SpringMVC异常处理之ResponseEntityExceptionHandler

ResponseEntityExceptionHandler中包装了各种SpringMVC在处理请求时可能抛出的异常的处理，处理结果都是封装成一个ResponseEntity对象。通过ResponseEntity我们可以指定需要响应的状态码、header和body等信息，响应的body会被HttpMessageConverter处理，所以如果你响应的body是一个对象，而你的HttpMessageConverter列表中有一个是可以把对象转换为JSON的HttpMessageConverter，那么客户端收到的就是一段JSON。ResponseEntityExceptionHandler是一个抽象类，通常我们需要定义一个用来处理异常的使用@ControllerAdvice注解标注的异常处理类来继承自ResponseEntityExceptionHandler。以下是ResponseEntityExceptionHandler的源码，从源码中我们可以看出它可以处理的异常，并为每个异常的处理都单独定义了一个方法，如果默认的处理不能满足你的需求，则可以重写对某个异常的处理。默认的实现最终都会调用handleExceptionInternal()方法，如果有通用的处理也可以从这里入手。

public abstract class ResponseEntityExceptionHandler {

	protected final Log logger = LogFactory.getLog(getClass());

	public static final String PAGE_NOT_FOUND_LOG_CATEGORY = "org.springframework.web.servlet.PageNotFound";

	protected static final Log pageNotFoundLogger = LogFactory.getLog(PAGE_NOT_FOUND_LOG_CATEGORY);

	@ExceptionHandler(value={
			NoSuchRequestHandlingMethodException.class,
			HttpRequestMethodNotSupportedException.class,
			HttpMediaTypeNotSupportedException.class,
			HttpMediaTypeNotAcceptableException.class,
			MissingServletRequestParameterException.class,
			ServletRequestBindingException.class,
			ConversionNotSupportedException.class,
			TypeMismatchException.class,
			HttpMessageNotReadableException.class,
			HttpMessageNotWritableException.class,
			MethodArgumentNotValidException.class,
			MissingServletRequestPartException.class,
			BindException.class,
			NoHandlerFoundException.class
		})
	public final ResponseEntity<Object> handleException(Exception ex, WebRequest request) {

		HttpHeaders headers = new HttpHeaders();

		if (ex instanceof NoSuchRequestHandlingMethodException) {
			HttpStatus status = HttpStatus.NOT_FOUND;
			return handleNoSuchRequestHandlingMethod((NoSuchRequestHandlingMethodException) ex, headers, status, request);
		}
		else if (ex instanceof HttpRequestMethodNotSupportedException) {
			HttpStatus status = HttpStatus.METHOD_NOT_ALLOWED;
			return handleHttpRequestMethodNotSupported((HttpRequestMethodNotSupportedException) ex, headers, status, request);
		}
		else if (ex instanceof HttpMediaTypeNotSupportedException) {
			HttpStatus status = HttpStatus.UNSUPPORTED_MEDIA_TYPE;
			return handleHttpMediaTypeNotSupported((HttpMediaTypeNotSupportedException) ex, headers, status, request);
		}
		else if (ex instanceof HttpMediaTypeNotAcceptableException) {
			HttpStatus status = HttpStatus.NOT_ACCEPTABLE;
			return handleHttpMediaTypeNotAcceptable((HttpMediaTypeNotAcceptableException) ex, headers, status, request);
		}
		else if (ex instanceof MissingServletRequestParameterException) {
			HttpStatus status = HttpStatus.BAD_REQUEST;
			return handleMissingServletRequestParameter((MissingServletRequestParameterException) ex, headers, status, request);
		}
		else if (ex instanceof ServletRequestBindingException) {
			HttpStatus status = HttpStatus.BAD_REQUEST;
			return handleServletRequestBindingException((ServletRequestBindingException) ex, headers, status, request);
		}
		else if (ex instanceof ConversionNotSupportedException) {
			HttpStatus status = HttpStatus.INTERNAL_SERVER_ERROR;
			return handleConversionNotSupported((ConversionNotSupportedException) ex, headers, status, request);
		}
		else if (ex instanceof TypeMismatchException) {
			HttpStatus status = HttpStatus.BAD_REQUEST;
			return handleTypeMismatch((TypeMismatchException) ex, headers, status, request);
		}
		else if (ex instanceof HttpMessageNotReadableException) {
			HttpStatus status = HttpStatus.BAD_REQUEST;
			return handleHttpMessageNotReadable((HttpMessageNotReadableException) ex, headers, status, request);
		}
		else if (ex instanceof HttpMessageNotWritableException) {
			HttpStatus status = HttpStatus.INTERNAL_SERVER_ERROR;
			return handleHttpMessageNotWritable((HttpMessageNotWritableException) ex, headers, status, request);
		}
		else if (ex instanceof MethodArgumentNotValidException) {
			HttpStatus status = HttpStatus.BAD_REQUEST;
			return handleMethodArgumentNotValid((MethodArgumentNotValidException) ex, headers, status, request);
		}
		else if (ex instanceof MissingServletRequestPartException) {
			HttpStatus status = HttpStatus.BAD_REQUEST;
			return handleMissingServletRequestPart((MissingServletRequestPartException) ex, headers, status, request);
		}
		else if (ex instanceof BindException) {
			HttpStatus status = HttpStatus.BAD_REQUEST;
			return handleBindException((BindException) ex, headers, status, request);
		}
		else if (ex instanceof NoHandlerFoundException) {
			HttpStatus status = HttpStatus.NOT_FOUND;
			return handleNoHandlerFoundException((NoHandlerFoundException) ex, headers, status, request);
		}
		else {
			logger.warn("Unknown exception type: " + ex.getClass().getName());
			HttpStatus status = HttpStatus.INTERNAL_SERVER_ERROR;
			return handleExceptionInternal(ex, null, headers, status, request);
		}
	}

	/**
	 * A single place to customize the response body of all Exception types.
	 * This method returns {@code null} by default.
	 * @param ex the exception
	 * @param body the body to use for the response
	 * @param headers the headers to be written to the response
	 * @param status the selected response status
	 * @param request the current request
	 */
	protected ResponseEntity<Object> handleExceptionInternal(Exception ex, Object body,
			HttpHeaders headers, HttpStatus status, WebRequest request) {

		if (HttpStatus.INTERNAL_SERVER_ERROR.equals(status)) {
			request.setAttribute("javax.servlet.error.exception", ex, WebRequest.SCOPE_REQUEST);
		}

		return new ResponseEntity<Object>(body, headers, status);
	}

	/**
	 * Customize the response for NoSuchRequestHandlingMethodException.
	 * This method logs a warning and delegates to
	 * {@link #handleExceptionInternal(Exception, Object, HttpHeaders, HttpStatus, WebRequest)}.
	 * @param ex the exception
	 * @param headers the headers to be written to the response
	 * @param status the selected response status
	 * @param request the current request
	 * @return a {@code ResponseEntity} instance
	 */
	protected ResponseEntity<Object> handleNoSuchRequestHandlingMethod(NoSuchRequestHandlingMethodException ex,
			HttpHeaders headers, HttpStatus status, WebRequest request) {

		pageNotFoundLogger.warn(ex.getMessage());

		return handleExceptionInternal(ex, null, headers, status, request);
	}

	/**
	 * Customize the response for HttpRequestMethodNotSupportedException.
	 * This method logs a warning, sets the "Allow" header, and delegates to
	 * {@link #handleExceptionInternal(Exception, Object, HttpHeaders, HttpStatus, WebRequest)}.
	 * @param ex the exception
	 * @param headers the headers to be written to the response
	 * @param status the selected response status
	 * @param request the current request
	 * @return a {@code ResponseEntity} instance
	 */
	protected ResponseEntity<Object> handleHttpRequestMethodNotSupported(HttpRequestMethodNotSupportedException ex,
			HttpHeaders headers, HttpStatus status, WebRequest request) {

		pageNotFoundLogger.warn(ex.getMessage());

		Set<HttpMethod> supportedMethods = ex.getSupportedHttpMethods();
		if (!supportedMethods.isEmpty()) {
			headers.setAllow(supportedMethods);
		}

		return handleExceptionInternal(ex, null, headers, status, request);
	}

	/**
	 * Customize the response for HttpMediaTypeNotSupportedException.
	 * This method sets the "Accept" header and delegates to
	 * {@link #handleExceptionInternal(Exception, Object, HttpHeaders, HttpStatus, WebRequest)}.
	 * @param ex the exception
	 * @param headers the headers to be written to the response
	 * @param status the selected response status
	 * @param request the current request
	 * @return a {@code ResponseEntity} instance
	 */
	protected ResponseEntity<Object> handleHttpMediaTypeNotSupported(HttpMediaTypeNotSupportedException ex,
			HttpHeaders headers, HttpStatus status, WebRequest request) {

		List<MediaType> mediaTypes = ex.getSupportedMediaTypes();
		if (!CollectionUtils.isEmpty(mediaTypes)) {
			headers.setAccept(mediaTypes);
		}

		return handleExceptionInternal(ex, null, headers, status, request);
	}

	/**
	 * Customize the response for HttpMediaTypeNotAcceptableException.
	 * This method delegates to {@link #handleExceptionInternal(Exception, Object, HttpHeaders, HttpStatus, WebRequest)}.
	 * @param ex the exception
	 * @param headers the headers to be written to the response
	 * @param status the selected response status
	 * @param request the current request
	 * @return a {@code ResponseEntity} instance
	 */
	protected ResponseEntity<Object> handleHttpMediaTypeNotAcceptable(HttpMediaTypeNotAcceptableException ex,
			HttpHeaders headers, HttpStatus status, WebRequest request) {

		return handleExceptionInternal(ex, null, headers, status, request);
	}

	/**
	 * Customize the response for MissingServletRequestParameterException.
	 * This method delegates to {@link #handleExceptionInternal(Exception, Object, HttpHeaders, HttpStatus, WebRequest)}.
	 * @param ex the exception
	 * @param headers the headers to be written to the response
	 * @param status the selected response status
	 * @param request the current request
	 * @return a {@code ResponseEntity} instance
	 */
	protected ResponseEntity<Object> handleMissingServletRequestParameter(MissingServletRequestParameterException ex,
			HttpHeaders headers, HttpStatus status, WebRequest request) {

		return handleExceptionInternal(ex, null, headers, status, request);
	}

	/**
	 * Customize the response for ServletRequestBindingException.
	 * This method delegates to {@link #handleExceptionInternal(Exception, Object, HttpHeaders, HttpStatus, WebRequest)}.
	 * @param ex the exception
	 * @param headers the headers to be written to the response
	 * @param status the selected response status
	 * @param request the current request
	 * @return a {@code ResponseEntity} instance
	 */
	protected ResponseEntity<Object> handleServletRequestBindingException(ServletRequestBindingException ex,
			HttpHeaders headers, HttpStatus status, WebRequest request) {

		return handleExceptionInternal(ex, null, headers, status, request);
	}

	/**
	 * Customize the response for ConversionNotSupportedException.
	 * This method delegates to {@link #handleExceptionInternal(Exception, Object, HttpHeaders, HttpStatus, WebRequest)}.
	 * @param ex the exception
	 * @param headers the headers to be written to the response
	 * @param status the selected response status
	 * @param request the current request
	 * @return a {@code ResponseEntity} instance
	 */
	protected ResponseEntity<Object> handleConversionNotSupported(ConversionNotSupportedException ex,
			HttpHeaders headers, HttpStatus status, WebRequest request) {

		return handleExceptionInternal(ex, null, headers, status, request);
	}

	/**
	 * Customize the response for TypeMismatchException.
	 * This method delegates to {@link #handleExceptionInternal(Exception, Object, HttpHeaders, HttpStatus, WebRequest)}.
	 * @param ex the exception
	 * @param headers the headers to be written to the response
	 * @param status the selected response status
	 * @param request the current request
	 * @return a {@code ResponseEntity} instance
	 */
	protected ResponseEntity<Object> handleTypeMismatch(TypeMismatchException ex, HttpHeaders headers,
			HttpStatus status, WebRequest request) {

		return handleExceptionInternal(ex, null, headers, status, request);
	}

	/**
	 * Customize the response for HttpMessageNotReadableException.
	 * This method delegates to {@link #handleExceptionInternal(Exception, Object, HttpHeaders, HttpStatus, WebRequest)}.
	 * @param ex the exception
	 * @param headers the headers to be written to the response
	 * @param status the selected response status
	 * @param request the current request
	 * @return a {@code ResponseEntity} instance
	 */
	protected ResponseEntity<Object> handleHttpMessageNotReadable(HttpMessageNotReadableException ex,
			HttpHeaders headers, HttpStatus status, WebRequest request) {

		return handleExceptionInternal(ex, null, headers, status, request);
	}

	/**
	 * Customize the response for HttpMessageNotWritableException.
	 * This method delegates to {@link #handleExceptionInternal(Exception, Object, HttpHeaders, HttpStatus, WebRequest)}.
	 * @param ex the exception
	 * @param headers the headers to be written to the response
	 * @param status the selected response status
	 * @param request the current request
	 * @return a {@code ResponseEntity} instance
	 */
	protected ResponseEntity<Object> handleHttpMessageNotWritable(HttpMessageNotWritableException ex,
			HttpHeaders headers, HttpStatus status, WebRequest request) {

		return handleExceptionInternal(ex, null, headers, status, request);
	}

	/**
	 * Customize the response for MethodArgumentNotValidException.
	 * This method delegates to {@link #handleExceptionInternal(Exception, Object, HttpHeaders, HttpStatus, WebRequest)}.
	 * @param ex the exception
	 * @param headers the headers to be written to the response
	 * @param status the selected response status
	 * @param request the current request
	 * @return a {@code ResponseEntity} instance
	 */
	protected ResponseEntity<Object> handleMethodArgumentNotValid(MethodArgumentNotValidException ex,
			HttpHeaders headers, HttpStatus status, WebRequest request) {

		return handleExceptionInternal(ex, null, headers, status, request);
	}

	/**
	 * Customize the response for MissingServletRequestPartException.
	 * This method delegates to {@link #handleExceptionInternal(Exception, Object, HttpHeaders, HttpStatus, WebRequest)}.
	 * @param ex the exception
	 * @param headers the headers to be written to the response
	 * @param status the selected response status
	 * @param request the current request
	 * @return a {@code ResponseEntity} instance
	 */
	protected ResponseEntity<Object> handleMissingServletRequestPart(MissingServletRequestPartException ex,
			HttpHeaders headers, HttpStatus status, WebRequest request) {

		return handleExceptionInternal(ex, null, headers, status, request);
	}

	/**
	 * Customize the response for BindException.
	 * This method delegates to {@link #handleExceptionInternal(Exception, Object, HttpHeaders, HttpStatus, WebRequest)}.
	 * @param ex the exception
	 * @param headers the headers to be written to the response
	 * @param status the selected response status
	 * @param request the current request
	 * @return a {@code ResponseEntity} instance
	 */
	protected ResponseEntity<Object> handleBindException(BindException ex, HttpHeaders headers,
			HttpStatus status, WebRequest request) {

		return handleExceptionInternal(ex, null, headers, status, request);
	}

	/**
	 * Customize the response for NoHandlerFoundException.
	 * This method delegates to {@link #handleExceptionInternal(Exception, Object, HttpHeaders, HttpStatus, WebRequest)}.
	 * @param ex the exception
	 * @param headers the headers to be written to the response
	 * @param status the selected response status
	 * @param request the current request
	 * @return a {@code ResponseEntity} instance
	 * @since 4.0
	 */
	protected ResponseEntity<Object> handleNoHandlerFoundException(NoHandlerFoundException ex, HttpHeaders headers,
	                                                     HttpStatus status, WebRequest request) {

		return handleExceptionInternal(ex, null, headers, status, request);
	}

}

比如下面实现中就重写了handleHttpRequestMethodNotSupported()方法。

@ControllerAdvice
public class MyResponseEntityExceptionHandler extends ResponseEntityExceptionHandler {

    @Override
    protected ResponseEntity<Object> handleHttpRequestMethodNotSupported(HttpRequestMethodNotSupportedException ex,
            HttpHeaders headers, HttpStatus status, WebRequest request) {
        String method = ex.getMethod();
        String[] supportedMethods = ex.getSupportedMethods();
        String body = "不支持的请求类型：" + method + "，支持的请求类型：" + Arrays.toString(supportedMethods);
        Map<String, Object> map = new HashMap<>();
        map.put("body", body);
        return super.handleExceptionInternal(ex, body, headers, status, request);
    }
    
}

（注：本文是基于Spring4.1.0所写）