Jersey Exception Handling

Jersey offers centralized Exception handling with "ExceptionMappers". This means you can allow Exceptions to be thrown up to the framework and then you can define how to handle them. It also means you are able to "catch" and handle exceptions that occur before and after the code that you write is being run.

 Let's say you want to handle "MyWebServiceException", you can create an ExceptionMapper "MyWebServiceExceptionMapper" like this:

@Provider public class MyWebServiceExceptionMapper implements ExceptionMapper<MyWebServiceException> { @Override public Response toResponse(Exception e) { GenericEntity<String> entity = new GenericEntity<String>(    “{\"statusCode\":\"ERR-100\",\"responseData\":\"Error Processing Web Service\"}” ){}; return Response.status(Status.OK).entity(entity).type(MediaType.APPLICATION_JSON).build(); } }

In order for this to be registered with Jersey, you'll need to put it in a package that's being scanned by Jersey to be resources or providers, so in the web.xml, have something like this:

<init-param>    <param-name>com.sun.jersey.config.property.packages</param-name>    <param-value>com.myws.resource;com.myws.provider</param-value> </init-param>

In this example, I separated the packages for resources and providers, providing 2 packages to be scanned.

To handle each exception differently, just create as many ExceptionMapper classes as you wish, and put them in the same package to be picked up and registered.

You can also use this to return a different HTTP status code for different errors, but as mentioned in the comments of an earlier POST, that's not going to work well with cross-domain Javascript REST requests.