Spring Boot @ExceptionHandler for Exception.class not invoking methods in ResponseEntityExceptionHan-CodePudding

I have already gone through official Spring Boot tutorial, a couple of Stack Overflow posts including this, tried @Ordered(Order=HIGHEST_PRECEDENCE) but any exception other than the ConstraintViolationException.class is being handled by DefaultHandlerExceptionResolver

VERSIONS

Spring Boot - 2.5.3
Spring - 5.3.9

PROBLEM

I want any exception in MyRestController be handled by handlers in ControllerAdvice defined by me so that I can manipulate the response object before sending to the client.

@Validated
@RestController
@RequestMapping(value = "/myctx", produces = MediaType.APPLICATION_JSON_VALUE)
public class MyRestController {

    private static final Logger logger = LoggerFactory.getLogger(MyRestController);

    @RequestMapping(
            path = "/{element}",
            method = RequestMethod.POST,
            consumes = MediaType.APPLICATION_JSON_VALUE,
            produces = MediaType.APPLICATION_JSON_VALUE)
    public ResponseEntity<ApiResponse> findAndSave(
            @Allowed(values = { "a1", "a2", "a3" }) @PathVariable String element,
            @ValidateMetadata @RequestBody Metadata metadata) {
                ...
                ...
    }
}

The annotations @Allowed and @ValidateMetadata defined by me are working as expected

@ControllerAdvice
//@Order(Ordered.HIGHEST_PRECEDENCE)
public class ErrorControllerAdvice extends ResponseEntityExceptionHandler {

    private static final Logger logger = LoggerFactory.getLogger(ErrorControllerAdvice.class);

    @ExceptionHandler({ ConstraintViolationException.class })
    public ResponseEntity<Object> handleConstraintViolationException(ConstraintViolationException ex, WebRequest request) {
        ApiResponse apiResponse = ApiResponse.builder()
                .timestamp(new Date())
                .status(HttpStatus.BAD_REQUEST)
                .message(ex.getLocalizedMessage())
                .path(((ServletWebRequest) request).getRequest().getRequestURI())
                //.metadata(metadata)
                .build();

        return handleExceptionInternal(ex, apiResponse, new HttpHeaders(), apiResponse.getStatus(), request);
    }

    @ExceptionHandler({ Exception.class })
    public ResponseEntity<Object> handleAll(Exception ex, WebRequest request) throws Exception {
        ResponseEntity<Object> tmpResponse = super.handleException(ex, request);
        ResponseEntity<Object> response = new ResponseEntity<>("Response from catch-all exception handler", tmpResponse.getHeaders(), tmpResponse.getStatusCode());

        return response;
    }
}

At this point when I test my endpoint with a POST request and inject a ContraintViolation, my custom error response is sent to the client. However, for any other Exception, handleAll() method in ErrorControllerAdvice is not even invoked. For example, from the test code, I try to send a GET instead of a POST or change the URI to contain myct instead of myctx

Why is it not working? Why do I get default error messages in case of the situations described above?

Update

I even tried throwing a NullPointerException from within the controller method but that also didn't invoke the handleAll() method.

CodePudding user response：

Your implementation is wrong, the handleException method will handle only those exceptions defined in the @ExceptionHandler annotation

@ExceptionHandler({
            HttpRequestMethodNotSupportedException.class,
            HttpMediaTypeNotSupportedException.class,
            HttpMediaTypeNotAcceptableException.class,
            MissingPathVariableException.class,
            MissingServletRequestParameterException.class,
            ServletRequestBindingException.class,
            ConversionNotSupportedException.class,
            TypeMismatchException.class,
            HttpMessageNotReadableException.class,
            HttpMessageNotWritableException.class,
            MethodArgumentNotValidException.class,
            MissingServletRequestPartException.class,
            BindException.class,
            NoHandlerFoundException.class,
            AsyncRequestTimeoutException.class
        })

so, these lines of code will always throw an exception.

try {
            tmpResponse = super.handleException(ex, request);
        } catch (Exception handlerEx) {
            logger.error(handlerEx.getMessage(), handlerEx);
        }

This idea is a mistake:

Since I am extending from ResourceEntityExceptionHandler, all the exceptions were being handled by handleException() method in that class.

CodePudding user response：

The ResponseEntityExceptionHandler handles a lot of exceptions so the handleAll will handle only the exceptions that are not included in ResponseEntityExceptionHandler, you can add a breakpoint in the handleException method inside ResponseEntityExceptionHandler to see if it is catching the exception. Another thing you can do is to throw a RuntimeException inside findAndSave and check if it is handle by handleAll

@ExceptionHandler({
            HttpRequestMethodNotSupportedException.class,
            HttpMediaTypeNotSupportedException.class,
            HttpMediaTypeNotAcceptableException.class,
            MissingPathVariableException.class,
            MissingServletRequestParameterException.class,
            ServletRequestBindingException.class,
            ConversionNotSupportedException.class,
            TypeMismatchException.class,
            HttpMessageNotReadableException.class,
            HttpMessageNotWritableException.class,
            MethodArgumentNotValidException.class,
            MissingServletRequestPartException.class,
            BindException.class,
            NoHandlerFoundException.class,
            AsyncRequestTimeoutException.class
        })

CodePudding user response：

I was able to solve it for myself. I minutely went over the details again that are posted here: Setting Precedence of Multiple @ControllerAdvice @ExceptionHandlers

This is how my @ControllerAdvice bean looks like now giving me that ability to stitch in a custom ApiResponse object for any exception that the Rest Controller throws.

@RestControllerAdvice
public class ErrorControllerAdvice extends ResponseEntityExceptionHandler {

    private static final Logger logger = LoggerFactory.getLogger(ErrorControllerAdvice.class);

    @ExceptionHandler({ ConstraintViolationException.class })
    public ResponseEntity<Object> handleConstraintViolationException(ConstraintViolationException ex, WebRequest request) {

        Metadata metadata = getRequestBody(request);

        ApiResponse apiResponse = new ApiResponse(); // details omitted

        return handleExceptionInternal(ex, apiResponse, new HttpHeaders(), apiResponse.getStatus(), request);
    }

    @ExceptionHandler({ Exception.class })
    public ResponseEntity<Object> handleAll(Exception ex, WebRequest request) {
        ResponseEntity<Object> tmpResponse = null;
        String message = null;

        try {
            tmpResponse = super.handleException(ex, request);
        } catch (Exception handlerEx) {
            logger.error(handlerEx.getMessage(), handlerEx);
        }

        HttpHeaders httpHeaders = tmpResponse == null ? new HttpHeaders() : tmpResponse.getHeaders();
        HttpStatus httpStatus = tmpResponse == null ? HttpStatus.INTERNAL_SERVER_ERROR : tmpResponse.getStatusCode();

        ApiResponse apiResponse = ApiResponse.builder()
                .timestamp(new Date())
                .status(httpStatus)
                .message(ex.getLocalizedMessage()) // ex and handlerEx will have same content because of line 98 in ResponseEntityExceptionHandler
                .path(((ServletWebRequest) request).getRequest().getRequestURI())
                .build();

        return new ResponseEntity<>(apiResponse, httpHeaders, httpStatus);
    }
}