RESTEasy Tutorial Part-1: Basics

RESTEasy Tutorial Series

RESTEasy Tutorial Part-1: Basics

RESTEasy Tutorial Part-2: Spring Integration

RESTEasy Tutorial Part 3 - Exception Handling

RESTEasy is a JAX-RS implementation from JBoss/RedHat and is in-built in JBoss 6 onwards.
Here I am going to show you how to develop a Simple RESTful Web Services application using RESTEasy and JBossAS7.1.1.FINAL.

Step#1: Configure RESTEasy dependencies using Maven.

	<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/maven-v4_0_0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<groupId>com.sivalabs</groupId>
	<artifactId>resteasy-demo</artifactId>
	<version>0.1</version>
	<packaging>war</packaging>
	<name>resteasy-demo Maven Webapp</name>
	<build>
	<finalName>resteasy-demo</finalName>
	</build>
	<dependencies>
	<dependency>
	<groupId>junit</groupId>
	<artifactId>junit</artifactId>
	<version>4.8.2</version>
	<scope>test</scope>
	</dependency>
	<dependency>
	<groupId>org.jboss.resteasy</groupId>
	<artifactId>resteasy-jaxrs</artifactId>
	<version>2.3.2.FINAL</version>
	<scope>provided</scope>
	</dependency>
	<dependency>
	<groupId>org.jboss.resteasy</groupId>
	<artifactId>resteasy-jaxb-provider</artifactId>
	<version>2.3.2.FINAL</version>
	<scope>provided</scope>
	</dependency>
	<dependency>
	<groupId>org.jboss.resteasy</groupId>
	<artifactId>jaxrs-api</artifactId>
	<version>2.3.0.GA</version>
	<scope>provided</scope>
	</dependency>
	<dependency>
	<groupId>org.apache.httpcomponents</groupId>
	<artifactId>httpclient</artifactId>
	<version>4.1.2</version>
	<scope>provided</scope>
	</dependency>
	</dependencies>
	</project>

view raw RESTEasy-Maven-POM.xml hosted with ❤ by GitHub

Step#2: Configure RESTEasy in web.xml

	<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns="http://java.sun.com/xml/ns/javaee"
	xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
	http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
	id="WebApp_ID" version="3.0">
	<listener>
	<listener-class>org.jboss.resteasy.plugins.server.servlet.ResteasyBootstrap</listener-class>
	</listener>
	<servlet>
	<servlet-name>Resteasy</servlet-name>
	<servlet-class>org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher</servlet-class>
	</servlet>
	<servlet-mapping>
	<servlet-name>Resteasy</servlet-name>
	<url-pattern>/rest/*</url-pattern>
	</servlet-mapping>
	<context-param>
	<param-name>resteasy.servlet.mapping.prefix</param-name>
	<param-value>/rest</param-value>
	</context-param>
	<context-param>
	<param-name>resteasy.scan</param-name>
	<param-value>true</param-value>
	</context-param>
	</web-app>

view raw RESTEasy-Web.xml hosted with ❤ by GitHub

Step#3: Create User domain class, MockUserTable class to store User objects in-memory for testing purpose and UserResource class to expose CRUD operations on User as RESTful webservices.

	package com.sivalabs.resteasydemo;
	import java.util.Date;
	import javax.xml.bind.annotation.XmlAccessType;
	import javax.xml.bind.annotation.XmlAccessorType;
	import javax.xml.bind.annotation.XmlRootElement;
	@XmlRootElement
	@XmlAccessorType(XmlAccessType.FIELD)
	public class User
	{
	private Integer id;
	private String name;
	private String email;
	private Date dob;
	//setters and getters
	}
	package com.sivalabs.resteasydemo;
	import java.util.ArrayList;
	import java.util.Date;
	import java.util.HashMap;
	import java.util.List;
	import java.util.Map;
	import com.sivalabs.resteasydemo.User;
	public class MockUserTable
	{
	private static Map<Integer, User> USER_MAP = new HashMap<Integer, User>();
	static
	{
	USER_MAP.put(1, new User(1,"admin","admin@gmail.com",new Date()));
	USER_MAP.put(2, new User(2,"test","test@gmail.com",new Date()));
	}
	public static void save(User user){
	USER_MAP.put(user.getId(), user);
	}
	public static User getById(Integer id){
	return USER_MAP.get(id);
	}
	public static List<User> getAll(){
	List<User> users = new ArrayList<User>(USER_MAP.values());
	return users;
	}
	public static void delete(Integer id){
	USER_MAP.remove(id);
	}
	}
	package com.sivalabs.resteasydemo;
	import java.util.List;
	import javax.ws.rs.DELETE;
	import javax.ws.rs.GET;
	import javax.ws.rs.POST;
	import javax.ws.rs.Path;
	import javax.ws.rs.PathParam;
	import javax.ws.rs.Produces;
	import javax.ws.rs.core.GenericEntity;
	import javax.ws.rs.core.MediaType;
	import javax.ws.rs.core.Response;
	import com.sivalabs.resteasydemo.MockUserTable;
	@Path("/users")
	@Produces(MediaType.APPLICATION_XML)
	public class UserResource
	{
	@Path("/")
	@GET
	public Response getUsersXML()
	{
	List<User> users = MockUserTable.getAll();
	GenericEntity<List<User>> ge = new GenericEntity<List<User>>(users){};
	return Response.ok(ge).build();
	}
	@Path("/{id}")
	@GET
	public Response getUserXMLById(@PathParam("id") Integer id) {
	return Response.ok(MockUserTable.getById(id)).build();
	}
	@Path("/")
	@POST
	public Response saveUser(User user) {
	MockUserTable.save(user);
	return Response.ok("<status>success</status>").build();
	}
	@Path("/{id}")
	@DELETE
	public Response deleteUser(@PathParam("id") Integer id) {
	MockUserTable.delete(id);
	return Response.ok("<status>success</status>").build();
	}
	}

view raw RESTEasy-Sample-Code.java hosted with ❤ by GitHub

Step#6: JUnit TestCase to test the REST Webservice.

	package com.sivalabs.resteasydemo;
	import java.util.List;
	import org.jboss.resteasy.client.ClientRequest;
	import org.jboss.resteasy.client.ClientResponse;
	import org.jboss.resteasy.util.GenericType;
	import org.junit.Assert;
	import org.junit.Test;
	import com.sivalabs.resteasydemo.User;
	public class UserResourceTest {
	static final String ROOT_URL = "http://localhost:8080/resteasy-demo/rest/";
	@Test
	public void testGetUsers() throws Exception
	{
	ClientRequest request = new ClientRequest(ROOT_URL+"users/");
	ClientResponse<List<User>> response = request.get(new GenericType<List<User>>(){});
	List<User> users = response.getEntity();
	Assert.assertNotNull(users);
	}
	@Test
	public void testGetUserById() throws Exception
	{
	ClientRequest request = new ClientRequest(ROOT_URL+"users/1");
	ClientResponse<User> response = request.get(User.class);
	User user = response.getEntity();
	Assert.assertNotNull(user);
	}
	@Test
	public void testSaveUser() throws Exception
	{
	User user = new User();
	user.setId(3);
	user.setName("User3");
	user.setEmail("user3@gmail.com");
	ClientRequest request = new ClientRequest(ROOT_URL+"users/");
	request.body("application/xml", user);
	ClientResponse<String> response = request.post(String.class);
	String statusXML = response.getEntity();
	Assert.assertNotNull(statusXML);
	}
	@Test
	public void testDeleteUser() throws Exception
	{
	ClientRequest request = new ClientRequest(ROOT_URL+"users/2");
	ClientResponse<String> response = request.delete(String.class);
	String statusXML = response.getEntity();
	Assert.assertNotNull(statusXML);
	}
	}

view raw UserResource-JUnit-TestCase.java hosted with ❤ by GitHub

Step#7: To test the REST service we can use the REST Client Tool. 
You can download REST Client Tool at http://code.google.com/a/eclipselabs.org/p/restclient-tool/


Important Things to Keep in mind:
1. org.jboss.resteasy.plugins.server.servlet.ResteasyBootstrap Listener should be registered before any other listener.

2. You should configure resteasy.servlet.mapping.prefix <context-param> if the HttpServletDispatcher servlet url-pattern is anything other than /*


3. Keep visiting my blog :-)