Create RESTful web service with HTML client

This demo application will show you how to create Simple Hello World Application Using JAX-RS and Jersey.

Note: If you are not familiar with RESTful web service and need depth introduction on it before developing application please read this documentation: RESTful web service introduction

In this example, the method helloWorld(@Context UriInfo uriInfo) is annotated with @GET and the @Produces(“text/html”) annotation. This method will process HTTP GET requests and read all url parameter enter by the HTML client then content in HTML.

Below technology are needed to build application:

Eclipse Kepler
Java 1.6
Tomcat 7.0
JAX-RS 1.1
Jersey 1.8
Maven 3.0

Steps:

Create maven project name: FirstRESTfulHelloWorld (If you are not sure how to create maven project in eclipse please follow this tutorial: Create Maven project eclipse)
Configure Tomcat server in eclipse (If you are not sure please follow this tutorial: Configure Tomcat server in eclipse)
Now create package name: com.javahonk inside src/main/java folder
Create class name HelloWorld.java and copy paste below code:

package com.javahonk;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.core.UriInfo;

@Path("/user")
public class HelloWorld {

	 @GET
	 @Path("/helloWorld")
	 @Produces(MediaType.TEXT_HTML)
	 public String helloWorld(@Context UriInfo uriInfo) {

		MultivaluedMap<String, String> queryParams = uriInfo.getQueryParameters(); 
	    String name = queryParams.getFirst("name");
	    String age = queryParams.getFirst("age");
	    String country = queryParams.getFirst("country");
	    String zip = queryParams.getFirst("zip");

		return "<html> " + "<title>" + "Hello World!" + "</title>"+ "<h2><body>Below user added:</br></br>"+
		"Name:  "+name+" </br>"+
		"Age:  "+age+" </br>"+
		"Coutry:  "+country+"</br>"+
		"Zip:  "+zip+"</br></body></h2>" + "</html> ";

	}

}

Note: Option 2: Above we have used UriInfo to read request parameter. Use below overloaded method to read parameter if you don’t want to use UriInfo to read request:

         @GET
	 @Path("/helloWorld")
	 @Produces(MediaType.TEXT_HTML)
	 public String helloWorldReadParameterFromURL(@QueryParam("name") String name,@QueryParam("age") String age,@QueryParam("country") String country,
			 @QueryParam("zip") String zip,@Context UriInfo uriInfo) {

		return "<html> " + "<title>" + "Hello World!" + "</title>"+ "<h2><body>Below user added:</br></br>"+
		"Name:  "+name+" </br>"+
		"Age:  "+age+" </br>"+
		"Coutry:  "+country+"</br>"+
		"Zip:  "+zip+"</br></body></h2>" + "</html> ";

	}

Create index.jsp inside webapp and copy paste below code:

<html>
<title>RESTful Hello World!</title>
<head>

</head>

<body>
	<h2>Fill out form to add user</h2>

	<form id="userForm" action="rest/user/helloWorld" method="GET">
		<table>
			<tr>
				<td>Name :</td>
				<td><input type="text" name="name" id="name" /></td>
			</tr>
			<tr>
				<td>Age :</td>
				<td><input type="text" name="age" id="age" /></td>
			</tr>
			<tr>
				<td>Country :</td>
				<td><input type="text" name="country" id="country" /></td>
			</tr>
			<tr>
				<td>Zip :</td>
				<td><input type="text" name="zip" id="zip" class="numericOnly" />
				</td>
			</tr>
			<tr>
				<td><input type="submit" value="Add User" /></td>				
			</tr>
		</table>
	</form>

</body>
</html>

Copy paste below maven dependency jar into your pom.xml file:

<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.javahorn</groupId>
  <artifactId>RestFulService</artifactId>
  <packaging>war</packaging>
  <version>0.0.1-SNAPSHOT</version>
  <name>RestFulService Maven Webapp</name>
  <url>http://maven.apache.org</url>
  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>com.sun.jersey</groupId>
        <artifactId>jersey-server</artifactId>
        <version>1.8</version>
    </dependency>
    <dependency>
        <groupId>com.sun.jersey</groupId>
        <artifactId>jersey-json</artifactId>
        <version>1.8</version>
    </dependency>  
    <dependency>
	<groupId>com.sun.jersey</groupId>
	<artifactId>jersey-bundle</artifactId>
	<version>1.10-b01</version>
</dependency>  
  </dependencies>
  <build>
    <finalName>RestFulService</finalName>
  </build>
</project>

Now copy paste below code in your web.xml file:

<!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>First RESTful Hello World</display-name>
  <servlet>
		<servlet-name>rest-servlet</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.javahonk</param-value>
		</init-param>
		<init-param>
			<param-name>com.sun.jersey.api.json.POJOMappingFeature</param-name>
			<param-value>true</param-value>
		</init-param>
		<load-on-startup>1</load-on-startup>
	</servlet>

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

	<welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>

</web-app>

After all steps your project should look as below:

Now refresh and clean your project.
To run project: Right click project –> Run As –> Run on Server
You will see below first index.jsp page click Add User button:

Once you click Add User button you will see below user added page:

That’s it. We have created our RESTful web service with HTML client.

Download project: FirstRESTfulHelloWorld

Create RESTful web service with HTML client

Create RESTful web service with HTML client

By Techi Works

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