The document discusses how to use jersey:exception-mapper in Mule to map Jersey exceptions to HTTP response codes. It shows an example Mule flow that exposes a REST API and uses a jersey:exception-mapper component to return a custom 404 message with HTTP status code 400 if a resource is not found. Testing a wrong URL demonstrates returning the custom message and status code.

1. By Anirban Sen Chowdhary

3. .

4. Here I will show you how ……

5. Let us consider we have a following Mule flow :-
As you can we have exposed a REST web service in our
application. Now if we test this web service it will fetch some
records from Database and display in browser

6. As you can see that we have hit the url
http://localhost:8082/getData/retrieve/?id=1 on browser and
getting the desired result on it

7. Now, let’s use jersey:exception-mapper in our Mule flow to map the
jersey based exception that allow mapping generic exceptions that may
be thrown in the component class to HTTP response codes like the
following :-
<flow name="MainService" doc:name="MainService">
<http:inbound-endpoint exchange-pattern="request-response" host="localhost"
port="8082" doc:name="HTTP"/>
<logger message="RequestLog :- #[message.payloadAs(java.lang.String)]" level="INFO"
doc:name="RequestLogger"/>
<jersey:resources doc:name="REST">
<component class="com.testservices.schema.maindata.v1.Impl.MainDataImpl"/>
<jersey:exception-mapper class="com.test.custom.response.NotFound" />
</jersey:resources>
<logger message="ResponseLog :- #[message.payloadAs(java.lang.String)]"
level="INFO" doc:name="ResponseLogger"/>
</flow>

8. That’s it…. Now our jersey:exception-mapper java class NotFound :-
public class NotFound implements
ExceptionMapper<NotFoundException> {
public Response toResponse(NotFoundException exception){
return Response.status(Response.Status.BAD_REQUEST).entity("No
Resources available at :- : " +
exception.getNotFoundUri().toString()).build();
}
}
You can see that we can also customize the http code and can generate
our custom message. Now generally if a resource is not found the http
code will be 404. But we can customize the http code even this
jersey:exception-mapper and we have put here http code 400

9. Now you can see that if we pass any wrong url it is displaying our custom
message that we have written in our Java :-

10. Also you can see that we have successfully customized and changed the
http status code to 400 :-

11. Hope you enjoyed the simple yet an amazing trick in Mule