如何在 Spring MVC 中捕获所有未处理的异常（即没有现有的 @ExceptionHandler）？

Question

I want to let HandlerExceptionResolver resolve any Exceptions that I don't explicit catch via @ExceptionHandler annotation.

Anyways, I want to apply specific logic on those exceptions. Eg send a mail notification or log additionally. I can achieve this by adding a @ExceptionHandler(Exception.class) catch as follows:

@RestControllerAdvice
public MyExceptionHandler {
    @ExceptionHandler(IOException.class)
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    public Object io(HttpServletRequest req, Exception e) {
        return ...
    }


    @ExceptionHandler(Exception.class)
    public Object exception(HttpServletRequest req, Exception e) {
        MailService.send();
        Logger.logInSpecificWay();

        //TODO how to continue in the "normal" spring way with HandlerExceptionResolver?
    }
}

Problem: if I add @ExceptionHandler(Exception.class) like that, I can catch those unhandled exceptions.

BUT I cannot let spring continue the normal workflow with HandlerExceptionResolver to create the response ModelAndView and set a HTTP STATUS code automatically.

Eg if someone tries a POST on a GET method, spring by default would return a 405 Method not allowed . But with an @ExceptionHandler(Exception.class) I would swallow this standard handling of spring...

So how can I keep the default HandlerExceptionResolver , but still apply my custom logic?

Answer 1

To provide a complete solution: it works just by extending ResponseEntityExceptionHandler , as that handles all the spring-mvc errors. And the ones not handled can then be caught using @ExceptionHandler(Exception.class) .

@RestControllerAdvice
public class MyExceptionHandler extends ResponseEntityExceptionHandler {
    @ExceptionHandler(Exception.class)
    public ResponseEntity<Object> exception(Exception ex) {
        MailService.send();
        Logger.logInSpecificWay();
        return ... custom exception 
    }
}

Answer 2

Well, I was facing the same problem some time back and have tried several ways like extending ResponseEntityExceptionHandler but all them were solving some problems but creating other ones.

Then I have decided to go with a custom solution which was also allowing me to send additional information and I have written below code

@RestControllerAdvice
public class MyExceptionHandler {

    private final Logger log = LoggerFactory.getLogger(this.getClass());

    @ExceptionHandler(NumberFormatException.class)
    public ResponseEntity<Object> handleNumberFormatException(NumberFormatException ex) {
        return new ResponseEntity<>(getBody(BAD_REQUEST, ex, "Please enter a valid value"), new HttpHeaders(), BAD_REQUEST);
    }

    @ExceptionHandler(IllegalArgumentException.class)
    public ResponseEntity<Object> handleIllegalArgumentException(IllegalArgumentException ex) {
        return new ResponseEntity<>(getBody(BAD_REQUEST, ex, ex.getMessage()), new HttpHeaders(), BAD_REQUEST);
    }

    @ExceptionHandler(AccessDeniedException.class)
    public ResponseEntity<Object> handleAccessDeniedException(AccessDeniedException ex) {
        return new ResponseEntity<>(getBody(FORBIDDEN, ex, ex.getMessage()), new HttpHeaders(), FORBIDDEN);
    }

    @ExceptionHandler(Exception.class)
    public ResponseEntity<Object> exception(Exception ex) {
        return new ResponseEntity<>(getBody(INTERNAL_SERVER_ERROR, ex, "Something Went Wrong"), new HttpHeaders(), INTERNAL_SERVER_ERROR);
    }

    public Map<String, Object> getBody(HttpStatus status, Exception ex, String message) {

        log.error(message, ex);

        Map<String, Object> body = new LinkedHashMap<>();
        body.put("message", message);
        body.put("timestamp", new Date());
        body.put("status", status.value());
        body.put("error", status.getReasonPhrase());
        body.put("exception", ex.toString());

        Throwable cause = ex.getCause();
        if (cause != null) {
            body.put("exceptionCause", ex.getCause().toString());
        }
        return body;
    }

}

Answer 3

Create classes for exception handling in this way

@RestControllerAdvice
public class MyExceptionHandler extends BaseExceptionHandler {

}

public class BaseExceptionHandler extends ResponseEntityExceptionHandler {

}

Here ResponseEntityExceptionHandler is provided by spring and override the several exception handler methods provided by it related to the requestMethodNotSupported,missingPathVariable,noHandlerFound,typeMismatch,asyncRequestTimeouts ....... with your own exception messages or error response objects and status codes

and have a method with @ExceptionHandler(Exception.class) in MyExceptionHandler where the thrown exception comes finally if it doesn't have a matching handler.

Answer 4

I had the same issue and solved it creating a implementation of the interface HandlerExceptionResolver and removing the generic @ExceptionHandler(Exception.class) from the generic handler method. .

It works this way:

Spring will try to handle the exception calling MyExceptionHandler first, but it will fail to find a handler because the annotation was removed from the generic handler. Next it will try other implementations of the interface HandlerExceptionResolver . It will enter this generic implementation that just delegates to the original generic error handler.

After that, I need to convert the ResponseEntity response to ModelAndView using MappingJackson2JsonView because this interface expects a ModelAndView as return type.

@Component
class GenericErrorHandler(
    private val errorHandler: MyExceptionHandler,
    private val objectMapper: ObjectMapper
) : HandlerExceptionResolver {

    override fun resolveException(request: HttpServletRequest, response: HttpServletResponse, handler: Any, ex: Exception): ModelAndView? {
        // handle exception
        val responseEntity = errorHandler.handleUnexpectedException(ex)

        // prepare JSON view
        val jsonView = MappingJackson2JsonView(objectMapper)
        jsonView.setExtractValueFromSingleKeyModel(true) // prevents creating the body key in the response json

        // prepare ModelAndView
        val mv = ModelAndView(jsonView, mapOf("body" to responseEntity.body))
        mv.status = responseEntity.statusCode
        mv.view = jsonView
        return mv
    }
}