Introduction
Web service is a technology that one programming language uses to communicate with another. You can use web services to interact with PHP and .Net with Java. So, web service provides a way to achieve coordination and consistency. Here we will see an example of JAX-RS using jersey implementation.
In this example, jersey jar files have been used for using jersey example for JAX-RS. You may download the required jar files.
So there are two parts of the code, one for the server side and the other for the client one. We will use four different files, of which the first three files will form the server side while the last one will act for the client side.
- Hello.java
- index.html
- web.xml
- HelloWorldClient.java
JAX-RS Server Code
File1: Hello.java
package com.cn.rest;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
@Path("/hello")
public class Hello {
// This method is called if HTML and XML are not requested
@GET
@Produces(MediaType.TEXT_PLAIN)
public String sayPlainTextHello() {
return "Hello Jersey";
}
// This method is called if XML is requested
@GET
@Produces(MediaType.TEXT_XML)
public String sayXMLHello() {
return "<?xml version=\"1.0\"?>" + "<hello> Hello Jersey" + "</hello>";
}
// This method is called if HTML is requested
@GET
@Produces(MediaType.TEXT_HTML)
public String sayHtmlHello() {
return "<html> " + "<title>" + "Hello Jersey" + "</title>"
+ "<body><h1>" + "Hello Jersey HTML" + "</h1></body>" + "</html> ";
}
} 
You can also try this code with Online Java Compiler
File2: index.html
<a href="rest/hello">Click Here</a>
File3: web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee"
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">
<servlet>
<servlet-name>Jersey REST Service</servlet-name>
<servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
<init-param>
<param-name>jersey.config.server.provider.packages</param-name>
<param-value>com.cn.rest</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>Jersey REST Service</servlet-name>
<url-pattern>/rest/*</url-pattern>
</servlet-mapping>
</web-app>
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