Chapter 6. Developing your first Spring Cloud Task application

A good place to start is with a simple "Hello World!" application so we’ll create the Spring Cloud Task equivalent to highlight the features of the framework. We’ll use Apache Maven as a build tool for this project since most IDEs have good support for it.

Note

The spring.io web site contains many “Getting Started” guides that use Spring Boot. If you’re looking to solve a specific problem; check there first. You can shortcut the steps below by going to start.spring.io and creating a new project. This will automatically generate a new project structure so that you can start coding right the way. Check the documentation for more details.

Before we begin, open a terminal to check that you have valid versions of Java and Maven installed.

$ 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)

$ 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".

Creating the POM

We need to start by creating a Maven pom.xml file. The pom.xml is the recipe that will be used to build your project. Open your favorite text editor and add the following:

<?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>

This should give you a working build. You can test it out by running mvn package (you can ignore the "jar will be empty - no content was marked for inclusion!" warning for now).

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 will continue to use a plain text editor for this example.