SpringMVC异常处理之ResponseEntityExceptionHandler

迈不过友情╰ 2022-04-23 13:36 362阅读 0赞

# 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）