How to Handle Exceptions in Jersey And Mule

This post describes how to handle exceptions in jersey component of mule .We can use ExceptionMappers for converting exception in jersey response . Here is the RestClass which throws a custom exception .

package com.test;
import java.io.File;
import javax.ws.rs.Consumes;
import javax.ws.rs.GET;
import javax.ws.rs.HeaderParam;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
@Path("/application")
public class RestClass {
   
  
  @GET
  @Path("/exception")
  @Produces(MediaType.TEXT_PLAIN)
  public Response exceptionTest() throws Exception{
   throw new MyException(401,"User is not Authorized");
  }
}

Exception Class .

package com.test;
public class MyException extends Exception 
{
 private int statusCode ;
 private String msg ;
 public MyException(int statusCode , String msg)
 {
  this.statusCode = statusCode ;
  this.msg = msg ;
 }
 public int getStatusCode()
 {
  return statusCode;
 }
 public void setStatusCode(int statusCode)
 {
  this.statusCode = statusCode;
 }
 public String getMsg()
 {
  return msg;
 }
 public void setMsg(String msg)
 {
  this.msg = msg;
 }
}

Here is the mapper class which will map our custom exception to JAX-RS response .

package com.test;
import javax.ws.rs.core.Response;
import javax.ws.rs.ext.ExceptionMapper;
public class JerseyExceptionMapper implements ExceptionMapper
{
 @Override
 public Response toResponse(MyException arg0)
 {
  System.out.println(arg0.getStatusCode());
  return Response.status(arg0.getStatusCode()).entity(arg0.getMsg()).build();
 }
}

Specify this exception mapper in jersey resource of mule flow .

<?xml version="1.0" encoding="UTF-8"?>
<mule xmlns:core="http://www.mulesoft.org/schema/mule/core" xmlns:json="http://www.mulesoft.org/schema/mule/json" xmlns:jersey="http://www.mulesoft.org/schema/mule/jersey" xmlns:vm="http://www.mulesoft.org/schema/mule/vm" xmlns:https="http://www.mulesoft.org/schema/mule/https" xmlns:http="http://www.mulesoft.org/schema/mule/http" xmlns:servlet="http://www.mulesoft.org/schema/mule/servlet" xmlns="http://www.mulesoft.org/schema/mule/core" xmlns:doc="http://www.mulesoft.org/schema/mule/documentation" xmlns:spring="http://www.springframework.org/schema/beans" version="CE-3.3.1" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="
http://www.mulesoft.org/schema/mule/http http://www.mulesoft.org/schema/mule/http/current/mule-http.xsd 
http://www.mulesoft.org/schema/mule/jersey http://www.mulesoft.org/schema/mule/jersey/current/mule-jersey.xsd 
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-current.xsd 
http://www.mulesoft.org/schema/mule/core http://www.mulesoft.org/schema/mule/core/current/mule.xsd 
http://www.mulesoft.org/schema/mule/json http://www.mulesoft.org/schema/mule/json/current/mule-json.xsd 
http://www.mulesoft.org/schema/mule/vm http://www.mulesoft.org/schema/mule/vm/current/mule-vm.xsd 
http://www.mulesoft.org/schema/mule/https http://www.mulesoft.org/schema/mule/https/current/mule-https.xsd 
http://www.mulesoft.org/schema/mule/servlet http://www.mulesoft.org/schema/mule/servlet/current/mule-servlet.xsd ">
   
    
 <flow name="servletTestFlow1" doc:name="servletTestFlow1">
        <http:inbound-endpoint exchange-pattern="request-response" host="localhost" port="8081" doc:name="HTTP"/>
        
        <jersey:resources doc:name="REST">
            <component class="com.test.RestClass" ></component>
            <jersey:exception-mapper class="com.test.JerseyExceptionMapper" />
        </jersey:resources>
        
    </flow>
    
</mule>