Commit 9cf59050 authored by Phillip Webb's avatar Phillip Webb

Documentation

parent ec36efd5
...@@ -3,7 +3,6 @@ Spring Boot is released under the non-restrictive Apache 2.0 license. If you wou ...@@ -3,7 +3,6 @@ Spring Boot is released under the non-restrictive Apache 2.0 license. If you wou
to contribute something, or simply want to hack on the code this document should help to contribute something, or simply want to hack on the code this document should help
you get started. you get started.
## Working with the code ## Working with the code
If you don't have an IDE preference we would recommend that you use If you don't have an IDE preference we would recommend that you use
[Spring Tools Suite](http://www.springsource.com/developer/sts) or [Spring Tools Suite](http://www.springsource.com/developer/sts) or
...@@ -11,7 +10,6 @@ If you don't have an IDE preference we would recommend that you use ...@@ -11,7 +10,6 @@ If you don't have an IDE preference we would recommend that you use
[m2eclipe](http://eclipse.org/m2e/) eclipse plugin for maven support. Other IDEs [m2eclipe](http://eclipse.org/m2e/) eclipse plugin for maven support. Other IDEs
and tools should also work without issue. and tools should also work without issue.
### Building from source ### Building from source
To build the source you will need to install To build the source you will need to install
[Apache Maven](http://maven.apache.org/run-maven/index.html) v3.0 or above. The project [Apache Maven](http://maven.apache.org/run-maven/index.html) v3.0 or above. The project
...@@ -24,7 +22,6 @@ to submit a pull request: ...@@ -24,7 +22,6 @@ to submit a pull request:
$ mvn clean install -DskipTests $ mvn clean install -DskipTests
### Importing into eclipse with m2eclipse ### Importing into eclipse with m2eclipse
We recommend the [m2eclipe](http://eclipse.org/m2e/) eclipse plugin when working with We recommend the [m2eclipe](http://eclipse.org/m2e/) eclipse plugin when working with
eclipse. If you don't already have m2eclipse installed it is available from the "eclipse eclipse. If you don't already have m2eclipse installed it is available from the "eclipse
...@@ -47,7 +44,6 @@ With the requisite eclipse plugins installed you can select ...@@ -47,7 +44,6 @@ With the requisite eclipse plugins installed you can select
`import existing maven projects` from the `file` menu to import the code. You will `import existing maven projects` from the `file` menu to import the code. You will
need to import the root `spring-boot` pom and the `spring-boot-samples` pom separately. need to import the root `spring-boot` pom and the `spring-boot-samples` pom separately.
### Importing into eclipse without m2eclipse ### Importing into eclipse without m2eclipse
If you prefer not to use m2eclipse you can generate eclipse project meta-data using the If you prefer not to use m2eclipse you can generate eclipse project meta-data using the
following command: following command:
...@@ -60,13 +56,10 @@ from the `file` menu. ...@@ -60,13 +56,10 @@ from the `file` menu.
### Importing into other IDEs ### Importing into other IDEs
Maven is well supported by most Java IDEs. Refer to you vendor documentation. Maven is well supported by most Java IDEs. Refer to you vendor documentation.
### Integration tests ### Integration tests
The sample application are used as integration tests during the build (when you
The sample application are used as integration tests during the build `mvn install`). Due to the fact that they make use of the `spring-boot-maven-plugin`
(when you `mvn install`). Due to the fact that they make use of the they cannot be called directly, and so instead are launched via the
`spring-package-maven-plugin` they cannot be called directly, and so `maven-invoker-plugin`. If you encounter build failures running the integration tests,
instead are launched via the `maven-invoker-plugin`. If you encounter check the `build.log` file in the appropriate sample directory.
build failures running the integration tests, check the `build.log`
file in the appropriate sample directory.
# Spring Boot # Spring Boot
Spring Boot is "Spring for Snowboarders". If you are kewl, or just impatient, and you Spring Boot makes it easy to create Spring-powered, production-grade applications and
want to use Spring, then this is the place to be. Spring Boot is the code-name for a services with absolute minimum fuss. It takes an opinionated view of the Spring platform
group of related technologies, that will get you up and running with so that new and existing users can quickly get to the bits they need.
Spring-powered, production-grade applications and services with absolute minimum fuss.
It takes an opinionated view of the Spring family so that new and existing users can You can use Spring Boot to create stand-alone Java applications that can be started using
quickly get to the bits they need. Assumes limited knowledge of the Java development `java -jar` or more traditional WAR deployments. We also provide a command line tool
ecosystem. Absolutely no code generation and no XML (unless you really want it). that runs spring scripts.
The goals are: Our primary goals are:
* Radically faster and widely accessible getting started experience for Spring * Provide a radically faster and widely accessible getting started experience for all
development Spring development
* Be opinionated out of the box, but get out of the way quickly as requirements start to * Be opinionated out of the box, but get out of the way quickly as requirements start to
diverge from the defaults diverge from the defaults
* Provide a range of non-functional features that are common to large classes of projects * Provide a range of non-functional features that are common to large classes of projects
(e.g. embedded servers, security, metrics, health checks, externalized configuration) (e.g. embedded servers, security, metrics, health checks, externalized configuration)
* First class support for REST-ful services, modern web applications, batch jobs, and * Absolutely no code generation and no requirement for XML configuration
enterprise integration
* Applications that adapt their behavior or configuration to their environment ## Quick Start Script Example
* Optionally use Groovy features like DSLs and AST transformations to accelerate the The Spring Zero command line tool uses [Groovy](http://groovy.codehaus.org/) underneath
implementation of basic business requirements so that we can present simple Spring snippets that can 'just run', for example:
```groovy
@Controller
class ThisWillActuallyRun {
@RequestMapping("/")
@ResponseBody
String home() {
return "Hello World!"
}
}
```
```
$ spring run app.groovy
$ curl localhost:8080
Hello World!
```
## Installing _See [below](#installing-the-cli) for command line tool installation instructions._
You need to [build from source](#building-from-source) for now, but when it's done
instructions will look like this:
1) Get Java. Download and install the Java SDK from [www.java.com](http://www.java.com) ## Quick Start Java Example
If you don't want to use the command line tool, or you would rather work using Java and
an IDE you can. Just add a `main()` method that calls `SpringApplication` and
add `@EnableAutoConfiguration`:
```java
import org.springframework.boot.*;
import org.springframework.boot.autoconfiguration.*;
import org.springframework.stereotype.*;
import org.springframework.web.bind.annotation.*;
2) Get Spring @Controller
@EnableAutoConfiguration
public class SampleController {
$ curl -s initializr.cfapps.io/installer | bash @RequestMapping("/")
@ResponseBody
String home() {
return "Hello World!"
}
public static void main(String[] args) throws Exception {
SpringApplication.run(SampleController.class, args);
}
or use the [Windows installer](#installing) }
```
_NOTE: the above example assumes your build system has imported the `spring-starter-web` maven pom._
## Installing the CLI
You need [Java SDK v1.6](http://www.java.com) or higher to run the command line tool. You
should check your current Java installation before you begin:
$ java -version
Complete installation instructions TBD. For now you can
[build from source](#building-from-source).
## Building from source ## Building from source
Spring Zero can be [built with maven](http://maven.apache.org/run-maven/index.html) v3.0 Spring Boot can be [built with maven](http://maven.apache.org/run-maven/index.html) v3.0
or above. or above.
$ mvn clean install $ mvn clean install
An `alias` can be used for the Spring Boot command line tool: You can use an `alias` for the Spring Boot command line tool:
$ alias spring="java -jar ~/.m2/repository/org/springframework/boot/spring-cli/0.5.0.BUILD-SNAPSHOT/spring-cli-0.5.0.BUILD-SNAPSHOT.jar" $ alias spring="java -jar ~/.m2/repository/org/springframework/boot/spring-cli/0.5.0.BUILD-SNAPSHOT/spring-cli-0.5.0.BUILD-SNAPSHOT.jar"
_Also see [docs/CONTRIBUTING](docs/CONTRIBUTING.md) if you want to submit pull requests._ _Also see [CONTRIBUTING.md] if you wish to submit pull requests._
## Spring Boot Modules
There are a number of modules in Spring Boot. Here are the important ones:
## Quick Start Example ### spring-boot
The Spring Zero command line tool uses Groovy underneath so that we can present simple The main library providing features that support the other parts of Spring Boot,
snippets that can just run, for example: these include:
$ cat > app.groovy
@Controller
class ThisWillActuallyRun {
@RequestMapping("/")
@ResponseBody
String home() {
return "Hello World!"
}
}
<ctrl-d>
$ spring run app.groovy
$ curl localhost:8080
Hello World!
* The `SpringApplication` class, providing static convenience methods that make it easy
to write a stand-alone Spring Application. Its sole job is to create and refresh an
appropriate Spring `ApplicationContext`
* Embedded web applications with a choice of container (Tomcat or Jetty for now)
* First class externalized configuration support
* Convenience `ApplicationContext` initializers, including support for sensible logging
defaults.
If you don't want to use the command line tool, or you would rather work using Java and _See [spring-boot/README.md](spring-boot/README.md)._
an IDE you can. Just add a `main()` method that calls `SpringApplication` and
add `@EnableAutoConfiguration`:
import org.springframework.stereotype.*;
import org.springframework.web.bind.annotation.*;
import org.springframework.boot.context.annotation.*;
@Controller ### spring-boot-autoconfigure
@EnableAutoConfiguration Spring Boot can configure large parts of common applications based on the content
public class SampleController { of their classpath. A single `@EnableAutoConfiguration` annotation triggers
auto-configuration of the Spring context.
@RequestMapping("/") Auto-configuration attempts to deduce which beans a user might need. For example, If
@ResponseBody 'HSQLDB' is on the classpath, and the user has not configured any database connections,
String home() { then they probably want an in-memory database to be defined. Auto-configuration will
return "Hello World!" always back away as the user starts to define their own beans.
}
public static void main(String[] args) throws Exception { _See [spring-boot-autoconfigure/README.md](spring-boot-autoconfigure/README.md)._
SpringApplication.run(SampleController.class, args);
}
}
_NOTE: the above example assumes your build system has imported the `spring-starter-web` ### spring-boot-starters
maven pom._ 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 technology
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 just include the `spring-boot-starter-data-jpa` dependency in your
project, and you are good to go.
_See [spring-boot-starters/README.md](spring-boot-starters/README.md)._
## Spring Boot Components
There are a number of components in Boot. Here are the important ones:
### The Spring CLI ### spring-boot-cli
The 'spring' command line application compiles and runs Groovy source, making it super The Spring command line application compiles and runs Groovy source, making it super
easy to write the absolute minimum of code to get an application running. Spring CLI easy to write the absolute minimum of code to get an application running. Spring CLI
can also watch files, automatically recompiling and restarting when they change. can also watch files, automatically recompiling and restarting when they change.
*See [spring-cli/README](spring-cli/README.md).* *See [spring-boot-cli/README.md](spring-boot-cli/README.md).*
### Spring Boot
The main library providing features that support the other parts of Spring Boot.
Features include:
* `SpringApplication` - a class with static convenience methods that make it really easy
to write a standalone Spring Application. Its sole job is to create and refresh an
appropriate Spring `ApplicationContext`.
* Embedded web applications with a choice of container (Tomcat or Jetty for now)
* First class externalized configuration support
_See [spring-boot/README](spring-boot/README.md)._
### Spring Autoconfigure
Spring Zero can configure large parts of common applications based on detecting the
content of the classpath and any existing application context. A single
`@EnableAutoConfigure` annotation triggers auto-configuration of the Spring context.
Auto-configuration attempts to guess what beans a user might want based on their ### spring-boot-ops
classpath. For example, If a 'HSQLDB' is on the classpath the user probably wants an Ops uses auto-configuration to decorate your application with features that
in-memory database to be defined. Auto-configuration will back away as the user starts
to define their own beans.
_See [spring-autoconfigure/README](spring-autoconfigure/README.md)._
### Spring Actuator
Spring Actuator uses auto-configuration to decorate your application with features that
make it instantly deployable and supportable in production. For instance if you are make it instantly deployable and supportable in production. For instance if you are
writing a JSON web service then it will provide a server, security, logging, externalized writing a JSON web service then it will provide a server, security, logging, externalized
configuration, management endpoints, an audit abstraction, and more. If you want to configuration, management endpoints, an audit abstraction, and more. If you want to
switch off the built in features, or extend or replace them, it makes that really easy as well. switch off the built in features, or extend or replace them, it makes that really easy as
well.
_See [spring-actuator/README](spring-actuator/README.md)._
### Spring Starters _See [spring-boot-ops/README.md](spring-boot-ops/README.md)._
Spring 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 technology
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 just include one dependency in your project, and you are good to go.
_See [spring-starters/README](spring-starters/README.md)._
### spring-boot-loader
Loader provides the secret sauce that allows you to build a single jar file that can be
launched using `java -jar`. Generally you will not need to use `spring-boot-loader`
directly but instead work with the
[Gradle](spring-boot-gradle-plugin/README.md) or
[Maven](spring-boot-maven-plugin/README.md) plugin.
### Packaging _See [spring-boot-loader/README.md](spring-boot-loader/README.md)._
The [spring-launcher](spring-launcher/) and
[spring-maven-packaging-plugin](spring-maven-packaging-plugin) provide a convenient way
to package you application for release. Applications can be released as a single jar
file that can simply be launched using `java -jar`.
_See [spring-launcher/README](spring-launcher/README.md) &
[spring-package-maven-plugin/README](spring-package-maven-plugin/README.md)._
## Samples ## Samples
Groovy samples for use with the command line application are available in Groovy samples for use with the command line application are available in
[spring-cli/samples](spring-cli/samples/#). To run the CLI samples type [spring-boot-cli/samples](spring-boot-cli/samples/#). To run the CLI samples type
`spring run <sample>.groovy` from samples directory. `spring run <sample>.groovy` from samples directory.
Java samples are available in [spring-boot-sample](spring-boot-samples/#) and should Java samples are available in [spring-boot-samples](spring-boot-samples/#) and should
be build with maven and run use `java -jar target/<sample>.jar`. The following java be build with maven and run use `java -jar target/<sample>.jar`. The following java
samples are provided: samples are provided:
* spring-boot-sample-simple - A simple command line application * [spring-boot-sample-simple](spring-boot-sample-simple) - A simple command line application
* spring-boot-sample-tomcat - Embedded Tomcat * [spring-boot-sample-tomcat](spring-boot-sample-tomcat) - Embedded Tomcat
* spring-boot-sample-jetty - Embedded Jetty * [spring-boot-sample-jetty](spring-boot-sample-jetty) - Embedded Jetty
* spring-boot-sample-actuator - Simple REST service with production features * [spring-boot-sample-ops](spring-boot-sample-ops) - Simple REST service with production features
* spring-boot-sample-actuator-ui - A web UI example with production features * [spring-boot-sample-ops-ui](spring-boot-sample-ops-ui) - A web UI example with production features
* spring-boot-sample-web-ui - A thymeleaf web application * [spring-boot-sample-web-ui](spring-boot-sample-web-ui) - A thymeleaf web application
* spring-sample-batch - Define and run a Batch job in a few lines of code * [spring-boot-sample-web-static](spring-boot-sample-web-static) - A web application service static files
* spring-sample-data-jpa - Spring Data JPA + Hibernate + HSQLDB * [spring-sample-batch](spring-sample-batch) - Define and run a Batch job in a few lines of code
* spring-boot-sample-integration - A spring integration application * [spring-sample-data-jpa](spring-sample-data-jpa) - Spring Data JPA + Hibernate + HSQLDB
* spring-boot-sample-profile - example showing Spring's `@profile` support * [spring-boot-sample-integration](spring-boot-sample-integration) - A spring integration application
* spring-boot-sample-traditional - shows Spring Zero with more traditional WAR packaging * [spring-boot-sample-profile](spring-boot-sample-profile) - example showing Spring's `@profile` support
* [spring-boot-sample-traditional](spring-boot-sample-traditional) - shows more traditional WAR packaging
(but also executable using `java -jar`) (but also executable using `java -jar`)
* spring-boot-sample-xml - Example show how Spring Boot can be mixed with traditional XML * [spring-boot-sample-xml](spring-boot-sample-xml) - Example show how Spring Boot can be mixed with traditional
configuration XML configuration (we generally recommend using Java `@Configuration` whenever possible)
# Docs without a home as yet :(
|Feature |Implementation |Notes |
|---|---|---|
|Launch Spring from Java main |SpringApplication | Plenty of convenience methods and customization opportunities |
|Server |Tomcat or Jetty | |
|Logging |Logback, Log4j or JDK | Sensible defaults configurations. |
|Externalized configuration | Properties or YAML | Support for Spring profiles. Bind automatically to @Bean. |
For a quick introduction and to get started quickly with a new
project, carry on reading. For more in depth coverage of the features
of Spring Boot.Strap, go to the [Feature Guide](docs/Features.md).
# Getting Started
You will need Java (6 at least) and a build tool (Maven is what we use
below, but you are more than welcome to use gradle). These can be
downloaded or installed easily in most operating systems. For Ubuntu:
$ sudo apt-get install openjdk-6-jdk maven
<!--FIXME: short instructions for Mac.-->
## A basic project
If you are using Maven create a really simple `pom.xml` with 2 dependencies:
`pom.xml`
```
<project>
<modelVersion>4.0.0</modelVersion>
<groupId>com.mycompany</groupId>
<artifactId>myproject</artifactId>
<version>1.0.0-SNAPSHOT</version>
<packaging>jar</packaging>
<properties>
<start-class>com.mycompany.Application</start-class>
</properties>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-starter-parent</artifactId>
<version>{{project.version}}</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-starter</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-package-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
```
If you like Gradle, that's fine, and you will know what to do with
those dependencies. The one dependency adds Spring Boot.Config auto
configuration and the Tomcat container to your application. If you
prefer Jetty you can just add the embedded Jetty jars to your
classpath instead of Tomcat.
Now write a simple main class
`Application.java`
```
package com.mycompany;
import org.springframework.boot.SpringApplication;
import org.springframework.context.annotation.Configuration;
@Configuration
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
```
You should be able to run it already:
$ mvn package
$ java -jar target/myproject-1.0.0-SNAPSHOT.jar
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
Spring Bootstrap
2013-07-19 17:13:51.673 INFO 18937 --- [ main] com.mycompany.Application ...
... <logs showing application starting up>
It doesn't do anything yet, but that's because all we did is start a
Spring `ApplicationContext` and let it close when the JVM stopped.
To make it do something a little bit more interesting you could bind
some command line arguments to the application:
`Application.java`
```
@Configuration
@ConfigurationProperties
@EnableConfigurationProperties
public class Application {
private String message;
@Override
public void run(String... args) throws Exception {
System.err.println(message);
}
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
}
```
The `@ConfigurationProperties` annotation binds the Spring
`Environment` (including command line arguments) to the `Application`
instance, and `CommandLineRunner` is a marker interface for anything
you want to be executed after the content is started. So run it
again and you will see the message:
```
$ mvn package
$ java -jar target/myproject-1.0.0-SNAPSHOT.jar --message="Hello World"
...
Hello World
```
To add more features, add some `@Bean` definitions to your
`Application` class, and read more in the
[Feature Guide](docs/Features.md).
\ No newline at end of file
# Spring Boot.Strap # Spring Boot
Spring Boot provides the central features for the other modules in the project. It is
Spring Boot.Strap provides features for the other parts of Spring relatively unopinionated and it has minimal dependencies which makes it usable as a
Boot. It is relatively unopinionated and therefore usable as a stand-alone library for anyone whose tastes diverge from ours.
standalone library for anyone whose tastes diverge from ours.
## SpringApplication
|Feature |Implementation |Notes | The `SpringApplication` class provides a convenient way to bootstrap a Spring application
|---|---|---| that will be started from a `main()` method. In many situations you can just delegate
|Launch Spring from Java main |SpringApplication | Plenty of convenience methods and customization opportunities | to the static `SpringApplication.run` method:
|Server |Tomcat or Jetty | |
|Logging |Logback, Log4j or JDK | Sensible defaults configurations. | ```java
|Externalized configuration | Properties or YAML | Support for Spring profiles. Bind automatically to @Bean. | public static void main(String[] args) {
SpringApplication.run(SpringConfiguration.class, args);
For a quick introduction and to get started quickly with a new }
project, carry on reading. For more in depth coverage of the features ```
of Spring Boot.Strap, go to the [Feature Guide](docs/Features.md).
# Getting Started
You will need Java (6 at least) and a build tool (Maven is what we use
below, but you are more than welcome to use gradle). These can be
downloaded or installed easily in most operating systems. For Ubuntu:
$ sudo apt-get install openjdk-6-jdk maven
<!--FIXME: short instructions for Mac.-->
## A basic project
If you are using Maven create a really simple `pom.xml` with 2 dependencies:
`pom.xml` When you application starts you should see something similar to the following:
``` ```
<project> . ____ _ __ _ _
<modelVersion>4.0.0</modelVersion> /\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
<groupId>com.mycompany</groupId> ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
<artifactId>myproject</artifactId> \\/ ___)| |_)| | | | | || (_| | ) ) ) )
<version>1.0.0-SNAPSHOT</version> ' |____| .__|_| |_|_| |_\__, | / / / /
<packaging>jar</packaging> =========|_|==============|___/=/_/_/_/
<properties> Spring Boot (v0.5.0.BUILD-SNAPSHOT)
<start-class>com.mycompany.Application</start-class>
</properties> 2013-07-31 00:08:16.117 INFO 56603 --- [ main] o.s.b.s.app.SampleApplication : Starting SampleApplication v0.1.0 on mycomputer with PID 56603 (/apps/myapp.jar started by pwebb)
<parent> 2013-07-31 00:08:16.166 INFO 56603 --- [ main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@6e5a8246: startup date [Wed Jul 31 00:08:16 PDT 2013]; root of context hierarchy
<groupId>org.springframework.boot</groupId>
<artifactId>spring-starter-parent</artifactId>
<version>{{project.version}}</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-starter</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-package-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
``` ```
If you like Gradle, that's fine, and you will know what to do with By default `INFO` logging messages will shown, including some relevant startup information
those dependencies. The one dependency adds Spring Boot.Config auto such as the user that started the application.
configuration and the Tomcat container to your application. If you
prefer Jetty you can just add the embedded Jetty jars to your
classpath instead of Tomcat.
Now write a simple main class ### Customizing SpringApplication
If the SpringApplication defaults aren't to your taste you can instead create a local
instance and customize it. For example, to turn off the banner you would write:
`Application.java` ```java
public static void main(String[] args) {
SpringApplication app = new SpringApplication(SpringConfiguration.class);
app.setShowBanner(false);
app.run(args);
}
``` ```
package com.mycompany;
import org.springframework.boot.SpringApplication; See the `SpringApplication` Javadoc for a complete list of the configuration options
import org.springframework.context.annotation.Configuration;
@Configuration ### Accessing command line properties
public class Application { By default `SpringApplication` will expose any command line arguments as Spring
Properties. This allows you to easily access arguments using by injecting them
as `@Values`
public static void main(String[] args) { ```java
SpringApplication.run(Application.class, args); import org.springframework.stereotype.*
} import org.springframework.beans.factory.annotation.*
@Component
public class MyBean {
@Value("${name}")
private String name;
// Running 'java -jar myapp.jar --name=Spring' will set this to "Spring"
// ...
} }
``` ```
You should be able to run it already: ### CommandLineRunner beans
If you wan't access to the raw command line argument, or you need to run some specific
code once the `SpringApplication` has started you can implement the `CommandLineRunner`
interface. The `run(String... args)` method will be called on all spring beans
implementing the interface.
$ mvn package ```java
$ java -jar target/myproject-1.0.0-SNAPSHOT.jar import org.springframework.boot.*
import org.springframework.stereotype.*
. ____ _ __ _ _ @Component
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \ public class MyBean implements CommandLineRunner {
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
Spring Bootstrap
2013-07-19 17:13:51.673 INFO 18937 --- [ main] com.mycompany.Application ... public void run(String... args) {
... <logs showing application starting up> // Do something...
}
It doesn't do anything yet, but that's because all we did is start a
Spring `ApplicationContext` and let it close when the JVM stopped. }
To make it do something a little bit more interesting you could bind
some command line arguments to the application:
`Application.java`
``` ```
@Configuration
@ConfigurationProperties
@EnableConfigurationProperties
public class Application {
private String message; You can additionally implement the `org.springframework.core.Ordered` interface or use
the `org.springframework.core.annotation.Order` annotation if serveral `CommandLineRunner`
beans are defined that must be called in a specific order.
@Override ### Application Exit
public void run(String... args) throws Exception {
System.err.println(message);
}
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
public String getMessage() {
return message;
}
public void setMessage(String message) { ## Embedded Servlet Container Support
this.message = message;
}
}
```
The `@ConfigurationProperties` annotation binds the Spring ## External Configuration
`Environment` (including command line arguments) to the `Application`
instance, and `CommandLineRunner` is a marker interface for anything
you want to be executed after the content is started. So run it
again and you will see the message:
``` ## Conditionals
$ mvn package
$ java -jar target/myproject-1.0.0-SNAPSHOT.jar --message="Hello World" ## ApplicationContextInitializers
...
Hello World
```
To add more features, add some `@Bean` definitions to your
`Application` class, and read more in the
[Feature Guide](docs/Features.md).
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