry or Heroku, the configprop:server.forward-headers-strategy[] property defaults to `NATIVE`. -In all other instances, it defaults to `NONE`. - - - -[[howto.webserver.use-behind-a-proxy-server.tomcat]] -==== Customize Tomcat's Proxy Configuration -If you use Tomcat, you can additionally configure the names of the headers used to carry "`forwarded`" information, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - server: - tomcat: - remoteip: - remote-ip-header: "x-your-remote-ip-header" - protocol-header: "x-your-protocol-header" ----- - -Tomcat is also configured with a default regular expression that matches internal proxies that are to be trusted. -By default, IP addresses in `10/8`, `192.168/16`, `169.254/16` and `127/8` are trusted. -You can customize the valve's configuration by adding an entry to `application.properties`, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - server: - tomcat: - remoteip: - internal-proxies: "192\\.168\\.\\d{1,3}\\.\\d{1,3}" ----- - -NOTE: You can trust all proxies by setting the `internal-proxies` to empty (but do not do so in production). - -You can take complete control of the configuration of Tomcat's `RemoteIpValve` by switching the automatic one off (to do so, set `server.forward-headers-strategy=NONE`) and adding a new valve instance using a `WebServerFactoryCustomizer` bean. - - - -[[howto.webserver.enable-multiple-connectors-in-tomcat]] -=== Enable Multiple Connectors with Tomcat -You can add an `org.apache.catalina.connector.Connector` to the `TomcatServletWebServerFactory`, which can allow multiple connectors, including HTTP and HTTPS connectors, as shown in the following example: - -[source,java,indent=0,subs="verbatim,quotes,attributes"] ----- -include::{include-howto}/embeddedwebservers/TomcatMultipleConnectorsConfiguration.java[tag=*] ----- - - - -[[howto.webserver.use-tomcat-legacycookieprocessor]] -=== Use Tomcat's LegacyCookieProcessor -By default, the embedded Tomcat used by Spring Boot does not support "Version 0" of the Cookie format, so you may see the following error: - -[indent=0] ----- - java.lang.IllegalArgumentException: An invalid character [32] was present in the Cookie value ----- - -If at all possible, you should consider updating your code to only store values compliant with later Cookie specifications. -If, however, you cannot change the way that cookies are written, you can instead configure Tomcat to use a `LegacyCookieProcessor`. -To switch to the `LegacyCookieProcessor`, use an `WebServerFactoryCustomizer` bean that adds a `TomcatContextCustomizer`, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-howto}/embeddedwebservers/LegacyCookieProcessorConfiguration.java[tag=*] ----- - - - -[[howto.webserver.enable-tomcat-mbean-registry]] -=== Enable Tomcat's MBean Registry -Embedded Tomcat's MBean registry is disabled by default. -This minimizes Tomcat's memory footprint. -If you want to use Tomcat's MBeans, for example so that they can be used to expose metrics via Micrometer, you must use the configprop:server.tomcat.mbeanregistry.enabled[] property to do so, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- -server: - tomcat: - mbeanregistry: - enabled: true ----- - - - -[[howto.webserver.enable-multiple-listeners-in-undertow]] -=== Enable Multiple Listeners with Undertow -Add an `UndertowBuilderCustomizer` to the `UndertowServletWebServerFactory` and add a listener to the `Builder`, as shown in the following example: - -[source,java,indent=0,subs="verbatim,quotes,attributes"] ----- -include::{include-howto}/embeddedwebservers/UndertowMultipleListenersConfiguration.java[tag=*] ----- - - - -[[howto.webserver.create-websocket-endpoints-using-serverendpoint]] -=== Create WebSocket Endpoints Using @ServerEndpoint -If you want to use `@ServerEndpoint` in a Spring Boot application that used an embedded container, you must declare a single `ServerEndpointExporter` `@Bean`, as shown in the following example: - -[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] ----- - @Bean - public ServerEndpointExporter serverEndpointExporter() { - return new ServerEndpointExporter(); - } ----- - -The bean shown in the preceding example registers any `@ServerEndpoint` annotated beans with the underlying WebSocket container. -When deployed to a standalone servlet container, this role is performed by a servlet container initializer, and the `ServerEndpointExporter` bean is not required. - - - -[[howto.spring-mvc]] -== Spring MVC -Spring Boot has a number of starters that include Spring MVC. -Note that some starters include a dependency on Spring MVC rather than include it directly. -This section answers common questions about Spring MVC and Spring Boot. - - - -[[howto.spring-mvc.write-json-rest-service]] -=== Write a JSON REST Service -Any Spring `@RestController` in a Spring Boot application should render JSON response by default as long as Jackson2 is on the classpath, as shown in the following example: - -[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] ----- - @RestController - public class MyController { - - @RequestMapping("/thing") - public MyThing thing() { - return new MyThing(); - } - - } ----- - -As long as `MyThing` can be serialized by Jackson2 (true for a normal POJO or Groovy object), then `http://localhost:8080/thing` serves a JSON representation of it by default. -Note that, in a browser, you might sometimes see XML responses, because browsers tend to send accept headers that prefer XML. - - - -[[howto.spring-mvc.write-xml-rest-service]] -=== Write an XML REST Service -If you have the Jackson XML extension (`jackson-dataformat-xml`) on the classpath, you can use it to render XML responses. -The previous example that we used for JSON would work. -To use the Jackson XML renderer, add the following dependency to your project: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - com.fasterxml.jackson.dataformat - jackson-dataformat-xml - ----- - -If Jackson's XML extension is not available and JAXB is available, XML can be rendered with the additional requirement of having `MyThing` annotated as `@XmlRootElement`, as shown in the following example: - -[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] ----- - @XmlRootElement - public class MyThing { - private String name; - // .. getters and setters - } ----- - -JAXB is only available out of the box with Java 8. -If you're using a more recent Java generation, add the following dependency to your project: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - org.glassfish.jaxb - jaxb-runtime - ----- - -NOTE: To get the server to render XML instead of JSON, you might have to send an `Accept: text/xml` header (or use a browser). - - - -[[howto.spring-mvc.customize-jackson-objectmapper]] -=== Customize the Jackson ObjectMapper -Spring MVC (client and server side) uses `HttpMessageConverters` to negotiate content conversion in an HTTP exchange. -If Jackson is on the classpath, you already get the default converter(s) provided by `Jackson2ObjectMapperBuilder`, an instance of which is auto-configured for you. - -The `ObjectMapper` (or `XmlMapper` for Jackson XML converter) instance (created by default) has the following customized properties: - -* `MapperFeature.DEFAULT_VIEW_INCLUSION` is disabled -* `DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES` is disabled -* `SerializationFeature.WRITE_DATES_AS_TIMESTAMPS` is disabled - -Spring Boot also has some features to make it easier to customize this behavior. - -You can configure the `ObjectMapper` and `XmlMapper` instances by using the environment. -Jackson provides an extensive suite of on/off features that can be used to configure various aspects of its processing. -These features are described in six enums (in Jackson) that map onto properties in the environment: - -|=== -| Enum | Property | Values - -| `com.fasterxml.jackson.databind.DeserializationFeature` -| `spring.jackson.deserialization.` -| `true`, `false` - -| `com.fasterxml.jackson.core.JsonGenerator.Feature` -| `spring.jackson.generator.` -| `true`, `false` - -| `com.fasterxml.jackson.databind.MapperFeature` -| `spring.jackson.mapper.` -| `true`, `false` - -| `com.fasterxml.jackson.core.JsonParser.Feature` -| `spring.jackson.parser.` -| `true`, `false` - -| `com.fasterxml.jackson.databind.SerializationFeature` -| `spring.jackson.serialization.` -| `true`, `false` - -| `com.fasterxml.jackson.annotation.JsonInclude.Include` -| configprop:spring.jackson.default-property-inclusion[] -| `always`, `non_null`, `non_absent`, `non_default`, `non_empty` -|=== - -For example, to enable pretty print, set `spring.jackson.serialization.indent_output=true`. -Note that, thanks to the use of <>, the case of `indent_output` does not have to match the case of the corresponding enum constant, which is `INDENT_OUTPUT`. - -This environment-based configuration is applied to the auto-configured `Jackson2ObjectMapperBuilder` bean and applies to any mappers created by using the builder, including the auto-configured `ObjectMapper` bean. - -The context's `Jackson2ObjectMapperBuilder` can be customized by one or more `Jackson2ObjectMapperBuilderCustomizer` beans. -Such customizer beans can be ordered (Boot's own customizer has an order of 0), letting additional customization be applied both before and after Boot's customization. - -Any beans of type `com.fasterxml.jackson.databind.Module` are automatically registered with the auto-configured `Jackson2ObjectMapperBuilder` and are applied to any `ObjectMapper` instances that it creates. -This provides a global mechanism for contributing custom modules when you add new features to your application. - -If you want to replace the default `ObjectMapper` completely, either define a `@Bean` of that type and mark it as `@Primary` or, if you prefer the builder-based approach, define a `Jackson2ObjectMapperBuilder` `@Bean`. -Note that, in either case, doing so disables all auto-configuration of the `ObjectMapper`. - -If you provide any `@Beans` of type `MappingJackson2HttpMessageConverter`, they replace the default value in the MVC configuration. -Also, a convenience bean of type `HttpMessageConverters` is provided (and is always available if you use the default MVC configuration). -It has some useful methods to access the default and user-enhanced message converters. - -See the "`<>`" section and the {spring-boot-autoconfigure-module-code}/web/servlet/WebMvcAutoConfiguration.java[`WebMvcAutoConfiguration`] source code for more details. - - - -[[howto.spring-mvc.customize-responsebody-rendering]] -=== Customize the @ResponseBody Rendering -Spring uses `HttpMessageConverters` to render `@ResponseBody` (or responses from `@RestController`). -You can contribute additional converters by adding beans of the appropriate type in a Spring Boot context. -If a bean you add is of a type that would have been included by default anyway (such as `MappingJackson2HttpMessageConverter` for JSON conversions), it replaces the default value. -A convenience bean of type `HttpMessageConverters` is provided and is always available if you use the default MVC configuration. -It has some useful methods to access the default and user-enhanced message converters (For example, it can be useful if you want to manually inject them into a custom `RestTemplate`). - -As in normal MVC usage, any `WebMvcConfigurer` beans that you provide can also contribute converters by overriding the `configureMessageConverters` method. -However, unlike with normal MVC, you can supply only additional converters that you need (because Spring Boot uses the same mechanism to contribute its defaults). -Finally, if you opt out of the Spring Boot default MVC configuration by providing your own `@EnableWebMvc` configuration, you can take control completely and do everything manually by using `getMessageConverters` from `WebMvcConfigurationSupport`. - -See the {spring-boot-autoconfigure-module-code}/web/servlet/WebMvcAutoConfiguration.java[`WebMvcAutoConfiguration`] source code for more details. - - - -[[howto.spring-mvc.multipart-file-uploads]] -=== Handling Multipart File Uploads -Spring Boot embraces the Servlet 3 `javax.servlet.http.Part` API to support uploading files. -By default, Spring Boot configures Spring MVC with a maximum size of 1MB per file and a maximum of 10MB of file data in a single request. -You may override these values, the location to which intermediate data is stored (for example, to the `/tmp` directory), and the threshold past which data is flushed to disk by using the properties exposed in the `MultipartProperties` class. -For example, if you want to specify that files be unlimited, set the configprop:spring.servlet.multipart.max-file-size[] property to `-1`. - -The multipart support is helpful when you want to receive multipart encoded file data as a `@RequestParam`-annotated parameter of type `MultipartFile` in a Spring MVC controller handler method. - -See the {spring-boot-autoconfigure-module-code}/web/servlet/MultipartAutoConfiguration.java[`MultipartAutoConfiguration`] source for more details. - -NOTE: It is recommended to use the container's built-in support for multipart uploads rather than introducing an additional dependency such as Apache Commons File Upload. - - - -[[howto.spring-mvc.switch-off-dispatcherservlet]] -=== Switch Off the Spring MVC DispatcherServlet -By default, all content is served from the root of your application (`/`). -If you would rather map to a different path, you can configure one as follows: - -[source,yaml,indent=0,subs="verbatim",configprops,configblocks] ----- - spring: - mvc: - servlet: - path: "/acme" ----- - -If you have additional servlets you can declare a `@Bean` of type `Servlet` or `ServletRegistrationBean` for each and Spring Boot will register them transparently to the container. -Because servlets are registered that way, they can be mapped to a sub-context of the `DispatcherServlet` without invoking it. - -Configuring the `DispatcherServlet` yourself is unusual but if you really need to do it, a `@Bean` of type `DispatcherServletPath` must be provided as well to provide the path of your custom `DispatcherServlet`. - - - -[[howto.spring-mvc.switch-off-default-configuration]] -=== Switch off the Default MVC Configuration -The easiest way to take complete control over MVC configuration is to provide your own `@Configuration` with the `@EnableWebMvc` annotation. -Doing so leaves all MVC configuration in your hands. - - - -[[howto.spring-mvc.customize-view-resolvers]] -=== Customize ViewResolvers -A `ViewResolver` is a core component of Spring MVC, translating view names in `@Controller` to actual `View` implementations. -Note that `ViewResolvers` are mainly used in UI applications, rather than REST-style services (a `View` is not used to render a `@ResponseBody`). -There are many implementations of `ViewResolver` to choose from, and Spring on its own is not opinionated about which ones you should use. -Spring Boot, on the other hand, installs one or two for you, depending on what it finds on the classpath and in the application context. -The `DispatcherServlet` uses all the resolvers it finds in the application context, trying each one in turn until it gets a result. -If you add your own, you have to be aware of the order and in which position your resolver is added. - -`WebMvcAutoConfiguration` adds the following `ViewResolvers` to your context: - -* An `InternalResourceViewResolver` named '`defaultViewResolver`'. - This one locates physical resources that can be rendered by using the `DefaultServlet` (including static resources and JSP pages, if you use those). - It applies a prefix and a suffix to the view name and then looks for a physical resource with that path in the servlet context (the defaults are both empty but are accessible for external configuration through `spring.mvc.view.prefix` and `spring.mvc.view.suffix`). - You can override it by providing a bean of the same type. -* A `BeanNameViewResolver` named '`beanNameViewResolver`'. - This is a useful member of the view resolver chain and picks up any beans with the same name as the `View` being resolved. - It should not be necessary to override or replace it. -* A `ContentNegotiatingViewResolver` named '`viewResolver`' is added only if there *are* actually beans of type `View` present. - This is a composite resolver, delegating to all the others and attempting to find a match to the '`Accept`' HTTP header sent by the client. - There is a useful https://spring.io/blog/2013/06/03/content-negotiation-using-views[blog about `ContentNegotiatingViewResolver`] that you might like to study to learn more, and you might also look at the source code for detail. - You can switch off the auto-configured `ContentNegotiatingViewResolver` by defining a bean named '`viewResolver`'. -* If you use Thymeleaf, you also have a `ThymeleafViewResolver` named '`thymeleafViewResolver`'. - It looks for resources by surrounding the view name with a prefix and suffix. - The prefix is `spring.thymeleaf.prefix`, and the suffix is `spring.thymeleaf.suffix`. - The values of the prefix and suffix default to '`classpath:/templates/`' and '`.html`', respectively. - You can override `ThymeleafViewResolver` by providing a bean of the same name. -* If you use FreeMarker, you also have a `FreeMarkerViewResolver` named '`freeMarkerViewResolver`'. - It looks for resources in a loader path (which is externalized to `spring.freemarker.templateLoaderPath` and has a default value of '`classpath:/templates/`') by surrounding the view name with a prefix and a suffix. - The prefix is externalized to `spring.freemarker.prefix`, and the suffix is externalized to `spring.freemarker.suffix`. - The default values of the prefix and suffix are empty and '`.ftlh`', respectively. - You can override `FreeMarkerViewResolver` by providing a bean of the same name. -* If you use Groovy templates (actually, if `groovy-templates` is on your classpath), you also have a `GroovyMarkupViewResolver` named '`groovyMarkupViewResolver`'. - It looks for resources in a loader path by surrounding the view name with a prefix and suffix (externalized to `spring.groovy.template.prefix` and `spring.groovy.template.suffix`). - The prefix and suffix have default values of '`classpath:/templates/`' and '`.tpl`', respectively. - You can override `GroovyMarkupViewResolver` by providing a bean of the same name. -* If you use Mustache, you also have a `MustacheViewResolver` named '`mustacheViewResolver`'. - It looks for resources by surrounding the view name with a prefix and suffix. - The prefix is `spring.mustache.prefix`, and the suffix is `spring.mustache.suffix`. - The values of the prefix and suffix default to '`classpath:/templates/`' and '`.mustache`', respectively. - You can override `MustacheViewResolver` by providing a bean of the same name. - -For more detail, see the following sections: - -* {spring-boot-autoconfigure-module-code}/web/servlet/WebMvcAutoConfiguration.java[`WebMvcAutoConfiguration`] -* {spring-boot-autoconfigure-module-code}/thymeleaf/ThymeleafAutoConfiguration.java[`ThymeleafAutoConfiguration`] -* {spring-boot-autoconfigure-module-code}/freemarker/FreeMarkerAutoConfiguration.java[`FreeMarkerAutoConfiguration`] -* {spring-boot-autoconfigure-module-code}/groovy/template/GroovyTemplateAutoConfiguration.java[`GroovyTemplateAutoConfiguration`] - - - -[[howto.testing-with-spring-security]] -== Testing With Spring Security -Spring Security provides support for running tests as a specific user. -For example, the test in the snippet below will run with an authenticated user that has the `ADMIN` role. - -[source,java,pending-extract=true,indent=0] ----- - @Test - @WithMockUser(roles="ADMIN") - public void requestProtectedUrlWithUser() throws Exception { - mvc - .perform(get("/")) - ... - } ----- - -Spring Security provides comprehensive integration with Spring MVC Test and this can also be used when testing controllers using the `@WebMvcTest` slice and `MockMvc`. - -For additional details on Spring Security's testing support, refer to Spring Security's {spring-security-docs}#test[reference documentation]). - - - -[[howto.jersey]] -== Jersey - - - -[[howto.jersey.spring-security]] -=== Secure Jersey endpoints with Spring Security -Spring Security can be used to secure a Jersey-based web application in much the same way as it can be used to secure a Spring MVC-based web application. -However, if you want to use Spring Security's method-level security with Jersey, you must configure Jersey to use `setStatus(int)` rather `sendError(int)`. -This prevents Jersey from committing the response before Spring Security has had an opportunity to report an authentication or authorization failure to the client. - -The `jersey.config.server.response.setStatusOverSendError` property must be set to `true` on the application's `ResourceConfig` bean, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-howto}/jersey/JerseySetStatusOverSendErrorConfig.java[tag=*] ----- - - - -[[howto.jersey.alongside-another-web-framework]] -=== Use Jersey Alongside Another Web Framework -To use Jersey alongside another web framework, such as Spring MVC, it should be configured so that it will allow the other framework to handle requests that it cannot handle. -First, configure Jersey to use a Filter rather than a Servlet by configuring the configprop:spring.jersey.type[] application property with a value of `filter`. -Second, configure your `ResourceConfig` to forward requests that would have resulted in a 404, as shown in the following example. - -[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] ----- - @Component - public class JerseyConfig extends ResourceConfig { - - public JerseyConfig() { - register(Endpoint.class); - property(ServletProperties.FILTER_FORWARD_ON_404, true); - } - - } ----- - - - -[[howto.http-clients]] -== HTTP Clients -Spring Boot offers a number of starters that work with HTTP clients. -This section answers questions related to using them. - - - -[[howto.http-clients.rest-template-proxy-configuration]] -=== Configure RestTemplate to Use a Proxy -As described in <>, you can use a `RestTemplateCustomizer` with `RestTemplateBuilder` to build a customized `RestTemplate`. -This is the recommended approach for creating a `RestTemplate` configured to use a proxy. - -The exact details of the proxy configuration depend on the underlying client request factory that is being used. -The following example configures `HttpComponentsClientRequestFactory` with an `HttpClient` that uses a proxy for all hosts except `192.168.0.5`: - -[source,java,indent=0] ----- -include::{include-springbootfeatures}/resttemplate/RestTemplateProxyCustomizer.java[tag=*] ----- - - - -[[howto.http-clients.webclient-reactor-netty-customization]] -=== Configure the TcpClient used by a Reactor Netty-based WebClient -When Reactor Netty is on the classpath a Reactor Netty-based `WebClient` is auto-configured. -To customize the client's handling of network connections, provide a `ClientHttpConnector` bean. -The following example configures a 60 second connect timeout and adds a `ReadTimeoutHandler`: - -[source,java,indent=0] ----- -include::{include-howto}/httpclients/CustomizeReactorNettyClientConfiguration.java[tag=*] ----- - -TIP: Note the use of `ReactorResourceFactory` for the connection provider and event loop resources. -This ensures efficient sharing of resources for the server receiving requests and the client making requests. - - - -[[howto.logging]] -== Logging -Spring Boot has no mandatory logging dependency, except for the Commons Logging API, which is typically provided by Spring Framework's `spring-jcl` module. -To use https://logback.qos.ch[Logback], you need to include it and `spring-jcl` on the classpath. -The recommended way to do that is through the starters, which all depend on `spring-boot-starter-logging`. -For a web application, you need only `spring-boot-starter-web`, since it depends transitively on the logging starter. -If you use Maven, the following dependency adds logging for you: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - org.springframework.boot - spring-boot-starter-web - ----- - -Spring Boot has a `LoggingSystem` abstraction that attempts to configure logging based on the content of the classpath. -If Logback is available, it is the first choice. - -If the only change you need to make to logging is to set the levels of various loggers, you can do so in `application.properties` by using the "logging.level" prefix, as shown in the following example: - -[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] ----- - logging: - level: - org.springframework.web: "debug" - org.hibernate: "error" ----- - -You can also set the location of a file to which to write the log (in addition to the console) by using `logging.file.name`. - -To configure the more fine-grained settings of a logging system, you need to use the native configuration format supported by the `LoggingSystem` in question. -By default, Spring Boot picks up the native configuration from its default location for the system (such as `classpath:logback.xml` for Logback), but you can set the location of the config file by using the configprop:logging.config[] property. - - - -[[howto.logging.logback]] -=== Configure Logback for Logging -If you need to apply customizations to logback beyond those that can be achieved with `application.properties`, you'll need to add a standard logback configuration file. -You can add a `logback.xml` file to the root of your classpath for logback to find. -You can also use `logback-spring.xml` if you want to use the <>. - -TIP: The Logback documentation has a https://logback.qos.ch/manual/configuration.html[dedicated section that covers configuration] in some detail. - -Spring Boot provides a number of logback configurations that be `included` from your own configuration. -These includes are designed to allow certain common Spring Boot conventions to be re-applied. - -The following files are provided under `org/springframework/boot/logging/logback/`: - -* `defaults.xml` - Provides conversion rules, pattern properties and common logger configurations. -* `console-appender.xml` - Adds a `ConsoleAppender` using the `CONSOLE_LOG_PATTERN`. -* `file-appender.xml` - Adds a `RollingFileAppender` using the `FILE_LOG_PATTERN` and `ROLLING_FILE_NAME_PATTERN` with appropriate settings. - -In addition, a legacy `base.xml` file is provided for compatibility with earlier versions of Spring Boot. - -A typical custom `logback.xml` file would look something like this: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - - - - - - - - ----- - -Your logback configuration file can also make use of System properties that the `LoggingSystem` takes care of creating for you: - -* `$\{PID}`: The current process ID. -* `$\{LOG_FILE}`: Whether `logging.file.name` was set in Boot's external configuration. -* `$\{LOG_PATH}`: Whether `logging.file.path` (representing a directory for log files to live in) was set in Boot's external configuration. -* `$\{LOG_EXCEPTION_CONVERSION_WORD}`: Whether `logging.exception-conversion-word` was set in Boot's external configuration. -* `$\{ROLLING_FILE_NAME_PATTERN}`: Whether `logging.pattern.rolling-file-name` was set in Boot's external configuration. - -Spring Boot also provides some nice ANSI color terminal output on a console (but not in a log file) by using a custom Logback converter. -See the `CONSOLE_LOG_PATTERN` in the `defaults.xml` configuration for an example. - -If Groovy is on the classpath, you should be able to configure Logback with `logback.groovy` as well. -If present, this setting is given preference. - -NOTE: Spring extensions are not supported with Groovy configuration. -Any `logback-spring.groovy` files will not be detected. - - - -[[howto.logging.logback.file-only-output]] -==== Configure Logback for File-only Output -If you want to disable console logging and write output only to a file, you need a custom `logback-spring.xml` that imports `file-appender.xml` but not `console-appender.xml`, as shown in the following example: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - - - - - - - - ----- - -You also need to add `logging.file.name` to your `application.properties` or `application.yaml`, as shown in the following example: - -[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] ----- - logging: - file: - name: "myapplication.log" ----- - - - -[[howto.logging.log4j]] -=== Configure Log4j for Logging -Spring Boot supports https://logging.apache.org/log4j/2.x/[Log4j 2] for logging configuration if it is on the classpath. -If you use the starters for assembling dependencies, you have to exclude Logback and then include log4j 2 instead. -If you do not use the starters, you need to provide (at least) `spring-jcl` in addition to Log4j 2. - -The recommended path is through the starters, even though it requires some jiggling. -The following example shows how to set up the starters in Maven: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - org.springframework.boot - spring-boot-starter-web - - - org.springframework.boot - spring-boot-starter - - - org.springframework.boot - spring-boot-starter-logging - - - - - org.springframework.boot - spring-boot-starter-log4j2 - ----- - -And the following example shows one way to set up the starters in Gradle: - -[source,groovy,indent=0,subs="verbatim,quotes,attributes"] ----- - dependencies { - compile 'org.springframework.boot:spring-boot-starter-web' - } - - configurations.all { - resolutionStrategy.dependencySubstitution.all { dependency -> - if (dependency.requested instanceof ModuleComponentSelector && dependency.requested.module == 'spring-boot-starter-logging') { - dependency.useTarget("org.springframework.boot:spring-boot-starter-log4j2:$dependency.requested.version", 'Use Log4j2 instead of Logback') - } - } - } -} ----- - -NOTE: The Log4j starters gather together the dependencies for common logging requirements (such as having Tomcat use `java.util.logging` but configuring the output using Log4j 2). - -NOTE: To ensure that debug logging performed using `java.util.logging` is routed into Log4j 2, configure its https://logging.apache.org/log4j/2.x/log4j-jul/index.html[JDK logging adapter] by setting the `java.util.logging.manager` system property to `org.apache.logging.log4j.jul.LogManager`. - - - -[[howto.logging.log4j.yaml-or-json-config]] -==== Use YAML or JSON to Configure Log4j 2 -In addition to its default XML configuration format, Log4j 2 also supports YAML and JSON configuration files. -To configure Log4j 2 to use an alternative configuration file format, add the appropriate dependencies to the classpath and name your configuration files to match your chosen file format, as shown in the following example: - -[cols="10,75a,15a"] -|=== -| Format | Dependencies | File names - -|YAML -| `com.fasterxml.jackson.core:jackson-databind` + `com.fasterxml.jackson.dataformat:jackson-dataformat-yaml` -| `log4j2.yaml` + `log4j2.yml` - -|JSON -| `com.fasterxml.jackson.core:jackson-databind` -| `log4j2.json` + `log4j2.jsn` -|=== - - - -[[howto.data-access]] -== Data Access -Spring Boot includes a number of starters for working with data sources. -This section answers questions related to doing so. - - - -[[howto.data-access.configure-custom-datasource]] -=== Configure a Custom DataSource -To configure your own `DataSource`, define a `@Bean` of that type in your configuration. -Spring Boot reuses your `DataSource` anywhere one is required, including database initialization. -If you need to externalize some settings, you can bind your `DataSource` to the environment (see "`<>`"). - -The following example shows how to define a data source in a bean: - -[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] ----- - @Bean - @ConfigurationProperties(prefix="app.datasource") - public DataSource dataSource() { - return new FancyDataSource(); - } ----- - -The following example shows how to define a data source by setting properties: - -[source,yaml,indent=0,configblocks] ----- - app: - datasource: - url: "jdbc:h2:mem:mydb" - username: "sa" - pool-size: 30 ----- - -Assuming that your `FancyDataSource` has regular JavaBean properties for the URL, the username, and the pool size, these settings are bound automatically before the `DataSource` is made available to other components. - -Spring Boot also provides a utility builder class, called `DataSourceBuilder`, that can be used to create one of the standard data sources (if it is on the classpath). -The builder can detect the one to use based on what's available on the classpath. -It also auto-detects the driver based on the JDBC URL. - -The following example shows how to create a data source by using a `DataSourceBuilder`: - -[source,java,indent=0,subs="verbatim,quotes,attributes"] ----- -include::{include-howto}/dataaccess/BasicDataSourceConfiguration.java[tag=*] ----- - -To run an app with that `DataSource`, all you need is the connection information. -Pool-specific settings can also be provided. -Check the implementation that is going to be used at runtime for more details. - -The following example shows how to define a JDBC data source by setting properties: - -[source,yaml,indent=0,configblocks] ----- - app: - datasource: - url: "jdbc:mysql://localhost/test" - username: "dbuser" - password: "dbpass" - pool-size: 30 ----- - -However, there is a catch. -Because the actual type of the connection pool is not exposed, no keys are generated in the metadata for your custom `DataSource` and no completion is available in your IDE (because the `DataSource` interface exposes no properties). -Also, if you happen to have Hikari on the classpath, this basic setup does not work, because Hikari has no `url` property (but does have a `jdbcUrl` property). -In that case, you must rewrite your configuration as follows: - -[source,yaml,indent=0,configblocks] ----- - app: - datasource: - jdbc-url: "jdbc:mysql://localhost/test" - username: "dbuser" - password: "dbpass" - pool-size: 30 ----- - -You can fix that by forcing the connection pool to use and return a dedicated implementation rather than `DataSource`. -You cannot change the implementation at runtime, but the list of options will be explicit. - -The following example shows how create a `HikariDataSource` with `DataSourceBuilder`: - -[source,java,indent=0,subs="verbatim,quotes,attributes"] ----- -include::{include-howto}/dataaccess/SimpleDataSourceConfiguration.java[tag=*] ----- - -You can even go further by leveraging what `DataSourceProperties` does for you -- that is, by providing a default embedded database with a sensible username and password if no URL is provided. -You can easily initialize a `DataSourceBuilder` from the state of any `DataSourceProperties` object, so you could also inject the DataSource that Spring Boot creates automatically. -However, that would split your configuration into two namespaces: `url`, `username`, `password`, `type`, and `driver` on `spring.datasource` and the rest on your custom namespace (`app.datasource`). -To avoid that, you can redefine a custom `DataSourceProperties` on your custom namespace, as shown in the following example: - -[source,java,indent=0,subs="verbatim,quotes,attributes"] ----- -include::{include-howto}/dataaccess/ConfigurableDataSourceConfiguration.java[tag=*] ----- - -This setup puts you _in sync_ with what Spring Boot does for you by default, except that a dedicated connection pool is chosen (in code) and its settings are exposed in the `app.datasource.configuration` sub namespace. -Because `DataSourceProperties` is taking care of the `url`/`jdbcUrl` translation for you, you can configure it as follows: - -[source,yaml,indent=0,configblocks] ----- - app: - datasource: - url: "jdbc:mysql://localhost/test" - username: "dbuser" - password: "dbpass" - configuration: - maximum-pool-size: 30 ----- - -TIP: Spring Boot will expose Hikari-specific settings to `spring.datasource.hikari`. -This example uses a more generic `configuration` sub namespace as the example does not support multiple datasource implementations. - -NOTE: Because your custom configuration chooses to go with Hikari, `app.datasource.type` has no effect. -In practice, the builder is initialized with whatever value you might set there and then overridden by the call to `.type()`. - -See "`<>`" in the "`Spring Boot features`" section and the {spring-boot-autoconfigure-module-code}/jdbc/DataSourceAutoConfiguration.java[`DataSourceAutoConfiguration`] class for more details. - - - -[[howto.data-access.configure-two-datasources]] -=== Configure Two DataSources -If you need to configure multiple data sources, you can apply the same tricks that are described in the previous section. -You must, however, mark one of the `DataSource` instances as `@Primary`, because various auto-configurations down the road expect to be able to get one by type. - -If you create your own `DataSource`, the auto-configuration backs off. -In the following example, we provide the _exact_ same feature set as the auto-configuration provides on the primary data source: - -[source,java,indent=0,subs="verbatim,quotes,attributes"] ----- -include::{include-howto}/dataaccess/SimpleDataSourcesConfiguration.java[tag=*] ----- - -TIP: `firstDataSourceProperties` has to be flagged as `@Primary` so that the database initializer feature uses your copy (if you use the initializer). - -Both data sources are also bound for advanced customizations. -For instance, you could configure them as follows: - -[source,yaml,indent=0,configblocks] ----- - app: - datasource: - first: - url: "jdbc:mysql://localhost/first" - username: "dbuser" - password: "dbpass" - configuration: - maximum-pool-size: 30 - - second: - url: "jdbc:mysql://localhost/second" - username: "dbuser" - password: "dbpass" - max-total: 30 ----- - -You can apply the same concept to the secondary `DataSource` as well, as shown in the following example: - -[source,java,indent=0,subs="verbatim,quotes,attributes"] ----- -include::{include-howto}/dataaccess/CompleteDataSourcesConfiguration.java[tag=*] ----- - -The preceding example configures two data sources on custom namespaces with the same logic as Spring Boot would use in auto-configuration. -Note that each `configuration` sub namespace provides advanced settings based on the chosen implementation. - - - -[[howto.data-access.spring-data-repositories]] -=== Use Spring Data Repositories -Spring Data can create implementations of `@Repository` interfaces of various flavors. -Spring Boot handles all of that for you, as long as those `@Repositories` are included in the same package (or a sub-package) of your `@EnableAutoConfiguration` class. - -For many applications, all you need is to put the right Spring Data dependencies on your classpath. -There is a `spring-boot-starter-data-jpa` for JPA, `spring-boot-starter-data-mongodb` for Mongodb, etc. -To get started, create some repository interfaces to handle your `@Entity` objects. - -Spring Boot tries to guess the location of your `@Repository` definitions, based on the `@EnableAutoConfiguration` it finds. -To get more control, use the `@EnableJpaRepositories` annotation (from Spring Data JPA). - -For more about Spring Data, see the {spring-data}[Spring Data project page]. - - - -[[howto.data-access.separate-entity-definitions-from-spring-configuration]] -=== Separate @Entity Definitions from Spring Configuration -Spring Boot tries to guess the location of your `@Entity` definitions, based on the `@EnableAutoConfiguration` it finds. -To get more control, you can use the `@EntityScan` annotation, as shown in the following example: - -[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] ----- - @Configuration(proxyBeanMethods = false) - @EnableAutoConfiguration - @EntityScan(basePackageClasses=City.class) - public class Application { - - //... - - } ----- - - - -[[howto.data-access.jpa-properties]] -=== Configure JPA Properties -Spring Data JPA already provides some vendor-independent configuration options (such as those for SQL logging), and Spring Boot exposes those options and a few more for Hibernate as external configuration properties. -Some of them are automatically detected according to the context so you should not have to set them. - -The `spring.jpa.hibernate.ddl-auto` is a special case, because, depending on runtime conditions, it has different defaults. -If an embedded database is used and no schema manager (such as Liquibase or Flyway) is handling the `DataSource`, it defaults to `create-drop`. -In all other cases, it defaults to `none`. - -The dialect to use is detected by the JPA provider. -If you prefer to set the dialect yourself, set the configprop:spring.jpa.database-platform[] property. - -The most common options to set are shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - jpa: - hibernate: - naming: - physical-strategy: "com.example.MyPhysicalNamingStrategy" - show-sql: true ----- - -In addition, all properties in `+spring.jpa.properties.*+` are passed through as normal JPA properties (with the prefix stripped) when the local `EntityManagerFactory` is created. - -[WARNING] -==== -You need to ensure that names defined under `+spring.jpa.properties.*+` exactly match those expected by your JPA provider. -Spring Boot will not attempt any kind of relaxed binding for these entries. - -For example, if you want to configure Hibernate's batch size you must use `+spring.jpa.properties.hibernate.jdbc.batch_size+`. -If you use other forms, such as `batchSize` or `batch-size`, Hibernate will not apply the setting. -==== - -TIP: If you need to apply advanced customization to Hibernate properties, consider registering a `HibernatePropertiesCustomizer` bean that will be invoked prior to creating the `EntityManagerFactory`. -This takes precedence to anything that is applied by the auto-configuration. - - - -[[howto.data-access.configure-hibernate-naming-strategy]] -=== Configure Hibernate Naming Strategy -Hibernate uses {hibernate-docs}#naming[two different naming strategies] to map names from the object model to the corresponding database names. -The fully qualified class name of the physical and the implicit strategy implementations can be configured by setting the `spring.jpa.hibernate.naming.physical-strategy` and `spring.jpa.hibernate.naming.implicit-strategy` properties, respectively. -Alternatively, if `ImplicitNamingStrategy` or `PhysicalNamingStrategy` beans are available in the application context, Hibernate will be automatically configured to use them. - -By default, Spring Boot configures the physical naming strategy with `SpringPhysicalNamingStrategy`. -This implementation provides the same table structure as Hibernate 4: all dots are replaced by underscores and camel casing is replaced by underscores as well. Additionally, by default, all table names are generated in lower case. For example, a `TelephoneNumber` entity is mapped to the `telephone_number` table. If your schema requires mixed-case identifiers, define a custom `SpringPhysicalNamingStrategy` bean, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-howto}/dataaccess/CaseSensitiveSpringPhysicalNamingStrategyConfiguration.java[tag=*] ----- - -If you prefer to use Hibernate 5's default instead, set the following property: - -[indent=0,subs="verbatim,quotes,attributes"] ----- - spring.jpa.hibernate.naming.physical-strategy=org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl ----- - -Alternatively, you can configure the following bean: - -[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] ----- - @Bean - public PhysicalNamingStrategy physicalNamingStrategy() { - return new PhysicalNamingStrategyStandardImpl(); - } ----- - -See {spring-boot-autoconfigure-module-code}/orm/jpa/HibernateJpaAutoConfiguration.java[`HibernateJpaAutoConfiguration`] and {spring-boot-autoconfigure-module-code}/orm/jpa/JpaBaseConfiguration.java[`JpaBaseConfiguration`] for more details. - - - -[[howto.data-access.configure-hibernate-second-level-caching]] -=== Configure Hibernate Second-Level Caching -Hibernate {hibernate-docs}#caching[second-level cache] can be configured for a range of cache providers. -Rather than configuring Hibernate to lookup the cache provider again, it is better to provide the one that is available in the context whenever possible. - -To do this with JCache, first make sure that `org.hibernate:hibernate-jcache` is available on the classpath. -Then, add a `HibernatePropertiesCustomizer` bean as shown in the following example: - -[source,java,indent=0] ----- -include::{include-howto}/dataaccess/HibernateSecondLevelCacheConfiguration.java[tag=*] ----- - -This customizer will configure Hibernate to use the same `CacheManager` as the one that the application uses. -It is also possible to use separate `CacheManager` instances. -For details, refer to {hibernate-docs}#caching-provider-jcache[the Hibernate user guide]. - - - -[[howto.data-access.dependency-injection-in-hibernate-components]] -=== Use Dependency Injection in Hibernate Components -By default, Spring Boot registers a `BeanContainer` implementation that uses the `BeanFactory` so that converters and entity listeners can use regular dependency injection. - -You can disable or tune this behaviour by registering a `HibernatePropertiesCustomizer` that removes or changes the `hibernate.resource.beans.container` property. - - - -[[howto.data-access.use-custom-entity-manager]] -=== Use a Custom EntityManagerFactory -To take full control of the configuration of the `EntityManagerFactory`, you need to add a `@Bean` named '`entityManagerFactory`'. -Spring Boot auto-configuration switches off its entity manager in the presence of a bean of that type. - - - -[[howto.data-access.use-multiple-entity-managers]] -[[howto.data-access.use-multiple-entity-managers]] -=== Using Multiple EntityManagerFactories -If you need to use JPA against multiple data sources, you likely need one `EntityManagerFactory` per data source. -The `LocalContainerEntityManagerFactoryBean` from Spring ORM allows you to configure an `EntityManagerFactory` for your needs. -You can also reuse `JpaProperties` to bind settings for each `EntityManagerFactory`, as shown in the following example: - -[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] ----- -include::{include-howto}/dataaccess/CustomEntityManagerFactoryExample.java[tag=*] ----- - -The example above creates an `EntityManagerFactory` using a `DataSource` bean named `firstDataSource`. -It scans entities located in the same package as `Order`. -It is possible to map additional JPA properties using the `app.first.jpa` namespace. - -NOTE: When you create a bean for `LocalContainerEntityManagerFactoryBean` yourself, any customization that was applied during the creation of the auto-configured `LocalContainerEntityManagerFactoryBean` is lost. -For example, in case of Hibernate, any properties under the `spring.jpa.hibernate` prefix will not be automatically applied to your `LocalContainerEntityManagerFactoryBean`. -If you were relying on these properties for configuring things like the naming strategy or the DDL mode, you will need to explicitly configure that when creating the `LocalContainerEntityManagerFactoryBean` bean. - -You should provide a similar configuration for any additional data sources for which you need JPA access. -To complete the picture, you need to configure a `JpaTransactionManager` for each `EntityManagerFactory` as well. -Alternatively, you might be able to use a JTA transaction manager that spans both. - -If you use Spring Data, you need to configure `@EnableJpaRepositories` accordingly, as shown in the following example: - -[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] ----- - @Configuration(proxyBeanMethods = false) - @EnableJpaRepositories(basePackageClasses = Order.class, - entityManagerFactoryRef = "firstEntityManagerFactory") - public class OrderConfiguration { - ... - } - - @Configuration(proxyBeanMethods = false) - @EnableJpaRepositories(basePackageClasses = Customer.class, - entityManagerFactoryRef = "secondEntityManagerFactory") - public class CustomerConfiguration { - ... - } ----- - - - -[[howto.data-access.use-traditional-persistence-xml]] -=== Use a Traditional persistence.xml File -Spring Boot will not search for or use a `META-INF/persistence.xml` by default. -If you prefer to use a traditional `persistence.xml`, you need to define your own `@Bean` of type `LocalEntityManagerFactoryBean` (with an ID of '`entityManagerFactory`') and set the persistence unit name there. - -See {spring-boot-autoconfigure-module-code}/orm/jpa/JpaBaseConfiguration.java[`JpaBaseConfiguration`] for the default settings. - - - -[[howto.data-access.use-spring-data-jpa-and-mongo-repositories]] -=== Use Spring Data JPA and Mongo Repositories -Spring Data JPA and Spring Data Mongo can both automatically create `Repository` implementations for you. -If they are both present on the classpath, you might have to do some extra configuration to tell Spring Boot which repositories to create. -The most explicit way to do that is to use the standard Spring Data `+@EnableJpaRepositories+` and `+@EnableMongoRepositories+` annotations and provide the location of your `Repository` interfaces. - -There are also flags (`+spring.data.*.repositories.enabled+` and `+spring.data.*.repositories.type+`) that you can use to switch the auto-configured repositories on and off in external configuration. -Doing so is useful, for instance, in case you want to switch off the Mongo repositories and still use the auto-configured `MongoTemplate`. - -The same obstacle and the same features exist for other auto-configured Spring Data repository types (Elasticsearch, Solr, and others). -To work with them, change the names of the annotations and flags accordingly. - - - -[[howto.data-access.customize-spring-data-web-support]] -=== Customize Spring Data's Web Support -Spring Data provides web support that simplifies the use of Spring Data repositories in a web application. -Spring Boot provides properties in the `spring.data.web` namespace for customizing its configuration. -Note that if you are using Spring Data REST, you must use the properties in the `spring.data.rest` namespace instead. - - - -[[howto.data-access.exposing-spring-data-repositories-as-rest]] -=== Expose Spring Data Repositories as REST Endpoint -Spring Data REST can expose the `Repository` implementations as REST endpoints for you, -provided Spring MVC has been enabled for the application. - -Spring Boot exposes a set of useful properties (from the `spring.data.rest` namespace) that customize the {spring-data-rest-api}/core/config/RepositoryRestConfiguration.html[`RepositoryRestConfiguration`]. -If you need to provide additional customization, you should use a {spring-data-rest-api}/webmvc/config/RepositoryRestConfigurer.html[`RepositoryRestConfigurer`] bean. - -NOTE: If you do not specify any order on your custom `RepositoryRestConfigurer`, it runs after the one Spring Boot uses internally. -If you need to specify an order, make sure it is higher than 0. - - - -[[howto.data-access.configure-a-component-that-is-used-by-jpa]] -=== Configure a Component that is Used by JPA -If you want to configure a component that JPA uses, then you need to ensure that the component is initialized before JPA. -When the component is auto-configured, Spring Boot takes care of this for you. -For example, when Flyway is auto-configured, Hibernate is configured to depend upon Flyway so that Flyway has a chance to initialize the database before Hibernate tries to use it. - -If you are configuring a component yourself, you can use an `EntityManagerFactoryDependsOnPostProcessor` subclass as a convenient way of setting up the necessary dependencies. -For example, if you use Hibernate Search with Elasticsearch as its index manager, any `EntityManagerFactory` beans must be configured to depend on the `elasticsearchClient` bean, as shown in the following example: - -[source,java,indent=0] ----- -include::{include-howto}/dataaccess/ElasticsearchEntityManagerFactoryDependsOnPostProcessor.java[tag=*] ----- - - - -[[howto.data-access.configure-jooq-with-multiple-datasources]] -=== Configure jOOQ with Two DataSources -If you need to use jOOQ with multiple data sources, you should create your own `DSLContext` for each one. -Refer to {spring-boot-autoconfigure-module-code}/jooq/JooqAutoConfiguration.java[JooqAutoConfiguration] for more details. - -TIP: In particular, `JooqExceptionTranslator` and `SpringTransactionProvider` can be reused to provide similar features to what the auto-configuration does with a single `DataSource`. - - - -[[howto.data-initialization]] -== Database Initialization -An SQL database can be initialized in different ways depending on what your stack is. -Of course, you can also do it manually, provided the database is a separate process. -It is recommended to use a single mechanism for schema generation. - - - -[[howto.data-initialization.using-jpa]] -=== Initialize a Database Using JPA -JPA has features for DDL generation, and these can be set up to run on startup against the database. -This is controlled through two external properties: - -* `spring.jpa.generate-ddl` (boolean) switches the feature on and off and is vendor independent. -* `spring.jpa.hibernate.ddl-auto` (enum) is a Hibernate feature that controls the behavior in a more fine-grained way. - This feature is described in more detail later in this guide. - - - -[[howto.data-initialization.using-hibernate]] -=== Initialize a Database Using Hibernate -You can set `spring.jpa.hibernate.ddl-auto` explicitly and the standard Hibernate property values are `none`, `validate`, `update`, `create`, and `create-drop`. -Spring Boot chooses a default value for you based on whether it thinks your database is embedded. -It defaults to `create-drop` if no schema manager has been detected or `none` in all other cases. -An embedded database is detected by looking at the `Connection` type and JDBC url. -`hsqldb`, `h2`, and `derby` are candidates, and others are not. -Be careful when switching from in-memory to a '`real`' database that you do not make assumptions about the existence of the tables and data in the new platform. -You either have to set `ddl-auto` explicitly or use one of the other mechanisms to initialize the database. - -NOTE: You can output the schema creation by enabling the `org.hibernate.SQL` logger. -This is done for you automatically if you enable the <>. - -In addition, a file named `import.sql` in the root of the classpath is executed on startup if Hibernate creates the schema from scratch (that is, if the `ddl-auto` property is set to `create` or `create-drop`). -This can be useful for demos and for testing if you are careful but is probably not something you want to be on the classpath in production. -It is a Hibernate feature (and has nothing to do with Spring). - - - -[[howto.data-initialization.using-basic-sql-scripts]] -=== Initialize a Database Using Basic SQL Scripts -Spring Boot can automatically create the schema (DDL scripts) of your JDBC `DataSource` or R2DBC `ConnectionFactory` and initialize it (DML scripts). -It loads SQL from the standard root classpath locations: `schema.sql` and `data.sql`, respectively. -In addition, Spring Boot processes the `schema-$\{platform}.sql` and `data-$\{platform}.sql` files (if present), where `platform` is the value of configprop:spring.sql.init.platform[]. -This allows you to switch to database-specific scripts if necessary. -For example, you might choose to set it to the vendor name of the database (`hsqldb`, `h2`, `oracle`, `mysql`, `postgresql`, and so on). -SQL database initialization can be disabled by setting configprop:spring.sql.init.enabled[] to `false`. -By default, Spring Boot enables the fail-fast feature of its script-based database initializer. -This means that, if the scripts cause exceptions, the application fails to start. -You can tune that behavior by setting configprop:spring.sql.init.continue-on-error[]. - -Script-based `DataSource` initialization is performed, by default, before any JPA `EntityManagerFactory` beans are created. -`schema.sql` can be used to create the schema for JPA-managed entities and `data.sql` can be used to populate it. -While we do not recommend using multiple data source initialization technologies, if you want script-based `DataSource` initialization to be able to build upon the schema creation performed by Hibernate, set configprop:spring.jpa.defer-datasource-initialization[] to `true`. -This will defer data source initialization until after any `EntityManagerFactory` beans have been created and initialized. -`schema.sql` can then be used to make additions to any schema creation performed by Hibernate and `data.sql` can be used to populate it. - -If you are using a <>, like Flyway or Liquibase, you should use them alone to create and initialize the schema. -Using the basic `schema.sql` and `data.sql` scripts alongside Flyway or Liquibase is not recommended and support will be removed in a future release. - - - -[[howto.data-initialization.batch]] -=== Initialize a Spring Batch Database -If you use Spring Batch, it comes pre-packaged with SQL initialization scripts for most popular database platforms. -Spring Boot can detect your database type and execute those scripts on startup. -If you use an embedded database, this happens by default. -You can also enable it for any database type, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - batch: - jdbc: - initialize-schema: "always" ----- - -You can also switch off the initialization explicitly by setting `spring.batch.jdbc.initialize-schema` to `never`. - - - -[[howto.data-initialization.migration-tool]] -=== Use a Higher-level Database Migration Tool -Spring Boot supports two higher-level migration tools: https://flywaydb.org/[Flyway] and https://www.liquibase.org/[Liquibase]. - - - -[[howto.data-initialization.migration-tool.flyway]] -==== Execute Flyway Database Migrations on Startup -To automatically run Flyway database migrations on startup, add the `org.flywaydb:flyway-core` to your classpath. - -Typically, migrations are scripts in the form `V__.sql` (with `` an underscore-separated version, such as '`1`' or '`2_1`'). -By default, they are in a directory called `classpath:db/migration`, but you can modify that location by setting `spring.flyway.locations`. -This is a comma-separated list of one or more `classpath:` or `filesystem:` locations. -For example, the following configuration would search for scripts in both the default classpath location and the `/opt/migration` directory: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - flyway: - locations: "classpath:db/migration,filesystem:/opt/migration" ----- - -You can also add a special `\{vendor}` placeholder to use vendor-specific scripts. -Assume the following: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - flyway: - locations: "classpath:db/migration/{vendor}" ----- - -Rather than using `db/migration`, the preceding configuration sets the directory to use according to the type of the database (such as `db/migration/mysql` for MySQL). -The list of supported databases is available in {spring-boot-module-code}/jdbc/DatabaseDriver.java[`DatabaseDriver`]. - -Migrations can also be written in Java. -Flyway will be auto-configured with any beans that implement `JavaMigration`. - -{spring-boot-autoconfigure-module-code}/flyway/FlywayProperties.java[`FlywayProperties`] provides most of Flyway's settings and a small set of additional properties that can be used to disable the migrations or switch off the location checking. -If you need more control over the configuration, consider registering a `FlywayConfigurationCustomizer` bean. - -Spring Boot calls `Flyway.migrate()` to perform the database migration. -If you would like more control, provide a `@Bean` that implements {spring-boot-autoconfigure-module-code}/flyway/FlywayMigrationStrategy.java[`FlywayMigrationStrategy`]. - -Flyway supports SQL and Java https://flywaydb.org/documentation/concepts/callbacks[callbacks]. -To use SQL-based callbacks, place the callback scripts in the `classpath:db/migration` directory. -To use Java-based callbacks, create one or more beans that implement `Callback`. -Any such beans are automatically registered with `Flyway`. -They can be ordered by using `@Order` or by implementing `Ordered`. -Beans that implement the deprecated `FlywayCallback` interface can also be detected, however they cannot be used alongside `Callback` beans. - -By default, Flyway autowires the (`@Primary`) `DataSource` in your context and uses that for migrations. -If you like to use a different `DataSource`, you can create one and mark its `@Bean` as `@FlywayDataSource`. -If you do so and want two data sources, remember to create another one and mark it as `@Primary`. -Alternatively, you can use Flyway's native `DataSource` by setting `spring.flyway.[url,user,password]` in external properties. -Setting either `spring.flyway.url` or `spring.flyway.user` is sufficient to cause Flyway to use its own `DataSource`. -If any of the three properties has not been set, the value of its equivalent `spring.datasource` property will be used. - -You can also use Flyway to provide data for specific scenarios. -For example, you can place test-specific migrations in `src/test/resources` and they are run only when your application starts for testing. -Also, you can use profile-specific configuration to customize `spring.flyway.locations` so that certain migrations run only when a particular profile is active. -For example, in `application-dev.properties`, you might specify the following setting: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - flyway: - locations: "classpath:/db/migration,classpath:/dev/db/migration" ----- - -With that setup, migrations in `dev/db/migration` run only when the `dev` profile is active. - - - -[[howto.data-initialization.migration-tool.liquibase]] -==== Execute Liquibase Database Migrations on Startup -To automatically run Liquibase database migrations on startup, add the `org.liquibase:liquibase-core` to your classpath. - -[NOTE] -==== -When you add the `org.liquibase:liquibase-core` to your classpath, database migrations run by default for both during application startup and before your tests run. -This behavior can be customized by using the configprop:spring.liquibase.enabled[] property, setting different values in the `main` and `test` configurations. -It is not possible to use two different ways to initialize the database (e.g. Liquibase for application startup, JPA for test runs). -==== - -By default, the master change log is read from `db/changelog/db.changelog-master.yaml`, but you can change the location by setting `spring.liquibase.change-log`. -In addition to YAML, Liquibase also supports JSON, XML, and SQL change log formats. - -By default, Liquibase autowires the (`@Primary`) `DataSource` in your context and uses that for migrations. -If you need to use a different `DataSource`, you can create one and mark its `@Bean` as `@LiquibaseDataSource`. -If you do so and you want two data sources, remember to create another one and mark it as `@Primary`. -Alternatively, you can use Liquibase's native `DataSource` by setting `spring.liquibase.[driver-class-name,url,user,password]` in external properties. -Setting either `spring.liquibase.url` or `spring.liquibase.user` is sufficient to cause Liquibase to use its own `DataSource`. -If any of the three properties has not been set, the value of its equivalent `spring.datasource` property will be used. - -See {spring-boot-autoconfigure-module-code}/liquibase/LiquibaseProperties.java[`LiquibaseProperties`] for details about available settings such as contexts, the default schema, and others. - - - -[[howto.data-initialization.dependencies]] -=== Depend Upon an Initialized Database -Database initialization is performed while the application is starting up as part of application context refresh. -To allow an initialized database to be accessed during startup, beans that act as database initializers and beans that require that database to have been initialized are detected automatically. -Beans whose initialization depends upon the database having been initialized are configured to depend upon those that initialize it. -If, during startup, your application tries to access the database and it has not been initialized, you can configure additional detection of beans that initialize the database and require the database to have been initialized. - - - -[[howto.data-initialization.dependencies.initializer-detection]] -==== Detect a Database Initializer -Spring Boot will automatically detect beans of the following types that initialize an SQL database: - -- `DataSourceScriptDatabaseInitializer` -- `EntityManagerFactory` -- `Flyway` -- `FlywayMigrationInitializer` -- `R2dbcScriptDatabaseInitializer` -- `SpringLiquibase` - -If you are using a third-party starter for a database initialization library, it may provide a detector such that beans of other types are also detected automatically. -To have other beans be detected, register an implementation of `DatabaseInitializerDetector` in `META-INF/spring-factories`. - - - -[[howto.data-initialization.dependencies.depends-on-initialization-detection]] -==== Detect a Bean That Depends On Database Initialization -Spring Boot will automatically detect beans of the following types that depends upon database initialization: - -- `AbstractEntityManagerFactoryBean` (unless configprop:spring.jpa.defer-datasource-initialization[] is set to `true`) -- `DSLContext` (jOOQ) -- `EntityManagerFactory` (unless configprop:spring.jpa.defer-datasource-initialization[] is set to `true`) -- `JdbcOperations` -- `NamedParameterJdbcOperations` - -If you are using a third-party starter data access library, it may provide a detector such that beans of other types are also detected automatically. -To have other beans be detected, register an implementation of `DependsOnDatabaseInitializationDetector` in `META-INF/spring-factories`. -Alternatively, annotate the bean's class or its `@Bean` method with `@DependsOnDatabaseInitialization`. - - - -[[howto.messaging]] -== Messaging -Spring Boot offers a number of starters that include messaging. -This section answers questions that arise from using messaging with Spring Boot. - - - -[[howto.messaging.disable-transacted-jms-session]] -=== Disable Transacted JMS Session -If your JMS broker does not support transacted sessions, you have to disable the support of transactions altogether. -If you create your own `JmsListenerContainerFactory`, there is nothing to do, since, by default it cannot be transacted. -If you want to use the `DefaultJmsListenerContainerFactoryConfigurer` to reuse Spring Boot's default, you can disable transacted sessions, as follows: - -[source,java,pending-extract=true,indent=0] ----- - @Bean - public DefaultJmsListenerContainerFactory jmsListenerContainerFactory( - ConnectionFactory connectionFactory, - DefaultJmsListenerContainerFactoryConfigurer configurer) { - DefaultJmsListenerContainerFactory listenerFactory = - new DefaultJmsListenerContainerFactory(); - configurer.configure(listenerFactory, connectionFactory); - listenerFactory.setTransactionManager(null); - listenerFactory.setSessionTransacted(false); - return listenerFactory; - } ----- - -The preceding example overrides the default factory, and it should be applied to any other factory that your application defines, if any. - - - -[[howto.batch]] -== Batch Applications -A number of questions often arise when people use Spring Batch from within a Spring Boot application. -This section addresses those questions. - - - -[[howto.batch.specifying-a-data-source]] -=== Specifying a Batch Data Source -By default, batch applications require a `DataSource` to store job details. -Spring Batch expects a single `DataSource` by default. -To have it use a `DataSource` other than the application’s main `DataSource`, declare a `DataSource` bean, annotating its `@Bean` method with `@BatchDataSource`. -If you do so and want two data sources, remember to mark the other one `@Primary`. -To take greater control, implement `BatchConfigurer`. -See {spring-batch-api}/core/configuration/annotation/EnableBatchProcessing.html[The Javadoc of `@EnableBatchProcessing`] for more details. - -For more info about Spring Batch, see the {spring-batch}[Spring Batch project page]. - - - -[[howto.batch.running-jobs-on-startup]] -=== Running Spring Batch Jobs on Startup -Spring Batch auto-configuration is enabled by adding `@EnableBatchProcessing` to one of your `@Configuration` classes. - -By default, it executes *all* `Jobs` in the application context on startup (see {spring-boot-autoconfigure-module-code}/batch/JobLauncherApplicationRunner.java[`JobLauncherApplicationRunner`] for details). -You can narrow down to a specific job or jobs by specifying `spring.batch.job.names` (which takes a comma-separated list of job name patterns). - -See {spring-boot-autoconfigure-module-code}/batch/BatchAutoConfiguration.java[BatchAutoConfiguration] and {spring-batch-api}/core/configuration/annotation/EnableBatchProcessing.html[@EnableBatchProcessing] for more details. - - - -[[howto.batch.?running-from-the-command-line]] -=== Running from the Command Line -Spring Boot converts any command line argument starting with `--` to a property to add to the `Environment`, see <>. -This should not be used to pass arguments to batch jobs. -To specify batch arguments on the command line, use the regular format (i.e. without `--`), as shown in the following example: - -[indent=0,subs="attributes"] ----- - $ java -jar myapp.jar someParameter=someValue anotherParameter=anotherValue ----- - -If you specify a property of the `Environment` on the command line, it is ignored by the job. -Consider the following command: - -[indent=0,subs="attributes"] ----- - $ java -jar myapp.jar --server.port=7070 someParameter=someValue ----- - -This provides only one argument to the batch job: `someParameter=someValue`. - - - -[[howto.batch.storing-job-repository]] -=== Storing the Job Repository -Spring Batch requires a data store for the `Job` repository. -If you use Spring Boot, you must use an actual database. -Note that it can be an in-memory database, see {spring-batch-docs}job.html#configuringJobRepository[Configuring a Job Repository]. - - - -[[howto.actuator]] -== Actuator -Spring Boot includes the Spring Boot Actuator. -This section answers questions that often arise from its use. - - - -[[howto.actuator.change-http-port-or-address]] -=== Change the HTTP Port or Address of the Actuator Endpoints -In a standalone application, the Actuator HTTP port defaults to the same as the main HTTP port. -To make the application listen on a different port, set the external property: configprop:management.server.port[]. -To listen on a completely different network address (such as when you have an internal network for management and an external one for user applications), you can also set `management.server.address` to a valid IP address to which the server is able to bind. - -For more detail, see the {spring-boot-actuator-autoconfigure-module-code}/web/server/ManagementServerProperties.java[`ManagementServerProperties`] source code and "`<>`" in the "`Production-ready features`" section. - - - -[[howto.actuator.customize-whitelabel-error-page]] -=== Customize the '`whitelabel`' Error Page -Spring Boot installs a '`whitelabel`' error page that you see in a browser client if you encounter a server error (machine clients consuming JSON and other media types should see a sensible response with the right error code). - -NOTE: Set `server.error.whitelabel.enabled=false` to switch the default error page off. -Doing so restores the default of the servlet container that you are using. -Note that Spring Boot still tries to resolve the error view, so you should probably add your own error page rather than disabling it completely. - -Overriding the error page with your own depends on the templating technology that you use. -For example, if you use Thymeleaf, you can add an `error.html` template. -If you use FreeMarker, you can add an `error.ftlh` template. -In general, you need a `View` that resolves with a name of `error` or a `@Controller` that handles the `/error` path. -Unless you replaced some of the default configuration, you should find a `BeanNameViewResolver` in your `ApplicationContext`, so a `@Bean` named `error` would be one way of doing that. -See {spring-boot-autoconfigure-module-code}/web/servlet/error/ErrorMvcAutoConfiguration.java[`ErrorMvcAutoConfiguration`] for more options. - -See also the section on "`<>`" for details of how to register handlers in the servlet container. - - - -[[howto.actuator.sanitize-sensitive-values]] -[[howto.actuator.sanitize-sensitive-values]] -=== Sanitize Sensitive Values -Information returned by the `env` and `configprops` endpoints can be somewhat sensitive so keys matching certain patterns are sanitized by default (i.e. their values are replaced by `+******+`). Spring Boot uses sensible defaults for such keys: any key ending with the word "password", "secret", "key", "token", "vcap_services", "sun.java.command" is entirely sanitized. -Additionally, any key that holds the word `credentials` (configured as a regular expression, i.e. `+*credentials.*+`) as part of the key is also entirely sanitized. - -Furthermore, Spring Boot sanitizes the sensitive portion of URI-like values for keys with one of the following endings: - -- `address` -- `addresses` -- `uri` -- `uris` -- `url` -- `urls` - -The sensitive portion of the URI is identified using the format `://:@:/`. -For example, for the property `myclient.uri=http://user1:password1@localhost:8081`, the resulting sanitized value is -`++http://user1:******@localhost:8081++`. - -The default patterns used by the `env` and `configprops` endpoints can be replaced using configprop:management.endpoint.env.keys-to-sanitize[] and configprop:management.endpoint.configprops.keys-to-sanitize[] respectively. -Alternatively, additional patterns can be configured using configprop:management.endpoint.env.additional-keys-to-sanitize[] and configprop:management.endpoint.configprops.additional-keys-to-sanitize[]. - - - -[[howto.actuator.map-health-indicators-to-metrics]] -=== Map Health Indicators to Micrometer Metrics -Spring Boot health indicators return a `Status` type to indicate the overall system health. -If you want to monitor or alert on levels of health for a particular application, you can export these statuses as metrics via Micrometer. -By default, the status codes "`UP`", "`DOWN`", "`OUT_OF_SERVICE`" and "`UNKNOWN`" are used by Spring Boot. -To export these, you'll need to convert these states to some set of numbers so that they can be used with a Micrometer `Gauge`. - -The following example shows one way to write such an exporter: - -[source,java,indent=0,subs="verbatim,quotes,attributes"] ----- -include::{include-howto}/actuator/MetricsHealthMicrometerExport.java[tag=*] ----- - - - -[[howto.security]] -== Security -This section addresses questions about security when working with Spring Boot, including questions that arise from using Spring Security with Spring Boot. - -For more about Spring Security, see the {spring-security}[Spring Security project page]. - - - -[[howto.security.switch-off-spring-boot-configuration]] -=== Switch off the Spring Boot Security Configuration -If you define a `@Configuration` with a `WebSecurityConfigurerAdapter` or a `SecurityFilterChain` bean in your application, it switches off the default webapp security settings in Spring Boot. - - - -[[howto.security.change-user-details-service-and-add-user-accounts]] -=== Change the UserDetailsService and Add User Accounts -If you provide a `@Bean` of type `AuthenticationManager`, `AuthenticationProvider`, or `UserDetailsService`, the default `@Bean` for `InMemoryUserDetailsManager` is not created. -This means you have the full feature set of Spring Security available (such as {spring-security-docs}#servlet-authentication[various authentication options]). - -The easiest way to add user accounts is to provide your own `UserDetailsService` bean. - - - -[[howto.security.enable-https]] -=== Enable HTTPS When Running behind a Proxy Server -Ensuring that all your main endpoints are only available over HTTPS is an important chore for any application. -If you use Tomcat as a servlet container, then Spring Boot adds Tomcat's own `RemoteIpValve` automatically if it detects some environment settings, and you should be able to rely on the `HttpServletRequest` to report whether it is secure or not (even downstream of a proxy server that handles the real SSL termination). -The standard behavior is determined by the presence or absence of certain request headers (`x-forwarded-for` and `x-forwarded-proto`), whose names are conventional, so it should work with most front-end proxies. -You can switch on the valve by adding some entries to `application.properties`, as shown in the following example: - -[source,yaml,indent=0,configprops,configblocks] ----- - server: - tomcat: - remoteip: - remote-ip-header: "x-forwarded-for" - protocol-header: "x-forwarded-proto" ----- - -(The presence of either of those properties switches on the valve. -Alternatively, you can add the `RemoteIpValve` by customizing the `TomcatServletWebServerFactory` using a `WebServerFactoryCustomizer` bean.) - -To configure Spring Security to require a secure channel for all (or some) requests, consider adding your own `SecurityFilterChain` bean that adds the following `HttpSecurity` configuration: - -[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] ----- - @Bean - public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception { - // Customize the application security - http.requiresChannel().anyRequest().requiresSecure(); - return http.build(); - } ----- - - - -[[howto.hotswapping]] -== Hot Swapping -Spring Boot supports hot swapping. -This section answers questions about how it works. - - - -[[howto.hotswapping.reload-static-content]] -=== Reload Static Content -There are several options for hot reloading. -The recommended approach is to use <>, as it provides additional development-time features, such as support for fast application restarts and LiveReload as well as sensible development-time configuration (such as template caching). -Devtools works by monitoring the classpath for changes. -This means that static resource changes must be "built" for the change to take effect. -By default, this happens automatically in Eclipse when you save your changes. -In IntelliJ IDEA, the Make Project command triggers the necessary build. -Due to the <>, changes to static resources do not trigger a restart of your application. -They do, however, trigger a live reload. - -Alternatively, running in an IDE (especially with debugging on) is a good way to do development (all modern IDEs allow reloading of static resources and usually also allow hot-swapping of Java class changes). - -Finally, the <> can be configured (see the `addResources` property) to support running from the command line with reloading of static files directly from source. -You can use that with an external css/js compiler process if you are writing that code with higher-level tools. - - - -[[howto.hotswapping.reload-templates]] -=== Reload Templates without Restarting the Container -Most of the templating technologies supported by Spring Boot include a configuration option to disable caching (described later in this document). -If you use the `spring-boot-devtools` module, these properties are <> for you at development time. - - - -[[howto.hotswapping.reload-templates.thymeleaf]] -==== Thymeleaf Templates -If you use Thymeleaf, set `spring.thymeleaf.cache` to `false`. -See {spring-boot-autoconfigure-module-code}/thymeleaf/ThymeleafAutoConfiguration.java[`ThymeleafAutoConfiguration`] for other Thymeleaf customization options. - - - -[[howto.hotswapping.reload-templates.freemarker]] -==== FreeMarker Templates -If you use FreeMarker, set `spring.freemarker.cache` to `false`. -See {spring-boot-autoconfigure-module-code}/freemarker/FreeMarkerAutoConfiguration.java[`FreeMarkerAutoConfiguration`] for other FreeMarker customization options. - - - -[[howto.hotswapping.reload-templates.groovy]] -==== Groovy Templates -If you use Groovy templates, set `spring.groovy.template.cache` to `false`. -See {spring-boot-autoconfigure-module-code}/groovy/template/GroovyTemplateAutoConfiguration.java[`GroovyTemplateAutoConfiguration`] for other Groovy customization options. - - - -[[howto.hotswapping.fast-application-restarts]] -=== Fast Application Restarts -The `spring-boot-devtools` module includes support for automatic application restarts. -While not as fast as technologies such as https://www.jrebel.com/products/jrebel[JRebel] it is usually significantly faster than a "`cold start`". -You should probably give it a try before investigating some of the more complex reload options discussed later in this document. - -For more details, see the <> section. - - - -[[howto.hotswapping.reload-java-classes-without-restarting]] -=== Reload Java Classes without Restarting the Container -Many modern IDEs (Eclipse, IDEA, and others) support hot swapping of bytecode. -Consequently, if you make a change that does not affect class or method signatures, it should reload cleanly with no side effects. - - - -[[howto.build]] -== Build -Spring Boot includes build plugins for Maven and Gradle. -This section answers common questions about these plugins. - - - -[[howto.build.generate-info]] -=== Generate Build Information -Both the Maven plugin and the Gradle plugin allow generating build information containing the coordinates, name, and version of the project. -The plugins can also be configured to add additional properties through configuration. -When such a file is present, Spring Boot auto-configures a `BuildProperties` bean. - -To generate build information with Maven, add an execution for the `build-info` goal, as shown in the following example: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - - - org.springframework.boot - spring-boot-maven-plugin - {spring-boot-version} - - - - build-info - - - - - - ----- - -TIP: See the {spring-boot-maven-plugin-docs}#goals-build-info[Spring Boot Maven Plugin documentation] for more details. - -The following example does the same with Gradle: - -[source,groovy,indent=0,subs="verbatim,attributes"] ----- - springBoot { - buildInfo() - } ----- - -TIP: See the {spring-boot-gradle-plugin-docs}#integrating-with-actuator-build-info[Spring Boot Gradle Plugin documentation] for more details. - - - -[[howto.build.generate-git-info]] -=== Generate Git Information -Both Maven and Gradle allow generating a `git.properties` file containing information about the state of your `git` source code repository when the project was built. - -For Maven users, the `spring-boot-starter-parent` POM includes a pre-configured plugin to generate a `git.properties` file. -To use it, add the following declaration to your POM: - -[source,xml,indent=0] ----- - - - - pl.project13.maven - git-commit-id-plugin - - - ----- - -Gradle users can achieve the same result by using the https://plugins.gradle.org/plugin/com.gorylenko.gradle-git-properties[`gradle-git-properties`] plugin, as shown in the following example: - -[source,groovy,indent=0] ----- - plugins { - id "com.gorylenko.gradle-git-properties" version "2.2.4" - } ----- - -Both the Maven and Gradle plugins allow the properties that are included in `git.properties` to be configured. - -TIP: The commit time in `git.properties` is expected to match the following format: `yyyy-MM-dd'T'HH:mm:ssZ`. -This is the default format for both plugins listed above. -Using this format lets the time be parsed into a `Date` and its format, when serialized to JSON, to be controlled by Jackson's date serialization configuration settings. - - - -[[howto.build.customize-dependency-versions]] -=== Customize Dependency Versions -The `spring-boot-dependencies` POM manages the versions of common dependencies. -The Spring Boot plugins for Maven and Gradle allow these managed dependency versions to be customized using build properties. - -WARNING: Each Spring Boot release is designed and tested against this specific set of third-party dependencies. -Overriding versions may cause compatibility issues. - -To override dependency versions with Maven, see {spring-boot-maven-plugin-docs}#using[this section] of the Maven plugin's documentation. - -To override dependency versions in Gradle, see {spring-boot-gradle-plugin-docs}#managing-dependencies-dependency-management-plugin-customizing[this section] of the Gradle plugin's documentation. - - - -[[howto.build.create-an-executable-jar-with-maven]] -=== Create an Executable JAR with Maven -The `spring-boot-maven-plugin` can be used to create an executable "`fat`" JAR. -If you use the `spring-boot-starter-parent` POM, you can declare the plugin and your jars are repackaged as follows: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - - - org.springframework.boot - spring-boot-maven-plugin - - - ----- - -If you do not use the parent POM, you can still use the plugin. -However, you must additionally add an `` section, as follows: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - - - org.springframework.boot - spring-boot-maven-plugin - {spring-boot-version} - - - - repackage - - - - - - ----- - -See the {spring-boot-maven-plugin-docs}#repackage[plugin documentation] for full usage details. - - - -[[howto.build.use-a-spring-boot-application-as-dependency]] -=== Use a Spring Boot Application as a Dependency -Like a war file, a Spring Boot application is not intended to be used as a dependency. -If your application contains classes that you want to share with other projects, the recommended approach is to move that code into a separate module. -The separate module can then be depended upon by your application and other projects. - -If you cannot rearrange your code as recommended above, Spring Boot's Maven and Gradle plugins must be configured to produce a separate artifact that is suitable for use as a dependency. -The executable archive cannot be used as a dependency as the <> packages application classes in `BOOT-INF/classes`. -This means that they cannot be found when the executable jar is used as a dependency. - -To produce the two artifacts, one that can be used as a dependency and one that is executable, a classifier must be specified. -This classifier is applied to the name of the executable archive, leaving the default archive for use as a dependency. - -To configure a classifier of `exec` in Maven, you can use the following configuration: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - - - org.springframework.boot - spring-boot-maven-plugin - - exec - - - - ----- - - - -[[howto.build.extract-specific-libraries-when-an-executable-jar-runs]] -=== Extract Specific Libraries When an Executable Jar Runs -Most nested libraries in an executable jar do not need to be unpacked in order to run. -However, certain libraries can have problems. -For example, JRuby includes its own nested jar support, which assumes that the `jruby-complete.jar` is always directly available as a file in its own right. - -To deal with any problematic libraries, you can flag that specific nested jars should be automatically unpacked when the executable jar first runs. -Such nested jars are written beneath the temporary directory identified by the `java.io.tmpdir` system property. - -WARNING: Care should be taken to ensure that your operating system is configured so that it will not delete the jars that have been unpacked to the temporary directory while the application is still running. - -For example, to indicate that JRuby should be flagged for unpacking by using the Maven Plugin, you would add the following configuration: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - - - org.springframework.boot - spring-boot-maven-plugin - - - - org.jruby - jruby-complete - - - - - - ----- - - - -[[howto.build.create-a-nonexecutable-jar]] -=== Create a Non-executable JAR with Exclusions -Often, if you have an executable and a non-executable jar as two separate build products, the executable version has additional configuration files that are not needed in a library jar. -For example, the `application.yml` configuration file might be excluded from the non-executable JAR. - -In Maven, the executable jar must be the main artifact and you can add a classified jar for the library, as follows: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - - - org.springframework.boot - spring-boot-maven-plugin - - - maven-jar-plugin - - - lib - package - - jar - - - lib - - application.yml - - - - - - - ----- - - - -[[howto.build.remote-debug-maven]] -=== Remote Debug a Spring Boot Application Started with Maven -To attach a remote debugger to a Spring Boot application that was started with Maven, you can use the `jvmArguments` property of the {spring-boot-maven-plugin-docs}[maven plugin]. - -See {spring-boot-maven-plugin-docs}#run-example-debug[this example] for more details. - - - -[[howto.build.build-an-executable-archive-with-ant-without-using-spring-boot-antlib]] -=== Build an Executable Archive from Ant without Using spring-boot-antlib -To build with Ant, you need to grab dependencies, compile, and then create a jar or war archive. -To make it executable, you can either use the `spring-boot-antlib` module or you can follow these instructions: - -. If you are building a jar, package the application's classes and resources in a nested `BOOT-INF/classes` directory. - If you are building a war, package the application's classes in a nested `WEB-INF/classes` directory as usual. -. Add the runtime dependencies in a nested `BOOT-INF/lib` directory for a jar or `WEB-INF/lib` for a war. - Remember *not* to compress the entries in the archive. -. Add the `provided` (embedded container) dependencies in a nested `BOOT-INF/lib` directory for a jar or `WEB-INF/lib-provided` for a war. - Remember *not* to compress the entries in the archive. -. Add the `spring-boot-loader` classes at the root of the archive (so that the `Main-Class` is available). -. Use the appropriate launcher (such as `JarLauncher` for a jar file) as a `Main-Class` attribute in the manifest and specify the other properties it needs as manifest entries -- principally, by setting a `Start-Class` property. - -The following example shows how to build an executable archive with Ant: - -[source,xml,indent=0] ----- - - - - - - - - - - - - - - - - - - - - - ----- - - - -[[howto.traditional-deployment]] -== Traditional Deployment -Spring Boot supports traditional deployment as well as more modern forms of deployment. -This section answers common questions about traditional deployment. - - - -[[howto.traditional-deployment.war]] -=== Create a Deployable War File - -WARNING: Because Spring WebFlux does not strictly depend on the Servlet API and applications are deployed by default on an embedded Reactor Netty server, War deployment is not supported for WebFlux applications. - -The first step in producing a deployable war file is to provide a `SpringBootServletInitializer` subclass and override its `configure` method. -Doing so makes use of Spring Framework's Servlet 3.0 support and lets you configure your application when it is launched by the servlet container. -Typically, you should update your application's main class to extend `SpringBootServletInitializer`, as shown in the following example: - -[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] ----- - @SpringBootApplication - public class Application extends SpringBootServletInitializer { - - @Override - protected SpringApplicationBuilder configure(SpringApplicationBuilder application) { - return application.sources(Application.class); - } - - public static void main(String[] args) { - SpringApplication.run(Application.class, args); - } - - } ----- - -The next step is to update your build configuration such that your project produces a war file rather than a jar file. -If you use Maven and `spring-boot-starter-parent` (which configures Maven's war plugin for you), all you need to do is to modify `pom.xml` to change the packaging to war, as follows: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - war ----- - -If you use Gradle, you need to modify `build.gradle` to apply the war plugin to the project, as follows: - -[source,groovy,indent=0,subs="verbatim,quotes,attributes"] ----- - apply plugin: 'war' ----- - -The final step in the process is to ensure that the embedded servlet container does not interfere with the servlet container to which the war file is deployed. -To do so, you need to mark the embedded servlet container dependency as being provided. - -If you use Maven, the following example marks the servlet container (Tomcat, in this case) as being provided: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - - - org.springframework.boot - spring-boot-starter-tomcat - provided - - - ----- - -If you use Gradle, the following example marks the servlet container (Tomcat, in this case) as being provided: - -[source,groovy,indent=0,subs="verbatim,quotes,attributes"] ----- - dependencies { - // … - providedRuntime 'org.springframework.boot:spring-boot-starter-tomcat' - // … - } ----- - -TIP: `providedRuntime` is preferred to Gradle's `compileOnly` configuration. -Among other limitations, `compileOnly` dependencies are not on the test classpath, so any web-based integration tests fail. - -If you use the <>, marking the embedded servlet container dependency as provided produces an executable war file with the provided dependencies packaged in a `lib-provided` directory. -This means that, in addition to being deployable to a servlet container, you can also run your application by using `java -jar` on the command line. - - - -[[howto.traditional-deployment.convert-existing-application]] -=== Convert an Existing Application to Spring Boot -To convert an existing non-web Spring application to a Spring Boot application, replace the code that creates your `ApplicationContext` and replace it with calls to `SpringApplication` or `SpringApplicationBuilder`. -Spring MVC web applications are generally amenable to first creating a deployable war application and then migrating it later to an executable war or jar. -See the https://spring.io/guides/gs/convert-jar-to-war/[Getting Started Guide on Converting a jar to a war]. - -To create a deployable war by extending `SpringBootServletInitializer` (for example, in a class called `Application`) and adding the Spring Boot `@SpringBootApplication` annotation, use code similar to that shown in the following example: - -[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] ----- - @SpringBootApplication - public class Application extends SpringBootServletInitializer { - - @Override - protected SpringApplicationBuilder configure(SpringApplicationBuilder application) { - // Customize the application or call application.sources(...) to add sources - // Since our example is itself a @Configuration class (via @SpringBootApplication) - // we actually don't need to override this method. - return application; - } - - } ----- - -Remember that, whatever you put in the `sources` is merely a Spring `ApplicationContext`. -Normally, anything that already works should work here. -There might be some beans you can remove later and let Spring Boot provide its own defaults for them, but it should be possible to get something working before you need to do that. - -Static resources can be moved to `/public` (or `/static` or `/resources` or `/META-INF/resources`) in the classpath root. -The same applies to `messages.properties` (which Spring Boot automatically detects in the root of the classpath). - -Vanilla usage of Spring `DispatcherServlet` and Spring Security should require no further changes. -If you have other features in your application (for instance, using other servlets or filters), you may need to add some configuration to your `Application` context, by replacing those elements from the `web.xml`, as follows: - -* A `@Bean` of type `Servlet` or `ServletRegistrationBean` installs that bean in the container as if it were a `` and `` in `web.xml`. -* A `@Bean` of type `Filter` or `FilterRegistrationBean` behaves similarly (as a `` and ``). -* An `ApplicationContext` in an XML file can be added through an `@ImportResource` in your `Application`. - Alternatively, cases where annotation configuration is heavily used already can be recreated in a few lines as `@Bean` definitions. - -Once the war file is working, you can make it executable by adding a `main` method to your `Application`, as shown in the following example: - -[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] ----- - public static void main(String[] args) { - SpringApplication.run(Application.class, args); - } ----- - -[NOTE] -==== -If you intend to start your application as a war or as an executable application, you need to share the customizations of the builder in a method that is both available to the `SpringBootServletInitializer` callback and in the `main` method in a class similar to the following: - -[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] ----- - @SpringBootApplication - public class Application extends SpringBootServletInitializer { - - @Override - protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) { - return configureApplication(builder); - } - - public static void main(String[] args) { - configureApplication(new SpringApplicationBuilder()).run(args); - } - - private static SpringApplicationBuilder configureApplication(SpringApplicationBuilder builder) { - return builder.sources(Application.class).bannerMode(Banner.Mode.OFF); - } - - } ----- -==== - -Applications can fall into more than one category: - -* Servlet 3.0+ applications with no `web.xml`. -* Applications with a `web.xml`. -* Applications with a context hierarchy. -* Applications without a context hierarchy. - -All of these should be amenable to translation, but each might require slightly different techniques. - -Servlet 3.0+ applications might translate pretty easily if they already use the Spring Servlet 3.0+ initializer support classes. -Normally, all the code from an existing `WebApplicationInitializer` can be moved into a `SpringBootServletInitializer`. -If your existing application has more than one `ApplicationContext` (for example, if it uses `AbstractDispatcherServletInitializer`) then you might be able to combine all your context sources into a single `SpringApplication`. -The main complication you might encounter is if combining does not work and you need to maintain the context hierarchy. -See the <> for examples. -An existing parent context that contains web-specific features usually needs to be broken up so that all the `ServletContextAware` components are in the child context. - -Applications that are not already Spring applications might be convertible to Spring Boot applications, and the previously mentioned guidance may help. -However, you may yet encounter problems. -In that case, we suggest https://stackoverflow.com/questions/tagged/spring-boot[asking questions on Stack Overflow with a tag of `spring-boot`]. - - - -[[howto.traditional-deployment.weblogic]] -=== Deploying a WAR to WebLogic -To deploy a Spring Boot application to WebLogic, you must ensure that your servlet initializer *directly* implements `WebApplicationInitializer` (even if you extend from a base class that already implements it). - -A typical initializer for WebLogic should resemble the following example: - -[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] ----- - import org.springframework.boot.autoconfigure.SpringBootApplication; - import org.springframework.boot.web.servlet.support.SpringBootServletInitializer; - import org.springframework.web.WebApplicationInitializer; - - @SpringBootApplication - public class MyApplication extends SpringBootServletInitializer implements WebApplicationInitializer { - - } ----- - -If you use Logback, you also need to tell WebLogic to prefer the packaged version rather than the version that was pre-installed with the server. -You can do so by adding a `WEB-INF/weblogic.xml` file with the following contents: - -[source,xml,indent=0] ----- - - - - - org.slf4j - - - ----- - - - -[[howto.jedis-instead-of-lettuce]] -== Use Jedis Instead of Lettuce -By default, the Spring Boot starter (`spring-boot-starter-data-redis`) uses https://github.com/lettuce-io/lettuce-core/[Lettuce]. -You need to exclude that dependency and include the https://github.com/xetorthio/jedis/[Jedis] one instead. -Spring Boot manages both of these dependencies so you can switch to Jedis without specifying a version. - -The following example shows how to do so in Maven: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - org.springframework.boot - spring-boot-starter-data-redis - - - io.lettuce - lettuce-core - - - - - redis.clients - jedis - ----- - -The following example shows how to do so in Gradle: - -[source,groovy,indent=0,subs="verbatim,quotes,attributes"] ----- - dependencies { - implementation('org.springframework.boot:spring-boot-starter-data-redis') { - exclude group: 'io.lettuce', module: 'lettuce-core' - } - implementation 'redis.clients:jedis' - // ... - } ----- - - - -[[howto.testcontainers]] -== Use Testcontainers for integration testing -The https://www.testcontainers.org/[Testcontainers] library provides a way to manage services running inside Docker containers. -It integrates with JUnit, allowing you to write a test class that can start up a container before any of the tests run. -Testcontainers is especially useful for writing integration tests that talk to a real backend service such as MySQL, MongoDB, Cassandra etc. -Testcontainers can be used in a Spring Boot test as follows: - -[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] ----- -@SpringBootTest -@Testcontainers -class ExampleIntegrationTests { - - @Container - static Neo4jContainer neo4j = new Neo4jContainer<>(); - -} ----- - -This will start up a docker container running Neo4j (if Docker is running locally) before any of the tests are run. -In most cases, you will need to configure the application using details from the running container, such as container IP or port. - -This can be done with a static `@DynamicPropertySource` method that allows adding dynamic property values to the Spring Environment. - -[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] ----- -@SpringBootTest -@Testcontainers -class ExampleIntegrationTests { - - @Container - static Neo4jContainer neo4j = new Neo4jContainer<>(); - - @DynamicPropertySource - static void neo4jProperties(DynamicPropertyRegistry registry) { - registry.add("spring.neo4j.uri", neo4j::getBoltUrl); - } - -} ----- - -The above configuration allows Neo4j-related beans in the application to communicate with Neo4j running inside the Testcontainers-managed Docker container. +include::howto/testcontainers.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/actuator.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/actuator.adoc new file mode 100644 index 0000000000..e0e9190c26 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/actuator.adoc @@ -0,0 +1,73 @@ +[[howto.actuator]] +== Actuator +Spring Boot includes the Spring Boot Actuator. +This section answers questions that often arise from its use. + + + +[[howto.actuator.change-http-port-or-address]] +=== Change the HTTP Port or Address of the Actuator Endpoints +In a standalone application, the Actuator HTTP port defaults to the same as the main HTTP port. +To make the application listen on a different port, set the external property: configprop:management.server.port[]. +To listen on a completely different network address (such as when you have an internal network for management and an external one for user applications), you can also set `management.server.address` to a valid IP address to which the server is able to bind. + +For more detail, see the {spring-boot-actuator-autoconfigure-module-code}/web/server/ManagementServerProperties.java[`ManagementServerProperties`] source code and "`<>`" in the "`Production-ready features`" section. + + + +[[howto.actuator.customize-whitelabel-error-page]] +=== Customize the '`whitelabel`' Error Page +Spring Boot installs a '`whitelabel`' error page that you see in a browser client if you encounter a server error (machine clients consuming JSON and other media types should see a sensible response with the right error code). + +NOTE: Set `server.error.whitelabel.enabled=false` to switch the default error page off. +Doing so restores the default of the servlet container that you are using. +Note that Spring Boot still tries to resolve the error view, so you should probably add your own error page rather than disabling it completely. + +Overriding the error page with your own depends on the templating technology that you use. +For example, if you use Thymeleaf, you can add an `error.html` template. +If you use FreeMarker, you can add an `error.ftlh` template. +In general, you need a `View` that resolves with a name of `error` or a `@Controller` that handles the `/error` path. +Unless you replaced some of the default configuration, you should find a `BeanNameViewResolver` in your `ApplicationContext`, so a `@Bean` named `error` would be one way of doing that. +See {spring-boot-autoconfigure-module-code}/web/servlet/error/ErrorMvcAutoConfiguration.java[`ErrorMvcAutoConfiguration`] for more options. + +See also the section on "`<>`" for details of how to register handlers in the servlet container. + + + +[[howto.actuator.sanitize-sensitive-values]] +[[howto.actuator.sanitize-sensitive-values]] +=== Sanitize Sensitive Values +Information returned by the `env` and `configprops` endpoints can be somewhat sensitive so keys matching certain patterns are sanitized by default (i.e. their values are replaced by `+******+`). Spring Boot uses sensible defaults for such keys: any key ending with the word "password", "secret", "key", "token", "vcap_services", "sun.java.command" is entirely sanitized. +Additionally, any key that holds the word `credentials` (configured as a regular expression, i.e. `+*credentials.*+`) as part of the key is also entirely sanitized. + +Furthermore, Spring Boot sanitizes the sensitive portion of URI-like values for keys with one of the following endings: + +- `address` +- `addresses` +- `uri` +- `uris` +- `url` +- `urls` + +The sensitive portion of the URI is identified using the format `://:@:/`. +For example, for the property `myclient.uri=http://user1:password1@localhost:8081`, the resulting sanitized value is +`++http://user1:******@localhost:8081++`. + +The default patterns used by the `env` and `configprops` endpoints can be replaced using configprop:management.endpoint.env.keys-to-sanitize[] and configprop:management.endpoint.configprops.keys-to-sanitize[] respectively. +Alternatively, additional patterns can be configured using configprop:management.endpoint.env.additional-keys-to-sanitize[] and configprop:management.endpoint.configprops.additional-keys-to-sanitize[]. + + + +[[howto.actuator.map-health-indicators-to-metrics]] +=== Map Health Indicators to Micrometer Metrics +Spring Boot health indicators return a `Status` type to indicate the overall system health. +If you want to monitor or alert on levels of health for a particular application, you can export these statuses as metrics via Micrometer. +By default, the status codes "`UP`", "`DOWN`", "`OUT_OF_SERVICE`" and "`UNKNOWN`" are used by Spring Boot. +To export these, you'll need to convert these states to some set of numbers so that they can be used with a Micrometer `Gauge`. + +The following example shows one way to write such an exporter: + +[source,java,indent=0,subs="verbatim,quotes,attributes"] +---- +include::{include-howto}/actuator/MetricsHealthMicrometerExport.java[tag=*] +---- diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/application.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/application.adoc new file mode 100644 index 0000000000..d6988d9037 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/application.adoc @@ -0,0 +1,111 @@ +[[howto.application]] +== Spring Boot Application +This section includes topics relating directly to Spring Boot applications. + + + +[[howto.application.failure-analyzer]] +=== Create Your Own FailureAnalyzer +{spring-boot-module-api}/diagnostics/FailureAnalyzer.html[`FailureAnalyzer`] is a great way to intercept an exception on startup and turn it into a human-readable message, wrapped in a {spring-boot-module-api}/diagnostics/FailureAnalysis.html[`FailureAnalysis`]. +Spring Boot provides such an analyzer for application-context-related exceptions, JSR-303 validations, and more. +You can also create your own. + +`AbstractFailureAnalyzer` is a convenient extension of `FailureAnalyzer` that checks the presence of a specified exception type in the exception to handle. +You can extend from that so that your implementation gets a chance to handle the exception only when it is actually present. +If, for whatever reason, you cannot handle the exception, return `null` to give another implementation a chance to handle the exception. + +`FailureAnalyzer` implementations must be registered in `META-INF/spring.factories`. +The following example registers `ProjectConstraintViolationFailureAnalyzer`: + +[source,properties,indent=0] +---- + org.springframework.boot.diagnostics.FailureAnalyzer=\ + com.example.ProjectConstraintViolationFailureAnalyzer +---- + +NOTE: If you need access to the `BeanFactory` or the `Environment`, your `FailureAnalyzer` can implement `BeanFactoryAware` or `EnvironmentAware` respectively. + + + +[[howto.application.troubleshoot-auto-configuration]] +=== Troubleshoot Auto-configuration +The Spring Boot auto-configuration tries its best to "`do the right thing`", but sometimes things fail, and it can be hard to tell why. + +There is a really useful `ConditionEvaluationReport` available in any Spring Boot `ApplicationContext`. +You can see it if you enable `DEBUG` logging output. +If you use the `spring-boot-actuator` (see <>), there is also a `conditions` endpoint that renders the report in JSON. +Use that endpoint to debug the application and see what features have been added (and which have not been added) by Spring Boot at runtime. + +Many more questions can be answered by looking at the source code and the Javadoc. +When reading the code, remember the following rules of thumb: + +* Look for classes called `+*AutoConfiguration+` and read their sources. + Pay special attention to the `+@Conditional*+` annotations to find out what features they enable and when. + Add `--debug` to the command line or a System property `-Ddebug` to get a log on the console of all the auto-configuration decisions that were made in your app. + In a running application with actuator enabled, look at the `conditions` endpoint (`/actuator/conditions` or the JMX equivalent) for the same information. +* Look for classes that are `@ConfigurationProperties` (such as {spring-boot-autoconfigure-module-code}/web/ServerProperties.java[`ServerProperties`]) and read from there the available external configuration options. + The `@ConfigurationProperties` annotation has a `name` attribute that acts as a prefix to external properties. + Thus, `ServerProperties` has `prefix="server"` and its configuration properties are `server.port`, `server.address`, and others. + In a running application with actuator enabled, look at the `configprops` endpoint. +* Look for uses of the `bind` method on the `Binder` to pull configuration values explicitly out of the `Environment` in a relaxed manner. + It is often used with a prefix. +* Look for `@Value` annotations that bind directly to the `Environment`. +* Look for `@ConditionalOnExpression` annotations that switch features on and off in response to SpEL expressions, normally evaluated with placeholders resolved from the `Environment`. + + + +[[howto.application.customize-the-environment-or-application-context]] +=== Customize the Environment or ApplicationContext Before It Starts +A `SpringApplication` has `ApplicationListeners` and `ApplicationContextInitializers` that are used to apply customizations to the context or environment. +Spring Boot loads a number of such customizations for use internally from `META-INF/spring.factories`. +There is more than one way to register additional customizations: + +* Programmatically, per application, by calling the `addListeners` and `addInitializers` methods on `SpringApplication` before you run it. +* Declaratively, per application, by setting the `context.initializer.classes` or `context.listener.classes` properties. +* Declaratively, for all applications, by adding a `META-INF/spring.factories` and packaging a jar file that the applications all use as a library. + +The `SpringApplication` sends some special `ApplicationEvents` to the listeners (some even before the context is created) and then registers the listeners for events published by the `ApplicationContext` as well. +See "`<>`" in the '`Spring Boot features`' section for a complete list. + +It is also possible to customize the `Environment` before the application context is refreshed by using `EnvironmentPostProcessor`. +Each implementation should be registered in `META-INF/spring.factories`, as shown in the following example: + +[indent=0] +---- + org.springframework.boot.env.EnvironmentPostProcessor=com.example.YourEnvironmentPostProcessor +---- + +The implementation can load arbitrary files and add them to the `Environment`. +For instance, the following example loads a YAML configuration file from the classpath: + +[source,java,indent=0] +---- +include::{include-howto}/springbootapplication/MyEnvironmentPostProcessor.java[tag=*] +---- + +TIP: The `Environment` has already been prepared with all the usual property sources that Spring Boot loads by default. +It is therefore possible to get the location of the file from the environment. +The preceding example adds the `custom-resource` property source at the end of the list so that a key defined in any of the usual other locations takes precedence. +A custom implementation may define another order. + +CAUTION: While using `@PropertySource` on your `@SpringBootApplication` may seem to be a convenient way to load a custom resource in the `Environment`, we do not recommend it. +Such property sources are not added to the `Environment` until the application context is being refreshed. +This is too late to configure certain properties such as `+logging.*+` and `+spring.main.*+` which are read before refresh begins. + + + +[[howto.application.context-hierarchy]] +=== Build an ApplicationContext Hierarchy (Adding a Parent or Root Context) +You can use the `ApplicationBuilder` class to create parent/child `ApplicationContext` hierarchies. +See "`<>`" in the '`Spring Boot features`' section for more information. + + + +[[howto.application.non-web-application]] +=== Create a Non-web Application +Not all Spring applications have to be web applications (or web services). +If you want to execute some code in a `main` method but also bootstrap a Spring application to set up the infrastructure to use, you can use the `SpringApplication` features of Spring Boot. +A `SpringApplication` changes its `ApplicationContext` class, depending on whether it thinks it needs a web application or not. +The first thing you can do to help it is to leave server-related dependencies (e.g. servlet API) off the classpath. +If you cannot do that (for example, you run two applications from the same code base) then you can explicitly call `setWebApplicationType(WebApplicationType.NONE)` on your `SpringApplication` instance or set the `applicationContextClass` property (through the Java API or with external properties). +Application code that you want to run as your business logic can be implemented as a `CommandLineRunner` and dropped into the context as a `@Bean` definition. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/batch.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/batch.adoc new file mode 100644 index 0000000000..508990bfd6 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/batch.adoc @@ -0,0 +1,59 @@ +[[howto.batch]] +== Batch Applications +A number of questions often arise when people use Spring Batch from within a Spring Boot application. +This section addresses those questions. + + + +[[howto.batch.specifying-a-data-source]] +=== Specifying a Batch Data Source +By default, batch applications require a `DataSource` to store job details. +Spring Batch expects a single `DataSource` by default. +To have it use a `DataSource` other than the application’s main `DataSource`, declare a `DataSource` bean, annotating its `@Bean` method with `@BatchDataSource`. +If you do so and want two data sources, remember to mark the other one `@Primary`. +To take greater control, implement `BatchConfigurer`. +See {spring-batch-api}/core/configuration/annotation/EnableBatchProcessing.html[The Javadoc of `@EnableBatchProcessing`] for more details. + +For more info about Spring Batch, see the {spring-batch}[Spring Batch project page]. + + + +[[howto.batch.running-jobs-on-startup]] +=== Running Spring Batch Jobs on Startup +Spring Batch auto-configuration is enabled by adding `@EnableBatchProcessing` to one of your `@Configuration` classes. + +By default, it executes *all* `Jobs` in the application context on startup (see {spring-boot-autoconfigure-module-code}/batch/JobLauncherApplicationRunner.java[`JobLauncherApplicationRunner`] for details). +You can narrow down to a specific job or jobs by specifying `spring.batch.job.names` (which takes a comma-separated list of job name patterns). + +See {spring-boot-autoconfigure-module-code}/batch/BatchAutoConfiguration.java[BatchAutoConfiguration] and {spring-batch-api}/core/configuration/annotation/EnableBatchProcessing.html[@EnableBatchProcessing] for more details. + + + +[[howto.batch.?running-from-the-command-line]] +=== Running from the Command Line +Spring Boot converts any command line argument starting with `--` to a property to add to the `Environment`, see <>. +This should not be used to pass arguments to batch jobs. +To specify batch arguments on the command line, use the regular format (i.e. without `--`), as shown in the following example: + +[indent=0,subs="attributes"] +---- + $ java -jar myapp.jar someParameter=someValue anotherParameter=anotherValue +---- + +If you specify a property of the `Environment` on the command line, it is ignored by the job. +Consider the following command: + +[indent=0,subs="attributes"] +---- + $ java -jar myapp.jar --server.port=7070 someParameter=someValue +---- + +This provides only one argument to the batch job: `someParameter=someValue`. + + + +[[howto.batch.storing-job-repository]] +=== Storing the Job Repository +Spring Batch requires a data store for the `Job` repository. +If you use Spring Boot, you must use an actual database. +Note that it can be an in-memory database, see {spring-batch-docs}job.html#configuringJobRepository[Configuring a Job Repository]. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/build.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/build.adoc new file mode 100644 index 0000000000..ddb688b602 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/build.adoc @@ -0,0 +1,298 @@ +[[howto.build]] +== Build +Spring Boot includes build plugins for Maven and Gradle. +This section answers common questions about these plugins. + + + +[[howto.build.generate-info]] +=== Generate Build Information +Both the Maven plugin and the Gradle plugin allow generating build information containing the coordinates, name, and version of the project. +The plugins can also be configured to add additional properties through configuration. +When such a file is present, Spring Boot auto-configures a `BuildProperties` bean. + +To generate build information with Maven, add an execution for the `build-info` goal, as shown in the following example: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + + + org.springframework.boot + spring-boot-maven-plugin + {spring-boot-version} + + + + build-info + + + + + + +---- + +TIP: See the {spring-boot-maven-plugin-docs}#goals-build-info[Spring Boot Maven Plugin documentation] for more details. + +The following example does the same with Gradle: + +[source,groovy,indent=0,subs="verbatim,attributes"] +---- + springBoot { + buildInfo() + } +---- + +TIP: See the {spring-boot-gradle-plugin-docs}#integrating-with-actuator-build-info[Spring Boot Gradle Plugin documentation] for more details. + + + +[[howto.build.generate-git-info]] +=== Generate Git Information +Both Maven and Gradle allow generating a `git.properties` file containing information about the state of your `git` source code repository when the project was built. + +For Maven users, the `spring-boot-starter-parent` POM includes a pre-configured plugin to generate a `git.properties` file. +To use it, add the following declaration to your POM: + +[source,xml,indent=0] +---- + + + + pl.project13.maven + git-commit-id-plugin + + + +---- + +Gradle users can achieve the same result by using the https://plugins.gradle.org/plugin/com.gorylenko.gradle-git-properties[`gradle-git-properties`] plugin, as shown in the following example: + +[source,groovy,indent=0] +---- + plugins { + id "com.gorylenko.gradle-git-properties" version "2.2.4" + } +---- + +Both the Maven and Gradle plugins allow the properties that are included in `git.properties` to be configured. + +TIP: The commit time in `git.properties` is expected to match the following format: `yyyy-MM-dd'T'HH:mm:ssZ`. +This is the default format for both plugins listed above. +Using this format lets the time be parsed into a `Date` and its format, when serialized to JSON, to be controlled by Jackson's date serialization configuration settings. + + + +[[howto.build.customize-dependency-versions]] +=== Customize Dependency Versions +The `spring-boot-dependencies` POM manages the versions of common dependencies. +The Spring Boot plugins for Maven and Gradle allow these managed dependency versions to be customized using build properties. + +WARNING: Each Spring Boot release is designed and tested against this specific set of third-party dependencies. +Overriding versions may cause compatibility issues. + +To override dependency versions with Maven, see {spring-boot-maven-plugin-docs}#using[this section] of the Maven plugin's documentation. + +To override dependency versions in Gradle, see {spring-boot-gradle-plugin-docs}#managing-dependencies-dependency-management-plugin-customizing[this section] of the Gradle plugin's documentation. + + + +[[howto.build.create-an-executable-jar-with-maven]] +=== Create an Executable JAR with Maven +The `spring-boot-maven-plugin` can be used to create an executable "`fat`" JAR. +If you use the `spring-boot-starter-parent` POM, you can declare the plugin and your jars are repackaged as follows: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + + + org.springframework.boot + spring-boot-maven-plugin + + + +---- + +If you do not use the parent POM, you can still use the plugin. +However, you must additionally add an `` section, as follows: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + + + org.springframework.boot + spring-boot-maven-plugin + {spring-boot-version} + + + + repackage + + + + + + +---- + +See the {spring-boot-maven-plugin-docs}#repackage[plugin documentation] for full usage details. + + + +[[howto.build.use-a-spring-boot-application-as-dependency]] +=== Use a Spring Boot Application as a Dependency +Like a war file, a Spring Boot application is not intended to be used as a dependency. +If your application contains classes that you want to share with other projects, the recommended approach is to move that code into a separate module. +The separate module can then be depended upon by your application and other projects. + +If you cannot rearrange your code as recommended above, Spring Boot's Maven and Gradle plugins must be configured to produce a separate artifact that is suitable for use as a dependency. +The executable archive cannot be used as a dependency as the <> packages application classes in `BOOT-INF/classes`. +This means that they cannot be found when the executable jar is used as a dependency. + +To produce the two artifacts, one that can be used as a dependency and one that is executable, a classifier must be specified. +This classifier is applied to the name of the executable archive, leaving the default archive for use as a dependency. + +To configure a classifier of `exec` in Maven, you can use the following configuration: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + + + org.springframework.boot + spring-boot-maven-plugin + + exec + + + + +---- + + + +[[howto.build.extract-specific-libraries-when-an-executable-jar-runs]] +=== Extract Specific Libraries When an Executable Jar Runs +Most nested libraries in an executable jar do not need to be unpacked in order to run. +However, certain libraries can have problems. +For example, JRuby includes its own nested jar support, which assumes that the `jruby-complete.jar` is always directly available as a file in its own right. + +To deal with any problematic libraries, you can flag that specific nested jars should be automatically unpacked when the executable jar first runs. +Such nested jars are written beneath the temporary directory identified by the `java.io.tmpdir` system property. + +WARNING: Care should be taken to ensure that your operating system is configured so that it will not delete the jars that have been unpacked to the temporary directory while the application is still running. + +For example, to indicate that JRuby should be flagged for unpacking by using the Maven Plugin, you would add the following configuration: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + + + org.springframework.boot + spring-boot-maven-plugin + + + + org.jruby + jruby-complete + + + + + + +---- + + + +[[howto.build.create-a-nonexecutable-jar]] +=== Create a Non-executable JAR with Exclusions +Often, if you have an executable and a non-executable jar as two separate build products, the executable version has additional configuration files that are not needed in a library jar. +For example, the `application.yml` configuration file might be excluded from the non-executable JAR. + +In Maven, the executable jar must be the main artifact and you can add a classified jar for the library, as follows: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + + + org.springframework.boot + spring-boot-maven-plugin + + + maven-jar-plugin + + + lib + package + + jar + + + lib + + application.yml + + + + + + + +---- + + + +[[howto.build.remote-debug-maven]] +=== Remote Debug a Spring Boot Application Started with Maven +To attach a remote debugger to a Spring Boot application that was started with Maven, you can use the `jvmArguments` property of the {spring-boot-maven-plugin-docs}[maven plugin]. + +See {spring-boot-maven-plugin-docs}#run-example-debug[this example] for more details. + + + +[[howto.build.build-an-executable-archive-with-ant-without-using-spring-boot-antlib]] +=== Build an Executable Archive from Ant without Using spring-boot-antlib +To build with Ant, you need to grab dependencies, compile, and then create a jar or war archive. +To make it executable, you can either use the `spring-boot-antlib` module or you can follow these instructions: + +. If you are building a jar, package the application's classes and resources in a nested `BOOT-INF/classes` directory. + If you are building a war, package the application's classes in a nested `WEB-INF/classes` directory as usual. +. Add the runtime dependencies in a nested `BOOT-INF/lib` directory for a jar or `WEB-INF/lib` for a war. + Remember *not* to compress the entries in the archive. +. Add the `provided` (embedded container) dependencies in a nested `BOOT-INF/lib` directory for a jar or `WEB-INF/lib-provided` for a war. + Remember *not* to compress the entries in the archive. +. Add the `spring-boot-loader` classes at the root of the archive (so that the `Main-Class` is available). +. Use the appropriate launcher (such as `JarLauncher` for a jar file) as a `Main-Class` attribute in the manifest and specify the other properties it needs as manifest entries -- principally, by setting a `Start-Class` property. + +The following example shows how to build an executable archive with Ant: + +[source,xml,indent=0] +---- + + + + + + + + + + + + + + + + + + + + + +---- diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/data-access.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/data-access.adoc new file mode 100644 index 0000000000..4040d80174 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/data-access.adoc @@ -0,0 +1,426 @@ +[[howto.data-access]] +== Data Access +Spring Boot includes a number of starters for working with data sources. +This section answers questions related to doing so. + + + +[[howto.data-access.configure-custom-datasource]] +=== Configure a Custom DataSource +To configure your own `DataSource`, define a `@Bean` of that type in your configuration. +Spring Boot reuses your `DataSource` anywhere one is required, including database initialization. +If you need to externalize some settings, you can bind your `DataSource` to the environment (see "`<>`"). + +The following example shows how to define a data source in a bean: + +[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] +---- + @Bean + @ConfigurationProperties(prefix="app.datasource") + public DataSource dataSource() { + return new FancyDataSource(); + } +---- + +The following example shows how to define a data source by setting properties: + +[source,yaml,indent=0,configblocks] +---- + app: + datasource: + url: "jdbc:h2:mem:mydb" + username: "sa" + pool-size: 30 +---- + +Assuming that your `FancyDataSource` has regular JavaBean properties for the URL, the username, and the pool size, these settings are bound automatically before the `DataSource` is made available to other components. + +Spring Boot also provides a utility builder class, called `DataSourceBuilder`, that can be used to create one of the standard data sources (if it is on the classpath). +The builder can detect the one to use based on what's available on the classpath. +It also auto-detects the driver based on the JDBC URL. + +The following example shows how to create a data source by using a `DataSourceBuilder`: + +[source,java,indent=0,subs="verbatim,quotes,attributes"] +---- +include::{include-howto}/dataaccess/BasicDataSourceConfiguration.java[tag=*] +---- + +To run an app with that `DataSource`, all you need is the connection information. +Pool-specific settings can also be provided. +Check the implementation that is going to be used at runtime for more details. + +The following example shows how to define a JDBC data source by setting properties: + +[source,yaml,indent=0,configblocks] +---- + app: + datasource: + url: "jdbc:mysql://localhost/test" + username: "dbuser" + password: "dbpass" + pool-size: 30 +---- + +However, there is a catch. +Because the actual type of the connection pool is not exposed, no keys are generated in the metadata for your custom `DataSource` and no completion is available in your IDE (because the `DataSource` interface exposes no properties). +Also, if you happen to have Hikari on the classpath, this basic setup does not work, because Hikari has no `url` property (but does have a `jdbcUrl` property). +In that case, you must rewrite your configuration as follows: + +[source,yaml,indent=0,configblocks] +---- + app: + datasource: + jdbc-url: "jdbc:mysql://localhost/test" + username: "dbuser" + password: "dbpass" + pool-size: 30 +---- + +You can fix that by forcing the connection pool to use and return a dedicated implementation rather than `DataSource`. +You cannot change the implementation at runtime, but the list of options will be explicit. + +The following example shows how create a `HikariDataSource` with `DataSourceBuilder`: + +[source,java,indent=0,subs="verbatim,quotes,attributes"] +---- +include::{include-howto}/dataaccess/SimpleDataSourceConfiguration.java[tag=*] +---- + +You can even go further by leveraging what `DataSourceProperties` does for you -- that is, by providing a default embedded database with a sensible username and password if no URL is provided. +You can easily initialize a `DataSourceBuilder` from the state of any `DataSourceProperties` object, so you could also inject the DataSource that Spring Boot creates automatically. +However, that would split your configuration into two namespaces: `url`, `username`, `password`, `type`, and `driver` on `spring.datasource` and the rest on your custom namespace (`app.datasource`). +To avoid that, you can redefine a custom `DataSourceProperties` on your custom namespace, as shown in the following example: + +[source,java,indent=0,subs="verbatim,quotes,attributes"] +---- +include::{include-howto}/dataaccess/ConfigurableDataSourceConfiguration.java[tag=*] +---- + +This setup puts you _in sync_ with what Spring Boot does for you by default, except that a dedicated connection pool is chosen (in code) and its settings are exposed in the `app.datasource.configuration` sub namespace. +Because `DataSourceProperties` is taking care of the `url`/`jdbcUrl` translation for you, you can configure it as follows: + +[source,yaml,indent=0,configblocks] +---- + app: + datasource: + url: "jdbc:mysql://localhost/test" + username: "dbuser" + password: "dbpass" + configuration: + maximum-pool-size: 30 +---- + +TIP: Spring Boot will expose Hikari-specific settings to `spring.datasource.hikari`. +This example uses a more generic `configuration` sub namespace as the example does not support multiple datasource implementations. + +NOTE: Because your custom configuration chooses to go with Hikari, `app.datasource.type` has no effect. +In practice, the builder is initialized with whatever value you might set there and then overridden by the call to `.type()`. + +See "`<>`" in the "`Spring Boot features`" section and the {spring-boot-autoconfigure-module-code}/jdbc/DataSourceAutoConfiguration.java[`DataSourceAutoConfiguration`] class for more details. + + + +[[howto.data-access.configure-two-datasources]] +=== Configure Two DataSources +If you need to configure multiple data sources, you can apply the same tricks that are described in the previous section. +You must, however, mark one of the `DataSource` instances as `@Primary`, because various auto-configurations down the road expect to be able to get one by type. + +If you create your own `DataSource`, the auto-configuration backs off. +In the following example, we provide the _exact_ same feature set as the auto-configuration provides on the primary data source: + +[source,java,indent=0,subs="verbatim,quotes,attributes"] +---- +include::{include-howto}/dataaccess/SimpleDataSourcesConfiguration.java[tag=*] +---- + +TIP: `firstDataSourceProperties` has to be flagged as `@Primary` so that the database initializer feature uses your copy (if you use the initializer). + +Both data sources are also bound for advanced customizations. +For instance, you could configure them as follows: + +[source,yaml,indent=0,configblocks] +---- + app: + datasource: + first: + url: "jdbc:mysql://localhost/first" + username: "dbuser" + password: "dbpass" + configuration: + maximum-pool-size: 30 + + second: + url: "jdbc:mysql://localhost/second" + username: "dbuser" + password: "dbpass" + max-total: 30 +---- + +You can apply the same concept to the secondary `DataSource` as well, as shown in the following example: + +[source,java,indent=0,subs="verbatim,quotes,attributes"] +---- +include::{include-howto}/dataaccess/CompleteDataSourcesConfiguration.java[tag=*] +---- + +The preceding example configures two data sources on custom namespaces with the same logic as Spring Boot would use in auto-configuration. +Note that each `configuration` sub namespace provides advanced settings based on the chosen implementation. + + + +[[howto.data-access.spring-data-repositories]] +=== Use Spring Data Repositories +Spring Data can create implementations of `@Repository` interfaces of various flavors. +Spring Boot handles all of that for you, as long as those `@Repositories` are included in the same package (or a sub-package) of your `@EnableAutoConfiguration` class. + +For many applications, all you need is to put the right Spring Data dependencies on your classpath. +There is a `spring-boot-starter-data-jpa` for JPA, `spring-boot-starter-data-mongodb` for Mongodb, etc. +To get started, create some repository interfaces to handle your `@Entity` objects. + +Spring Boot tries to guess the location of your `@Repository` definitions, based on the `@EnableAutoConfiguration` it finds. +To get more control, use the `@EnableJpaRepositories` annotation (from Spring Data JPA). + +For more about Spring Data, see the {spring-data}[Spring Data project page]. + + + +[[howto.data-access.separate-entity-definitions-from-spring-configuration]] +=== Separate @Entity Definitions from Spring Configuration +Spring Boot tries to guess the location of your `@Entity` definitions, based on the `@EnableAutoConfiguration` it finds. +To get more control, you can use the `@EntityScan` annotation, as shown in the following example: + +[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] +---- + @Configuration(proxyBeanMethods = false) + @EnableAutoConfiguration + @EntityScan(basePackageClasses=City.class) + public class Application { + + //... + + } +---- + + + +[[howto.data-access.jpa-properties]] +=== Configure JPA Properties +Spring Data JPA already provides some vendor-independent configuration options (such as those for SQL logging), and Spring Boot exposes those options and a few more for Hibernate as external configuration properties. +Some of them are automatically detected according to the context so you should not have to set them. + +The `spring.jpa.hibernate.ddl-auto` is a special case, because, depending on runtime conditions, it has different defaults. +If an embedded database is used and no schema manager (such as Liquibase or Flyway) is handling the `DataSource`, it defaults to `create-drop`. +In all other cases, it defaults to `none`. + +The dialect to use is detected by the JPA provider. +If you prefer to set the dialect yourself, set the configprop:spring.jpa.database-platform[] property. + +The most common options to set are shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + jpa: + hibernate: + naming: + physical-strategy: "com.example.MyPhysicalNamingStrategy" + show-sql: true +---- + +In addition, all properties in `+spring.jpa.properties.*+` are passed through as normal JPA properties (with the prefix stripped) when the local `EntityManagerFactory` is created. + +[WARNING] +==== +You need to ensure that names defined under `+spring.jpa.properties.*+` exactly match those expected by your JPA provider. +Spring Boot will not attempt any kind of relaxed binding for these entries. + +For example, if you want to configure Hibernate's batch size you must use `+spring.jpa.properties.hibernate.jdbc.batch_size+`. +If you use other forms, such as `batchSize` or `batch-size`, Hibernate will not apply the setting. +==== + +TIP: If you need to apply advanced customization to Hibernate properties, consider registering a `HibernatePropertiesCustomizer` bean that will be invoked prior to creating the `EntityManagerFactory`. +This takes precedence to anything that is applied by the auto-configuration. + + + +[[howto.data-access.configure-hibernate-naming-strategy]] +=== Configure Hibernate Naming Strategy +Hibernate uses {hibernate-docs}#naming[two different naming strategies] to map names from the object model to the corresponding database names. +The fully qualified class name of the physical and the implicit strategy implementations can be configured by setting the `spring.jpa.hibernate.naming.physical-strategy` and `spring.jpa.hibernate.naming.implicit-strategy` properties, respectively. +Alternatively, if `ImplicitNamingStrategy` or `PhysicalNamingStrategy` beans are available in the application context, Hibernate will be automatically configured to use them. + +By default, Spring Boot configures the physical naming strategy with `SpringPhysicalNamingStrategy`. +This implementation provides the same table structure as Hibernate 4: all dots are replaced by underscores and camel casing is replaced by underscores as well. Additionally, by default, all table names are generated in lower case. For example, a `TelephoneNumber` entity is mapped to the `telephone_number` table. If your schema requires mixed-case identifiers, define a custom `SpringPhysicalNamingStrategy` bean, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-howto}/dataaccess/CaseSensitiveSpringPhysicalNamingStrategyConfiguration.java[tag=*] +---- + +If you prefer to use Hibernate 5's default instead, set the following property: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + spring.jpa.hibernate.naming.physical-strategy=org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl +---- + +Alternatively, you can configure the following bean: + +[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] +---- + @Bean + public PhysicalNamingStrategy physicalNamingStrategy() { + return new PhysicalNamingStrategyStandardImpl(); + } +---- + +See {spring-boot-autoconfigure-module-code}/orm/jpa/HibernateJpaAutoConfiguration.java[`HibernateJpaAutoConfiguration`] and {spring-boot-autoconfigure-module-code}/orm/jpa/JpaBaseConfiguration.java[`JpaBaseConfiguration`] for more details. + + + +[[howto.data-access.configure-hibernate-second-level-caching]] +=== Configure Hibernate Second-Level Caching +Hibernate {hibernate-docs}#caching[second-level cache] can be configured for a range of cache providers. +Rather than configuring Hibernate to lookup the cache provider again, it is better to provide the one that is available in the context whenever possible. + +To do this with JCache, first make sure that `org.hibernate:hibernate-jcache` is available on the classpath. +Then, add a `HibernatePropertiesCustomizer` bean as shown in the following example: + +[source,java,indent=0] +---- +include::{include-howto}/dataaccess/HibernateSecondLevelCacheConfiguration.java[tag=*] +---- + +This customizer will configure Hibernate to use the same `CacheManager` as the one that the application uses. +It is also possible to use separate `CacheManager` instances. +For details, refer to {hibernate-docs}#caching-provider-jcache[the Hibernate user guide]. + + + +[[howto.data-access.dependency-injection-in-hibernate-components]] +=== Use Dependency Injection in Hibernate Components +By default, Spring Boot registers a `BeanContainer` implementation that uses the `BeanFactory` so that converters and entity listeners can use regular dependency injection. + +You can disable or tune this behaviour by registering a `HibernatePropertiesCustomizer` that removes or changes the `hibernate.resource.beans.container` property. + + + +[[howto.data-access.use-custom-entity-manager]] +=== Use a Custom EntityManagerFactory +To take full control of the configuration of the `EntityManagerFactory`, you need to add a `@Bean` named '`entityManagerFactory`'. +Spring Boot auto-configuration switches off its entity manager in the presence of a bean of that type. + + + +[[howto.data-access.use-multiple-entity-managers]] +[[howto.data-access.use-multiple-entity-managers]] +=== Using Multiple EntityManagerFactories +If you need to use JPA against multiple data sources, you likely need one `EntityManagerFactory` per data source. +The `LocalContainerEntityManagerFactoryBean` from Spring ORM allows you to configure an `EntityManagerFactory` for your needs. +You can also reuse `JpaProperties` to bind settings for each `EntityManagerFactory`, as shown in the following example: + +[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] +---- +include::{include-howto}/dataaccess/CustomEntityManagerFactoryExample.java[tag=*] +---- + +The example above creates an `EntityManagerFactory` using a `DataSource` bean named `firstDataSource`. +It scans entities located in the same package as `Order`. +It is possible to map additional JPA properties using the `app.first.jpa` namespace. + +NOTE: When you create a bean for `LocalContainerEntityManagerFactoryBean` yourself, any customization that was applied during the creation of the auto-configured `LocalContainerEntityManagerFactoryBean` is lost. +For example, in case of Hibernate, any properties under the `spring.jpa.hibernate` prefix will not be automatically applied to your `LocalContainerEntityManagerFactoryBean`. +If you were relying on these properties for configuring things like the naming strategy or the DDL mode, you will need to explicitly configure that when creating the `LocalContainerEntityManagerFactoryBean` bean. + +You should provide a similar configuration for any additional data sources for which you need JPA access. +To complete the picture, you need to configure a `JpaTransactionManager` for each `EntityManagerFactory` as well. +Alternatively, you might be able to use a JTA transaction manager that spans both. + +If you use Spring Data, you need to configure `@EnableJpaRepositories` accordingly, as shown in the following example: + +[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] +---- + @Configuration(proxyBeanMethods = false) + @EnableJpaRepositories(basePackageClasses = Order.class, + entityManagerFactoryRef = "firstEntityManagerFactory") + public class OrderConfiguration { + ... + } + + @Configuration(proxyBeanMethods = false) + @EnableJpaRepositories(basePackageClasses = Customer.class, + entityManagerFactoryRef = "secondEntityManagerFactory") + public class CustomerConfiguration { + ... + } +---- + + + +[[howto.data-access.use-traditional-persistence-xml]] +=== Use a Traditional persistence.xml File +Spring Boot will not search for or use a `META-INF/persistence.xml` by default. +If you prefer to use a traditional `persistence.xml`, you need to define your own `@Bean` of type `LocalEntityManagerFactoryBean` (with an ID of '`entityManagerFactory`') and set the persistence unit name there. + +See {spring-boot-autoconfigure-module-code}/orm/jpa/JpaBaseConfiguration.java[`JpaBaseConfiguration`] for the default settings. + + + +[[howto.data-access.use-spring-data-jpa-and-mongo-repositories]] +=== Use Spring Data JPA and Mongo Repositories +Spring Data JPA and Spring Data Mongo can both automatically create `Repository` implementations for you. +If they are both present on the classpath, you might have to do some extra configuration to tell Spring Boot which repositories to create. +The most explicit way to do that is to use the standard Spring Data `+@EnableJpaRepositories+` and `+@EnableMongoRepositories+` annotations and provide the location of your `Repository` interfaces. + +There are also flags (`+spring.data.*.repositories.enabled+` and `+spring.data.*.repositories.type+`) that you can use to switch the auto-configured repositories on and off in external configuration. +Doing so is useful, for instance, in case you want to switch off the Mongo repositories and still use the auto-configured `MongoTemplate`. + +The same obstacle and the same features exist for other auto-configured Spring Data repository types (Elasticsearch, Solr, and others). +To work with them, change the names of the annotations and flags accordingly. + + + +[[howto.data-access.customize-spring-data-web-support]] +=== Customize Spring Data's Web Support +Spring Data provides web support that simplifies the use of Spring Data repositories in a web application. +Spring Boot provides properties in the `spring.data.web` namespace for customizing its configuration. +Note that if you are using Spring Data REST, you must use the properties in the `spring.data.rest` namespace instead. + + + +[[howto.data-access.exposing-spring-data-repositories-as-rest]] +=== Expose Spring Data Repositories as REST Endpoint +Spring Data REST can expose the `Repository` implementations as REST endpoints for you, +provided Spring MVC has been enabled for the application. + +Spring Boot exposes a set of useful properties (from the `spring.data.rest` namespace) that customize the {spring-data-rest-api}/core/config/RepositoryRestConfiguration.html[`RepositoryRestConfiguration`]. +If you need to provide additional customization, you should use a {spring-data-rest-api}/webmvc/config/RepositoryRestConfigurer.html[`RepositoryRestConfigurer`] bean. + +NOTE: If you do not specify any order on your custom `RepositoryRestConfigurer`, it runs after the one Spring Boot uses internally. +If you need to specify an order, make sure it is higher than 0. + + + +[[howto.data-access.configure-a-component-that-is-used-by-jpa]] +=== Configure a Component that is Used by JPA +If you want to configure a component that JPA uses, then you need to ensure that the component is initialized before JPA. +When the component is auto-configured, Spring Boot takes care of this for you. +For example, when Flyway is auto-configured, Hibernate is configured to depend upon Flyway so that Flyway has a chance to initialize the database before Hibernate tries to use it. + +If you are configuring a component yourself, you can use an `EntityManagerFactoryDependsOnPostProcessor` subclass as a convenient way of setting up the necessary dependencies. +For example, if you use Hibernate Search with Elasticsearch as its index manager, any `EntityManagerFactory` beans must be configured to depend on the `elasticsearchClient` bean, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-howto}/dataaccess/ElasticsearchEntityManagerFactoryDependsOnPostProcessor.java[tag=*] +---- + + + +[[howto.data-access.configure-jooq-with-multiple-datasources]] +=== Configure jOOQ with Two DataSources +If you need to use jOOQ with multiple data sources, you should create your own `DSLContext` for each one. +Refer to {spring-boot-autoconfigure-module-code}/jooq/JooqAutoConfiguration.java[JooqAutoConfiguration] for more details. + +TIP: In particular, `JooqExceptionTranslator` and `SpringTransactionProvider` can be reused to provide similar features to what the auto-configuration does with a single `DataSource`. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/data-initialization.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/data-initialization.adoc new file mode 100644 index 0000000000..c13895492f --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/data-initialization.adoc @@ -0,0 +1,217 @@ +[[howto.data-initialization]] +== Database Initialization +An SQL database can be initialized in different ways depending on what your stack is. +Of course, you can also do it manually, provided the database is a separate process. +It is recommended to use a single mechanism for schema generation. + + + +[[howto.data-initialization.using-jpa]] +=== Initialize a Database Using JPA +JPA has features for DDL generation, and these can be set up to run on startup against the database. +This is controlled through two external properties: + +* `spring.jpa.generate-ddl` (boolean) switches the feature on and off and is vendor independent. +* `spring.jpa.hibernate.ddl-auto` (enum) is a Hibernate feature that controls the behavior in a more fine-grained way. + This feature is described in more detail later in this guide. + + + +[[howto.data-initialization.using-hibernate]] +=== Initialize a Database Using Hibernate +You can set `spring.jpa.hibernate.ddl-auto` explicitly and the standard Hibernate property values are `none`, `validate`, `update`, `create`, and `create-drop`. +Spring Boot chooses a default value for you based on whether it thinks your database is embedded. +It defaults to `create-drop` if no schema manager has been detected or `none` in all other cases. +An embedded database is detected by looking at the `Connection` type and JDBC url. +`hsqldb`, `h2`, and `derby` are candidates, and others are not. +Be careful when switching from in-memory to a '`real`' database that you do not make assumptions about the existence of the tables and data in the new platform. +You either have to set `ddl-auto` explicitly or use one of the other mechanisms to initialize the database. + +NOTE: You can output the schema creation by enabling the `org.hibernate.SQL` logger. +This is done for you automatically if you enable the <>. + +In addition, a file named `import.sql` in the root of the classpath is executed on startup if Hibernate creates the schema from scratch (that is, if the `ddl-auto` property is set to `create` or `create-drop`). +This can be useful for demos and for testing if you are careful but is probably not something you want to be on the classpath in production. +It is a Hibernate feature (and has nothing to do with Spring). + + + +[[howto.data-initialization.using-basic-sql-scripts]] +=== Initialize a Database Using Basic SQL Scripts +Spring Boot can automatically create the schema (DDL scripts) of your JDBC `DataSource` or R2DBC `ConnectionFactory` and initialize it (DML scripts). +It loads SQL from the standard root classpath locations: `schema.sql` and `data.sql`, respectively. +In addition, Spring Boot processes the `schema-$\{platform}.sql` and `data-$\{platform}.sql` files (if present), where `platform` is the value of configprop:spring.sql.init.platform[]. +This allows you to switch to database-specific scripts if necessary. +For example, you might choose to set it to the vendor name of the database (`hsqldb`, `h2`, `oracle`, `mysql`, `postgresql`, and so on). +SQL database initialization can be disabled by setting configprop:spring.sql.init.enabled[] to `false`. +By default, Spring Boot enables the fail-fast feature of its script-based database initializer. +This means that, if the scripts cause exceptions, the application fails to start. +You can tune that behavior by setting configprop:spring.sql.init.continue-on-error[]. + +Script-based `DataSource` initialization is performed, by default, before any JPA `EntityManagerFactory` beans are created. +`schema.sql` can be used to create the schema for JPA-managed entities and `data.sql` can be used to populate it. +While we do not recommend using multiple data source initialization technologies, if you want script-based `DataSource` initialization to be able to build upon the schema creation performed by Hibernate, set configprop:spring.jpa.defer-datasource-initialization[] to `true`. +This will defer data source initialization until after any `EntityManagerFactory` beans have been created and initialized. +`schema.sql` can then be used to make additions to any schema creation performed by Hibernate and `data.sql` can be used to populate it. + +If you are using a <>, like Flyway or Liquibase, you should use them alone to create and initialize the schema. +Using the basic `schema.sql` and `data.sql` scripts alongside Flyway or Liquibase is not recommended and support will be removed in a future release. + + + +[[howto.data-initialization.batch]] +=== Initialize a Spring Batch Database +If you use Spring Batch, it comes pre-packaged with SQL initialization scripts for most popular database platforms. +Spring Boot can detect your database type and execute those scripts on startup. +If you use an embedded database, this happens by default. +You can also enable it for any database type, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + batch: + jdbc: + initialize-schema: "always" +---- + +You can also switch off the initialization explicitly by setting `spring.batch.jdbc.initialize-schema` to `never`. + + + +[[howto.data-initialization.migration-tool]] +=== Use a Higher-level Database Migration Tool +Spring Boot supports two higher-level migration tools: https://flywaydb.org/[Flyway] and https://www.liquibase.org/[Liquibase]. + + + +[[howto.data-initialization.migration-tool.flyway]] +==== Execute Flyway Database Migrations on Startup +To automatically run Flyway database migrations on startup, add the `org.flywaydb:flyway-core` to your classpath. + +Typically, migrations are scripts in the form `V__.sql` (with `` an underscore-separated version, such as '`1`' or '`2_1`'). +By default, they are in a directory called `classpath:db/migration`, but you can modify that location by setting `spring.flyway.locations`. +This is a comma-separated list of one or more `classpath:` or `filesystem:` locations. +For example, the following configuration would search for scripts in both the default classpath location and the `/opt/migration` directory: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + flyway: + locations: "classpath:db/migration,filesystem:/opt/migration" +---- + +You can also add a special `\{vendor}` placeholder to use vendor-specific scripts. +Assume the following: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + flyway: + locations: "classpath:db/migration/{vendor}" +---- + +Rather than using `db/migration`, the preceding configuration sets the directory to use according to the type of the database (such as `db/migration/mysql` for MySQL). +The list of supported databases is available in {spring-boot-module-code}/jdbc/DatabaseDriver.java[`DatabaseDriver`]. + +Migrations can also be written in Java. +Flyway will be auto-configured with any beans that implement `JavaMigration`. + +{spring-boot-autoconfigure-module-code}/flyway/FlywayProperties.java[`FlywayProperties`] provides most of Flyway's settings and a small set of additional properties that can be used to disable the migrations or switch off the location checking. +If you need more control over the configuration, consider registering a `FlywayConfigurationCustomizer` bean. + +Spring Boot calls `Flyway.migrate()` to perform the database migration. +If you would like more control, provide a `@Bean` that implements {spring-boot-autoconfigure-module-code}/flyway/FlywayMigrationStrategy.java[`FlywayMigrationStrategy`]. + +Flyway supports SQL and Java https://flywaydb.org/documentation/concepts/callbacks[callbacks]. +To use SQL-based callbacks, place the callback scripts in the `classpath:db/migration` directory. +To use Java-based callbacks, create one or more beans that implement `Callback`. +Any such beans are automatically registered with `Flyway`. +They can be ordered by using `@Order` or by implementing `Ordered`. +Beans that implement the deprecated `FlywayCallback` interface can also be detected, however they cannot be used alongside `Callback` beans. + +By default, Flyway autowires the (`@Primary`) `DataSource` in your context and uses that for migrations. +If you like to use a different `DataSource`, you can create one and mark its `@Bean` as `@FlywayDataSource`. +If you do so and want two data sources, remember to create another one and mark it as `@Primary`. +Alternatively, you can use Flyway's native `DataSource` by setting `spring.flyway.[url,user,password]` in external properties. +Setting either `spring.flyway.url` or `spring.flyway.user` is sufficient to cause Flyway to use its own `DataSource`. +If any of the three properties has not been set, the value of its equivalent `spring.datasource` property will be used. + +You can also use Flyway to provide data for specific scenarios. +For example, you can place test-specific migrations in `src/test/resources` and they are run only when your application starts for testing. +Also, you can use profile-specific configuration to customize `spring.flyway.locations` so that certain migrations run only when a particular profile is active. +For example, in `application-dev.properties`, you might specify the following setting: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + flyway: + locations: "classpath:/db/migration,classpath:/dev/db/migration" +---- + +With that setup, migrations in `dev/db/migration` run only when the `dev` profile is active. + + + +[[howto.data-initialization.migration-tool.liquibase]] +==== Execute Liquibase Database Migrations on Startup +To automatically run Liquibase database migrations on startup, add the `org.liquibase:liquibase-core` to your classpath. + +[NOTE] +==== +When you add the `org.liquibase:liquibase-core` to your classpath, database migrations run by default for both during application startup and before your tests run. +This behavior can be customized by using the configprop:spring.liquibase.enabled[] property, setting different values in the `main` and `test` configurations. +It is not possible to use two different ways to initialize the database (e.g. Liquibase for application startup, JPA for test runs). +==== + +By default, the master change log is read from `db/changelog/db.changelog-master.yaml`, but you can change the location by setting `spring.liquibase.change-log`. +In addition to YAML, Liquibase also supports JSON, XML, and SQL change log formats. + +By default, Liquibase autowires the (`@Primary`) `DataSource` in your context and uses that for migrations. +If you need to use a different `DataSource`, you can create one and mark its `@Bean` as `@LiquibaseDataSource`. +If you do so and you want two data sources, remember to create another one and mark it as `@Primary`. +Alternatively, you can use Liquibase's native `DataSource` by setting `spring.liquibase.[driver-class-name,url,user,password]` in external properties. +Setting either `spring.liquibase.url` or `spring.liquibase.user` is sufficient to cause Liquibase to use its own `DataSource`. +If any of the three properties has not been set, the value of its equivalent `spring.datasource` property will be used. + +See {spring-boot-autoconfigure-module-code}/liquibase/LiquibaseProperties.java[`LiquibaseProperties`] for details about available settings such as contexts, the default schema, and others. + + + +[[howto.data-initialization.dependencies]] +=== Depend Upon an Initialized Database +Database initialization is performed while the application is starting up as part of application context refresh. +To allow an initialized database to be accessed during startup, beans that act as database initializers and beans that require that database to have been initialized are detected automatically. +Beans whose initialization depends upon the database having been initialized are configured to depend upon those that initialize it. +If, during startup, your application tries to access the database and it has not been initialized, you can configure additional detection of beans that initialize the database and require the database to have been initialized. + + + +[[howto.data-initialization.dependencies.initializer-detection]] +==== Detect a Database Initializer +Spring Boot will automatically detect beans of the following types that initialize an SQL database: + +- `DataSourceScriptDatabaseInitializer` +- `EntityManagerFactory` +- `Flyway` +- `FlywayMigrationInitializer` +- `R2dbcScriptDatabaseInitializer` +- `SpringLiquibase` + +If you are using a third-party starter for a database initialization library, it may provide a detector such that beans of other types are also detected automatically. +To have other beans be detected, register an implementation of `DatabaseInitializerDetector` in `META-INF/spring-factories`. + + + +[[howto.data-initialization.dependencies.depends-on-initialization-detection]] +==== Detect a Bean That Depends On Database Initialization +Spring Boot will automatically detect beans of the following types that depends upon database initialization: + +- `AbstractEntityManagerFactoryBean` (unless configprop:spring.jpa.defer-datasource-initialization[] is set to `true`) +- `DSLContext` (jOOQ) +- `EntityManagerFactory` (unless configprop:spring.jpa.defer-datasource-initialization[] is set to `true`) +- `JdbcOperations` +- `NamedParameterJdbcOperations` + +If you are using a third-party starter data access library, it may provide a detector such that beans of other types are also detected automatically. +To have other beans be detected, register an implementation of `DependsOnDatabaseInitializationDetector` in `META-INF/spring-factories`. +Alternatively, annotate the bean's class or its `@Bean` method with `@DependsOnDatabaseInitialization`. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/hotswapping.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/hotswapping.adoc new file mode 100644 index 0000000000..9a6ec3f495 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/hotswapping.adoc @@ -0,0 +1,67 @@ +[[howto.hotswapping]] +== Hot Swapping +Spring Boot supports hot swapping. +This section answers questions about how it works. + + + +[[howto.hotswapping.reload-static-content]] +=== Reload Static Content +There are several options for hot reloading. +The recommended approach is to use <>, as it provides additional development-time features, such as support for fast application restarts and LiveReload as well as sensible development-time configuration (such as template caching). +Devtools works by monitoring the classpath for changes. +This means that static resource changes must be "built" for the change to take effect. +By default, this happens automatically in Eclipse when you save your changes. +In IntelliJ IDEA, the Make Project command triggers the necessary build. +Due to the <>, changes to static resources do not trigger a restart of your application. +They do, however, trigger a live reload. + +Alternatively, running in an IDE (especially with debugging on) is a good way to do development (all modern IDEs allow reloading of static resources and usually also allow hot-swapping of Java class changes). + +Finally, the <> can be configured (see the `addResources` property) to support running from the command line with reloading of static files directly from source. +You can use that with an external css/js compiler process if you are writing that code with higher-level tools. + + + +[[howto.hotswapping.reload-templates]] +=== Reload Templates without Restarting the Container +Most of the templating technologies supported by Spring Boot include a configuration option to disable caching (described later in this document). +If you use the `spring-boot-devtools` module, these properties are <> for you at development time. + + + +[[howto.hotswapping.reload-templates.thymeleaf]] +==== Thymeleaf Templates +If you use Thymeleaf, set `spring.thymeleaf.cache` to `false`. +See {spring-boot-autoconfigure-module-code}/thymeleaf/ThymeleafAutoConfiguration.java[`ThymeleafAutoConfiguration`] for other Thymeleaf customization options. + + + +[[howto.hotswapping.reload-templates.freemarker]] +==== FreeMarker Templates +If you use FreeMarker, set `spring.freemarker.cache` to `false`. +See {spring-boot-autoconfigure-module-code}/freemarker/FreeMarkerAutoConfiguration.java[`FreeMarkerAutoConfiguration`] for other FreeMarker customization options. + + + +[[howto.hotswapping.reload-templates.groovy]] +==== Groovy Templates +If you use Groovy templates, set `spring.groovy.template.cache` to `false`. +See {spring-boot-autoconfigure-module-code}/groovy/template/GroovyTemplateAutoConfiguration.java[`GroovyTemplateAutoConfiguration`] for other Groovy customization options. + + + +[[howto.hotswapping.fast-application-restarts]] +=== Fast Application Restarts +The `spring-boot-devtools` module includes support for automatic application restarts. +While not as fast as technologies such as https://www.jrebel.com/products/jrebel[JRebel] it is usually significantly faster than a "`cold start`". +You should probably give it a try before investigating some of the more complex reload options discussed later in this document. + +For more details, see the <> section. + + + +[[howto.hotswapping.reload-java-classes-without-restarting]] +=== Reload Java Classes without Restarting the Container +Many modern IDEs (Eclipse, IDEA, and others) support hot swapping of bytecode. +Consequently, if you make a change that does not affect class or method signatures, it should reload cleanly with no side effects. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/http-clients.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/http-clients.adoc new file mode 100644 index 0000000000..1d6c050878 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/http-clients.adoc @@ -0,0 +1,35 @@ +[[howto.http-clients]] +== HTTP Clients +Spring Boot offers a number of starters that work with HTTP clients. +This section answers questions related to using them. + + + +[[howto.http-clients.rest-template-proxy-configuration]] +=== Configure RestTemplate to Use a Proxy +As described in <>, you can use a `RestTemplateCustomizer` with `RestTemplateBuilder` to build a customized `RestTemplate`. +This is the recommended approach for creating a `RestTemplate` configured to use a proxy. + +The exact details of the proxy configuration depend on the underlying client request factory that is being used. +The following example configures `HttpComponentsClientRequestFactory` with an `HttpClient` that uses a proxy for all hosts except `192.168.0.5`: + +[source,java,indent=0] +---- +include::{include-springbootfeatures}/resttemplate/RestTemplateProxyCustomizer.java[tag=*] +---- + + + +[[howto.http-clients.webclient-reactor-netty-customization]] +=== Configure the TcpClient used by a Reactor Netty-based WebClient +When Reactor Netty is on the classpath a Reactor Netty-based `WebClient` is auto-configured. +To customize the client's handling of network connections, provide a `ClientHttpConnector` bean. +The following example configures a 60 second connect timeout and adds a `ReadTimeoutHandler`: + +[source,java,indent=0] +---- +include::{include-howto}/httpclients/CustomizeReactorNettyClientConfiguration.java[tag=*] +---- + +TIP: Note the use of `ReactorResourceFactory` for the connection provider and event loop resources. +This ensures efficient sharing of resources for the server receiving requests and the client making requests. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/jedis-instead-of-lettuce.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/jedis-instead-of-lettuce.adoc new file mode 100644 index 0000000000..87a30edb8c --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/jedis-instead-of-lettuce.adoc @@ -0,0 +1,38 @@ +[[howto.jedis-instead-of-lettuce]] +== Use Jedis Instead of Lettuce +By default, the Spring Boot starter (`spring-boot-starter-data-redis`) uses https://github.com/lettuce-io/lettuce-core/[Lettuce]. +You need to exclude that dependency and include the https://github.com/xetorthio/jedis/[Jedis] one instead. +Spring Boot manages both of these dependencies so you can switch to Jedis without specifying a version. + +The following example shows how to do so in Maven: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + org.springframework.boot + spring-boot-starter-data-redis + + + io.lettuce + lettuce-core + + + + + redis.clients + jedis + +---- + +The following example shows how to do so in Gradle: + +[source,groovy,indent=0,subs="verbatim,quotes,attributes"] +---- + dependencies { + implementation('org.springframework.boot:spring-boot-starter-data-redis') { + exclude group: 'io.lettuce', module: 'lettuce-core' + } + implementation 'redis.clients:jedis' + // ... + } +---- diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/jersey.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/jersey.adoc new file mode 100644 index 0000000000..2aadd44a7b --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/jersey.adoc @@ -0,0 +1,38 @@ +[[howto.jersey]] +== Jersey + + + +[[howto.jersey.spring-security]] +=== Secure Jersey endpoints with Spring Security +Spring Security can be used to secure a Jersey-based web application in much the same way as it can be used to secure a Spring MVC-based web application. +However, if you want to use Spring Security's method-level security with Jersey, you must configure Jersey to use `setStatus(int)` rather `sendError(int)`. +This prevents Jersey from committing the response before Spring Security has had an opportunity to report an authentication or authorization failure to the client. + +The `jersey.config.server.response.setStatusOverSendError` property must be set to `true` on the application's `ResourceConfig` bean, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-howto}/jersey/JerseySetStatusOverSendErrorConfig.java[tag=*] +---- + + + +[[howto.jersey.alongside-another-web-framework]] +=== Use Jersey Alongside Another Web Framework +To use Jersey alongside another web framework, such as Spring MVC, it should be configured so that it will allow the other framework to handle requests that it cannot handle. +First, configure Jersey to use a Filter rather than a Servlet by configuring the configprop:spring.jersey.type[] application property with a value of `filter`. +Second, configure your `ResourceConfig` to forward requests that would have resulted in a 404, as shown in the following example. + +[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] +---- + @Component + public class JerseyConfig extends ResourceConfig { + + public JerseyConfig() { + register(Endpoint.class); + property(ServletProperties.FILTER_FORWARD_ON_404, true); + } + + } +---- diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/logging.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/logging.adoc new file mode 100644 index 0000000000..2e77961618 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/logging.adoc @@ -0,0 +1,189 @@ +[[howto.logging]] +== Logging +Spring Boot has no mandatory logging dependency, except for the Commons Logging API, which is typically provided by Spring Framework's `spring-jcl` module. +To use https://logback.qos.ch[Logback], you need to include it and `spring-jcl` on the classpath. +The recommended way to do that is through the starters, which all depend on `spring-boot-starter-logging`. +For a web application, you need only `spring-boot-starter-web`, since it depends transitively on the logging starter. +If you use Maven, the following dependency adds logging for you: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + org.springframework.boot + spring-boot-starter-web + +---- + +Spring Boot has a `LoggingSystem` abstraction that attempts to configure logging based on the content of the classpath. +If Logback is available, it is the first choice. + +If the only change you need to make to logging is to set the levels of various loggers, you can do so in `application.properties` by using the "logging.level" prefix, as shown in the following example: + +[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] +---- + logging: + level: + org.springframework.web: "debug" + org.hibernate: "error" +---- + +You can also set the location of a file to which to write the log (in addition to the console) by using `logging.file.name`. + +To configure the more fine-grained settings of a logging system, you need to use the native configuration format supported by the `LoggingSystem` in question. +By default, Spring Boot picks up the native configuration from its default location for the system (such as `classpath:logback.xml` for Logback), but you can set the location of the config file by using the configprop:logging.config[] property. + + + +[[howto.logging.logback]] +=== Configure Logback for Logging +If you need to apply customizations to logback beyond those that can be achieved with `application.properties`, you'll need to add a standard logback configuration file. +You can add a `logback.xml` file to the root of your classpath for logback to find. +You can also use `logback-spring.xml` if you want to use the <>. + +TIP: The Logback documentation has a https://logback.qos.ch/manual/configuration.html[dedicated section that covers configuration] in some detail. + +Spring Boot provides a number of logback configurations that be `included` from your own configuration. +These includes are designed to allow certain common Spring Boot conventions to be re-applied. + +The following files are provided under `org/springframework/boot/logging/logback/`: + +* `defaults.xml` - Provides conversion rules, pattern properties and common logger configurations. +* `console-appender.xml` - Adds a `ConsoleAppender` using the `CONSOLE_LOG_PATTERN`. +* `file-appender.xml` - Adds a `RollingFileAppender` using the `FILE_LOG_PATTERN` and `ROLLING_FILE_NAME_PATTERN` with appropriate settings. + +In addition, a legacy `base.xml` file is provided for compatibility with earlier versions of Spring Boot. + +A typical custom `logback.xml` file would look something like this: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + + + + + + + + +---- + +Your logback configuration file can also make use of System properties that the `LoggingSystem` takes care of creating for you: + +* `$\{PID}`: The current process ID. +* `$\{LOG_FILE}`: Whether `logging.file.name` was set in Boot's external configuration. +* `$\{LOG_PATH}`: Whether `logging.file.path` (representing a directory for log files to live in) was set in Boot's external configuration. +* `$\{LOG_EXCEPTION_CONVERSION_WORD}`: Whether `logging.exception-conversion-word` was set in Boot's external configuration. +* `$\{ROLLING_FILE_NAME_PATTERN}`: Whether `logging.pattern.rolling-file-name` was set in Boot's external configuration. + +Spring Boot also provides some nice ANSI color terminal output on a console (but not in a log file) by using a custom Logback converter. +See the `CONSOLE_LOG_PATTERN` in the `defaults.xml` configuration for an example. + +If Groovy is on the classpath, you should be able to configure Logback with `logback.groovy` as well. +If present, this setting is given preference. + +NOTE: Spring extensions are not supported with Groovy configuration. +Any `logback-spring.groovy` files will not be detected. + + + +[[howto.logging.logback.file-only-output]] +==== Configure Logback for File-only Output +If you want to disable console logging and write output only to a file, you need a custom `logback-spring.xml` that imports `file-appender.xml` but not `console-appender.xml`, as shown in the following example: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + + + + + + + + +---- + +You also need to add `logging.file.name` to your `application.properties` or `application.yaml`, as shown in the following example: + +[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] +---- + logging: + file: + name: "myapplication.log" +---- + + + +[[howto.logging.log4j]] +=== Configure Log4j for Logging +Spring Boot supports https://logging.apache.org/log4j/2.x/[Log4j 2] for logging configuration if it is on the classpath. +If you use the starters for assembling dependencies, you have to exclude Logback and then include log4j 2 instead. +If you do not use the starters, you need to provide (at least) `spring-jcl` in addition to Log4j 2. + +The recommended path is through the starters, even though it requires some jiggling. +The following example shows how to set up the starters in Maven: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + org.springframework.boot + spring-boot-starter-web + + + org.springframework.boot + spring-boot-starter + + + org.springframework.boot + spring-boot-starter-logging + + + + + org.springframework.boot + spring-boot-starter-log4j2 + +---- + +And the following example shows one way to set up the starters in Gradle: + +[source,groovy,indent=0,subs="verbatim,quotes,attributes"] +---- + dependencies { + compile 'org.springframework.boot:spring-boot-starter-web' + } + + configurations.all { + resolutionStrategy.dependencySubstitution.all { dependency -> + if (dependency.requested instanceof ModuleComponentSelector && dependency.requested.module == 'spring-boot-starter-logging') { + dependency.useTarget("org.springframework.boot:spring-boot-starter-log4j2:$dependency.requested.version", 'Use Log4j2 instead of Logback') + } + } + } +} +---- + +NOTE: The Log4j starters gather together the dependencies for common logging requirements (such as having Tomcat use `java.util.logging` but configuring the output using Log4j 2). + +NOTE: To ensure that debug logging performed using `java.util.logging` is routed into Log4j 2, configure its https://logging.apache.org/log4j/2.x/log4j-jul/index.html[JDK logging adapter] by setting the `java.util.logging.manager` system property to `org.apache.logging.log4j.jul.LogManager`. + + + +[[howto.logging.log4j.yaml-or-json-config]] +==== Use YAML or JSON to Configure Log4j 2 +In addition to its default XML configuration format, Log4j 2 also supports YAML and JSON configuration files. +To configure Log4j 2 to use an alternative configuration file format, add the appropriate dependencies to the classpath and name your configuration files to match your chosen file format, as shown in the following example: + +[cols="10,75a,15a"] +|=== +| Format | Dependencies | File names + +|YAML +| `com.fasterxml.jackson.core:jackson-databind` + `com.fasterxml.jackson.dataformat:jackson-dataformat-yaml` +| `log4j2.yaml` + `log4j2.yml` + +|JSON +| `com.fasterxml.jackson.core:jackson-databind` +| `log4j2.json` + `log4j2.jsn` +|=== diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/messaging.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/messaging.adoc new file mode 100644 index 0000000000..1a5dc15da8 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/messaging.adoc @@ -0,0 +1,29 @@ +[[howto.messaging]] +== Messaging +Spring Boot offers a number of starters that include messaging. +This section answers questions that arise from using messaging with Spring Boot. + + + +[[howto.messaging.disable-transacted-jms-session]] +=== Disable Transacted JMS Session +If your JMS broker does not support transacted sessions, you have to disable the support of transactions altogether. +If you create your own `JmsListenerContainerFactory`, there is nothing to do, since, by default it cannot be transacted. +If you want to use the `DefaultJmsListenerContainerFactoryConfigurer` to reuse Spring Boot's default, you can disable transacted sessions, as follows: + +[source,java,pending-extract=true,indent=0] +---- + @Bean + public DefaultJmsListenerContainerFactory jmsListenerContainerFactory( + ConnectionFactory connectionFactory, + DefaultJmsListenerContainerFactoryConfigurer configurer) { + DefaultJmsListenerContainerFactory listenerFactory = + new DefaultJmsListenerContainerFactory(); + configurer.configure(listenerFactory, connectionFactory); + listenerFactory.setTransactionManager(null); + listenerFactory.setSessionTransacted(false); + return listenerFactory; + } +---- + +The preceding example overrides the default factory, and it should be applied to any other factory that your application defines, if any. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/properties-and-configuration.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/properties-and-configuration.adoc new file mode 100644 index 0000000000..413fc98699 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/properties-and-configuration.adoc @@ -0,0 +1,278 @@ +[[howto.properties-and-configuration]] +== Properties and Configuration +This section includes topics about setting and reading properties and configuration settings and their interaction with Spring Boot applications. + + + +[[howto.properties-and-configuration.expand-properties]] +=== Automatically Expand Properties at Build Time +Rather than hardcoding some properties that are also specified in your project's build configuration, you can automatically expand them by instead using the existing build configuration. +This is possible in both Maven and Gradle. + + + +[[howto.properties-and-configuration.expand-properties.maven]] +==== Automatic Property Expansion Using Maven +You can automatically expand properties from the Maven project by using resource filtering. +If you use the `spring-boot-starter-parent`, you can then refer to your Maven '`project properties`' with `@..@` placeholders, as shown in the following example: + +[source,yaml,indent=0,configblocks] +---- + app: + encoding: "@project.build.sourceEncoding@" + java: + version: "@java.version@" +---- + +NOTE: Only production configuration is filtered that way (in other words, no filtering is applied on `src/test/resources`). + +TIP: If you enable the `addResources` flag, the `spring-boot:run` goal can add `src/main/resources` directly to the classpath (for hot reloading purposes). +Doing so circumvents the resource filtering and this feature. +Instead, you can use the `exec:java` goal or customize the plugin's configuration. +See the {spring-boot-maven-plugin-docs}#getting-started[plugin usage page] for more details. + +If you do not use the starter parent, you need to include the following element inside the `` element of your `pom.xml`: + +[source,xml,indent=0] +---- + + + src/main/resources + true + + +---- + +You also need to include the following element inside ``: + +[source,xml,indent=0] +---- + + org.apache.maven.plugins + maven-resources-plugin + 2.7 + + + @ + + false + + +---- + +NOTE: The `useDefaultDelimiters` property is important if you use standard Spring placeholders (such as `$\{placeholder}`) in your configuration. +If that property is not set to `false`, these may be expanded by the build. + + + +[[howto.properties-and-configuration.expand-properties.gradle]] +==== Automatic Property Expansion Using Gradle +You can automatically expand properties from the Gradle project by configuring the Java plugin's `processResources` task to do so, as shown in the following example: + +[source,groovy,indent=0] +---- + processResources { + expand(project.properties) + } +---- + +You can then refer to your Gradle project's properties by using placeholders, as shown in the following example: + +[source,yaml,indent=0,configblocks] +---- + app: + name: "${name}" + description: "${description}" +---- + +NOTE: Gradle's `expand` method uses Groovy's `SimpleTemplateEngine`, which transforms `${..}` tokens. +The `${..}` style conflicts with Spring's own property placeholder mechanism. +To use Spring property placeholders together with automatic expansion, escape the Spring property placeholders as follows: `\${..}`. + + + +[[howto.properties-and-configuration.externalize-configuration]] +=== Externalize the Configuration of SpringApplication +A `SpringApplication` has bean properties (mainly setters), so you can use its Java API as you create the application to modify its behavior. +Alternatively, you can externalize the configuration by setting properties in `+spring.main.*+`. +For example, in `application.properties`, you might have the following settings: + +[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] +---- + spring: + main: + web-application-type: "none" + banner-mode: "off" +---- + +Then the Spring Boot banner is not printed on startup, and the application is not starting an embedded web server. + +Properties defined in external configuration override the values specified with the Java API, with the notable exception of the sources used to create the `ApplicationContext`. +Consider the following application: + +[source,java,pending-extract=true,indent=0] +---- + new SpringApplicationBuilder() + .bannerMode(Banner.Mode.OFF) + .sources(demo.MyApp.class) + .run(args); +---- + +Now consider the following configuration: + +[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] +---- + spring: + main: + sources: "com.acme.Config,com.acme.ExtraConfig" + banner-mode: "console" +---- + +The actual application _now_ shows the banner (as overridden by configuration) and uses three sources for the `ApplicationContext` (in the following order): `demo.MyApp`, `com.acme.Config`, and `com.acme.ExtraConfig`. + + + +[[howto.properties-and-configuration.external-properties-location]] +=== Change the Location of External Properties of an Application +By default, properties from different sources are added to the Spring `Environment` in a defined order (see "`<>`" in the '`Spring Boot features`' section for the exact order). + +You can also provide the following System properties (or environment variables) to change the behavior: + +* configprop:spring.config.name[] (configprop:spring.config.name[format=envvar]): Defaults to `application` as the root of the file name. +* configprop:spring.config.location[] (configprop:spring.config.location[format=envvar]): The file to load (such as a classpath resource or a URL). + A separate `Environment` property source is set up for this document and it can be overridden by system properties, environment variables, or the command line. + +No matter what you set in the environment, Spring Boot always loads `application.properties` as described above. +By default, if YAML is used, then files with the '`.yml`' extension are also added to the list. + +Spring Boot logs the configuration files that are loaded at the `DEBUG` level and the candidates it has not found at `TRACE` level. + +See {spring-boot-module-code}/context/config/ConfigFileApplicationListener.java[`ConfigFileApplicationListener`] for more detail. + + + +[[howto.properties-and-configuration.short-command-line-arguments]] +=== Use '`Short`' Command Line Arguments +Some people like to use (for example) `--port=9000` instead of `--server.port=9000` to set configuration properties on the command line. +You can enable this behavior by using placeholders in `application.properties`, as shown in the following example: + +[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] +---- + server: + port: "${port:8080}" +---- + +TIP: If you inherit from the `spring-boot-starter-parent` POM, the default filter token of the `maven-resources-plugins` has been changed from `+${*}+` to `@` (that is, `@maven.token@` instead of `${maven.token}`) to prevent conflicts with Spring-style placeholders. +If you have enabled Maven filtering for the `application.properties` directly, you may want to also change the default filter token to use https://maven.apache.org/plugins/maven-resources-plugin/resources-mojo.html#delimiters[other delimiters]. + +NOTE: In this specific case, the port binding works in a PaaS environment such as Heroku or Cloud Foundry. +In those two platforms, the `PORT` environment variable is set automatically and Spring can bind to capitalized synonyms for `Environment` properties. + + + +[[howto.properties-and-configuration.yaml]] +=== Use YAML for External Properties +YAML is a superset of JSON and, as such, is a convenient syntax for storing external properties in a hierarchical format, as shown in the following example: + +[source,yaml,indent=0,subs="verbatim,quotes,attributes"] +---- + spring: + application: + name: "cruncher" + datasource: + driver-class-name: "com.mysql.jdbc.Driver" + url: "jdbc:mysql://localhost/test" + server: + port: 9000 +---- + +Create a file called `application.yml` and put it in the root of your classpath. +Then add `snakeyaml` to your dependencies (Maven coordinates `org.yaml:snakeyaml`, already included if you use the `spring-boot-starter`). +A YAML file is parsed to a Java `Map` (like a JSON object), and Spring Boot flattens the map so that it is one level deep and has period-separated keys, as many people are used to with `Properties` files in Java. + +The preceding example YAML corresponds to the following `application.properties` file: + +[source,properties,indent=0,subs="verbatim,quotes,attributes",configprops] +---- + spring.application.name=cruncher + spring.datasource.driver-class-name=com.mysql.jdbc.Driver + spring.datasource.url=jdbc:mysql://localhost/test + server.port=9000 +---- + +See "`<>`" in the '`Spring Boot features`' section for more information about YAML. + + + +[[howto.properties-and-configuration.set-active-spring-profiles]] +=== Set the Active Spring Profiles +The Spring `Environment` has an API for this, but you would normally set a System property (configprop:spring.profiles.active[]) or an OS environment variable (configprop:spring.profiles.active[format=envvar]). +Also, you can launch your application with a `-D` argument (remember to put it before the main class or jar archive), as follows: + +[indent=0,subs="verbatim,quotes,attributes"] +---- + $ java -jar -Dspring.profiles.active=production demo-0.0.1-SNAPSHOT.jar +---- + +In Spring Boot, you can also set the active profile in `application.properties`, as shown in the following example: + +[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] +---- + spring: + profiles: + active: "production" +---- + +A value set this way is replaced by the System property or environment variable setting but not by the `SpringApplicationBuilder.profiles()` method. +Thus, the latter Java API can be used to augment the profiles without changing the defaults. + +See "`<>`" in the "`Spring Boot features`" section for more information. + + + +[[howto.properties-and-configuration.change-configuration-depending-on-the-environment]] +=== Change Configuration Depending on the Environment +Spring Boot supports multi-document YAML and Properties files (see <> for details) which can be activated conditionally based on the active profiles. + +If a document contains a `spring.config.activate.on-profile` key, then the profiles value (a comma-separated list of profiles or a profile expression) is fed into the Spring `Environment.acceptsProfiles()` method. +If the profile expression matches then that document is included in the final merge (otherwise, it is not), as shown in the following example: + +[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] +---- + server: + port: 9000 + --- + spring: + config: + activate: + on-profile: "development" + server: + port: 9001 + --- + spring: + config: + activate: + on-profile: "production" + server: + port: 0 +---- + +In the preceding example, the default port is 9000. +However, if the Spring profile called '`development`' is active, then the port is 9001. +If '`production`' is active, then the port is 0. + +NOTE: The documents are merged in the order in which they are encountered. +Later values override earlier values. + + + +[[howto.properties-and-configuration.discover-build-in-options-for-external-properties]] +=== Discover Built-in Options for External Properties +Spring Boot binds external properties from `application.properties` (or `.yml` files and other places) into an application at runtime. +There is not (and technically cannot be) an exhaustive list of all supported properties in a single location, because contributions can come from additional jar files on your classpath. + +A running application with the Actuator features has a `configprops` endpoint that shows all the bound and bindable properties available through `@ConfigurationProperties`. + +The appendix includes an <> example with a list of the most common properties supported by Spring Boot. +The definitive list comes from searching the source code for `@ConfigurationProperties` and `@Value` annotations as well as the occasional use of `Binder`. +For more about the exact ordering of loading properties, see "<>". diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/security.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/security.adoc new file mode 100644 index 0000000000..b15950435a --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/security.adoc @@ -0,0 +1,53 @@ +[[howto.security]] +== Security +This section addresses questions about security when working with Spring Boot, including questions that arise from using Spring Security with Spring Boot. + +For more about Spring Security, see the {spring-security}[Spring Security project page]. + + + +[[howto.security.switch-off-spring-boot-configuration]] +=== Switch off the Spring Boot Security Configuration +If you define a `@Configuration` with a `WebSecurityConfigurerAdapter` or a `SecurityFilterChain` bean in your application, it switches off the default webapp security settings in Spring Boot. + + + +[[howto.security.change-user-details-service-and-add-user-accounts]] +=== Change the UserDetailsService and Add User Accounts +If you provide a `@Bean` of type `AuthenticationManager`, `AuthenticationProvider`, or `UserDetailsService`, the default `@Bean` for `InMemoryUserDetailsManager` is not created. +This means you have the full feature set of Spring Security available (such as {spring-security-docs}#servlet-authentication[various authentication options]). + +The easiest way to add user accounts is to provide your own `UserDetailsService` bean. + + + +[[howto.security.enable-https]] +=== Enable HTTPS When Running behind a Proxy Server +Ensuring that all your main endpoints are only available over HTTPS is an important chore for any application. +If you use Tomcat as a servlet container, then Spring Boot adds Tomcat's own `RemoteIpValve` automatically if it detects some environment settings, and you should be able to rely on the `HttpServletRequest` to report whether it is secure or not (even downstream of a proxy server that handles the real SSL termination). +The standard behavior is determined by the presence or absence of certain request headers (`x-forwarded-for` and `x-forwarded-proto`), whose names are conventional, so it should work with most front-end proxies. +You can switch on the valve by adding some entries to `application.properties`, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + server: + tomcat: + remoteip: + remote-ip-header: "x-forwarded-for" + protocol-header: "x-forwarded-proto" +---- + +(The presence of either of those properties switches on the valve. +Alternatively, you can add the `RemoteIpValve` by customizing the `TomcatServletWebServerFactory` using a `WebServerFactoryCustomizer` bean.) + +To configure Spring Security to require a secure channel for all (or some) requests, consider adding your own `SecurityFilterChain` bean that adds the following `HttpSecurity` configuration: + +[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] +---- + @Bean + public SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception { + // Customize the application security + http.requiresChannel().anyRequest().requiresSecure(); + return http.build(); + } +---- diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/spring-mvc.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/spring-mvc.adoc new file mode 100644 index 0000000000..ebf2c76b22 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/spring-mvc.adoc @@ -0,0 +1,243 @@ +[[howto.spring-mvc]] +== Spring MVC +Spring Boot has a number of starters that include Spring MVC. +Note that some starters include a dependency on Spring MVC rather than include it directly. +This section answers common questions about Spring MVC and Spring Boot. + + + +[[howto.spring-mvc.write-json-rest-service]] +=== Write a JSON REST Service +Any Spring `@RestController` in a Spring Boot application should render JSON response by default as long as Jackson2 is on the classpath, as shown in the following example: + +[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] +---- + @RestController + public class MyController { + + @RequestMapping("/thing") + public MyThing thing() { + return new MyThing(); + } + + } +---- + +As long as `MyThing` can be serialized by Jackson2 (true for a normal POJO or Groovy object), then `http://localhost:8080/thing` serves a JSON representation of it by default. +Note that, in a browser, you might sometimes see XML responses, because browsers tend to send accept headers that prefer XML. + + + +[[howto.spring-mvc.write-xml-rest-service]] +=== Write an XML REST Service +If you have the Jackson XML extension (`jackson-dataformat-xml`) on the classpath, you can use it to render XML responses. +The previous example that we used for JSON would work. +To use the Jackson XML renderer, add the following dependency to your project: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + com.fasterxml.jackson.dataformat + jackson-dataformat-xml + +---- + +If Jackson's XML extension is not available and JAXB is available, XML can be rendered with the additional requirement of having `MyThing` annotated as `@XmlRootElement`, as shown in the following example: + +[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] +---- + @XmlRootElement + public class MyThing { + private String name; + // .. getters and setters + } +---- + +JAXB is only available out of the box with Java 8. +If you're using a more recent Java generation, add the following dependency to your project: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + org.glassfish.jaxb + jaxb-runtime + +---- + +NOTE: To get the server to render XML instead of JSON, you might have to send an `Accept: text/xml` header (or use a browser). + + + +[[howto.spring-mvc.customize-jackson-objectmapper]] +=== Customize the Jackson ObjectMapper +Spring MVC (client and server side) uses `HttpMessageConverters` to negotiate content conversion in an HTTP exchange. +If Jackson is on the classpath, you already get the default converter(s) provided by `Jackson2ObjectMapperBuilder`, an instance of which is auto-configured for you. + +The `ObjectMapper` (or `XmlMapper` for Jackson XML converter) instance (created by default) has the following customized properties: + +* `MapperFeature.DEFAULT_VIEW_INCLUSION` is disabled +* `DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES` is disabled +* `SerializationFeature.WRITE_DATES_AS_TIMESTAMPS` is disabled + +Spring Boot also has some features to make it easier to customize this behavior. + +You can configure the `ObjectMapper` and `XmlMapper` instances by using the environment. +Jackson provides an extensive suite of on/off features that can be used to configure various aspects of its processing. +These features are described in six enums (in Jackson) that map onto properties in the environment: + +|=== +| Enum | Property | Values + +| `com.fasterxml.jackson.databind.DeserializationFeature` +| `spring.jackson.deserialization.` +| `true`, `false` + +| `com.fasterxml.jackson.core.JsonGenerator.Feature` +| `spring.jackson.generator.` +| `true`, `false` + +| `com.fasterxml.jackson.databind.MapperFeature` +| `spring.jackson.mapper.` +| `true`, `false` + +| `com.fasterxml.jackson.core.JsonParser.Feature` +| `spring.jackson.parser.` +| `true`, `false` + +| `com.fasterxml.jackson.databind.SerializationFeature` +| `spring.jackson.serialization.` +| `true`, `false` + +| `com.fasterxml.jackson.annotation.JsonInclude.Include` +| configprop:spring.jackson.default-property-inclusion[] +| `always`, `non_null`, `non_absent`, `non_default`, `non_empty` +|=== + +For example, to enable pretty print, set `spring.jackson.serialization.indent_output=true`. +Note that, thanks to the use of <>, the case of `indent_output` does not have to match the case of the corresponding enum constant, which is `INDENT_OUTPUT`. + +This environment-based configuration is applied to the auto-configured `Jackson2ObjectMapperBuilder` bean and applies to any mappers created by using the builder, including the auto-configured `ObjectMapper` bean. + +The context's `Jackson2ObjectMapperBuilder` can be customized by one or more `Jackson2ObjectMapperBuilderCustomizer` beans. +Such customizer beans can be ordered (Boot's own customizer has an order of 0), letting additional customization be applied both before and after Boot's customization. + +Any beans of type `com.fasterxml.jackson.databind.Module` are automatically registered with the auto-configured `Jackson2ObjectMapperBuilder` and are applied to any `ObjectMapper` instances that it creates. +This provides a global mechanism for contributing custom modules when you add new features to your application. + +If you want to replace the default `ObjectMapper` completely, either define a `@Bean` of that type and mark it as `@Primary` or, if you prefer the builder-based approach, define a `Jackson2ObjectMapperBuilder` `@Bean`. +Note that, in either case, doing so disables all auto-configuration of the `ObjectMapper`. + +If you provide any `@Beans` of type `MappingJackson2HttpMessageConverter`, they replace the default value in the MVC configuration. +Also, a convenience bean of type `HttpMessageConverters` is provided (and is always available if you use the default MVC configuration). +It has some useful methods to access the default and user-enhanced message converters. + +See the "`<>`" section and the {spring-boot-autoconfigure-module-code}/web/servlet/WebMvcAutoConfiguration.java[`WebMvcAutoConfiguration`] source code for more details. + + + +[[howto.spring-mvc.customize-responsebody-rendering]] +=== Customize the @ResponseBody Rendering +Spring uses `HttpMessageConverters` to render `@ResponseBody` (or responses from `@RestController`). +You can contribute additional converters by adding beans of the appropriate type in a Spring Boot context. +If a bean you add is of a type that would have been included by default anyway (such as `MappingJackson2HttpMessageConverter` for JSON conversions), it replaces the default value. +A convenience bean of type `HttpMessageConverters` is provided and is always available if you use the default MVC configuration. +It has some useful methods to access the default and user-enhanced message converters (For example, it can be useful if you want to manually inject them into a custom `RestTemplate`). + +As in normal MVC usage, any `WebMvcConfigurer` beans that you provide can also contribute converters by overriding the `configureMessageConverters` method. +However, unlike with normal MVC, you can supply only additional converters that you need (because Spring Boot uses the same mechanism to contribute its defaults). +Finally, if you opt out of the Spring Boot default MVC configuration by providing your own `@EnableWebMvc` configuration, you can take control completely and do everything manually by using `getMessageConverters` from `WebMvcConfigurationSupport`. + +See the {spring-boot-autoconfigure-module-code}/web/servlet/WebMvcAutoConfiguration.java[`WebMvcAutoConfiguration`] source code for more details. + + + +[[howto.spring-mvc.multipart-file-uploads]] +=== Handling Multipart File Uploads +Spring Boot embraces the Servlet 3 `javax.servlet.http.Part` API to support uploading files. +By default, Spring Boot configures Spring MVC with a maximum size of 1MB per file and a maximum of 10MB of file data in a single request. +You may override these values, the location to which intermediate data is stored (for example, to the `/tmp` directory), and the threshold past which data is flushed to disk by using the properties exposed in the `MultipartProperties` class. +For example, if you want to specify that files be unlimited, set the configprop:spring.servlet.multipart.max-file-size[] property to `-1`. + +The multipart support is helpful when you want to receive multipart encoded file data as a `@RequestParam`-annotated parameter of type `MultipartFile` in a Spring MVC controller handler method. + +See the {spring-boot-autoconfigure-module-code}/web/servlet/MultipartAutoConfiguration.java[`MultipartAutoConfiguration`] source for more details. + +NOTE: It is recommended to use the container's built-in support for multipart uploads rather than introducing an additional dependency such as Apache Commons File Upload. + + + +[[howto.spring-mvc.switch-off-dispatcherservlet]] +=== Switch Off the Spring MVC DispatcherServlet +By default, all content is served from the root of your application (`/`). +If you would rather map to a different path, you can configure one as follows: + +[source,yaml,indent=0,subs="verbatim",configprops,configblocks] +---- + spring: + mvc: + servlet: + path: "/acme" +---- + +If you have additional servlets you can declare a `@Bean` of type `Servlet` or `ServletRegistrationBean` for each and Spring Boot will register them transparently to the container. +Because servlets are registered that way, they can be mapped to a sub-context of the `DispatcherServlet` without invoking it. + +Configuring the `DispatcherServlet` yourself is unusual but if you really need to do it, a `@Bean` of type `DispatcherServletPath` must be provided as well to provide the path of your custom `DispatcherServlet`. + + + +[[howto.spring-mvc.switch-off-default-configuration]] +=== Switch off the Default MVC Configuration +The easiest way to take complete control over MVC configuration is to provide your own `@Configuration` with the `@EnableWebMvc` annotation. +Doing so leaves all MVC configuration in your hands. + + + +[[howto.spring-mvc.customize-view-resolvers]] +=== Customize ViewResolvers +A `ViewResolver` is a core component of Spring MVC, translating view names in `@Controller` to actual `View` implementations. +Note that `ViewResolvers` are mainly used in UI applications, rather than REST-style services (a `View` is not used to render a `@ResponseBody`). +There are many implementations of `ViewResolver` to choose from, and Spring on its own is not opinionated about which ones you should use. +Spring Boot, on the other hand, installs one or two for you, depending on what it finds on the classpath and in the application context. +The `DispatcherServlet` uses all the resolvers it finds in the application context, trying each one in turn until it gets a result. +If you add your own, you have to be aware of the order and in which position your resolver is added. + +`WebMvcAutoConfiguration` adds the following `ViewResolvers` to your context: + +* An `InternalResourceViewResolver` named '`defaultViewResolver`'. + This one locates physical resources that can be rendered by using the `DefaultServlet` (including static resources and JSP pages, if you use those). + It applies a prefix and a suffix to the view name and then looks for a physical resource with that path in the servlet context (the defaults are both empty but are accessible for external configuration through `spring.mvc.view.prefix` and `spring.mvc.view.suffix`). + You can override it by providing a bean of the same type. +* A `BeanNameViewResolver` named '`beanNameViewResolver`'. + This is a useful member of the view resolver chain and picks up any beans with the same name as the `View` being resolved. + It should not be necessary to override or replace it. +* A `ContentNegotiatingViewResolver` named '`viewResolver`' is added only if there *are* actually beans of type `View` present. + This is a composite resolver, delegating to all the others and attempting to find a match to the '`Accept`' HTTP header sent by the client. + There is a useful https://spring.io/blog/2013/06/03/content-negotiation-using-views[blog about `ContentNegotiatingViewResolver`] that you might like to study to learn more, and you might also look at the source code for detail. + You can switch off the auto-configured `ContentNegotiatingViewResolver` by defining a bean named '`viewResolver`'. +* If you use Thymeleaf, you also have a `ThymeleafViewResolver` named '`thymeleafViewResolver`'. + It looks for resources by surrounding the view name with a prefix and suffix. + The prefix is `spring.thymeleaf.prefix`, and the suffix is `spring.thymeleaf.suffix`. + The values of the prefix and suffix default to '`classpath:/templates/`' and '`.html`', respectively. + You can override `ThymeleafViewResolver` by providing a bean of the same name. +* If you use FreeMarker, you also have a `FreeMarkerViewResolver` named '`freeMarkerViewResolver`'. + It looks for resources in a loader path (which is externalized to `spring.freemarker.templateLoaderPath` and has a default value of '`classpath:/templates/`') by surrounding the view name with a prefix and a suffix. + The prefix is externalized to `spring.freemarker.prefix`, and the suffix is externalized to `spring.freemarker.suffix`. + The default values of the prefix and suffix are empty and '`.ftlh`', respectively. + You can override `FreeMarkerViewResolver` by providing a bean of the same name. +* If you use Groovy templates (actually, if `groovy-templates` is on your classpath), you also have a `GroovyMarkupViewResolver` named '`groovyMarkupViewResolver`'. + It looks for resources in a loader path by surrounding the view name with a prefix and suffix (externalized to `spring.groovy.template.prefix` and `spring.groovy.template.suffix`). + The prefix and suffix have default values of '`classpath:/templates/`' and '`.tpl`', respectively. + You can override `GroovyMarkupViewResolver` by providing a bean of the same name. +* If you use Mustache, you also have a `MustacheViewResolver` named '`mustacheViewResolver`'. + It looks for resources by surrounding the view name with a prefix and suffix. + The prefix is `spring.mustache.prefix`, and the suffix is `spring.mustache.suffix`. + The values of the prefix and suffix default to '`classpath:/templates/`' and '`.mustache`', respectively. + You can override `MustacheViewResolver` by providing a bean of the same name. + +For more detail, see the following sections: + +* {spring-boot-autoconfigure-module-code}/web/servlet/WebMvcAutoConfiguration.java[`WebMvcAutoConfiguration`] +* {spring-boot-autoconfigure-module-code}/thymeleaf/ThymeleafAutoConfiguration.java[`ThymeleafAutoConfiguration`] +* {spring-boot-autoconfigure-module-code}/freemarker/FreeMarkerAutoConfiguration.java[`FreeMarkerAutoConfiguration`] +* {spring-boot-autoconfigure-module-code}/groovy/template/GroovyTemplateAutoConfiguration.java[`GroovyTemplateAutoConfiguration`] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/testcontainers.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/testcontainers.adoc new file mode 100644 index 0000000000..cf29279e09 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/testcontainers.adoc @@ -0,0 +1,42 @@ +[[howto.testcontainers]] +== Use Testcontainers for integration testing +The https://www.testcontainers.org/[Testcontainers] library provides a way to manage services running inside Docker containers. +It integrates with JUnit, allowing you to write a test class that can start up a container before any of the tests run. +Testcontainers is especially useful for writing integration tests that talk to a real backend service such as MySQL, MongoDB, Cassandra etc. +Testcontainers can be used in a Spring Boot test as follows: + +[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] +---- +@SpringBootTest +@Testcontainers +class ExampleIntegrationTests { + + @Container + static Neo4jContainer neo4j = new Neo4jContainer<>(); + +} +---- + +This will start up a docker container running Neo4j (if Docker is running locally) before any of the tests are run. +In most cases, you will need to configure the application using details from the running container, such as container IP or port. + +This can be done with a static `@DynamicPropertySource` method that allows adding dynamic property values to the Spring Environment. + +[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] +---- +@SpringBootTest +@Testcontainers +class ExampleIntegrationTests { + + @Container + static Neo4jContainer neo4j = new Neo4jContainer<>(); + + @DynamicPropertySource + static void neo4jProperties(DynamicPropertyRegistry registry) { + registry.add("spring.neo4j.uri", neo4j::getBoltUrl); + } + +} +---- + +The above configuration allows Neo4j-related beans in the application to communicate with Neo4j running inside the Testcontainers-managed Docker container. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/testing-with-spring-security.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/testing-with-spring-security.adoc new file mode 100644 index 0000000000..445cec7dde --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/testing-with-spring-security.adoc @@ -0,0 +1,19 @@ +[[howto.testing-with-spring-security]] +== Testing With Spring Security +Spring Security provides support for running tests as a specific user. +For example, the test in the snippet below will run with an authenticated user that has the `ADMIN` role. + +[source,java,pending-extract=true,indent=0] +---- + @Test + @WithMockUser(roles="ADMIN") + public void requestProtectedUrlWithUser() throws Exception { + mvc + .perform(get("/")) + ... + } +---- + +Spring Security provides comprehensive integration with Spring MVC Test and this can also be used when testing controllers using the `@WebMvcTest` slice and `MockMvc`. + +For additional details on Spring Security's testing support, refer to Spring Security's {spring-security-docs}#test[reference documentation]). diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/traditional-deployment.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/traditional-deployment.adoc new file mode 100644 index 0000000000..ec65d4e9ff --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/traditional-deployment.adoc @@ -0,0 +1,219 @@ +[[howto.traditional-deployment]] +== Traditional Deployment +Spring Boot supports traditional deployment as well as more modern forms of deployment. +This section answers common questions about traditional deployment. + + + +[[howto.traditional-deployment.war]] +=== Create a Deployable War File + +WARNING: Because Spring WebFlux does not strictly depend on the Servlet API and applications are deployed by default on an embedded Reactor Netty server, War deployment is not supported for WebFlux applications. + +The first step in producing a deployable war file is to provide a `SpringBootServletInitializer` subclass and override its `configure` method. +Doing so makes use of Spring Framework's Servlet 3.0 support and lets you configure your application when it is launched by the servlet container. +Typically, you should update your application's main class to extend `SpringBootServletInitializer`, as shown in the following example: + +[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] +---- + @SpringBootApplication + public class Application extends SpringBootServletInitializer { + + @Override + protected SpringApplicationBuilder configure(SpringApplicationBuilder application) { + return application.sources(Application.class); + } + + public static void main(String[] args) { + SpringApplication.run(Application.class, args); + } + + } +---- + +The next step is to update your build configuration such that your project produces a war file rather than a jar file. +If you use Maven and `spring-boot-starter-parent` (which configures Maven's war plugin for you), all you need to do is to modify `pom.xml` to change the packaging to war, as follows: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + war +---- + +If you use Gradle, you need to modify `build.gradle` to apply the war plugin to the project, as follows: + +[source,groovy,indent=0,subs="verbatim,quotes,attributes"] +---- + apply plugin: 'war' +---- + +The final step in the process is to ensure that the embedded servlet container does not interfere with the servlet container to which the war file is deployed. +To do so, you need to mark the embedded servlet container dependency as being provided. + +If you use Maven, the following example marks the servlet container (Tomcat, in this case) as being provided: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + + + org.springframework.boot + spring-boot-starter-tomcat + provided + + + +---- + +If you use Gradle, the following example marks the servlet container (Tomcat, in this case) as being provided: + +[source,groovy,indent=0,subs="verbatim,quotes,attributes"] +---- + dependencies { + // … + providedRuntime 'org.springframework.boot:spring-boot-starter-tomcat' + // … + } +---- + +TIP: `providedRuntime` is preferred to Gradle's `compileOnly` configuration. +Among other limitations, `compileOnly` dependencies are not on the test classpath, so any web-based integration tests fail. + +If you use the <>, marking the embedded servlet container dependency as provided produces an executable war file with the provided dependencies packaged in a `lib-provided` directory. +This means that, in addition to being deployable to a servlet container, you can also run your application by using `java -jar` on the command line. + + + +[[howto.traditional-deployment.convert-existing-application]] +=== Convert an Existing Application to Spring Boot +To convert an existing non-web Spring application to a Spring Boot application, replace the code that creates your `ApplicationContext` and replace it with calls to `SpringApplication` or `SpringApplicationBuilder`. +Spring MVC web applications are generally amenable to first creating a deployable war application and then migrating it later to an executable war or jar. +See the https://spring.io/guides/gs/convert-jar-to-war/[Getting Started Guide on Converting a jar to a war]. + +To create a deployable war by extending `SpringBootServletInitializer` (for example, in a class called `Application`) and adding the Spring Boot `@SpringBootApplication` annotation, use code similar to that shown in the following example: + +[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] +---- + @SpringBootApplication + public class Application extends SpringBootServletInitializer { + + @Override + protected SpringApplicationBuilder configure(SpringApplicationBuilder application) { + // Customize the application or call application.sources(...) to add sources + // Since our example is itself a @Configuration class (via @SpringBootApplication) + // we actually don't need to override this method. + return application; + } + + } +---- + +Remember that, whatever you put in the `sources` is merely a Spring `ApplicationContext`. +Normally, anything that already works should work here. +There might be some beans you can remove later and let Spring Boot provide its own defaults for them, but it should be possible to get something working before you need to do that. + +Static resources can be moved to `/public` (or `/static` or `/resources` or `/META-INF/resources`) in the classpath root. +The same applies to `messages.properties` (which Spring Boot automatically detects in the root of the classpath). + +Vanilla usage of Spring `DispatcherServlet` and Spring Security should require no further changes. +If you have other features in your application (for instance, using other servlets or filters), you may need to add some configuration to your `Application` context, by replacing those elements from the `web.xml`, as follows: + +* A `@Bean` of type `Servlet` or `ServletRegistrationBean` installs that bean in the container as if it were a `` and `` in `web.xml`. +* A `@Bean` of type `Filter` or `FilterRegistrationBean` behaves similarly (as a `` and ``). +* An `ApplicationContext` in an XML file can be added through an `@ImportResource` in your `Application`. + Alternatively, cases where annotation configuration is heavily used already can be recreated in a few lines as `@Bean` definitions. + +Once the war file is working, you can make it executable by adding a `main` method to your `Application`, as shown in the following example: + +[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] +---- + public static void main(String[] args) { + SpringApplication.run(Application.class, args); + } +---- + +[NOTE] +==== +If you intend to start your application as a war or as an executable application, you need to share the customizations of the builder in a method that is both available to the `SpringBootServletInitializer` callback and in the `main` method in a class similar to the following: + +[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] +---- + @SpringBootApplication + public class Application extends SpringBootServletInitializer { + + @Override + protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) { + return configureApplication(builder); + } + + public static void main(String[] args) { + configureApplication(new SpringApplicationBuilder()).run(args); + } + + private static SpringApplicationBuilder configureApplication(SpringApplicationBuilder builder) { + return builder.sources(Application.class).bannerMode(Banner.Mode.OFF); + } + + } +---- +==== + +Applications can fall into more than one category: + +* Servlet 3.0+ applications with no `web.xml`. +* Applications with a `web.xml`. +* Applications with a context hierarchy. +* Applications without a context hierarchy. + +All of these should be amenable to translation, but each might require slightly different techniques. + +Servlet 3.0+ applications might translate pretty easily if they already use the Spring Servlet 3.0+ initializer support classes. +Normally, all the code from an existing `WebApplicationInitializer` can be moved into a `SpringBootServletInitializer`. +If your existing application has more than one `ApplicationContext` (for example, if it uses `AbstractDispatcherServletInitializer`) then you might be able to combine all your context sources into a single `SpringApplication`. +The main complication you might encounter is if combining does not work and you need to maintain the context hierarchy. +See the <> for examples. +An existing parent context that contains web-specific features usually needs to be broken up so that all the `ServletContextAware` components are in the child context. + +Applications that are not already Spring applications might be convertible to Spring Boot applications, and the previously mentioned guidance may help. +However, you may yet encounter problems. +In that case, we suggest https://stackoverflow.com/questions/tagged/spring-boot[asking questions on Stack Overflow with a tag of `spring-boot`]. + + + +[[howto.traditional-deployment.weblogic]] +=== Deploying a WAR to WebLogic +To deploy a Spring Boot application to WebLogic, you must ensure that your servlet initializer *directly* implements `WebApplicationInitializer` (even if you extend from a base class that already implements it). + +A typical initializer for WebLogic should resemble the following example: + +[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] +---- + import org.springframework.boot.autoconfigure.SpringBootApplication; + import org.springframework.boot.web.servlet.support.SpringBootServletInitializer; + import org.springframework.web.WebApplicationInitializer; + + @SpringBootApplication + public class MyApplication extends SpringBootServletInitializer implements WebApplicationInitializer { + + } +---- + +If you use Logback, you also need to tell WebLogic to prefer the packaged version rather than the version that was pre-installed with the server. +You can do so by adding a `WEB-INF/weblogic.xml` file with the following contents: + +[source,xml,indent=0] +---- + + + + + org.slf4j + + + +---- diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/webserver.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/webserver.adoc new file mode 100644 index 0000000000..f338788b6b --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/howto/webserver.adoc @@ -0,0 +1,532 @@ +[[howto.webserver]] +== Embedded Web Servers +Each Spring Boot web application includes an embedded web server. +This feature leads to a number of how-to questions, including how to change the embedded server and how to configure the embedded server. +This section answers those questions. + + + +[[howto.webserver.use-another]] +=== Use Another Web Server +Many Spring Boot starters include default embedded containers. + +* For servlet stack applications, the `spring-boot-starter-web` includes Tomcat by including `spring-boot-starter-tomcat`, but you can use `spring-boot-starter-jetty` or `spring-boot-starter-undertow` instead. +* For reactive stack applications, the `spring-boot-starter-webflux` includes Reactor Netty by including `spring-boot-starter-reactor-netty`, but you can use `spring-boot-starter-tomcat`, `spring-boot-starter-jetty`, or `spring-boot-starter-undertow` instead. + +When switching to a different HTTP server, you need to swap the default dependencies for those that you need instead. +To help with this process, Spring Boot provides a separate starter for each of the supported HTTP servers. + +The following Maven example shows how to exclude Tomcat and include Jetty for Spring MVC: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + 3.1.0 + + + org.springframework.boot + spring-boot-starter-web + + + + org.springframework.boot + spring-boot-starter-tomcat + + + + + + org.springframework.boot + spring-boot-starter-jetty + +---- + +NOTE: The version of the Servlet API has been overridden as, unlike Tomcat 9 and Undertow 2, Jetty 9.4 does not support Servlet 4.0. +If you wish to use Jetty 10, which does support Servlet 4.0, override the `jetty.version` property rather than the `servlet-api.version` property. + +The following Gradle example shows how to use Undertow in place of Reactor Netty for Spring WebFlux: + +[source,groovy,indent=0,subs="verbatim,quotes,attributes"] +---- + configurations.all { + resolutionStrategy.dependencySubstitution.all { dependency -> + if (dependency.requested instanceof ModuleComponentSelector && dependency.requested.module == 'spring-boot-starter-reactor-netty') { + dependency.useTarget("org.springframework.boot:spring-boot-starter-undertow:$dependency.requested.version", 'Use Undertow instead of Reactor Netty') + } + } + } + + dependencies { + compile 'org.springframework.boot:spring-boot-starter-webflux' + // ... + } +---- + +NOTE: `spring-boot-starter-reactor-netty` is required to use the `WebClient` class, so you may need to keep a dependency on Netty even when you need to include a different HTTP server. + + + +[[howto.webserver.disable]] +=== Disabling the Web Server +If your classpath contains the necessary bits to start a web server, Spring Boot will automatically start it. +To disable this behavior configure the `WebApplicationType` in your `application.properties`, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + main: + web-application-type: "none" +---- + + + +[[howto.webserver.change-port]] +=== Change the HTTP Port +In a standalone application, the main HTTP port defaults to `8080` but can be set with configprop:server.port[] (for example, in `application.properties` or as a System property). +Thanks to relaxed binding of `Environment` values, you can also use configprop:server.port[format=envvar] (for example, as an OS environment variable). + +To switch off the HTTP endpoints completely but still create a `WebApplicationContext`, use `server.port=-1` (doing so is sometimes useful for testing). + +For more details, see "`<>`" in the '`Spring Boot Features`' section, or the {spring-boot-autoconfigure-module-code}/web/ServerProperties.java[`ServerProperties`] source code. + + + +[[howto.webserver.use-random-port]] +=== Use a Random Unassigned HTTP Port +To scan for a free port (using OS natives to prevent clashes) use `server.port=0`. + + + +[[howto.webserver.discover-port]] +=== Discover the HTTP Port at Runtime +You can access the port the server is running on from log output or from the `WebServerApplicationContext` through its `WebServer`. +The best way to get that and be sure it has been initialized is to add a `@Bean` of type `ApplicationListener` and pull the container out of the event when it is published. + +Tests that use `@SpringBootTest(webEnvironment=WebEnvironment.RANDOM_PORT)` can also inject the actual port into a field by using the `@LocalServerPort` annotation, as shown in the following example: + +[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] +---- + @SpringBootTest(webEnvironment=WebEnvironment.RANDOM_PORT) + public class MyWebIntegrationTests { + + @LocalServerPort + int port; + + // ... + + } +---- + +[NOTE] +==== +`@LocalServerPort` is a meta-annotation for `@Value("${local.server.port}")`. +Do not try to inject the port in a regular application. +As we just saw, the value is set only after the container has been initialized. +Contrary to a test, application code callbacks are processed early (before the value is actually available). +==== + + + +[[howto.webserver.enable-response-compression]] +=== Enable HTTP Response Compression +HTTP response compression is supported by Jetty, Tomcat, and Undertow. +It can be enabled in `application.properties`, as follows: + +[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] +---- + server: + compression: + enabled: true +---- + +By default, responses must be at least 2048 bytes in length for compression to be performed. +You can configure this behavior by setting the configprop:server.compression.min-response-size[] property. + +By default, responses are compressed only if their content type is one of the following: + +* `text/html` +* `text/xml` +* `text/plain` +* `text/css` +* `text/javascript` +* `application/javascript` +* `application/json` +* `application/xml` + +You can configure this behavior by setting the configprop:server.compression.mime-types[] property. + + + +[[howto.webserver.configure-ssl]] +=== Configure SSL +SSL can be configured declaratively by setting the various `+server.ssl.*+` properties, typically in `application.properties` or `application.yml`. +The following example shows setting SSL properties in `application.properties`: + +[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] +---- + server: + port: 8443 + ssl: + key-store: "classpath:keystore.jks" + key-store-password: "secret" + key-password: "another-secret" +---- + +See {spring-boot-module-code}/web/server/Ssl.java[`Ssl`] for details of all of the supported properties. + +Using configuration such as the preceding example means the application no longer supports a plain HTTP connector at port 8080. +Spring Boot does not support the configuration of both an HTTP connector and an HTTPS connector through `application.properties`. +If you want to have both, you need to configure one of them programmatically. +We recommend using `application.properties` to configure HTTPS, as the HTTP connector is the easier of the two to configure programmatically. + + + +[[howto.webserver.configure-http2]] +=== Configure HTTP/2 +You can enable HTTP/2 support in your Spring Boot application with the configprop:server.http2.enabled[] configuration property. +Both `h2` (HTTP/2 over TLS) and `h2c` (HTTP/2 over TCP) are supported. +To use `h2`, SSL must also be enabled. +When SSL is not enabled, `h2c` will be used. +The details of the `h2` support depend on the chosen web server and the application environment, since that protocol is not supported out-of-the-box by all JDK 8 releases. + + + +[[howto.webserver.configure-http2.tomcat]] +==== HTTP/2 with Tomcat +Spring Boot ships by default with Tomcat 9.0.x which supports `h2c` out of the box and `h2` out of the box when using JDK 9 or later. +Alternatively, `h2` can be used on JDK 8 if the `libtcnative` library and its dependencies are installed on the host operating system. + +The library directory must be made available, if not already, to the JVM library path. +You can do so with a JVM argument such as `-Djava.library.path=/usr/local/opt/tomcat-native/lib`. +More on this in the https://tomcat.apache.org/tomcat-9.0-doc/apr.html[official Tomcat documentation]. + +Starting Tomcat 9.0.x on JDK 8 with HTTP/2 and SSL enabled but without that native support logs the following error: + +[indent=0,subs="attributes"] +---- + ERROR 8787 --- [ main] o.a.coyote.http11.Http11NioProtocol : The upgrade handler [org.apache.coyote.http2.Http2Protocol] for [h2] only supports upgrade via ALPN but has been configured for the ["https-jsse-nio-8443"] connector that does not support ALPN. +---- + +This error is not fatal, and the application still starts with HTTP/1.1 SSL support. + + + +[[howto.webserver.configure-http2.jetty]] +==== HTTP/2 with Jetty +For HTTP/2 support, Jetty requires the additional `org.eclipse.jetty.http2:http2-server` dependency. +To use `h2c` no other dependencies are required. +To use `h2`, you also need to choose one of the following dependencies, depending on your deployment: + +* `org.eclipse.jetty:jetty-alpn-java-server` for applications running on JDK9+ +* `org.eclipse.jetty:jetty-alpn-openjdk8-server` for applications running on JDK8u252+ +* `org.eclipse.jetty:jetty-alpn-conscrypt-server` and the https://www.conscrypt.org/[Conscrypt library] with no JDK requirement + + + +[[howto.webserver.configure-http2.netty]] +==== HTTP/2 with Reactor Netty +The `spring-boot-webflux-starter` is using by default Reactor Netty as a server. +Reactor Netty supports `h2c` using JDK 8 or later with no additional dependencies. +Reactor Netty supports `h2` using the JDK support with JDK 9 or later. +For JDK 8 environments, or for optimal runtime performance, this server also supports `h2` with native libraries. +To enable that, your application needs to have an additional dependency. + +Spring Boot manages the version for the `io.netty:netty-tcnative-boringssl-static` "uber jar", containing native libraries for all platforms. +Developers can choose to import only the required dependencies using a classifier (see https://netty.io/wiki/forked-tomcat-native.html[the Netty official documentation]). + + + +[[howto.webserver.configure-http2.undertow]] +==== HTTP/2 with Undertow +As of Undertow 1.4.0+, both `h2` and `h2c` are supported on JDK 8 without any additional dependencies. + + + +[[howto.webserver.configure]] +=== Configure the Web Server +Generally, you should first consider using one of the many available configuration keys and customize your web server by adding new entries in your `application.properties` (or `application.yml`, or environment, etc. see "`<>`"). +The `server.{asterisk}` namespace is quite useful here, and it includes namespaces like `server.tomcat.{asterisk}`, `server.jetty.{asterisk}` and others, for server-specific features. +See the list of <>. + +The previous sections covered already many common use cases, such as compression, SSL or HTTP/2. +However, if a configuration key doesn't exist for your use case, you should then look at {spring-boot-module-api}/web/server/WebServerFactoryCustomizer.html[`WebServerFactoryCustomizer`]. +You can declare such a component and get access to the server factory relevant to your choice: you should select the variant for the chosen Server (Tomcat, Jetty, Reactor Netty, Undertow) and the chosen web stack (Servlet or Reactive). + +The example below is for Tomcat with the `spring-boot-starter-web` (Servlet stack): + +[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] +---- + @Component + public class MyTomcatWebServerCustomizer + implements WebServerFactoryCustomizer { + + @Override + public void customize(TomcatServletWebServerFactory factory) { + // customize the factory here + } + } +---- + +NOTE: Spring Boot uses that infrastructure internally to auto-configure the server. +Auto-configured `WebServerFactoryCustomizer` beans have an order of `0` and will be processed before any user-defined customizers, unless it has an explicit order that states otherwise. + +Once you've got access to a `WebServerFactory` using the customizer, you can use it to configure specific parts, like connectors, server resources, or the server itself - all using server-specific APIs. + +In addition Spring Boot provides: + +[[howto-configure-webserver-customizers]] +[cols="1,2,2", options="header"] +|=== +| Server | Servlet stack | Reactive stack + +| Tomcat +| `TomcatServletWebServerFactory` +| `TomcatReactiveWebServerFactory` + +| Jetty +| `JettyServletWebServerFactory` +| `JettyReactiveWebServerFactory` + +| Undertow +| `UndertowServletWebServerFactory` +| `UndertowReactiveWebServerFactory` + +| Reactor +| N/A +| `NettyReactiveWebServerFactory` +|=== + +As a last resort, you can also declare your own `WebServerFactory` bean, which will override the one provided by Spring Boot. +When you do so, auto-configured customizers are still applied on your custom factory, so use that option carefully. + + + +[[howto.webserver.add-servlet-filter-listener]] +=== Add a Servlet, Filter, or Listener to an Application +In a servlet stack application, i.e. with the `spring-boot-starter-web`, there are two ways to add `Servlet`, `Filter`, `ServletContextListener`, and the other listeners supported by the Servlet API to your application: + +* <> +* <> + + + +[[howto.webserver.add-servlet-filter-listener.spring-bean]] +==== Add a Servlet, Filter, or Listener by Using a Spring Bean +To add a `Servlet`, `Filter`, or Servlet `*Listener` by using a Spring bean, you must provide a `@Bean` definition for it. +Doing so can be very useful when you want to inject configuration or dependencies. +However, you must be very careful that they do not cause eager initialization of too many other beans, because they have to be installed in the container very early in the application lifecycle. +(For example, it is not a good idea to have them depend on your `DataSource` or JPA configuration.) +You can work around such restrictions by initializing the beans lazily when first used instead of on initialization. + +In the case of `Filters` and `Servlets`, you can also add mappings and init parameters by adding a `FilterRegistrationBean` or a `ServletRegistrationBean` instead of or in addition to the underlying component. + +[NOTE] +==== +If no `dispatcherType` is specified on a filter registration, `REQUEST` is used. +This aligns with the Servlet Specification's default dispatcher type. +==== + +Like any other Spring bean, you can define the order of Servlet filter beans; please make sure to check the "`<>`" section. + + + +[[howto.webserver.add-servlet-filter-listener.spring-bean.disable]] +===== Disable Registration of a Servlet or Filter +As <>, any `Servlet` or `Filter` beans are registered with the servlet container automatically. +To disable registration of a particular `Filter` or `Servlet` bean, create a registration bean for it and mark it as disabled, as shown in the following example: + +[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] +---- + @Bean + public FilterRegistrationBean registration(MyFilter filter) { + FilterRegistrationBean registration = new FilterRegistrationBean(filter); + registration.setEnabled(false); + return registration; + } +---- + + + +[[howto.webserver.add-servlet-filter-listener.using-scanning]] +==== Add Servlets, Filters, and Listeners by Using Classpath Scanning +`@WebServlet`, `@WebFilter`, and `@WebListener` annotated classes can be automatically registered with an embedded servlet container by annotating a `@Configuration` class with `@ServletComponentScan` and specifying the package(s) containing the components that you want to register. +By default, `@ServletComponentScan` scans from the package of the annotated class. + + + +[[howto.webserver.configure-access-logs]] +=== Configure Access Logging +Access logs can be configured for Tomcat, Undertow, and Jetty through their respective namespaces. + +For instance, the following settings log access on Tomcat with a {tomcat-docs}/config/valve.html#Access_Logging[custom pattern]. + +[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] +---- + server: + tomcat: + basedir: "my-tomcat" + accesslog: + enabled: true + pattern: "%t %a %r %s (%D ms)" +---- + +NOTE: The default location for logs is a `logs` directory relative to the Tomcat base directory. +By default, the `logs` directory is a temporary directory, so you may want to fix Tomcat's base directory or use an absolute path for the logs. +In the preceding example, the logs are available in `my-tomcat/logs` relative to the working directory of the application. + +Access logging for Undertow can be configured in a similar fashion, as shown in the following example: + +[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] +---- + server: + undertow: + accesslog: + enabled: true + pattern: "%t %a %r %s (%D ms)" +---- + +Logs are stored in a `logs` directory relative to the working directory of the application. +You can customize this location by setting the configprop:server.undertow.accesslog.dir[] property. + +Finally, access logging for Jetty can also be configured as follows: + +[source,yaml,indent=0,subs="verbatim,quotes,attributes",configprops,configblocks] +---- + server: + jetty: + accesslog: + enabled: true + filename: "/var/log/jetty-access.log" +---- + +By default, logs are redirected to `System.err`. +For more details, see the Jetty documentation. + + + +[[howto.webserver.use-behind-a-proxy-server]] +=== Running Behind a Front-end Proxy Server +If your application is running behind a proxy, a load-balancer or in the cloud, the request information (like the host, port, scheme...) might change along the way. +Your application may be running on `10.10.10.10:8080`, but HTTP clients should only see `example.org`. + +https://tools.ietf.org/html/rfc7239[RFC7239 "Forwarded Headers"] defines the `Forwarded` HTTP header; proxies can use this header to provide information about the original request. +You can configure your application to read those headers and automatically use that information when creating links and sending them to clients in HTTP 302 responses, JSON documents or HTML pages. +There are also non-standard headers, like `X-Forwarded-Host`, `X-Forwarded-Port`, `X-Forwarded-Proto`, `X-Forwarded-Ssl`, and `X-Forwarded-Prefix`. + +If the proxy adds the commonly used `X-Forwarded-For` and `X-Forwarded-Proto` headers, setting `server.forward-headers-strategy` to `NATIVE` is enough to support those. +With this option, the Web servers themselves natively support this feature; you can check their specific documentation to learn about specific behavior. + +If this is not enough, Spring Framework provides a {spring-framework-docs}/web.html#filters-forwarded-headers[ForwardedHeaderFilter]. +You can register it as a Servlet Filter in your application by setting `server.forward-headers-strategy` is set to `FRAMEWORK`. + +TIP: If you are using Tomcat and terminating SSL at the proxy, configprop:server.tomcat.redirect-context-root[] should be set to `false`. +This allows the `X-Forwarded-Proto` header to be honored before any redirects are performed. + +NOTE: If your application runs in Cloud Foundry or Heroku, the configprop:server.forward-headers-strategy[] property defaults to `NATIVE`. +In all other instances, it defaults to `NONE`. + + + +[[howto.webserver.use-behind-a-proxy-server.tomcat]] +==== Customize Tomcat's Proxy Configuration +If you use Tomcat, you can additionally configure the names of the headers used to carry "`forwarded`" information, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + server: + tomcat: + remoteip: + remote-ip-header: "x-your-remote-ip-header" + protocol-header: "x-your-protocol-header" +---- + +Tomcat is also configured with a default regular expression that matches internal proxies that are to be trusted. +By default, IP addresses in `10/8`, `192.168/16`, `169.254/16` and `127/8` are trusted. +You can customize the valve's configuration by adding an entry to `application.properties`, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- + server: + tomcat: + remoteip: + internal-proxies: "192\\.168\\.\\d{1,3}\\.\\d{1,3}" +---- + +NOTE: You can trust all proxies by setting the `internal-proxies` to empty (but do not do so in production). + +You can take complete control of the configuration of Tomcat's `RemoteIpValve` by switching the automatic one off (to do so, set `server.forward-headers-strategy=NONE`) and adding a new valve instance using a `WebServerFactoryCustomizer` bean. + + + +[[howto.webserver.enable-multiple-connectors-in-tomcat]] +=== Enable Multiple Connectors with Tomcat +You can add an `org.apache.catalina.connector.Connector` to the `TomcatServletWebServerFactory`, which can allow multiple connectors, including HTTP and HTTPS connectors, as shown in the following example: + +[source,java,indent=0,subs="verbatim,quotes,attributes"] +---- +include::{include-howto}/embeddedwebservers/TomcatMultipleConnectorsConfiguration.java[tag=*] +---- + + + +[[howto.webserver.use-tomcat-legacycookieprocessor]] +=== Use Tomcat's LegacyCookieProcessor +By default, the embedded Tomcat used by Spring Boot does not support "Version 0" of the Cookie format, so you may see the following error: + +[indent=0] +---- + java.lang.IllegalArgumentException: An invalid character [32] was present in the Cookie value +---- + +If at all possible, you should consider updating your code to only store values compliant with later Cookie specifications. +If, however, you cannot change the way that cookies are written, you can instead configure Tomcat to use a `LegacyCookieProcessor`. +To switch to the `LegacyCookieProcessor`, use an `WebServerFactoryCustomizer` bean that adds a `TomcatContextCustomizer`, as shown in the following example: + +[source,java,indent=0] +---- +include::{include-howto}/embeddedwebservers/LegacyCookieProcessorConfiguration.java[tag=*] +---- + + + +[[howto.webserver.enable-tomcat-mbean-registry]] +=== Enable Tomcat's MBean Registry +Embedded Tomcat's MBean registry is disabled by default. +This minimizes Tomcat's memory footprint. +If you want to use Tomcat's MBeans, for example so that they can be used to expose metrics via Micrometer, you must use the configprop:server.tomcat.mbeanregistry.enabled[] property to do so, as shown in the following example: + +[source,yaml,indent=0,configprops,configblocks] +---- +server: + tomcat: + mbeanregistry: + enabled: true +---- + + + +[[howto.webserver.enable-multiple-listeners-in-undertow]] +=== Enable Multiple Listeners with Undertow +Add an `UndertowBuilderCustomizer` to the `UndertowServletWebServerFactory` and add a listener to the `Builder`, as shown in the following example: + +[source,java,indent=0,subs="verbatim,quotes,attributes"] +---- +include::{include-howto}/embeddedwebservers/UndertowMultipleListenersConfiguration.java[tag=*] +---- + + + +[[howto.webserver.create-websocket-endpoints-using-serverendpoint]] +=== Create WebSocket Endpoints Using @ServerEndpoint +If you want to use `@ServerEndpoint` in a Spring Boot application that used an embedded container, you must declare a single `ServerEndpointExporter` `@Bean`, as shown in the following example: + +[source,java,pending-extract=true,indent=0,subs="verbatim,quotes,attributes"] +---- + @Bean + public ServerEndpointExporter serverEndpointExporter() { + return new ServerEndpointExporter(); + } +---- + +The bean shown in the preceding example registers any `@ServerEndpoint` annotated beans with the underlying WebSocket container. +When deployed to a standalone servlet container, this role is performed by a servlet container initializer, and the `ServerEndpointExporter` bean is not required. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/index.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/index.adoc index 73f409e566..fa23f79cd8 100644 --- a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/index.adoc +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/index.adoc @@ -1,31 +1,32 @@ [[index]] = Spring Boot Reference Documentation include::authors.adoc[] -:docinfo: shared include::attributes.adoc[] + + *{spring-boot-version}* The reference documentation consists of the following sections: [horizontal] -<> :: Legal information. -<> :: About the Documentation, Getting Help, First Steps, and more. -<> :: Introducing Spring Boot, System Requirements, Servlet Containers, Installing Spring Boot, Developing Your First Spring Boot Application -<> :: Build Systems, Structuring Your Code, Configuration, Spring Beans and Dependency Injection, DevTools, and more. -<> :: Profiles, Logging, Security, Caching, Spring Integration, Testing, and more. -<> :: Monitoring, Metrics, Auditing, and more. -<> :: Deploying to the Cloud, Installing as a Unix application. -<> :: Installing the CLI, Using the CLI, Configuring the CLI, and more. -<> :: Maven Plugin, Gradle Plugin, Antlib, and more. -<> :: Application Development, Configuration, Embedded Servers, Data Access, and many more. +<> :: Legal information. +<> :: About the Documentation, Getting Help, First Steps, and more. +<> :: Introducing Spring Boot, System Requirements, Servlet Containers, Installing Spring Boot, Developing Your First Spring Boot Application +<> :: Build Systems, Structuring Your Code, Configuration, Spring Beans and Dependency Injection, DevTools, and more. +<> :: Profiles, Logging, Security, Caching, Spring Integration, Testing, and more. +<> :: Monitoring, Metrics, Auditing, and more. +<> :: Deploying to the Cloud, Installing as a Unix application. +<> :: Installing the CLI, Using the CLI, Configuring the CLI, and more. +<> :: Maven Plugin, Gradle Plugin, Antlib, and more. +<> :: Application Development, Configuration, Embedded Servers, Data Access, and many more. The reference documentation has the following appendices: [horizontal] -<> :: Common application properties that can be used to configure your application. -<> :: Metadata used to describe configuration properties. -<> :: Auto-configuration classes provided by Spring Boot. -<> :: Test-autoconfiguration annotations used to test slices of your application. -<> :: Spring Boot's executable jars, their launchers, and their format. -<> :: Details of the dependencies that are managed by Spring Boot. +<> :: Common application properties that can be used to configure your application. +<> :: Metadata used to describe configuration properties. +<> :: Auto-configuration classes provided by Spring Boot. +<> :: Test auto-configuration annotations used to test slices of your application. +<> :: Spring Boot's executable jars, their launchers, and their format. +<> :: Details of the dependencies that are managed by Spring Boot. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/index.singleadoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/index.singleadoc index cc25156720..86f38e9088 100644 --- a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/index.singleadoc +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/index.singleadoc @@ -1,30 +1,46 @@ [[spring-boot-reference-documentation]] = Spring Boot Reference Documentation include::authors.adoc[] -:docinfo: shared include::attributes.adoc[] + + *{spring-boot-version}* include::legal.adoc[leveloffset=+1] + include::documentation.adoc[leveloffset=+1] + include::getting-started.adoc[leveloffset=+1] + include::using.adoc[leveloffset=+1] + include::features.adoc[leveloffset=+1] + include::actuator.adoc[leveloffset=+1] + include::deployment.adoc[leveloffset=+1] + include::cli.adoc[leveloffset=+1] + include::build-tool-plugins.adoc[leveloffset=+1] + include::howto.adoc[leveloffset=+1] +:sectnums!: [[appendix]] == Appendices -include::common-application-properties.adoc[leveloffset=+2] -include::configuration-metadata.adoc[leveloffset=+2] -include::auto-configuration-classes.adoc[leveloffset=+2] -include::test-auto-configuration.adoc[leveloffset=+2] -include::executable-jar.adoc[leveloffset=+2] -include::dependency-versions.adoc[leveloffset=+2] +include::application-properties.adoc[leveloffset=+1] + +include::configuration-metadata.adoc[leveloffset=+1] + +include::auto-configuration-classes.adoc[leveloffset=+1] + +include::test-auto-configuration.adoc[leveloffset=+1] + +include::executable-jar.adoc[leveloffset=+1] + +include::dependency-versions.adoc[leveloffset=+1] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/test-auto-configuration.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/test-auto-configuration.adoc index 8f9e375b32..9b2605b6b4 100644 --- a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/test-auto-configuration.adoc +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/test-auto-configuration.adoc @@ -1,15 +1,12 @@ [appendix] -[[appendix.test-auto-configuration]] +[[test-auto-configuration]] = Test Auto-configuration Annotations include::attributes.adoc[] + + This appendix describes the `@…Test` auto-configuration annotations that Spring Boot provides to test slices of your application. -[[appendix.test-auto-configuration.slices]] -== Test Slices - -The following table lists the various `@…Test` annotations that can be used to test slices of your application and the auto-configuration that they import by default: - -include::test-slice-auto-configuration.adoc[] +include::test-auto-configuration/slices.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/test-auto-configuration/slices.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/test-auto-configuration/slices.adoc new file mode 100644 index 0000000000..a8567d196e --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/test-auto-configuration/slices.adoc @@ -0,0 +1,6 @@ +[[test-auto-configuration.slices]] +== Test Slices + +The following table lists the various `@…Test` annotations that can be used to test slices of your application and the auto-configuration that they import by default: + +include::documented-slices.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using.adoc index 1dbb9728fa..7f45c5faac 100644 --- a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using.adoc +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using.adoc @@ -2,949 +2,33 @@ = Using Spring Boot include::attributes.adoc[] + + This section goes into more detail about how you should use Spring Boot. It covers topics such as build systems, auto-configuration, and how to run your applications. We also cover some Spring Boot best practices. Although there is nothing particularly special about Spring Boot (it is just another library that you can consume), there are a few recommendations that, when followed, make your development process a little easier. -If you are starting out with Spring Boot, you should probably read the _<>_ guide before diving into this section. +If you are starting out with Spring Boot, you should probably read the _<>_ guide before diving into this section. -[[using.build-systems]] -== Build Systems -It is strongly recommended that you choose a build system that supports <> and that can consume artifacts published to the "`Maven Central`" repository. -We would recommend that you choose Maven or Gradle. -It is possible to get Spring Boot to work with other build systems (Ant, for example), but they are not particularly well supported. +include::using/build-systems.adoc[] +include::using/structuring-your-code.adoc[] +include::using/configuration-classes.adoc[] -[[using.build-systems.dependency-management]] -=== Dependency Management -Each release of Spring Boot provides a curated list of dependencies that it supports. -In practice, you do not need to provide a version for any of these dependencies in your build configuration, as Spring Boot manages that for you. -When you upgrade Spring Boot itself, these dependencies are upgraded as well in a consistent way. +include::using/auto-configuration.adoc[] -NOTE: You can still specify a version and override Spring Boot's recommendations if you need to do so. +include::using/spring-beans-and-dependency-injection.adoc[] -The curated list contains all the Spring modules that you can use with Spring Boot as well as a refined list of third party libraries. -The list is available as a standard Bills of Materials (`spring-boot-dependencies`) that can be used with both <> and <>. +include::using/using-the-springbootapplication-annotation.adoc[] -WARNING: Each release of Spring Boot is associated with a base version of the Spring Framework. -We **highly** recommend that you not specify its version. +include::using/running-your-application.adoc[] +include::using/devtools.adoc[] +include::using/packaging-for-production.adoc[] -[[using.build-systems.maven]] -=== Maven -To learn about using Spring Boot with Maven, please refer to the documentation for Spring Boot's Maven plugin: - -* Reference ({spring-boot-maven-plugin-docs}[HTML] and {spring-boot-maven-plugin-pdfdocs}[PDF]) -* {spring-boot-maven-plugin-api}[API] - - - -[[using.build-systems.gradle]] -=== Gradle -To learn about using Spring Boot with Gradle, please refer to the documentation for Spring Boot's Gradle plugin: - -* Reference ({spring-boot-gradle-plugin-docs}[HTML] and {spring-boot-gradle-plugin-pdfdocs}[PDF]) -* {spring-boot-gradle-plugin-api}[API] - - - -[[using.build-systems.ant]] -=== Ant -It is possible to build a Spring Boot project using Apache Ant+Ivy. -The `spring-boot-antlib` "`AntLib`" module is also available to help Ant create executable jars. - -To declare dependencies, a typical `ivy.xml` file looks something like the following example: - -[source,xml,indent=0] ----- - - - - - - - - - - ----- - -A typical `build.xml` looks like the following example: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ----- - -TIP: If you do not want to use the `spring-boot-antlib` module, see the _<>_ "`How-to`" . - - - -[[using.build-systems.starters]] -=== Starters -Starters are a set of convenient dependency descriptors that you can include in your application. -You get a one-stop shop for all the Spring and related technologies that you need without having to hunt through sample code and copy-paste loads of dependency descriptors. -For example, if you want to get started using Spring and JPA for database access, include the `spring-boot-starter-data-jpa` dependency in your project. - -The starters contain a lot of the dependencies that you need to get a project up and running quickly and with a consistent, supported set of managed transitive dependencies. - -.What's in a name -**** -All **official** starters follow a similar naming pattern; `+spring-boot-starter-*+`, where `+*+` is a particular type of application. -This naming structure is intended to help when you need to find a starter. -The Maven integration in many IDEs lets you search dependencies by name. -For example, with the appropriate Eclipse or STS plugin installed, you can press `ctrl-space` in the POM editor and type "`spring-boot-starter`" for a complete list. - -As explained in the "`<>`" section, third party starters should not start with `spring-boot`, as it is reserved for official Spring Boot artifacts. -Rather, a third-party starter typically starts with the name of the project. -For example, a third-party starter project called `thirdpartyproject` would typically be named `thirdpartyproject-spring-boot-starter`. -**** - -The following application starters are provided by Spring Boot under the `org.springframework.boot` group: - -.Spring Boot application starters -include::starters/application-starters.adoc[] - -In addition to the application starters, the following starters can be used to add _<>_ features: - -.Spring Boot production starters -include::starters/production-starters.adoc[] - -Finally, Spring Boot also includes the following starters that can be used if you want to exclude or swap specific technical facets: - -.Spring Boot technical starters -include::starters/technical-starters.adoc[] - -To learn how to swap technical facets, please see the how-to documentation for <> and <>. - -TIP: For a list of additional community contributed starters, see the {spring-boot-latest-code}/spring-boot-project/spring-boot-starters/README.adoc[README file] in the `spring-boot-starters` module on GitHub. - - - -[[using.structuring-your-code]] -== Structuring Your Code -Spring Boot does not require any specific code layout to work. -However, there are some best practices that help. - - - -[[using.structuring-your-code.using-the-default-package]] -=== Using the "`default`" Package -When a class does not include a `package` declaration, it is considered to be in the "`default package`". -The use of the "`default package`" is generally discouraged and should be avoided. -It can cause particular problems for Spring Boot applications that use the `@ComponentScan`, `@ConfigurationPropertiesScan`, `@EntityScan`, or `@SpringBootApplication` annotations, since every class from every jar is read. - -TIP: We recommend that you follow Java's recommended package naming conventions and use a reversed domain name (for example, `com.example.project`). - - - -[[using.structuring-your-code.locating-the-main-class]] -=== Locating the Main Application Class -We generally recommend that you locate your main application class in a root package above other classes. -The <> is often placed on your main class, and it implicitly defines a base "`search package`" for certain items. -For example, if you are writing a JPA application, the package of the `@SpringBootApplication` annotated class is used to search for `@Entity` items. -Using a root package also allows component scan to apply only on your project. - -TIP: If you don't want to use `@SpringBootApplication`, the `@EnableAutoConfiguration` and `@ComponentScan` annotations that it imports defines that behaviour so you can also use those instead. - -The following listing shows a typical layout: - -[indent=0] ----- - com - +- example - +- myapplication - +- Application.java - | - +- customer - | +- Customer.java - | +- CustomerController.java - | +- CustomerService.java - | +- CustomerRepository.java - | - +- order - +- Order.java - +- OrderController.java - +- OrderService.java - +- OrderRepository.java ----- - -The `Application.java` file would declare the `main` method, along with the basic `@SpringBootApplication`, as follows: - -[source,java,pending-extract=true,indent=0] ----- - package com.example.myapplication; - - import org.springframework.boot.SpringApplication; - import org.springframework.boot.autoconfigure.SpringBootApplication; - - @SpringBootApplication - public class Application { - - public static void main(String[] args) { - SpringApplication.run(Application.class, args); - } - - } ----- - - - -[[using.configuration-classes]] -== Configuration Classes -Spring Boot favors Java-based configuration. -Although it is possible to use `SpringApplication` with XML sources, we generally recommend that your primary source be a single `@Configuration` class. -Usually the class that defines the `main` method is a good candidate as the primary `@Configuration`. - -TIP: Many Spring configuration examples have been published on the Internet that use XML configuration. -If possible, always try to use the equivalent Java-based configuration. -Searching for `+Enable*+` annotations can be a good starting point. - - - -[[using.configuration-classes.importing-additional-configuration]] -=== Importing Additional Configuration Classes -You need not put all your `@Configuration` into a single class. -The `@Import` annotation can be used to import additional configuration classes. -Alternatively, you can use `@ComponentScan` to automatically pick up all Spring components, including `@Configuration` classes. - - - -[[using.configuration-classes.importing-xml-configuration]] -=== Importing XML Configuration -If you absolutely must use XML based configuration, we recommend that you still start with a `@Configuration` class. -You can then use an `@ImportResource` annotation to load XML configuration files. - - - -[[using.auto-configuration]] -== Auto-configuration -Spring Boot auto-configuration attempts to automatically configure your Spring application based on the jar dependencies that you have added. -For example, if `HSQLDB` is on your classpath, and you have not manually configured any database connection beans, then Spring Boot auto-configures an in-memory database. - -You need to opt-in to auto-configuration by adding the `@EnableAutoConfiguration` or `@SpringBootApplication` annotations to one of your `@Configuration` classes. - -TIP: You should only ever add one `@SpringBootApplication` or `@EnableAutoConfiguration` annotation. -We generally recommend that you add one or the other to your primary `@Configuration` class only. - - - -[[using.auto-configuration.replacing]] -=== Gradually Replacing Auto-configuration -Auto-configuration is non-invasive. -At any point, you can start to define your own configuration to replace specific parts of the auto-configuration. -For example, if you add your own `DataSource` bean, the default embedded database support backs away. - -If you need to find out what auto-configuration is currently being applied, and why, start your application with the `--debug` switch. -Doing so enables debug logs for a selection of core loggers and logs a conditions report to the console. - - - -[[using.auto-configuration.disabling-specific]] -=== Disabling Specific Auto-configuration Classes -If you find that specific auto-configuration classes that you do not want are being applied, you can use the exclude attribute of `@SpringBootApplication` to disable them, as shown in the following example: - -[source,java,pending-extract=true,indent=0] ----- - import org.springframework.boot.autoconfigure.*; - import org.springframework.boot.autoconfigure.jdbc.*; - - @SpringBootApplication(exclude={DataSourceAutoConfiguration.class}) - public class MyApplication { - } ----- - -If the class is not on the classpath, you can use the `excludeName` attribute of the annotation and specify the fully qualified name instead. -If you prefer to use `@EnableAutoConfiguration` rather than `@SpringBootApplication`, `exclude` and `excludeName` are also available. -Finally, you can also control the list of auto-configuration classes to exclude by using the configprop:spring.autoconfigure.exclude[] property. - -TIP: You can define exclusions both at the annotation level and by using the property. - -NOTE: Even though auto-configuration classes are `public`, the only aspect of the class that is considered public API is the name of the class which can be used for disabling the auto-configuration. -The actual contents of those classes, such as nested configuration classes or bean methods are for internal use only and we do not recommend using those directly. - - - -[[using.spring-beans-and-dependency-injection]] -== Spring Beans and Dependency Injection -You are free to use any of the standard Spring Framework techniques to define your beans and their injected dependencies. -We often find that using `@ComponentScan` (to find your beans) and using `@Autowired` (to do constructor injection) works well. - -If you structure your code as suggested above (locating your application class in a root package), you can add `@ComponentScan` without any arguments. -All of your application components (`@Component`, `@Service`, `@Repository`, `@Controller` etc.) are automatically registered as Spring Beans. - -The following example shows a `@Service` Bean that uses constructor injection to obtain a required `RiskAssessor` bean: - -[source,java,pending-extract=true,indent=0] ----- - package com.example.service; - - import org.springframework.beans.factory.annotation.Autowired; - import org.springframework.stereotype.Service; - - @Service - public class DatabaseAccountService implements AccountService { - - private final RiskAssessor riskAssessor; - - @Autowired - public DatabaseAccountService(RiskAssessor riskAssessor) { - this.riskAssessor = riskAssessor; - } - - // ... - - } ----- - -If a bean has one constructor, you can omit the `@Autowired`, as shown in the following example: - -[source,java,pending-extract=true,indent=0] ----- - @Service - public class DatabaseAccountService implements AccountService { - - private final RiskAssessor riskAssessor; - - public DatabaseAccountService(RiskAssessor riskAssessor) { - this.riskAssessor = riskAssessor; - } - - // ... - - } ----- - -TIP: Notice how using constructor injection lets the `riskAssessor` field be marked as `final`, indicating that it cannot be subsequently changed. - - - -[[using.using-the-springbootapplication-annotation]] -== Using the @SpringBootApplication Annotation -Many Spring Boot developers like their apps to use auto-configuration, component scan and be able to define extra configuration on their "application class". -A single `@SpringBootApplication` annotation can be used to enable those three features, that is: - -* `@EnableAutoConfiguration`: enable <> -* `@ComponentScan`: enable `@Component` scan on the package where the application is located (see <>) -* `@Configuration`: allow to register extra beans in the context or import additional configuration classes - -[source,java,pending-extract=true,indent=0] ----- - package com.example.myapplication; - - import org.springframework.boot.SpringApplication; - import org.springframework.boot.autoconfigure.SpringBootApplication; - - @SpringBootApplication // same as @Configuration @EnableAutoConfiguration @ComponentScan - public class Application { - - public static void main(String[] args) { - SpringApplication.run(Application.class, args); - } - - } ----- - -NOTE: `@SpringBootApplication` also provides aliases to customize the attributes of `@EnableAutoConfiguration` and `@ComponentScan`. - -[NOTE] -==== -None of these features are mandatory and you may choose to replace this single annotation by any of the features that it enables. -For instance, you may not want to use component scan or configuration properties scan in your application: - -[source,java,pending-extract=true,indent=0] ----- - package com.example.myapplication; - - import org.springframework.boot.SpringApplication; - import org.springframework.context.annotation.ComponentScan - import org.springframework.context.annotation.Configuration; - import org.springframework.context.annotation.Import; - - @Configuration(proxyBeanMethods = false) - @EnableAutoConfiguration - @Import({ MyConfig.class, MyAnotherConfig.class }) - public class Application { - - public static void main(String[] args) { - SpringApplication.run(Application.class, args); - } - - } ----- - -In this example, `Application` is just like any other Spring Boot application except that `@Component`-annotated classes and `@ConfigurationProperties`-annotated classes are not detected automatically and the user-defined beans are imported explicitly (see `@Import`). -==== - - - -[[using.running-your-application]] -== Running Your Application -One of the biggest advantages of packaging your application as a jar and using an embedded HTTP server is that you can run your application as you would any other. -The sample applies to debugging Spring Boot applications. -You do not need any special IDE plugins or extensions. - -NOTE: This section only covers jar based packaging. -If you choose to package your application as a war file, you should refer to your server and IDE documentation. - - - -[[using.running-your-application.from-an-ide]] -=== Running from an IDE -You can run a Spring Boot application from your IDE as a Java application. -However, you first need to import your project. -Import steps vary depending on your IDE and build system. -Most IDEs can import Maven projects directly. -For example, Eclipse users can select `Import...` -> `Existing Maven Projects` from the `File` menu. - -If you cannot directly import your project into your IDE, you may be able to generate IDE metadata by using a build plugin. -Maven includes plugins for https://maven.apache.org/plugins/maven-eclipse-plugin/[Eclipse] and https://maven.apache.org/plugins/maven-idea-plugin/[IDEA]. -Gradle offers plugins for {gradle-docs}/userguide.html[various IDEs]. - -TIP: If you accidentally run a web application twice, you see a "`Port already in use`" error. -STS users can use the `Relaunch` button rather than the `Run` button to ensure that any existing instance is closed. - - - -[[using.running-your-application.as-a-packaged-application]] -=== Running as a Packaged Application -If you use the Spring Boot Maven or Gradle plugins to create an executable jar, you can run your application using `java -jar`, as shown in the following example: - -[indent=0,subs="attributes"] ----- - $ java -jar target/myapplication-0.0.1-SNAPSHOT.jar ----- - -It is also possible to run a packaged application with remote debugging support enabled. -Doing so lets you attach a debugger to your packaged application, as shown in the following example: - -[indent=0,subs="attributes"] ----- - $ java -Xdebug -Xrunjdwp:server=y,transport=dt_socket,address=8000,suspend=n \ - -jar target/myapplication-0.0.1-SNAPSHOT.jar ----- - - - -[[using.running-your-application.with-the-maven-plugin]] -=== Using the Maven Plugin -The Spring Boot Maven plugin includes a `run` goal that can be used to quickly compile and run your application. -Applications run in an exploded form, as they do in your IDE. -The following example shows a typical Maven command to run a Spring Boot application: - -[indent=0,subs="attributes"] ----- - $ mvn spring-boot:run ----- - -You might also want to use the `MAVEN_OPTS` operating system environment variable, as shown in the following example: - -[indent=0,subs="attributes"] ----- - $ export MAVEN_OPTS=-Xmx1024m ----- - - - -[[using.running-your-application.with-the-gradle-plugin]] -=== Using the Gradle Plugin -The Spring Boot Gradle plugin also includes a `bootRun` task that can be used to run your application in an exploded form. -The `bootRun` task is added whenever you apply the `org.springframework.boot` and `java` plugins and is shown in the following example: - -[indent=0,subs="attributes"] ----- - $ gradle bootRun ----- - -You might also want to use the `JAVA_OPTS` operating system environment variable, as shown in the following example: - -[indent=0,subs="attributes"] ----- - $ export JAVA_OPTS=-Xmx1024m ----- - - - -[[using.running-your-application.hot-swapping]] -=== Hot Swapping -Since Spring Boot applications are plain Java applications, JVM hot-swapping should work out of the box. -JVM hot swapping is somewhat limited with the bytecode that it can replace. -For a more complete solution, https://www.jrebel.com/products/jrebel[JRebel] can be used. - -The `spring-boot-devtools` module also includes support for quick application restarts. -See the <> section later in this chapter and the <> for details. - - - -[[using.devtools]] -== Developer Tools -Spring Boot includes an additional set of tools that can make the application development experience a little more pleasant. -The `spring-boot-devtools` module can be included in any project to provide additional development-time features. -To include devtools support, add the module dependency to your build, as shown in the following listings for Maven and Gradle: - -.Maven -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - - org.springframework.boot - spring-boot-devtools - true - - ----- - -.Gradle -[source,groovy,indent=0,subs="attributes"] ----- - dependencies { - developmentOnly("org.springframework.boot:spring-boot-devtools") - } ----- - -NOTE: Developer tools are automatically disabled when running a fully packaged application. -If your application is launched from `java -jar` or if it is started from a special classloader, then it is considered a "`production application`". -You can control this behavior by using the `spring.devtools.restart.enabled` system property. -To enable devtools, irrespective of the classloader used to launch your application, set the `-Dspring.devtools.restart.enabled=true` system property. -This must not be done in a production environment where running devtools is a security risk. -To disable devtools, exclude the dependency or set the `-Dspring.devtools.restart.enabled=false` system property. - -TIP: Flagging the dependency as optional in Maven or using the `developmentOnly` configuration in Gradle (as shown above) prevents devtools from being transitively applied to other modules that use your project. - -TIP: Repackaged archives do not contain devtools by default. -If you want to use a <>, you need to include it. -When using the Maven plugin, set the `excludeDevtools` property to `false`. -When using the Gradle plugin, {spring-boot-gradle-plugin-docs}#packaging-executable-configuring-including-development-only-dependencies[configure the task's classpath to include the `developmentOnly` configuration]. - - - -[[using.devtools.property-defaults]] -=== Property Defaults -Several of the libraries supported by Spring Boot use caches to improve performance. -For example, <> cache compiled templates to avoid repeatedly parsing template files. -Also, Spring MVC can add HTTP caching headers to responses when serving static resources. - -While caching is very beneficial in production, it can be counter-productive during development, preventing you from seeing the changes you just made in your application. -For this reason, spring-boot-devtools disables the caching options by default. - -Cache options are usually configured by settings in your `application.properties` file. -For example, Thymeleaf offers the configprop:spring.thymeleaf.cache[] property. -Rather than needing to set these properties manually, the `spring-boot-devtools` module automatically applies sensible development-time configuration. - -Because you need more information about web requests while developing Spring MVC and Spring WebFlux applications, developer tools will enable `DEBUG` logging for the `web` logging group. -This will give you information about the incoming request, which handler is processing it, the response outcome, etc. -If you wish to log all request details (including potentially sensitive information), you can turn on the configprop:spring.mvc.log-request-details[] or configprop:spring.codec.log-request-details[] configuration properties. - -NOTE: If you don't want property defaults to be applied you can set configprop:spring.devtools.add-properties[] to `false` in your `application.properties`. - -TIP: For a complete list of the properties that are applied by the devtools, see {spring-boot-devtools-module-code}/env/DevToolsPropertyDefaultsPostProcessor.java[DevToolsPropertyDefaultsPostProcessor]. - - - -[[using.devtools.restart]] -=== Automatic Restart -Applications that use `spring-boot-devtools` automatically restart whenever files on the classpath change. -This can be a useful feature when working in an IDE, as it gives a very fast feedback loop for code changes. -By default, any entry on the classpath that points to a directory is monitored for changes. -Note that certain resources, such as static assets and view templates, <>. - -.Triggering a restart -**** -As DevTools monitors classpath resources, the only way to trigger a restart is to update the classpath. -The way in which you cause the classpath to be updated depends on the IDE that you are using: - -* In Eclipse, saving a modified file causes the classpath to be updated and triggers a restart. -* In IntelliJ IDEA, building the project (`Build +->+ Build Project`) has the same effect. -* If using a build plugin, running `mvn compile` for Maven or `gradle build` for Gradle will trigger a restart. -**** - -NOTE: If you are restarting with Maven or Gradle using the build plugin you must leave the `forking` set to `enabled`. -If you disable forking, the isolated application classloader used by devtools will not be created and restarts will not operate properly. - -TIP: Automatic restart works very well when used with LiveReload. -<> for details. -If you use JRebel, automatic restarts are disabled in favor of dynamic class reloading. -Other devtools features (such as LiveReload and property overrides) can still be used. - -NOTE: DevTools relies on the application context's shutdown hook to close it during a restart. -It does not work correctly if you have disabled the shutdown hook (`SpringApplication.setRegisterShutdownHook(false)`). - -NOTE: DevTools needs to customize the `ResourceLoader` used by the `ApplicationContext`. -If your application provides one already, it is going to be wrapped. -Direct override of the `getResource` method on the `ApplicationContext` is not supported. - -[[using-spring-boot-restart-vs-reload]] -.Restart vs Reload -**** -The restart technology provided by Spring Boot works by using two classloaders. -Classes that do not change (for example, those from third-party jars) are loaded into a _base_ classloader. -Classes that you are actively developing are loaded into a _restart_ classloader. -When the application is restarted, the _restart_ classloader is thrown away and a new one is created. -This approach means that application restarts are typically much faster than "`cold starts`", since the _base_ classloader is already available and populated. - -If you find that restarts are not quick enough for your applications or you encounter classloading issues, you could consider reloading technologies such as https://jrebel.com/software/jrebel/[JRebel] from ZeroTurnaround. -These work by rewriting classes as they are loaded to make them more amenable to reloading. -**** - - - -[[using.devtools.restart.logging-condition-delta]] -==== Logging changes in condition evaluation -By default, each time your application restarts, a report showing the condition evaluation delta is logged. -The report shows the changes to your application's auto-configuration as you make changes such as adding or removing beans and setting configuration properties. - -To disable the logging of the report, set the following property: - -[source,yaml,indent=0,configblocks] ----- - spring: - devtools: - restart: - log-condition-evaluation-delta: false ----- - - - -[[using.devtools.restart.excluding-resources]] -==== Excluding Resources -Certain resources do not necessarily need to trigger a restart when they are changed. -For example, Thymeleaf templates can be edited in-place. -By default, changing resources in `/META-INF/maven`, `/META-INF/resources`, `/resources`, `/static`, `/public`, or `/templates` does not trigger a restart but does trigger a <>. -If you want to customize these exclusions, you can use the configprop:spring.devtools.restart.exclude[] property. -For example, to exclude only `/static` and `/public` you would set the following property: - -[source,yaml,indent=0,configblocks] ----- - spring: - devtools: - restart: - exclude: "static/**,public/**" ----- - -TIP: If you want to keep those defaults and _add_ additional exclusions, use the configprop:spring.devtools.restart.additional-exclude[] property instead. - - - -[[using.devtools.restart.watching-additional-paths]] -==== Watching Additional Paths -You may want your application to be restarted or reloaded when you make changes to files that are not on the classpath. -To do so, use the configprop:spring.devtools.restart.additional-paths[] property to configure additional paths to watch for changes. -You can use the configprop:spring.devtools.restart.exclude[] property <> to control whether changes beneath the additional paths trigger a full restart or a <>. - - - -[[using.devtools.restart.disable]] -==== Disabling Restart -If you do not want to use the restart feature, you can disable it by using the configprop:spring.devtools.restart.enabled[] property. -In most cases, you can set this property in your `application.properties` (doing so still initializes the restart classloader, but it does not watch for file changes). - -If you need to _completely_ disable restart support (for example, because it does not work with a specific library), you need to set the configprop:spring.devtools.restart.enabled[] `System` property to `false` before calling `SpringApplication.run(...)`, as shown in the following example: - -[source,java,pending-extract=true,indent=0] ----- - public static void main(String[] args) { - System.setProperty("spring.devtools.restart.enabled", "false"); - SpringApplication.run(MyApp.class, args); - } ----- - - - -[[using.devtools.restart.triggerfile]] -==== Using a Trigger File -If you work with an IDE that continuously compiles changed files, you might prefer to trigger restarts only at specific times. -To do so, you can use a "`trigger file`", which is a special file that must be modified when you want to actually trigger a restart check. - -NOTE: Any update to the file will trigger a check, but restart only actually occurs if Devtools has detected it has something to do. - -To use a trigger file, set the configprop:spring.devtools.restart.trigger-file[] property to the name (excluding any path) of your trigger file. -The trigger file must appear somewhere on your classpath. - -For example, if you have a project with the following structure: - -[indent=0] ----- - src - +- main - +- resources - +- .reloadtrigger ----- - -Then your `trigger-file` property would be: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - devtools: - restart: - trigger-file: ".reloadtrigger" ----- - -Restarts will now only happen when the `src/main/resources/.reloadtrigger` is updated. - -TIP: You might want to set `spring.devtools.restart.trigger-file` as a <>, so that all your projects behave in the same way. - -Some IDEs have features that save you from needing to update your trigger file manually. -https://spring.io/tools[Spring Tools for Eclipse] and https://www.jetbrains.com/idea/[IntelliJ IDEA (Ultimate Edition)] both have such support. -With Spring Tools, you can use the "`reload`" button from the console view (as long as your `trigger-file` is named `.reloadtrigger`). -For IntelliJ IDEA, you can follow the https://www.jetbrains.com/help/idea/spring-boot.html#application-update-policies[instructions in their documentation]. - - - -[[using.devtools.restart.customizing-the-classload]] -==== Customizing the Restart Classloader -As described earlier in the <> section, restart functionality is implemented by using two classloaders. -For most applications, this approach works well. -However, it can sometimes cause classloading issues. - -By default, any open project in your IDE is loaded with the "`restart`" classloader, and any regular `.jar` file is loaded with the "`base`" classloader. -If you work on a multi-module project, and not every module is imported into your IDE, you may need to customize things. -To do so, you can create a `META-INF/spring-devtools.properties` file. - -The `spring-devtools.properties` file can contain properties prefixed with `restart.exclude` and `restart.include`. -The `include` elements are items that should be pulled up into the "`restart`" classloader, and the `exclude` elements are items that should be pushed down into the "`base`" classloader. -The value of the property is a regex pattern that is applied to the classpath, as shown in the following example: - -[source,yaml,indent=0,configblocks] ----- - restart: - exclude: - companycommonlibs: "/mycorp-common-[\\w\\d-\\.]+\\.jar" - include: - projectcommon: "/mycorp-myproj-[\\w\\d-\\.]+\\.jar" ----- - -NOTE: All property keys must be unique. -As long as a property starts with `restart.include.` or `restart.exclude.` it is considered. - -TIP: All `META-INF/spring-devtools.properties` from the classpath are loaded. -You can package files inside your project, or in the libraries that the project consumes. - - - -[[using.devtools.restart.limitations]] -==== Known Limitations -Restart functionality does not work well with objects that are deserialized by using a standard `ObjectInputStream`. -If you need to deserialize data, you may need to use Spring's `ConfigurableObjectInputStream` in combination with `Thread.currentThread().getContextClassLoader()`. - -Unfortunately, several third-party libraries deserialize without considering the context classloader. -If you find such a problem, you need to request a fix with the original authors. - - - -[[using.devtools.livereload]] -=== LiveReload -The `spring-boot-devtools` module includes an embedded LiveReload server that can be used to trigger a browser refresh when a resource is changed. -LiveReload browser extensions are freely available for Chrome, Firefox and Safari from http://livereload.com/extensions/[livereload.com]. - -If you do not want to start the LiveReload server when your application runs, you can set the configprop:spring.devtools.livereload.enabled[] property to `false`. - -NOTE: You can only run one LiveReload server at a time. -Before starting your application, ensure that no other LiveReload servers are running. -If you start multiple applications from your IDE, only the first has LiveReload support. - -WARNING: To trigger LiveReload when a file changes, <> must be enabled. - - - -[[using.devtools.globalsettings]] -=== Global Settings -You can configure global devtools settings by adding any of the following files to the `$HOME/.config/spring-boot` directory: - -. `spring-boot-devtools.properties` -. `spring-boot-devtools.yaml` -. `spring-boot-devtools.yml` - -Any properties added to these file apply to _all_ Spring Boot applications on your machine that use devtools. -For example, to configure restart to always use a <>, you would add the following property to your `spring-boot-devtools` file: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - devtools: - restart: - trigger-file: ".reloadtrigger" ----- - -NOTE: If devtools configuration files are not found in `$HOME/.config/spring-boot`, the root of the `$HOME` directory is searched for the presence of a `.spring-boot-devtools.properties` file. -This allows you to share the devtools global configuration with applications that are on an older version of Spring Boot that does not support the `$HOME/.config/spring-boot` location. - -[NOTE] -==== -Profiles are not supported in devtools properties/yaml files. - -Any profiles activated in `.spring-boot-devtools.properties` will not affect the loading of <>. -Profile specific filenames (of the form `spring-boot-devtools-.properties`) and `spring.config.activate.on-profile` documents in both YAML and Properties files are not supported. -==== - - - -[[using.devtools.globalsettings.configuring-file-system-watcher]] -==== Configuring File System Watcher -{spring-boot-devtools-module-code}/filewatch/FileSystemWatcher.java[FileSystemWatcher] works by polling the class changes with a certain time interval, and then waiting for a predefined quiet period to make sure there are no more changes. -Since Spring Boot relies entirely on the IDE to compile and copy files into the location from where Spring Boot can read them, you might find that there are times when certain changes are not reflected when devtools restarts the application. -If you observe such problems constantly, try increasing the `spring.devtools.restart.poll-interval` and `spring.devtools.restart.quiet-period` parameters to the values that fit your development environment: - -[source,yaml,indent=0,configprops,configblocks] ----- - spring: - devtools: - restart: - poll-interval: "2s" - quiet-period: "1s" ----- - -The monitored classpath directories are now polled every 2 seconds for changes, and a 1 second quiet period is maintained to make sure there are no additional class changes. - - - -[[using.devtools.remote-applications]] -=== Remote Applications -The Spring Boot developer tools are not limited to local development. -You can also use several features when running applications remotely. -Remote support is opt-in as enabling it can be a security risk. -It should only be enabled when running on a trusted network or when secured with SSL. -If neither of these options is available to you, you should not use DevTools' remote support. -You should never enable support on a production deployment. - -To enable it, you need to make sure that `devtools` is included in the repackaged archive, as shown in the following listing: - -[source,xml,indent=0,subs="verbatim,quotes,attributes"] ----- - - - - org.springframework.boot - spring-boot-maven-plugin - - false - - - - ----- - -Then you need to set the configprop:spring.devtools.remote.secret[] property. -Like any important password or secret, the value should be unique and strong such that it cannot be guessed or brute-forced. - -Remote devtools support is provided in two parts: a server-side endpoint that accepts connections and a client application that you run in your IDE. -The server component is automatically enabled when the configprop:spring.devtools.remote.secret[] property is set. -The client component must be launched manually. - - - -[[using.devtools.remote-applications.client]] -==== Running the Remote Client Application -The remote client application is designed to be run from within your IDE. -You need to run `org.springframework.boot.devtools.RemoteSpringApplication` with the same classpath as the remote project that you connect to. -The application's single required argument is the remote URL to which it connects. - -For example, if you are using Eclipse or STS and you have a project named `my-app` that you have deployed to Cloud Foundry, you would do the following: - -* Select `Run Configurations...` from the `Run` menu. -* Create a new `Java Application` "`launch configuration`". -* Browse for the `my-app` project. -* Use `org.springframework.boot.devtools.RemoteSpringApplication` as the main class. -* Add `+++https://myapp.cfapps.io+++` to the `Program arguments` (or whatever your remote URL is). - -A running remote client might resemble the following listing: - -[indent=0,subs="attributes"] ----- - . ____ _ __ _ _ - /\\ / ___'_ __ _ _(_)_ __ __ _ ___ _ \ \ \ \ - ( ( )\___ | '_ | '_| | '_ \/ _` | | _ \___ _ __ ___| |_ ___ \ \ \ \ - \\/ ___)| |_)| | | | | || (_| []::::::[] / -_) ' \/ _ \ _/ -_) ) ) ) ) - ' |____| .__|_| |_|_| |_\__, | |_|_\___|_|_|_\___/\__\___|/ / / / - =========|_|==============|___/===================================/_/_/_/ - :: Spring Boot Remote :: {spring-boot-version} - - 2015-06-10 18:25:06.632 INFO 14938 --- [ main] o.s.b.devtools.RemoteSpringApplication : Starting RemoteSpringApplication on pwmbp with PID 14938 (/Users/pwebb/projects/spring-boot/code/spring-boot-project/spring-boot-devtools/target/classes started by pwebb in /Users/pwebb/projects/spring-boot/code) - 2015-06-10 18:25:06.671 INFO 14938 --- [ main] s.c.a.AnnotationConfigApplicationContext : Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@2a17b7b6: startup date [Wed Jun 10 18:25:06 PDT 2015]; root of context hierarchy - 2015-06-10 18:25:07.043 WARN 14938 --- [ main] o.s.b.d.r.c.RemoteClientConfiguration : The connection to http://localhost:8080 is insecure. You should use a URL starting with 'https://'. - 2015-06-10 18:25:07.074 INFO 14938 --- [ main] o.s.b.d.a.OptionalLiveReloadServer : LiveReload server is running on port 35729 - 2015-06-10 18:25:07.130 INFO 14938 --- [ main] o.s.b.devtools.RemoteSpringApplication : Started RemoteSpringApplication in 0.74 seconds (JVM running for 1.105) ----- - -NOTE: Because the remote client is using the same classpath as the real application it can directly read application properties. -This is how the configprop:spring.devtools.remote.secret[] property is read and passed to the server for authentication. - -TIP: It is always advisable to use `https://` as the connection protocol, so that traffic is encrypted and passwords cannot be intercepted. - -TIP: If you need to use a proxy to access the remote application, configure the `spring.devtools.remote.proxy.host` and `spring.devtools.remote.proxy.port` properties. - - - -[[using.devtools.remote-applications.update]] -==== Remote Update -The remote client monitors your application classpath for changes in the same way as the <>. -Any updated resource is pushed to the remote application and (_if required_) triggers a restart. -This can be helpful if you iterate on a feature that uses a cloud service that you do not have locally. -Generally, remote updates and restarts are much quicker than a full rebuild and deploy cycle. - -On a slower development environment, it may happen that the quiet period is not enough, and the changes in the classes may be split into batches. -The server is restarted after the first batch of class changes is uploaded. -The next batch can’t be sent to the application, since the server is restarting. - -This is typically manifested by a warning in the `RemoteSpringApplication` logs about failing to upload some of the classes, and a consequent retry. -But it may also lead to application code inconsistency and failure to restart after the first batch of changes is uploaded. -If you observe such problems constantly, try increasing the `spring.devtools.restart.poll-interval` and `spring.devtools.restart.quiet-period` parameters to the values that fit your development environment. -See the <> section for configuring these properties. - -NOTE: Files are only monitored when the remote client is running. -If you change a file before starting the remote client, it is not pushed to the remote server. - - - -[[using.packaging-for-production]] -== Packaging Your Application for Production -Executable jars can be used for production deployment. -As they are self-contained, they are also ideally suited for cloud-based deployment. - -For additional "`production ready`" features, such as health, auditing, and metric REST or JMX end-points, consider adding `spring-boot-actuator`. -See _<>_ for details. - - - -[[using.whats-next]] -== What to Read Next -You should now understand how you can use Spring Boot and some best practices that you should follow. -You can now go on to learn about specific _<>_ in depth, or you could skip ahead and read about the "`<>`" aspects of Spring Boot. +include::using/whats-next.adoc[] diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/auto-configuration.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/auto-configuration.adoc new file mode 100644 index 0000000000..73cd587fd1 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/auto-configuration.adoc @@ -0,0 +1,45 @@ +[[using.auto-configuration]] +== Auto-configuration +Spring Boot auto-configuration attempts to automatically configure your Spring application based on the jar dependencies that you have added. +For example, if `HSQLDB` is on your classpath, and you have not manually configured any database connection beans, then Spring Boot auto-configures an in-memory database. + +You need to opt-in to auto-configuration by adding the `@EnableAutoConfiguration` or `@SpringBootApplication` annotations to one of your `@Configuration` classes. + +TIP: You should only ever add one `@SpringBootApplication` or `@EnableAutoConfiguration` annotation. +We generally recommend that you add one or the other to your primary `@Configuration` class only. + + + +[[using.auto-configuration.replacing]] +=== Gradually Replacing Auto-configuration +Auto-configuration is non-invasive. +At any point, you can start to define your own configuration to replace specific parts of the auto-configuration. +For example, if you add your own `DataSource` bean, the default embedded database support backs away. + +If you need to find out what auto-configuration is currently being applied, and why, start your application with the `--debug` switch. +Doing so enables debug logs for a selection of core loggers and logs a conditions report to the console. + + + +[[using.auto-configuration.disabling-specific]] +=== Disabling Specific Auto-configuration Classes +If you find that specific auto-configuration classes that you do not want are being applied, you can use the exclude attribute of `@SpringBootApplication` to disable them, as shown in the following example: + +[source,java,pending-extract=true,indent=0] +---- + import org.springframework.boot.autoconfigure.*; + import org.springframework.boot.autoconfigure.jdbc.*; + + @SpringBootApplication(exclude={DataSourceAutoConfiguration.class}) + public class MyApplication { + } +---- + +If the class is not on the classpath, you can use the `excludeName` attribute of the annotation and specify the fully qualified name instead. +If you prefer to use `@EnableAutoConfiguration` rather than `@SpringBootApplication`, `exclude` and `excludeName` are also available. +Finally, you can also control the list of auto-configuration classes to exclude by using the configprop:spring.autoconfigure.exclude[] property. + +TIP: You can define exclusions both at the annotation level and by using the property. + +NOTE: Even though auto-configuration classes are `public`, the only aspect of the class that is considered public API is the name of the class which can be used for disabling the auto-configuration. +The actual contents of those classes, such as nested configuration classes or bean methods are for internal use only and we do not recommend using those directly. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/build-systems.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/build-systems.adoc new file mode 100644 index 0000000000..52605a7c75 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/build-systems.adoc @@ -0,0 +1,145 @@ +[[using.build-systems]] +== Build Systems +It is strongly recommended that you choose a build system that supports <> and that can consume artifacts published to the "`Maven Central`" repository. +We would recommend that you choose Maven or Gradle. +It is possible to get Spring Boot to work with other build systems (Ant, for example), but they are not particularly well supported. + + + +[[using.build-systems.dependency-management]] +=== Dependency Management +Each release of Spring Boot provides a curated list of dependencies that it supports. +In practice, you do not need to provide a version for any of these dependencies in your build configuration, as Spring Boot manages that for you. +When you upgrade Spring Boot itself, these dependencies are upgraded as well in a consistent way. + +NOTE: You can still specify a version and override Spring Boot's recommendations if you need to do so. + +The curated list contains all the Spring modules that you can use with Spring Boot as well as a refined list of third party libraries. +The list is available as a standard Bills of Materials (`spring-boot-dependencies`) that can be used with both <> and <>. + +WARNING: Each release of Spring Boot is associated with a base version of the Spring Framework. +We **highly** recommend that you not specify its version. + + + +[[using.build-systems.maven]] +=== Maven +To learn about using Spring Boot with Maven, please refer to the documentation for Spring Boot's Maven plugin: + +* Reference ({spring-boot-maven-plugin-docs}[HTML] and {spring-boot-maven-plugin-pdfdocs}[PDF]) +* {spring-boot-maven-plugin-api}[API] + + + +[[using.build-systems.gradle]] +=== Gradle +To learn about using Spring Boot with Gradle, please refer to the documentation for Spring Boot's Gradle plugin: + +* Reference ({spring-boot-gradle-plugin-docs}[HTML] and {spring-boot-gradle-plugin-pdfdocs}[PDF]) +* {spring-boot-gradle-plugin-api}[API] + + + +[[using.build-systems.ant]] +=== Ant +It is possible to build a Spring Boot project using Apache Ant+Ivy. +The `spring-boot-antlib` "`AntLib`" module is also available to help Ant create executable jars. + +To declare dependencies, a typical `ivy.xml` file looks something like the following example: + +[source,xml,indent=0] +---- + + + + + + + + + + +---- + +A typical `build.xml` looks like the following example: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +---- + +TIP: If you do not want to use the `spring-boot-antlib` module, see the _<>_ "`How-to`" . + + + +[[using.build-systems.starters]] +=== Starters +Starters are a set of convenient dependency descriptors that you can include in your application. +You get a one-stop shop for all the Spring and related technologies that you need without having to hunt through sample code and copy-paste loads of dependency descriptors. +For example, if you want to get started using Spring and JPA for database access, include the `spring-boot-starter-data-jpa` dependency in your project. + +The starters contain a lot of the dependencies that you need to get a project up and running quickly and with a consistent, supported set of managed transitive dependencies. + +.What's in a name +**** +All **official** starters follow a similar naming pattern; `+spring-boot-starter-*+`, where `+*+` is a particular type of application. +This naming structure is intended to help when you need to find a starter. +The Maven integration in many IDEs lets you search dependencies by name. +For example, with the appropriate Eclipse or STS plugin installed, you can press `ctrl-space` in the POM editor and type "`spring-boot-starter`" for a complete list. + +As explained in the "`<>`" section, third party starters should not start with `spring-boot`, as it is reserved for official Spring Boot artifacts. +Rather, a third-party starter typically starts with the name of the project. +For example, a third-party starter project called `thirdpartyproject` would typically be named `thirdpartyproject-spring-boot-starter`. +**** + +The following application starters are provided by Spring Boot under the `org.springframework.boot` group: + +.Spring Boot application starters +include::starters/application-starters.adoc[] + +In addition to the application starters, the following starters can be used to add _<>_ features: + +.Spring Boot production starters +include::starters/production-starters.adoc[] + +Finally, Spring Boot also includes the following starters that can be used if you want to exclude or swap specific technical facets: + +.Spring Boot technical starters +include::starters/technical-starters.adoc[] + +To learn how to swap technical facets, please see the how-to documentation for <> and <>. + +TIP: For a list of additional community contributed starters, see the {spring-boot-latest-code}/spring-boot-project/spring-boot-starters/README.adoc[README file] in the `spring-boot-starters` module on GitHub. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/configuration-classes.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/configuration-classes.adoc new file mode 100644 index 0000000000..b73af3b0fb --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/configuration-classes.adoc @@ -0,0 +1,24 @@ +[[using.configuration-classes]] +== Configuration Classes +Spring Boot favors Java-based configuration. +Although it is possible to use `SpringApplication` with XML sources, we generally recommend that your primary source be a single `@Configuration` class. +Usually the class that defines the `main` method is a good candidate as the primary `@Configuration`. + +TIP: Many Spring configuration examples have been published on the Internet that use XML configuration. +If possible, always try to use the equivalent Java-based configuration. +Searching for `+Enable*+` annotations can be a good starting point. + + + +[[using.configuration-classes.importing-additional-configuration]] +=== Importing Additional Configuration Classes +You need not put all your `@Configuration` into a single class. +The `@Import` annotation can be used to import additional configuration classes. +Alternatively, you can use `@ComponentScan` to automatically pick up all Spring components, including `@Configuration` classes. + + + +[[using.configuration-classes.importing-xml-configuration]] +=== Importing XML Configuration +If you absolutely must use XML based configuration, we recommend that you still start with a `@Configuration` class. +You can then use an `@ImportResource` annotation to load XML configuration files. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/devtools.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/devtools.adoc new file mode 100644 index 0000000000..8990ecdf66 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/devtools.adoc @@ -0,0 +1,417 @@ +[[using.devtools]] +== Developer Tools +Spring Boot includes an additional set of tools that can make the application development experience a little more pleasant. +The `spring-boot-devtools` module can be included in any project to provide additional development-time features. +To include devtools support, add the module dependency to your build, as shown in the following listings for Maven and Gradle: + +.Maven +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + + org.springframework.boot + spring-boot-devtools + true + + +---- + +.Gradle +[source,groovy,indent=0,subs="attributes"] +---- + dependencies { + developmentOnly("org.springframework.boot:spring-boot-devtools") + } +---- + +NOTE: Developer tools are automatically disabled when running a fully packaged application. +If your application is launched from `java -jar` or if it is started from a special classloader, then it is considered a "`production application`". +You can control this behavior by using the `spring.devtools.restart.enabled` system property. +To enable devtools, irrespective of the classloader used to launch your application, set the `-Dspring.devtools.restart.enabled=true` system property. +This must not be done in a production environment where running devtools is a security risk. +To disable devtools, exclude the dependency or set the `-Dspring.devtools.restart.enabled=false` system property. + +TIP: Flagging the dependency as optional in Maven or using the `developmentOnly` configuration in Gradle (as shown above) prevents devtools from being transitively applied to other modules that use your project. + +TIP: Repackaged archives do not contain devtools by default. +If you want to use a <>, you need to include it. +When using the Maven plugin, set the `excludeDevtools` property to `false`. +When using the Gradle plugin, {spring-boot-gradle-plugin-docs}#packaging-executable-configuring-including-development-only-dependencies[configure the task's classpath to include the `developmentOnly` configuration]. + + + +[[using.devtools.property-defaults]] +=== Property Defaults +Several of the libraries supported by Spring Boot use caches to improve performance. +For example, <> cache compiled templates to avoid repeatedly parsing template files. +Also, Spring MVC can add HTTP caching headers to responses when serving static resources. + +While caching is very beneficial in production, it can be counter-productive during development, preventing you from seeing the changes you just made in your application. +For this reason, spring-boot-devtools disables the caching options by default. + +Cache options are usually configured by settings in your `application.properties` file. +For example, Thymeleaf offers the configprop:spring.thymeleaf.cache[] property. +Rather than needing to set these properties manually, the `spring-boot-devtools` module automatically applies sensible development-time configuration. + +Because you need more information about web requests while developing Spring MVC and Spring WebFlux applications, developer tools will enable `DEBUG` logging for the `web` logging group. +This will give you information about the incoming request, which handler is processing it, the response outcome, etc. +If you wish to log all request details (including potentially sensitive information), you can turn on the configprop:spring.mvc.log-request-details[] or configprop:spring.codec.log-request-details[] configuration properties. + +NOTE: If you don't want property defaults to be applied you can set configprop:spring.devtools.add-properties[] to `false` in your `application.properties`. + +TIP: For a complete list of the properties that are applied by the devtools, see {spring-boot-devtools-module-code}/env/DevToolsPropertyDefaultsPostProcessor.java[DevToolsPropertyDefaultsPostProcessor]. + + + +[[using.devtools.restart]] +=== Automatic Restart +Applications that use `spring-boot-devtools` automatically restart whenever files on the classpath change. +This can be a useful feature when working in an IDE, as it gives a very fast feedback loop for code changes. +By default, any entry on the classpath that points to a directory is monitored for changes. +Note that certain resources, such as static assets and view templates, <>. + +.Triggering a restart +**** +As DevTools monitors classpath resources, the only way to trigger a restart is to update the classpath. +The way in which you cause the classpath to be updated depends on the IDE that you are using: + +* In Eclipse, saving a modified file causes the classpath to be updated and triggers a restart. +* In IntelliJ IDEA, building the project (`Build +->+ Build Project`) has the same effect. +* If using a build plugin, running `mvn compile` for Maven or `gradle build` for Gradle will trigger a restart. +**** + +NOTE: If you are restarting with Maven or Gradle using the build plugin you must leave the `forking` set to `enabled`. +If you disable forking, the isolated application classloader used by devtools will not be created and restarts will not operate properly. + +TIP: Automatic restart works very well when used with LiveReload. +<> for details. +If you use JRebel, automatic restarts are disabled in favor of dynamic class reloading. +Other devtools features (such as LiveReload and property overrides) can still be used. + +NOTE: DevTools relies on the application context's shutdown hook to close it during a restart. +It does not work correctly if you have disabled the shutdown hook (`SpringApplication.setRegisterShutdownHook(false)`). + +NOTE: DevTools needs to customize the `ResourceLoader` used by the `ApplicationContext`. +If your application provides one already, it is going to be wrapped. +Direct override of the `getResource` method on the `ApplicationContext` is not supported. + +[[using-spring-boot-restart-vs-reload]] +.Restart vs Reload +**** +The restart technology provided by Spring Boot works by using two classloaders. +Classes that do not change (for example, those from third-party jars) are loaded into a _base_ classloader. +Classes that you are actively developing are loaded into a _restart_ classloader. +When the application is restarted, the _restart_ classloader is thrown away and a new one is created. +This approach means that application restarts are typically much faster than "`cold starts`", since the _base_ classloader is already available and populated. + +If you find that restarts are not quick enough for your applications or you encounter classloading issues, you could consider reloading technologies such as https://jrebel.com/software/jrebel/[JRebel] from ZeroTurnaround. +These work by rewriting classes as they are loaded to make them more amenable to reloading. +**** + + + +[[using.devtools.restart.logging-condition-delta]] +==== Logging changes in condition evaluation +By default, each time your application restarts, a report showing the condition evaluation delta is logged. +The report shows the changes to your application's auto-configuration as you make changes such as adding or removing beans and setting configuration properties. + +To disable the logging of the report, set the following property: + +[source,yaml,indent=0,configblocks] +---- + spring: + devtools: + restart: + log-condition-evaluation-delta: false +---- + + + +[[using.devtools.restart.excluding-resources]] +==== Excluding Resources +Certain resources do not necessarily need to trigger a restart when they are changed. +For example, Thymeleaf templates can be edited in-place. +By default, changing resources in `/META-INF/maven`, `/META-INF/resources`, `/resources`, `/static`, `/public`, or `/templates` does not trigger a restart but does trigger a <>. +If you want to customize these exclusions, you can use the configprop:spring.devtools.restart.exclude[] property. +For example, to exclude only `/static` and `/public` you would set the following property: + +[source,yaml,indent=0,configblocks] +---- + spring: + devtools: + restart: + exclude: "static/**,public/**" +---- + +TIP: If you want to keep those defaults and _add_ additional exclusions, use the configprop:spring.devtools.restart.additional-exclude[] property instead. + + + +[[using.devtools.restart.watching-additional-paths]] +==== Watching Additional Paths +You may want your application to be restarted or reloaded when you make changes to files that are not on the classpath. +To do so, use the configprop:spring.devtools.restart.additional-paths[] property to configure additional paths to watch for changes. +You can use the configprop:spring.devtools.restart.exclude[] property <> to control whether changes beneath the additional paths trigger a full restart or a <>. + + + +[[using.devtools.restart.disable]] +==== Disabling Restart +If you do not want to use the restart feature, you can disable it by using the configprop:spring.devtools.restart.enabled[] property. +In most cases, you can set this property in your `application.properties` (doing so still initializes the restart classloader, but it does not watch for file changes). + +If you need to _completely_ disable restart support (for example, because it does not work with a specific library), you need to set the configprop:spring.devtools.restart.enabled[] `System` property to `false` before calling `SpringApplication.run(...)`, as shown in the following example: + +[source,java,pending-extract=true,indent=0] +---- + public static void main(String[] args) { + System.setProperty("spring.devtools.restart.enabled", "false"); + SpringApplication.run(MyApp.class, args); + } +---- + + + +[[using.devtools.restart.triggerfile]] +==== Using a Trigger File +If you work with an IDE that continuously compiles changed files, you might prefer to trigger restarts only at specific times. +To do so, you can use a "`trigger file`", which is a special file that must be modified when you want to actually trigger a restart check. + +NOTE: Any update to the file will trigger a check, but restart only actually occurs if Devtools has detected it has something to do. + +To use a trigger file, set the configprop:spring.devtools.restart.trigger-file[] property to the name (excluding any path) of your trigger file. +The trigger file must appear somewhere on your classpath. + +For example, if you have a project with the following structure: + +[indent=0] +---- + src + +- main + +- resources + +- .reloadtrigger +---- + +Then your `trigger-file` property would be: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + devtools: + restart: + trigger-file: ".reloadtrigger" +---- + +Restarts will now only happen when the `src/main/resources/.reloadtrigger` is updated. + +TIP: You might want to set `spring.devtools.restart.trigger-file` as a <>, so that all your projects behave in the same way. + +Some IDEs have features that save you from needing to update your trigger file manually. +https://spring.io/tools[Spring Tools for Eclipse] and https://www.jetbrains.com/idea/[IntelliJ IDEA (Ultimate Edition)] both have such support. +With Spring Tools, you can use the "`reload`" button from the console view (as long as your `trigger-file` is named `.reloadtrigger`). +For IntelliJ IDEA, you can follow the https://www.jetbrains.com/help/idea/spring-boot.html#application-update-policies[instructions in their documentation]. + + + +[[using.devtools.restart.customizing-the-classload]] +==== Customizing the Restart Classloader +As described earlier in the <> section, restart functionality is implemented by using two classloaders. +For most applications, this approach works well. +However, it can sometimes cause classloading issues. + +By default, any open project in your IDE is loaded with the "`restart`" classloader, and any regular `.jar` file is loaded with the "`base`" classloader. +If you work on a multi-module project, and not every module is imported into your IDE, you may need to customize things. +To do so, you can create a `META-INF/spring-devtools.properties` file. + +The `spring-devtools.properties` file can contain properties prefixed with `restart.exclude` and `restart.include`. +The `include` elements are items that should be pulled up into the "`restart`" classloader, and the `exclude` elements are items that should be pushed down into the "`base`" classloader. +The value of the property is a regex pattern that is applied to the classpath, as shown in the following example: + +[source,yaml,indent=0,configblocks] +---- + restart: + exclude: + companycommonlibs: "/mycorp-common-[\\w\\d-\\.]+\\.jar" + include: + projectcommon: "/mycorp-myproj-[\\w\\d-\\.]+\\.jar" +---- + +NOTE: All property keys must be unique. +As long as a property starts with `restart.include.` or `restart.exclude.` it is considered. + +TIP: All `META-INF/spring-devtools.properties` from the classpath are loaded. +You can package files inside your project, or in the libraries that the project consumes. + + + +[[using.devtools.restart.limitations]] +==== Known Limitations +Restart functionality does not work well with objects that are deserialized by using a standard `ObjectInputStream`. +If you need to deserialize data, you may need to use Spring's `ConfigurableObjectInputStream` in combination with `Thread.currentThread().getContextClassLoader()`. + +Unfortunately, several third-party libraries deserialize without considering the context classloader. +If you find such a problem, you need to request a fix with the original authors. + + + +[[using.devtools.livereload]] +=== LiveReload +The `spring-boot-devtools` module includes an embedded LiveReload server that can be used to trigger a browser refresh when a resource is changed. +LiveReload browser extensions are freely available for Chrome, Firefox and Safari from http://livereload.com/extensions/[livereload.com]. + +If you do not want to start the LiveReload server when your application runs, you can set the configprop:spring.devtools.livereload.enabled[] property to `false`. + +NOTE: You can only run one LiveReload server at a time. +Before starting your application, ensure that no other LiveReload servers are running. +If you start multiple applications from your IDE, only the first has LiveReload support. + +WARNING: To trigger LiveReload when a file changes, <> must be enabled. + + + +[[using.devtools.globalsettings]] +=== Global Settings +You can configure global devtools settings by adding any of the following files to the `$HOME/.config/spring-boot` directory: + +. `spring-boot-devtools.properties` +. `spring-boot-devtools.yaml` +. `spring-boot-devtools.yml` + +Any properties added to these file apply to _all_ Spring Boot applications on your machine that use devtools. +For example, to configure restart to always use a <>, you would add the following property to your `spring-boot-devtools` file: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + devtools: + restart: + trigger-file: ".reloadtrigger" +---- + +NOTE: If devtools configuration files are not found in `$HOME/.config/spring-boot`, the root of the `$HOME` directory is searched for the presence of a `.spring-boot-devtools.properties` file. +This allows you to share the devtools global configuration with applications that are on an older version of Spring Boot that does not support the `$HOME/.config/spring-boot` location. + +[NOTE] +==== +Profiles are not supported in devtools properties/yaml files. + +Any profiles activated in `.spring-boot-devtools.properties` will not affect the loading of <>. +Profile specific filenames (of the form `spring-boot-devtools-.properties`) and `spring.config.activate.on-profile` documents in both YAML and Properties files are not supported. +==== + + + +[[using.devtools.globalsettings.configuring-file-system-watcher]] +==== Configuring File System Watcher +{spring-boot-devtools-module-code}/filewatch/FileSystemWatcher.java[FileSystemWatcher] works by polling the class changes with a certain time interval, and then waiting for a predefined quiet period to make sure there are no more changes. +Since Spring Boot relies entirely on the IDE to compile and copy files into the location from where Spring Boot can read them, you might find that there are times when certain changes are not reflected when devtools restarts the application. +If you observe such problems constantly, try increasing the `spring.devtools.restart.poll-interval` and `spring.devtools.restart.quiet-period` parameters to the values that fit your development environment: + +[source,yaml,indent=0,configprops,configblocks] +---- + spring: + devtools: + restart: + poll-interval: "2s" + quiet-period: "1s" +---- + +The monitored classpath directories are now polled every 2 seconds for changes, and a 1 second quiet period is maintained to make sure there are no additional class changes. + + + +[[using.devtools.remote-applications]] +=== Remote Applications +The Spring Boot developer tools are not limited to local development. +You can also use several features when running applications remotely. +Remote support is opt-in as enabling it can be a security risk. +It should only be enabled when running on a trusted network or when secured with SSL. +If neither of these options is available to you, you should not use DevTools' remote support. +You should never enable support on a production deployment. + +To enable it, you need to make sure that `devtools` is included in the repackaged archive, as shown in the following listing: + +[source,xml,indent=0,subs="verbatim,quotes,attributes"] +---- + + + + org.springframework.boot + spring-boot-maven-plugin + + false + + + + +---- + +Then you need to set the configprop:spring.devtools.remote.secret[] property. +Like any important password or secret, the value should be unique and strong such that it cannot be guessed or brute-forced. + +Remote devtools support is provided in two parts: a server-side endpoint that accepts connections and a client application that you run in your IDE. +The server component is automatically enabled when the configprop:spring.devtools.remote.secret[] property is set. +The client component must be launched manually. + + + +[[using.devtools.remote-applications.client]] +==== Running the Remote Client Application +The remote client application is designed to be run from within your IDE. +You need to run `org.springframework.boot.devtools.RemoteSpringApplication` with the same classpath as the remote project that you connect to. +The application's single required argument is the remote URL to which it connects. + +For example, if you are using Eclipse or STS and you have a project named `my-app` that you have deployed to Cloud Foundry, you would do the following: + +* Select `Run Configurations...` from the `Run` menu. +* Create a new `Java Application` "`launch configuration`". +* Browse for the `my-app` project. +* Use `org.springframework.boot.devtools.RemoteSpringApplication` as the main class. +* Add `+++https://myapp.cfapps.io+++` to the `Program arguments` (or whatever your remote URL is). + +A running remote client might resemble the following listing: + +[indent=0,subs="attributes"] +---- + . ____ _ __ _ _ + /\\ / ___'_ __ _ _(_)_ __ __ _ ___ _ \ \ \ \ + ( ( )\___ | '_ | '_| | '_ \/ _` | | _ \___ _ __ ___| |_ ___ \ \ \ \ + \\/ ___)| |_)| | | | | || (_| []::::::[] / -_) ' \/ _ \ _/ -_) ) ) ) ) + ' |____| .__|_| |_|_| |_\__, | |_|_\___|_|_|_\___/\__\___|/ / / / + =========|_|==============|___/===================================/_/_/_/ + :: Spring Boot Remote :: {spring-boot-version} + + 2015-06-10 18:25:06.632 INFO 14938 --- [ main] o.s.b.devtools.RemoteSpringApplication : Starting RemoteSpringApplication on pwmbp with PID 14938 (/Users/pwebb/projects/spring-boot/code/spring-boot-project/spring-boot-devtools/target/classes started by pwebb in /Users/pwebb/projects/spring-boot/code) + 2015-06-10 18:25:06.671 INFO 14938 --- [ main] s.c.a.AnnotationConfigApplicationContext : Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@2a17b7b6: startup date [Wed Jun 10 18:25:06 PDT 2015]; root of context hierarchy + 2015-06-10 18:25:07.043 WARN 14938 --- [ main] o.s.b.d.r.c.RemoteClientConfiguration : The connection to http://localhost:8080 is insecure. You should use a URL starting with 'https://'. + 2015-06-10 18:25:07.074 INFO 14938 --- [ main] o.s.b.d.a.OptionalLiveReloadServer : LiveReload server is running on port 35729 + 2015-06-10 18:25:07.130 INFO 14938 --- [ main] o.s.b.devtools.RemoteSpringApplication : Started RemoteSpringApplication in 0.74 seconds (JVM running for 1.105) +---- + +NOTE: Because the remote client is using the same classpath as the real application it can directly read application properties. +This is how the configprop:spring.devtools.remote.secret[] property is read and passed to the server for authentication. + +TIP: It is always advisable to use `https://` as the connection protocol, so that traffic is encrypted and passwords cannot be intercepted. + +TIP: If you need to use a proxy to access the remote application, configure the `spring.devtools.remote.proxy.host` and `spring.devtools.remote.proxy.port` properties. + + + +[[using.devtools.remote-applications.update]] +==== Remote Update +The remote client monitors your application classpath for changes in the same way as the <>. +Any updated resource is pushed to the remote application and (_if required_) triggers a restart. +This can be helpful if you iterate on a feature that uses a cloud service that you do not have locally. +Generally, remote updates and restarts are much quicker than a full rebuild and deploy cycle. + +On a slower development environment, it may happen that the quiet period is not enough, and the changes in the classes may be split into batches. +The server is restarted after the first batch of class changes is uploaded. +The next batch can’t be sent to the application, since the server is restarting. + +This is typically manifested by a warning in the `RemoteSpringApplication` logs about failing to upload some of the classes, and a consequent retry. +But it may also lead to application code inconsistency and failure to restart after the first batch of changes is uploaded. +If you observe such problems constantly, try increasing the `spring.devtools.restart.poll-interval` and `spring.devtools.restart.quiet-period` parameters to the values that fit your development environment. +See the <> section for configuring these properties. + +NOTE: Files are only monitored when the remote client is running. +If you change a file before starting the remote client, it is not pushed to the remote server. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/packaging-for-production.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/packaging-for-production.adoc new file mode 100644 index 0000000000..2adc987456 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/packaging-for-production.adoc @@ -0,0 +1,7 @@ +[[using.packaging-for-production]] +== Packaging Your Application for Production +Executable jars can be used for production deployment. +As they are self-contained, they are also ideally suited for cloud-based deployment. + +For additional "`production ready`" features, such as health, auditing, and metric REST or JMX end-points, consider adding `spring-boot-actuator`. +See _<>_ for details. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/running-your-application.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/running-your-application.adoc new file mode 100644 index 0000000000..3f80a4b21c --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/running-your-application.adoc @@ -0,0 +1,95 @@ +[[using.running-your-application]] +== Running Your Application +One of the biggest advantages of packaging your application as a jar and using an embedded HTTP server is that you can run your application as you would any other. +The sample applies to debugging Spring Boot applications. +You do not need any special IDE plugins or extensions. + +NOTE: This section only covers jar based packaging. +If you choose to package your application as a war file, you should refer to your server and IDE documentation. + + + +[[using.running-your-application.from-an-ide]] +=== Running from an IDE +You can run a Spring Boot application from your IDE as a Java application. +However, you first need to import your project. +Import steps vary depending on your IDE and build system. +Most IDEs can import Maven projects directly. +For example, Eclipse users can select `Import...` -> `Existing Maven Projects` from the `File` menu. + +If you cannot directly import your project into your IDE, you may be able to generate IDE metadata by using a build plugin. +Maven includes plugins for https://maven.apache.org/plugins/maven-eclipse-plugin/[Eclipse] and https://maven.apache.org/plugins/maven-idea-plugin/[IDEA]. +Gradle offers plugins for {gradle-docs}/userguide.html[various IDEs]. + +TIP: If you accidentally run a web application twice, you see a "`Port already in use`" error. +STS users can use the `Relaunch` button rather than the `Run` button to ensure that any existing instance is closed. + + + +[[using.running-your-application.as-a-packaged-application]] +=== Running as a Packaged Application +If you use the Spring Boot Maven or Gradle plugins to create an executable jar, you can run your application using `java -jar`, as shown in the following example: + +[indent=0,subs="attributes"] +---- + $ java -jar target/myapplication-0.0.1-SNAPSHOT.jar +---- + +It is also possible to run a packaged application with remote debugging support enabled. +Doing so lets you attach a debugger to your packaged application, as shown in the following example: + +[indent=0,subs="attributes"] +---- + $ java -Xdebug -Xrunjdwp:server=y,transport=dt_socket,address=8000,suspend=n \ + -jar target/myapplication-0.0.1-SNAPSHOT.jar +---- + + + +[[using.running-your-application.with-the-maven-plugin]] +=== Using the Maven Plugin +The Spring Boot Maven plugin includes a `run` goal that can be used to quickly compile and run your application. +Applications run in an exploded form, as they do in your IDE. +The following example shows a typical Maven command to run a Spring Boot application: + +[indent=0,subs="attributes"] +---- + $ mvn spring-boot:run +---- + +You might also want to use the `MAVEN_OPTS` operating system environment variable, as shown in the following example: + +[indent=0,subs="attributes"] +---- + $ export MAVEN_OPTS=-Xmx1024m +---- + + + +[[using.running-your-application.with-the-gradle-plugin]] +=== Using the Gradle Plugin +The Spring Boot Gradle plugin also includes a `bootRun` task that can be used to run your application in an exploded form. +The `bootRun` task is added whenever you apply the `org.springframework.boot` and `java` plugins and is shown in the following example: + +[indent=0,subs="attributes"] +---- + $ gradle bootRun +---- + +You might also want to use the `JAVA_OPTS` operating system environment variable, as shown in the following example: + +[indent=0,subs="attributes"] +---- + $ export JAVA_OPTS=-Xmx1024m +---- + + + +[[using.running-your-application.hot-swapping]] +=== Hot Swapping +Since Spring Boot applications are plain Java applications, JVM hot-swapping should work out of the box. +JVM hot swapping is somewhat limited with the bytecode that it can replace. +For a more complete solution, https://www.jrebel.com/products/jrebel[JRebel] can be used. + +The `spring-boot-devtools` module also includes support for quick application restarts. +See the <> for details. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/spring-beans-and-dependency-injection.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/spring-beans-and-dependency-injection.adoc new file mode 100644 index 0000000000..a0e23710e4 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/spring-beans-and-dependency-injection.adoc @@ -0,0 +1,51 @@ +[[using.spring-beans-and-dependency-injection]] +== Spring Beans and Dependency Injection +You are free to use any of the standard Spring Framework techniques to define your beans and their injected dependencies. +We often find that using `@ComponentScan` (to find your beans) and using `@Autowired` (to do constructor injection) works well. + +If you structure your code as suggested above (locating your application class in a root package), you can add `@ComponentScan` without any arguments. +All of your application components (`@Component`, `@Service`, `@Repository`, `@Controller` etc.) are automatically registered as Spring Beans. + +The following example shows a `@Service` Bean that uses constructor injection to obtain a required `RiskAssessor` bean: + +[source,java,pending-extract=true,indent=0] +---- + package com.example.service; + + import org.springframework.beans.factory.annotation.Autowired; + import org.springframework.stereotype.Service; + + @Service + public class DatabaseAccountService implements AccountService { + + private final RiskAssessor riskAssessor; + + @Autowired + public DatabaseAccountService(RiskAssessor riskAssessor) { + this.riskAssessor = riskAssessor; + } + + // ... + + } +---- + +If a bean has one constructor, you can omit the `@Autowired`, as shown in the following example: + +[source,java,pending-extract=true,indent=0] +---- + @Service + public class DatabaseAccountService implements AccountService { + + private final RiskAssessor riskAssessor; + + public DatabaseAccountService(RiskAssessor riskAssessor) { + this.riskAssessor = riskAssessor; + } + + // ... + + } +---- + +TIP: Notice how using constructor injection lets the `riskAssessor` field be marked as `final`, indicating that it cannot be subsequently changed. diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/structuring-your-code.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/structuring-your-code.adoc new file mode 100644 index 0000000000..830e66c7f7 --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/structuring-your-code.adoc @@ -0,0 +1,66 @@ +[[using.structuring-your-code]] +== Structuring Your Code +Spring Boot does not require any specific code layout to work. +However, there are some best practices that help. + + + +[[using.structuring-your-code.using-the-default-package]] +=== Using the "`default`" Package +When a class does not include a `package` declaration, it is considered to be in the "`default package`". +The use of the "`default package`" is generally discouraged and should be avoided. +It can cause particular problems for Spring Boot applications that use the `@ComponentScan`, `@ConfigurationPropertiesScan`, `@EntityScan`, or `@SpringBootApplication` annotations, since every class from every jar is read. + +TIP: We recommend that you follow Java's recommended package naming conventions and use a reversed domain name (for example, `com.example.project`). + + + +[[using.structuring-your-code.locating-the-main-class]] +=== Locating the Main Application Class +We generally recommend that you locate your main application class in a root package above other classes. +The <> is often placed on your main class, and it implicitly defines a base "`search package`" for certain items. +For example, if you are writing a JPA application, the package of the `@SpringBootApplication` annotated class is used to search for `@Entity` items. +Using a root package also allows component scan to apply only on your project. + +TIP: If you don't want to use `@SpringBootApplication`, the `@EnableAutoConfiguration` and `@ComponentScan` annotations that it imports defines that behaviour so you can also use those instead. + +The following listing shows a typical layout: + +[indent=0] +---- + com + +- example + +- myapplication + +- Application.java + | + +- customer + | +- Customer.java + | +- CustomerController.java + | +- CustomerService.java + | +- CustomerRepository.java + | + +- order + +- Order.java + +- OrderController.java + +- OrderService.java + +- OrderRepository.java +---- + +The `Application.java` file would declare the `main` method, along with the basic `@SpringBootApplication`, as follows: + +[source,java,pending-extract=true,indent=0] +---- + package com.example.myapplication; + + import org.springframework.boot.SpringApplication; + import org.springframework.boot.autoconfigure.SpringBootApplication; + + @SpringBootApplication + public class Application { + + public static void main(String[] args) { + SpringApplication.run(Application.class, args); + } + + } +---- diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/using-the-springbootapplication-annotation.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/using-the-springbootapplication-annotation.adoc new file mode 100644 index 0000000000..423b8a9afa --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/using-the-springbootapplication-annotation.adoc @@ -0,0 +1,56 @@ +[[using.using-the-springbootapplication-annotation]] +== Using the @SpringBootApplication Annotation +Many Spring Boot developers like their apps to use auto-configuration, component scan and be able to define extra configuration on their "application class". +A single `@SpringBootApplication` annotation can be used to enable those three features, that is: + +* `@EnableAutoConfiguration`: enable <> +* `@ComponentScan`: enable `@Component` scan on the package where the application is located (see <>) +* `@Configuration`: allow to register extra beans in the context or import additional configuration classes + +[source,java,pending-extract=true,indent=0] +---- + package com.example.myapplication; + + import org.springframework.boot.SpringApplication; + import org.springframework.boot.autoconfigure.SpringBootApplication; + + @SpringBootApplication // same as @Configuration @EnableAutoConfiguration @ComponentScan + public class Application { + + public static void main(String[] args) { + SpringApplication.run(Application.class, args); + } + + } +---- + +NOTE: `@SpringBootApplication` also provides aliases to customize the attributes of `@EnableAutoConfiguration` and `@ComponentScan`. + +[NOTE] +==== +None of these features are mandatory and you may choose to replace this single annotation by any of the features that it enables. +For instance, you may not want to use component scan or configuration properties scan in your application: + +[source,java,pending-extract=true,indent=0] +---- + package com.example.myapplication; + + import org.springframework.boot.SpringApplication; + import org.springframework.context.annotation.ComponentScan + import org.springframework.context.annotation.Configuration; + import org.springframework.context.annotation.Import; + + @Configuration(proxyBeanMethods = false) + @EnableAutoConfiguration + @Import({ MyConfig.class, MyAnotherConfig.class }) + public class Application { + + public static void main(String[] args) { + SpringApplication.run(Application.class, args); + } + + } +---- + +In this example, `Application` is just like any other Spring Boot application except that `@Component`-annotated classes and `@ConfigurationProperties`-annotated classes are not detected automatically and the user-defined beans are imported explicitly (see `@Import`). +==== diff --git a/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/whats-next.adoc b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/whats-next.adoc new file mode 100644 index 0000000000..6aaf2da0ba --- /dev/null +++ b/spring-boot-project/spring-boot-docs/src/docs/asciidoc/using/whats-next.adoc @@ -0,0 +1,4 @@ +[[using.whats-next]] +== What to Read Next +You should now understand how you can use Spring Boot and some best practices that you should follow. +You can now go on to learn about specific _<>_ in depth, or you could skip ahead and read about the "`<>`" aspects of Spring Boot.