Error message in URL using Spring REST

Question

I am developing a project using Spring REST web services, where I need to show graceful error messages when an exception/error occurs. I followed this tutorial (http://www.javacodegeeks.com/2013/02/exception-handling-for-rest-with-spring-3-2.html) for exception handling using SpringREST. I get the proper output when there is no exception/error i.e. in form of an XML. The issue arises when an exception occurs. Here is part of the code base where an exception occurs if I do not pass the testId in

localhost:8080/test?testId=

The class outputs a response in form of a XML, so when an exception occurs, instead of showing the error message as figure 1 below, it shows error message as figure 2. If I do "View Page Source", I get the correct exception message (as figure 1). But I need the exception message directly. Could anyone, please suggest a solution?

 @RequestMapping(value = "/test",
       method = RequestMethod.GET,
       produces = "application/xml")
 public @ResponseBody String testResource(
        @RequestParam(value="testId", required=true) String testId)
                throws CustomRestException{

    if (testId == null || testId.equals(""))
    {
        LOG.error( "testResource(): " + TestUtilsException.NULL_TEST_ID_ERROR_MSG );
                    //The error message is: The test Id is required and cannot be null or empty
        throw new CustomRestException(TestUtilsException.NULL_TEST_ID_ERROR_MSG);
    }
}

Figure 1 Figure 2

Other helper classes:

@ControllerAdvice
public class RestResponseEntityExceptionHandler extends ResponseEntityExceptionHandler {

    public RestResponseEntityExceptionHandler() {
       super();
    }

    @ExceptionHandler(value = { CustomRestException.class })
    @ResponseBody
    protected ResponseEntity<Object> handleNotFound(final RuntimeException ex, final WebRequest  request) {
         final String bodyOfResponse = ex.getMessage();
         return handleExceptionInternal(ex, bodyOfResponse, new HttpHeaders(),   HttpStatus.INTERNAL_SERVER_ERROR, request);
     }
}

 public class CustomRestException extends RuntimeException {

    public CustomRestException() {
        super();
    }
    public CustomRestException(final String message, final Throwable cause) {
        super(message, cause);
    }
    public CustomRestException(final String message) {
        super(message);
    }
    public CustomRestException(final Throwable cause) {
        super(cause);
    }
}

Answer 1

The @ControllerAdvice approach should work, although I don't think there's any need for the base class - you can just use @ExceptionHandler with Spring 4. But you are returning a response body that cannot be converted to Xml (it's a plain String), so you are getting an empty response and probably a 405 instead of a 500. If you want an Xml response you have to provide a body that can be converted (or else provide an HttpMessageConverter that can do it).

Answer 2

Consider doing this.

public class BaseController{

    @ExceptionHandler(value = { CustomRestException.class })
    protected @ResponseBody ResponseEntity<ErrorResponse > handleNotFound(final RuntimeException ex, final WebRequest  request) {
        System.out.println("is executed in handler");
         final String bodyOfResponse = ex.getMessage();
         return new ResponseEntity<ErrorResponse >(new ErrorResponse (bodyOfResponse), null, HttpStatus.NOT_FOUND);
     }
}

In your controller do this.

@Controller
public class HomeController extends BaseController {//Your code here} 

And create this class.

@XmlRootElement
public class ErrorResponse {

    public String error;
}

Finally add to your class the following code

if (testId == null || testId.equals(""))
                {
                    throw new CustomRestException("DD");
                }

That will create an XML response as follows.

This XML file does not appear to have any style information associated with it. The document tree is shown below.

<successResponse> <error>DD</error> </successResponse>

This will handle all the exception an is not needed to add @ControllerAdvice, that seems need to add their own MessageConverters that is why the answer is not converted to XML, I read that here.

I added ,produces = "application/xml" and remove it, and is still working as I think you want. Please let me know if this was useful.