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Updated getting started docs to use Spring Initializer

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resolves #423
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Glenn Renfro
2018-07-23 17:52:00 -04:00
parent cba26ed968
commit c719f8b1f9
1 changed files with 50 additions and 129 deletions
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spring-cloud-task-docs/src/main/asciidoc/getting-started.adoc
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@@ -52,126 +52,37 @@ http://start.spring.io/[Spring Initializr] and creating a new project. Doing so
automatically generates a new project structure so that you can start coding right away.
We recommend experimenting with the Spring Initializr to become familiar with it.
Before we begin, open a terminal to check that you have valid versions of Java and Maven
installed, as shown in the following two listings:
[[getting-started-creating-project]]
=== Creating the Spring Task Project using Spring Initializr
Now we can create and test an application that prints `Hello, World!` to the console.
[source]
$ java -version
java version "1.8.0_31"
Java(TM) SE Runtime Environment (build 1.8.0_31-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.31-b07, mixed mode)
To do so:
[source]
$ mvn -v
Apache Maven 3.2.3 (33f8c3e1027c3ddde99d3cdebad2656a31e8fdf4; 2014-08-11T15:58:10-05:00)
Maven home: /usr/local/Cellar/maven/3.2.3/libexec
Java version: 1.8.0_31, vendor: Oracle Corporation
NOTE: This sample needs to be created in its own folder. Subsequent instructions assume
you have created a suitable folder and that it is your "`current directory.`"
[[getting-started-creating-the-pom]]
=== Creating the POM
We need to start by creating a Maven `pom.xml` file. The `pom.xml` file contains the
recipe that Maven uses to build your project. To create the pom.xml file, open your
favorite text editor and add the following:
[code,xml]
----
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.example</groupId>
<artifactId>myproject</artifactId>
<packaging>jar</packaging>
<version>0.0.1-SNAPSHOT</version>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.2.RELEASE</version>
</parent>
<properties>
<start-class>com.example.SampleTask</start-class>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
----
Creating a `pom.xml` file with the preceding content 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 IDE's
include built-in support for Maven). For simplicity, we continue to use a plain text
editor for this example.
[[getting-started-adding-classpath-dependencies]]
=== Adding classpath dependencies
A Spring Cloud Task is made up of a Spring Boot application that is expected to end. In
the `pom.xml` file we showed earlier, we created the shell of a Spring Boot application by
setting our parent to use the `spring-boot-starter-parent`.
Spring Boot provides a number of additional "`Starter POMs`". Some of them are appropriate
for use within tasks (`spring-boot-starter-batch`, `spring-boot-starter-jdbc`, and
others), and some may not be ('spring-boot-starter-web` is probably not going to be used
in a task). The best indicator of which starter makes sense is whether the resulting
application should end. Batch-based applications typically end. Conversely, the
`spring-boot-starter-web` dependency bootstraps a servlet container, which better suits
applications that continue.
For this example, we need only to add a single additional dependency -- the one for
Spring Cloud Task itself:
[source,xml]
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-task</artifactId>
<version>1.2.3.RELEASE</version>
</dependency>
. Visit the link:https://start.spring.io/[Spring Initialzr] site.
.. Create a new Maven project with a *Group* name of `io.spring.demo` and an *Artifact* name of `helloworld`.
.. In the Dependencies text box, type `task` and then select the `Cloud Task` dependency.
.. In the Dependencies text box, type `jdbc` and then select the `JDBC` dependency.
.. In the Dependencies text box, type `h2` and then select the `H2`. (or your favorite database)
.. Click the *Generate Project* button
. Unzip the timestamp.zip file and import the project into your favorite IDE.
[[getting-started-writing-the-code]]
=== Writing the Code
To finish our application, we need to create a single Java file. By default, Maven
compiles the sources from `src/main/java`, so you need to create that folder structure.
Then you need to add a file named `src/main/java/com/example/SampleTask.java`, as shown
in the following example:
To finish our application, we need to update the generated `HelloworldApplication` with the following contents so that it launches a Task.
[source,java]
----
package com.example;
package io.spring.demo.helloworld;
import org.springframework.boot.*;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.task.configuration.EnableTask;
import org.springframework.context.annotation.Bean;
@SpringBootApplication
@EnableTask
public class SampleTask {
public class HelloworldApplication {
@Bean
public CommandLineRunner commandLineRunner() {
@@ -179,7 +90,7 @@ public class SampleTask {
}
public static void main(String[] args) {
SpringApplication.run(SampleTask.class, args);
SpringApplication.run(HelloworldApplication.class, args);
}
public static class HelloWorldCommandLineRunner implements CommandLineRunner {
@@ -196,11 +107,15 @@ While it may seem small, quite a bit is going on. For more about Spring
Boot specifics, see the
http://docs.spring.io/spring-boot/docs/current/reference/html/[Spring Boot reference documentation].
We also need to create an `application.properties` file in `src/main/resources`. We need
to configure two properties in `application.properties`: We need to set the application
name (which is translated to the task name), and we need to set the logging for Spring
Cloud Task to `DEBUG` so that we can see what's going on. The following example shows how
to do both:
Now we can open the `application.properties` file in `src/main/resources`.
We need to configure two properties in `application.properties`:
* `application.name`: To set the application name (which is translated to the task name)
* `logging.level`: To set the logging for Spring Cloud Task to `DEBUG` in order to
get a view of what is going on.
The following example shows how to do both:
[source]
----
@@ -217,24 +132,23 @@ default, it imports an additional configuration class (`SimpleTaskConfiguration`
additional configuration registers the `TaskRepository` and the infrastructure for its
use.
Out of the box, the `TaskRepository` uses an in-memory `Map` to record the results
of a task. A `Map` is not a practical solution for a production environment, since
the `Map` goes away once the task ends. However, for a quick getting-started
experience, we use this as a default as well as echoing to the logs what is being updated
In our demo, the `TaskRepository` uses an embedded H2 database to record the results
of a task. This H2 embedded database is not a practical solution for a production environment, since
the H2 DB goes away once the task ends. However, for a quick getting-started
experience, we can use this in our example as well as echoing to the logs what is being updated
in that repository. In the <<features-configuration>> section (later in this
documentation), we cover how to customize the configuration of the pieces provided by
Spring Cloud Task.
When our sample application runs, Spring Boot launches our `HelloWorldCommandLineRunner`
and outputs our "`Hello, World!`" message to standard out. The `TaskLifecyceListener`
and outputs our "`Hello, World!`" message to standard out. The `TaskLifecycleListener`
records the start of the task and the end of the task in the repository.
[[getting-started-main-method]]
==== The main method
The main method serves as the entry point to any java application. Our main method
delegates to Spring Boot's `SpringApplication` class. You can read more about it in the
Spring Boot documentation.
delegates to Spring Boot's https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-spring-application.html[SpringApplication] class.
[[getting-started-clr]]
==== The CommandLineRunner
@@ -266,25 +180,32 @@ $ mvn clean spring-boot:run
....... . . . (Maven log output here)
....... . . .
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v1.3.3.RELEASE)
:: Spring Boot :: (v2.0.3.RELEASE)
2016-01-25 11:08:10.183 INFO 12943 --- [ main] com.example.SampleTask : Starting SampleTask on Michaels-MacBook-Pro-2.local with PID 12943 (/Users/mminella/Documents/IntelliJWorkspace/spring-cloud-task-example/target/classes started by mminella in /Users/mminella/Documents/IntelliJWorkspace/spring-cloud-task-example)
2016-01-25 11:08:10.185 INFO 12943 --- [ main] com.example.SampleTask : No active profile set, falling back to default profiles: default
2016-01-25 11:08:10.226 INFO 12943 --- [ main] s.c.a.AnnotationConfigApplicationContext : Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@2a2c3676: startup date [Mon Jan 25 11:08:10 CST 2016]; root of context hierarchy
2016-01-25 11:08:11.051 INFO 12943 --- [ main] o.s.j.e.a.AnnotationMBeanExporter : Registering beans for JMX exposure on startup
2016-01-25 11:08:11.065 INFO 12943 --- [ main] o.s.c.t.r.support.SimpleTaskRepository : Creating: TaskExecution{executionId=0, externalExecutionID='null', exitCode=0, taskName='application', startTime=Mon Jan 25 11:08:11 CST 2016, endTime=null, statusCode='null', exitMessage='null', arguments=[]}
2018-07-23 17:44:34.426 INFO 1978 --- [ main] i.s.d.helloworld.HelloworldApplication : Starting HelloworldApplication on Glenns-MBP-2.attlocal.net with PID 1978 (/Users/glennrenfro/project/helloworld/target/classes started by glennrenfro in /Users/glennrenfro/project/helloworld)
2018-07-23 17:44:34.430 INFO 1978 --- [ main] i.s.d.helloworld.HelloworldApplication : No active profile set, falling back to default profiles: default
2018-07-23 17:44:34.472 INFO 1978 --- [ main] s.c.a.AnnotationConfigApplicationContext : Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@1d24f32d: startup date [Mon Jul 23 17:44:34 EDT 2018]; root of context hierarchy
2018-07-23 17:44:35.280 INFO 1978 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Starting...
2018-07-23 17:44:35.410 INFO 1978 --- [ main] com.zaxxer.hikari.HikariDataSource : HikariPool-1 - Start completed.
2018-07-23 17:44:35.419 DEBUG 1978 --- [ main] o.s.c.t.c.SimpleTaskConfiguration : Using org.springframework.cloud.task.configuration.DefaultTaskConfigurer TaskConfigurer
2018-07-23 17:44:35.420 DEBUG 1978 --- [ main] o.s.c.t.c.DefaultTaskConfigurer : No EntityManager was found, using DataSourceTransactionManager
2018-07-23 17:44:35.522 DEBUG 1978 --- [ main] o.s.c.t.r.s.TaskRepositoryInitializer : Initializing task schema for h2 database
2018-07-23 17:44:35.525 INFO 1978 --- [ main] o.s.jdbc.datasource.init.ScriptUtils : Executing SQL script from class path resource [org/springframework/cloud/task/schema-h2.sql]
2018-07-23 17:44:35.558 INFO 1978 --- [ main] o.s.jdbc.datasource.init.ScriptUtils : Executed SQL script from class path resource [org/springframework/cloud/task/schema-h2.sql] in 33 ms.
2018-07-23 17:44:35.728 INFO 1978 --- [ main] o.s.j.e.a.AnnotationMBeanExporter : Registering beans for JMX exposure on startup
2018-07-23 17:44:35.730 INFO 1978 --- [ main] o.s.j.e.a.AnnotationMBeanExporter : Bean with name 'dataSource' has been autodetected for JMX exposure
2018-07-23 17:44:35.733 INFO 1978 --- [ main] o.s.j.e.a.AnnotationMBeanExporter : Located MBean 'dataSource': registering with JMX server as MBean [com.zaxxer.hikari:name=dataSource,type=HikariDataSource]
2018-07-23 17:44:35.738 INFO 1978 --- [ main] o.s.c.support.DefaultLifecycleProcessor : Starting beans in phase 0
2018-07-23 17:44:35.762 DEBUG 1978 --- [ main] o.s.c.t.r.support.SimpleTaskRepository : Creating: TaskExecution{executionId=0, parentExecutionId=null, exitCode=null, taskName='application', startTime=Mon Jul 23 17:44:35 EDT 2018, endTime=null, exitMessage='null', externalExecutionId='null', errorMessage='null', arguments=[]}
2018-07-23 17:44:35.772 INFO 1978 --- [ main] i.s.d.helloworld.HelloworldApplication : Started HelloworldApplication in 1.625 seconds (JVM running for 4.764)
Hello, World!
2016-01-25 11:08:11.071 INFO 12943 --- [ main] com.example.SampleTask : Started SampleTask in 1.095 seconds (JVM running for 3.826)
2016-01-25 11:08:11.220 INFO 12943 --- [ Thread-1] s.c.a.AnnotationConfigApplicationContext : Closing org.springframework.context.annotation.AnnotationConfigApplicationContext@2a2c3676: startup date [Mon Jan 25 11:08:10 CST 2016]; root of context hierarchy
2016-01-25 11:08:11.222 INFO 12943 --- [ Thread-1] o.s.c.t.r.support.SimpleTaskRepository : Updating: TaskExecution{executionId=0, externalExecutionID='null', exitCode=0, taskName='application', startTime=Mon Jan 25 11:08:11 CST 2016, endTime=Mon Jan 25 11:08:11 CST 2016, statusCode='null', exitMessage='null', arguments=[]}
2016-01-25 11:08:11.222 INFO 12943 --- [ Thread-1] o.s.j.e.a.AnnotationMBeanExporter : Unregistering JMX-exposed beans on shutdown
2018-07-23 17:44:35.782 DEBUG 1978 --- [ main] o.s.c.t.r.support.SimpleTaskRepository : Updating: TaskExecution with executionId=1 with the following {exitCode=0, endTime=Mon Jul 23 17:44:35 EDT 2018, exitMessage='null', errorMessage='null'}
----
The preceding output has three lines that of interest to us here: