JAX-RS With Apache CXF ~ TECHIE KERNEL

Apache CXF helps you build and develop services using frontend programming APIs, like JAX-WS and JAX-RS. These services can speak a variety of protocols such as SOAP, XML/HTTP, RESTful HTTP, or CORBA and work over a variety of transports such as HTTP, JMS or JBI. In this tutorial, I will show you how to use Apache CXF to create a simple RESTful web service.

I am going to use the following tools and technologies.

Apache CXF 2.2.12
JDK 1.7
Tomcat 7.0
Maven
Eclipse

I am going to take you to the following areas in this tutorial.

Service Class and Mapping Configuration
BootStrap Implimentation
Front Controller Configuration
Application Deployment
Testing

Before start coding let's create a dynamic web project using the following maven command.

1	mvn archetype:generate -DgroupId=com.techiekernel.rest -DartifactId=JAXRS-CXF -DarchetypeArtifactId=maven-archetype-webapp -DinteractiveMode=false

After executing, the project will be get created with pom.xml file. As I am using JDK 7 and annotations, I have to specify the updated maven plugin. After giving the CXF dependency, the pom.xml looks as following.

<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.techiekernel.rest</groupId>
  <artifactId>JAXRS-CXF</artifactId>
  <packaging>war</packaging>
  <version>1.0-SNAPSHOT</version>
  <name>JAXRS-Jersey 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>org.apache.cxf</groupId>
      <artifactId>cxf-rt-frontend-jaxrs</artifactId>
      <version>2.2.12</version>
      <type>jar</type>
      <scope>compile</scope>
    </dependency>
  </dependencies>
  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-war-plugin</artifactId>
        <version>2.1.1</version>
      </plugin>
      <plugin>
        <artifactId>maven-compiler-plugin</artifactId>
        <configuration>
          <source>1.5</source>
          <target>1.5</target>
        </configuration>
      </plugin>
    </plugins>
    <finalName>JAXRS-CXF</finalName>
  </build>
</project>

Service Class and Mapping Configuration:

package com.techiekernel.rest;

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

@Path("/foobar")
public class FooBarService {
  @GET
  @Path("/{param}")
  public Response getMsg(@PathParam("param") String msg) {
 
    String output = "FooBar say : " + msg;
 
    return Response.status(200).entity(output).build();
 
  }
}

Front Controller Configuration:

As we are not using any framework like spring we have to write our own implimentation to make the service available. We are going to achieve this giving a implimentation to "javax.ws.rs.core.Application".

package com.techiekernel.rest;

import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

import javax.ws.rs.core.Application;
import javax.ws.rs.ext.Provider;

@Provider
public class CXFApplication extends Application {
  private Set<Object> singletons = new HashSet<Object>();
   
  public CXFApplication() {
    singletons.add(new FooBarService());
  }
 
  @Override
  public Set<Object> getSingletons() {
    return singletons;
  }

  @Override
  public Set<Class<?>> getClasses() {
    // TODO Auto-generated method stub
    return Collections.emptySet();
  }
}

Front Controller Configuration:

<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>JAXRS-CXF</display-name>
  <servlet>
    <servlet-name>CXFApplication</servlet-name>
    <display-name>CXFApplication</display-name>
    <servlet-class>
      org.apache.cxf.jaxrs.servlet.CXFNonSpringJaxrsServlet
    </servlet-class>
    <init-param>
      <param-name>javax.ws.rs.Application</param-name>
      <param-value>com.techiekernel.rest.CXFApplication</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
  </servlet>

  <servlet-mapping>
    <servlet-name>CXFApplication</servlet-name>
    <url-pattern>/ws/*</url-pattern>
  </servlet-mapping>
</web-app>

Application Deployment:

Now every thing is ready and time to build for creating a war file.

1	mvn clean install;

On successful completion of the above command a war file will be get created in target folder. Copy the war file to webapp folder of your tomcat and start the tomcat.

Testing:

Once tomcat is started use the following url to access the web service.

1	http://localhost:8080/JAXRS-CXF/ws/foobar/foobar

Output:

Once you hit the url in the browser, you are going to get the following output.

1	FooBar say : foobar

Source Code:

You can pull the code from GitHub.

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Sunday, December 9, 2012

JAX-RS With Apache CXF

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