Using Spring 3, I like to create an exception handler using the ExceptionHandler annotation that will handle \"no page found (404)\" requests.
@ExceptionHandler
-annotated methods are invoked when a @RequestMapping
method on that same class throws an exception. So when you added the mapping which threw the NullPointerException
, that worked, since the mapped method and exception handler were together in the same class.
When no mapping is found, Spring has no way of associating the NoSuchRequestHandlingMethodException
with your @ExceptionHandler
, because it didn't get as far as matching the request to a handler method. This isn't mentioned explicitly in the docs, but is the behaviour I've observed.
If you want to handle this exception specially, you're going to have to use the more general HandlerExceptionResolver approach, rather than the more specialised @ExceptionHandler
technique.
In Spring 3.2 you can use @ContollerAdvice to have an ExceptionHandler for all your Controllers like this:
@ControllerAdvice
public class GeneralHandler {
@ExceptionHandler
public ModelAndView handleException (NoSuchRequestHandlingMethodException ex) {
ModelAndView mav = new ModelAndView();
...
return mav;
}
}
You can even add more annotations to return serialized json
@ExceptionHandler
@ResponseBody
@ResponseStatus(HttpStatus.BAD_REQUEST)
public RestError resolveBindingException ( MethodArgumentNotValidException methodArgumentNotValidException, Locale locale )
{
BindingResult bindingResult = methodArgumentNotValidException.getBindingResult();
return getRestError(bindingResult, locale);
}
You could go with this approach, it is great idea and works, necessity to throw exceptions only withing particular Handler makes @ExceptionHandler not so useful as it looks.