Jersey hello world example

Jersey, reference implementation to develope RESTful web service based on the JAX-RS (JSR 311) specification.

In this tutorial, we show you how to develop a simple hello world REST web application with Jersey.

Technologies and Tools used in this article:

Jersey 1.8

JDK 1.6

Tomcat 6.0

Maven 3.0.3

Eclipse 3.6

1. Directory Structure

This is the final web project structure of this tutorial.

2. Standard Web Project

Create a standard Maven web project structure.

mvn archetype:generate -DgroupId=com.mkyong.rest -DartifactId=RESTfulExample
-DarchetypeArtifactId=maven-archetype-webapp -DinteractiveMode=false

Note

To support Eclipse, use Maven command :

mvn eclipse:eclipse -Dwtpversion=2.0

3. Project Dependencies

Jersey is published in

Java.net

Maven repository. To develop Jersey REST application , just declares “

jersey-server

” in Maven

pom.xml

.

File :

pom.xml

<project ...>

<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>com.sun.jersey</groupId>
<artifactId>jersey-server</artifactId>
<version>1.8</version>
</dependency>

</dependencies>

</project>

4. REST Service

Simple REST service with Jersey.

package com.mkyong.rest;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.core.Response;

@Path("/hello")
public class HelloWorldService {

@GET
@Path("/{param}")
public Response getMsg(@PathParam("param") String msg) {

String output = "Jersey say : " + msg;

return Response.status(200).entity(output).build();

}

}

5. web.xml

In

web.xml

, register “

com.sun.jersey.spi.container.servlet.ServletContainer

“, and puts your Jersey service folder under “

init-param

“, “

com.sun.jersey.config.property.packages

“.

File :

web.xml

<web-app id="WebApp_ID" version="2.4"
xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"> <display-name>Restful 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.mkyong.rest</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>

<servlet-mapping>
<servlet-name>jersey-serlvet</servlet-name>
<url-pattern>/rest/*</url-pattern>
</servlet-mapping>

</web-app>

6. Demo

In this example, web request from “

projectURL/rest/hello/

” will match to “

HelloWorldService

“, via

@Path("/hello")

.

And the “

{any values}

” from “

projectURL/rest/hello/{any values}

” will match to parameter annotated with

@PathParam

.

URL : http://localhost:8080/RESTfulExample/rest/hello/mkyong