Create REST service using Apache Camel

This post has the working example of creating a REST service using Apache camel.

1) Add below maven dependencies in your pom.xml

pom.xml

<properties>
  <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
  <camelspring.version>2.16.0</camelspring.version>
  <spring.version>3.2.10.RELEASE</spring.version>
 </properties>

 <dependencies>
  <!-- Camel Dependencies -->
  <dependency>
   <groupId>org.apache.camel</groupId>
   <artifactId>camel-core</artifactId>
   <version>${camelspring.version}</version>
  </dependency>
  <dependency>
   <groupId>org.apache.camel</groupId>
   <artifactId>camel-cxf</artifactId>
   <version>${camelspring.version}</version>
  </dependency>
  <dependency>
   <groupId>org.apache.camel</groupId>
   <artifactId>camel-servlet</artifactId>
   <version>${camelspring.version}</version>
  </dependency>
  <!-- End of Camel Dependencies -->

  <!-- Spring Dependencies -->
  <dependency>
   <groupId>org.springframework</groupId>
   <artifactId>spring-core</artifactId>
   <version>${spring.version}</version>
  </dependency>
  <dependency>
   <groupId>org.springframework</groupId>
   <artifactId>spring-context</artifactId>
   <version>${spring.version}</version>
  </dependency>
  <dependency>
   <groupId>org.springframework</groupId>
   <artifactId>spring-context-support</artifactId>
   <version>${spring.version}</version>
  </dependency>
  <dependency>
   <groupId>org.springframework</groupId>
   <artifactId>spring-web</artifactId>
   <version>${spring.version}</version>
  </dependency>
  <dependency>
   <groupId>org.springframework</groupId>
   <artifactId>spring-beans</artifactId>
   <version>${spring.version}</version>
  </dependency>
  <!-- End of Spring dependencies -->

  <!-- Jackson dependencies -->
  <dependency>
   <groupId>org.codehaus.jackson</groupId>
   <artifactId>jackson-jaxrs</artifactId>
   <version>1.9.13</version>
  </dependency>
  <dependency>
   <groupId>org.codehaus.jackson</groupId>
   <artifactId>jackson-core-asl</artifactId>
   <version>1.9.13</version>
  </dependency>
 <dependencies/> 

2) Define CXFServlet and camel-context xml in your web.xml

web.xml

<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app 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>Apache Camel CXF Rest Web Application</display-name>
 <context-param>
  <param-name>contextConfigLocation</param-name>
  <param-value>classpath:camel-cxfrs-config.xml</param-value>
 </context-param>
  <servlet>
  <servlet-name>CXF Servlet</servlet-name>
  <servlet-class>org.apache.cxf.transport.servlet.CXFServlet</servlet-class>
 </servlet>
 <servlet-mapping>
  <servlet-name>CXF Servlet</servlet-name>
  <url-pattern>/*</url-pattern>
 </servlet-mapping>
 <listener>
  <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
 </listener>
</web-app> 

3) Define your camel-context xml

camel-cxfrs-config.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:cxf="http://camel.apache.org/schema/cxf"
       xmlns:jaxrs="http://cxf.apache.org/jaxrs"
       xsi:schemaLocation="
       http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://camel.apache.org/schema/cxf
       http://camel.apache.org/schema/cxf/camel-cxf.xsd
       http://cxf.apache.org/jaxrs
       http://cxf.apache.org/schemas/jaxrs.xsd
       http://camel.apache.org/schema/spring
       http://camel.apache.org/schema/spring/camel-spring.xsd
    ">

 <import resource="classpath:META-INF/cxf/cxf.xml" />
 <import resource="classpath:META-INF/cxf/cxf-servlet.xml" />

 <bean id="userServiceBean" class="com.poc.rest.UserServiceImpl" />

 <cxf:rsServer id="userSvcServer" address="/"
  loggingFeatureEnabled="true">
  <cxf:serviceBeans>
   <ref bean="userServiceBean" />
  </cxf:serviceBeans>
  <cxf:providers>
   <bean class="org.codehaus.jackson.jaxrs.JacksonJsonProvider" />
  </cxf:providers>
 </cxf:rsServer>

 <camelContext id="context" xmlns="http://camel.apache.org/schema/spring">
  <route>
   <from uri="cxfrs:bean:userSvcServer" />
   <log message="Processing CXF route....http method ${header.CamelHttpMethod}" />
   <log message="Processing CXF route....path is ${header.CamelHttpPath}" />
   <log message="Processing CXF route....body is ${body}" />
   <choice>
    <when>
     <simple>${header.operationName} == 'details'</simple>
     <to uri="direct:invokeDetails" />
    </when>
    <when>
     <simple>${header.operationName} == 'add'</simple>
     <to uri="direct:invokeAdd" />
    </when>
   </choice>
  </route>

  <route id="invokeDetails">
   <from uri="direct:invokeDetails" />
   <log message="Processing invokeDetails....Start ${body}" />
   <bean ref="userServiceBean" method="details" />
   <log message="Processing invokeDetails....End is ${body}" />
  </route>
  <route id="invokeAdd">
   <from uri="direct:invokeAdd" />
   <log message="Processing invokeAdd....Start is ${body}" />
   <bean ref="userServiceBean" method="add" />
   <log message="Processing invokeAdd....End is ${body}" />
  </route>
 </camelContext>
</beans>

4) Define your REST interface

Rest Interface using Jax-RS

package com.poc.rest;

import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;

import com.poc.rest.beans.AddReq;

@Path("/user")
public interface UserService {

 @GET
 @Path("/details/{id}")
 @Produces(MediaType.APPLICATION_JSON)
 public Response details(@PathParam("id") String id);

 @POST
 @Path("/add")
 @Produces(MediaType.APPLICATION_JSON)
 public Response add(AddReq input);

}

5) Implementation code

UserServiceImpl.java

package com.poc.rest;

import javax.ws.rs.core.Response;
import javax.ws.rs.core.Response.Status;

import com.poc.rest.beans.AddReq;
import com.poc.rest.beans.AddResp;
import com.poc.rest.beans.DetailsResp;

public class UserServiceImpl implements UserService {

 public Response details(String id) {
  
     System.out.println("UserServiceImpl Java details start");
  
     DetailsResp resp = new DetailsResp();
     resp.setId(id);
     resp.setName("kswaughs");
     resp.setStatus("Success");
  
     return Response.status(Status.OK).
                entity(resp).build();

 }

 public Response add(AddReq req) {
  
     System.out.println("UserServiceImpl Java add start");
  
     AddResp resp = new AddResp();
     resp.setId(req.getId());
     resp.setStatus("Success");
  
     return Response.status(Status.OK).
                entity(resp).build();
 }

}

6) Testing the service. Run the maven build and generated the war with name 'camel-rest' and deployed in Jboss 7 server.

  
 Test 1 : 
 operation : details
 method : GET
 URL : http://127.0.0.1:8080/camel-rest-0.0.1-SNAPSHOT/user/details/123
 Response :
 
  {
   "status": "Success",
   "id": "12345",
   "name": "kswaughs"
  }

Test 2 :
operation : add
method : POST
URL : http://127.0.0.1:8080/camel-rest-0.0.1-SNAPSHOT/user/add
Request
{ "id" : "12345" , "name":"kswaughs" }

Response
{
   "id": "12345",
   "status": "Success"
}