JAX-RS Jersey hello world example

I have written a number of posts on JAX-RS RESTEasy concepts and how to. Now I have started exploring Jersey which is another popular framework for making RESTFul applications. To start with, I am writing my hello world application in this post, which I will modify in next posts to show demos of other features Jersey provide.

Step 1) Make a eclipse web project using maven

Learn to make eclipse maven project here

Step 2) Update Jersey dependencies in pom.xml file

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<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.howtodoinjava</groupId>   <artifactId>JerseyHelloWorld</artifactId>   <packaging>war</packaging>   <version>1.0-SNAPSHOT</version>   <name>JerseyHelloWorld Maven Webapp</name>   <url>http://maven.apache.org</url>   <repositories>         <repository>             <id>maven2-repository.java.net</id>             <name>Java.net Repository for Maven</name>             <url>http://download.java.net/maven/2/</url>             <layout>default</layout>         </repository>     </repositories>   <dependencies>     <dependency>       <groupId>junit</groupId>       <artifactId>junit</artifactId>       <version>4.11</version>       <scope>test</scope>     </dependency>     <dependency>         <groupId>com.sun.jersey</groupId>         <artifactId>jersey-server</artifactId>         <version>1.17.1</version>     </dependency>     <dependency>         <groupId>com.sun.jersey</groupId>         <artifactId>jersey-core</artifactId>         <version>1.17.1</version>     </dependency>     <dependency>         <groupId>com.sun.jersey</groupId>         <artifactId>jersey-servlet</artifactId>         <version>1.17.1</version>     </dependency>   </dependencies>       <build>     <finalName>JerseyHelloWorld</finalName>         <plugins>             <plugin>               <artifactId>maven-compiler-plugin</artifactId>                 <configuration>                   <source>1.6</source>                   <target>1.6</target>                 </configuration>             </plugin>       </plugins>   </build> </project>

Step 3) Update web.xml file with servlet mapping to com.sun.jersey.spi.container.servlet.ServletContainer

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<!DOCTYPE web-app PUBLIC  "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"  "http://java.sun.com/dtd/web-app_2_3.dtd" > <web-app>   <display-name>Archetype Created Web Application</display-name>       <servlet>         <servlet-name>jersey-serlvet</servlet-name>         <servlet-class>com.sun.jersey.spi.container.servlet.ServletContainer</servlet-class>         <init-param>              <param-name>com.sun.jersey.config.property.packages</param-name>              <param-value>com.howtodoinjava.rest</param-value>         </init-param>         <load-on-startup>1</load-on-startup>     </servlet>        <servlet-mapping>         <servlet-name>jersey-serlvet</servlet-name>         <url-pattern>/rest-points/*</url-pattern>     </servlet-mapping>       </web-app>

Step 4) Write first REST service class

The service class will look like exactly as RESTEasy because of common annotations used from JAX-RS.

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package com.howtodoinjava.rest; import javax.ws.rs.GET; import javax.ws.rs.Path; import javax.ws.rs.PathParam; import javax.ws.rs.core.Response; @Path("/show-on-screen") public class JerseyHelloWorldService {     @GET     @Path("/{message}")     public Response getMsg(@PathParam("message") String msg)     {         String output = "Message requested : " + msg;         //Simply return the parameter passed as message         return Response.status(200).entity(output).build();     } }