spring mvc异常吃掉的问题

本文主要是介绍spring mvc异常吃掉的问题，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

今天发现spring mvc把一个view参数匹配异常（org.springframework.web.bind.MissingServletRequestParameterException: Required String parameter 'tagSet' is not present）吃掉了：

 

1.通过debug发现Exception

 

2.异常被processHanderException方法处理，但直接返回Null，没有打印异常。

 

 

 

问题查找

通过debug发现是通过org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver.handleMissingServletRequestParameter()

处理的：

protected ModelAndView doResolveException(HttpServletRequest request, HttpServletResponse response,Object handler, Exception ex) {try {if (ex instanceof NoSuchRequestHandlingMethodException) {return handleNoSuchRequestHandlingMethod((NoSuchRequestHandlingMethodException) ex, request, response,handler);}else if (ex instanceof HttpRequestMethodNotSupportedException) {return handleHttpRequestMethodNotSupported((HttpRequestMethodNotSupportedException) ex, request,response, handler);}else if (ex instanceof HttpMediaTypeNotSupportedException) {return handleHttpMediaTypeNotSupported((HttpMediaTypeNotSupportedException) ex, request, response,handler);}else if (ex instanceof HttpMediaTypeNotAcceptableException) {return handleHttpMediaTypeNotAcceptable((HttpMediaTypeNotAcceptableException) ex, request, response,handler);}else if (ex instanceof MissingServletRequestParameterException) {return handleMissingServletRequestParameter((MissingServletRequestParameterException) ex, request,response, handler);}else if (ex instanceof ServletRequestBindingException) {return handleServletRequestBindingException((ServletRequestBindingException) ex, request, response,handler);}else if (ex instanceof ConversionNotSupportedException) {return handleConversionNotSupported((ConversionNotSupportedException) ex, request, response, handler);}else if (ex instanceof TypeMismatchException) {return handleTypeMismatch((TypeMismatchException) ex, request, response, handler);}else if (ex instanceof HttpMessageNotReadableException) {return handleHttpMessageNotReadable((HttpMessageNotReadableException) ex, request, response, handler);}else if (ex instanceof HttpMessageNotWritableException) {return handleHttpMessageNotWritable((HttpMessageNotWritableException) ex, request, response, handler);}else if (ex instanceof MethodArgumentNotValidException) {return handleMethodArgumentNotValidException((MethodArgumentNotValidException) ex, request, response, handler);}else if (ex instanceof MissingServletRequestPartException) {return handleMissingServletRequestPartException((MissingServletRequestPartException) ex, request, response, handler);}}catch (Exception handlerException) {logger.warn("Handling of [" + ex.getClass().getName() + "] resulted in Exception", handlerException);}return null;}

 

	protected ModelAndView handleMissingServletRequestParameter(MissingServletRequestParameterException ex,HttpServletRequest request, HttpServletResponse response, Object handler) throws IOException {response.sendError(HttpServletResponse.SC_BAD_REQUEST);return new ModelAndView();}

那么DefaultHandlerExceptionResolver怎么被初始化的？ 发现是在DispatcherServlet.initHandlerExceptionResolvers()负责初始化。

private void initHandlerExceptionResolvers(ApplicationContext context) {this.handlerExceptionResolvers = null;if (this.detectAllHandlerExceptionResolvers) {// Find all HandlerExceptionResolvers in the ApplicationContext, including ancestor contexts.Map<String, HandlerExceptionResolver> matchingBeans = BeanFactoryUtils.beansOfTypeIncludingAncestors(context, HandlerExceptionResolver.class, true, false);if (!matchingBeans.isEmpty()) {this.handlerExceptionResolvers = new ArrayList<HandlerExceptionResolver>(matchingBeans.values());// We keep HandlerExceptionResolvers in sorted order.OrderComparator.sort(this.handlerExceptionResolvers);}}else {try {HandlerExceptionResolver her =context.getBean(HANDLER_EXCEPTION_RESOLVER_BEAN_NAME, HandlerExceptionResolver.class);this.handlerExceptionResolvers = Collections.singletonList(her);}catch (NoSuchBeanDefinitionException ex) {// Ignore, no HandlerExceptionResolver is fine too.}}// Ensure we have at least some HandlerExceptionResolvers, by registering// default HandlerExceptionResolvers if no other resolvers are found.if (this.handlerExceptionResolvers == null) {this.handlerExceptionResolvers = getDefaultStrategies(context, HandlerExceptionResolver.class);if (logger.isDebugEnabled()) {logger.debug("No HandlerExceptionResolvers found in servlet '" + getServletName() + "': using default");}}}

 那么我们只需要实现一个继承于DefaultHandlerExceptionResolver的类，然后会被spring通过BeanFactoryUtils.beansOfTypeIncludingAncestors(context, HandlerExceptionResolver.class, true, false);加载

 

 

这篇关于spring mvc异常吃掉的问题的文章就介绍到这儿，希望我们推荐的文章对编程师们有所帮助！

---