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WebServices- JAX-RS JERSEY

JAX-RS JERSEY

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

If we want to implement Webservices using Jersey we need to download Jersey jar files from Jersey website

The major change between JERSEY & RESTEASY is just changing the configuration in web.xml

Download & install Maven, configure maven in Eclipse

Steps to Create Jersey Web Service Application

  1. Create Dynamic web project in eclipse, convert that into Maven Project

  2. Add Jersey jar files manually / through Maven by writing repo details in pom.xml

  3. Create RESTFul webservice

  4. Configure web.xml

  5. Test Webservice directly by using URL / writing webservice client


Example: JAXRS-Jersey-HelloWorld

1. Create Dynamic web project in eclipse, convert that into Maven Project

New → Dynamic web project → Provide project details finish

Right-click on Project →Configure → Convert to Maven Project .

C:\Users\kaveti_s\Desktop\temp.png

Figure 1 Directory Structure after adding all files

2. Add Jersey jar files manually / through Maven by writing repo details in pom.xml

Jersey is published in Java.net Maven repository. To develop Jersey REST application, just declares -jersey-server” in Maven 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>  
 <dependency>
 	<groupId>com.sun.jersey</groupId>
 	<artifactId>jersey-client</artifactId>
 	<version>1.19.3</version>
 </dependency>
	</dependencies>
</project>

3. Create RESTFul webservice at Server End

package service;

@Path("/hellojersey")  
public class HelloWorldWebService {  
  // This method is called if HTML and XML is not requested  
  @GET  
  @Produces(MediaType.TEXT_PLAIN)  
  public String sayPlainTextHello() {  
    return "Hello Jersey Plain";  
  }  

  // This method is called if HTML is requested  
  @GET  
  @Produces(MediaType.TEXT_HTML)  
  public String sayHtmlHello() {  
    return "<h1>" + "Hello Jersey HTML" + "</h1>";  
  }  
}

4.Configure web.xml

In web.xml,

  • register -com.sun.jersey.spi.container.servlet.ServletContainer-,

  • In -com.sun.jersey.config.property.packages-., provide package name, where WebService classes are implemented

<?xml version="1.0" encoding="UTF-8"?>
<web-app>
	<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>service</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>

5. Test Webservice directly by using URL / writing webservice client

In this example, web request from -projectURL/rest/hellojersy/” will match to -HelloWorldWebService”, via @Path(“/hellojersey”) So we are created a test index.html conatining following url for testing purpose

Index.html

<h1>Test JERSEY WEBSERVICE </h1>
<h3><a href="rest/hellojersey">Default</a></h3>

Direct Testing URL : http://localhost:8080/JAXRS-Jersey-HelloWorld/rest/hellojersey

We can write The HelloworldClientTest.java file is created inside the server application. But you can run client code by other application also by having service interface and jersey jar file.

package client;

import java.net.URI;
import javax.ws.rs.client.Client;
import javax.ws.rs.client.ClientBuilder;
import javax.ws.rs.client.WebTarget;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.UriBuilder;
import org.glassfish.jersey.client.ClientConfig;

public class HelloworldClientTest {
	public static void main(String[] args) {
 ClientConfig config = new ClientConfig();
 Client client = ClientBuilder.newClient(config);
 WebTarget target = client.target(getBaseURI());
 // Now printing the server code of different media type
 System.out.println(target.path("rest").path("hellojersey").request().accept(MediaType.TEXT_PLAIN).get(String.class));
  System.out.println(target.path("rest").path("hellojersey").request().accept(MediaType.TEXT_HTML).get(String.class));
	}

	private static URI getBaseURI() {
 // here server is running on 4444 port number and project name is
 // restfuljersey
 return UriBuilder.fromUri("http://localhost:8080/JAXRS-Jersey-HelloWorld/rest/hellojersey").build();
	}
}

If we got 404 error , follow below steps java.lang.ClassNotFoundException: com.sun.jersey.spi.container.servlet.ServletContainer

Right click on Project Properties Deployment Assembly : add : Java BuildPath Entities Maven Dependencies Finish

C:\Users\kaveti_s\Desktop\temp.png

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