JAX-RS jersey ExceptionMappers User-Defined Exception

Question

I am new to this, trying to achieve reading some docs but its not working, please bear with me.

I have created a UserNotFoundMapper using ExceptionMappers like this:

public class UserNotFoundMapper implements ExceptionMapper<UserNotFoundException> {

@Override
public Response toResponse(UserNotFoundException ex) {
    return Response.status(404).entity(ex.getMessage()).type("text/plain").build();
}

}

This in my service:

@GET
@Path("/user")
public Response getUser(@QueryParam("id") String id) throws UserNotFoundException{
    //Some user validation code with DB hit, if not found then
    throw new UserNotFoundException();
}

The UserNotFoundException is an User-Defined Exception.

I tried this:

public class UserNotFoundException extends Exception {
       //SOME block of code 
}

But when I invoke the service, the UserDefinedExceptionMapper is not getting invoked. It seems I might be missing something in the UserDefinedException. How to define this exception then?

Please let me know how to define the UserNotFoundException.

Answer 1

You need to annotate your exception mapper with @Provider, otherwise it will never get registered with the JAX-RS runtime.

@Provider
public class UserNotFoundMapper implements
        ExceptionMapper<UserNotFoundException> {
    @Override
    public Response toResponse(UserNotFoundException ex) {
        return Response.status(404).entity(ex.getMessage()).type("text/plain")
                .build();
    }
}