29.springmvc源码学习（二十九）异常解析器HandlerExceptionResolver
29.springmvc源码学习（二十九）异常解析器HandlerExceptionResolver
目录
前言
HandlerExceptionResolver用于处理在请求处理过程中抛出的异常。
一、HandlerExceptionResolver的初始化
1、在WebMvcConfigurationSupport中定义了@Bean HandlerExceptionResolver
@Bean
public HandlerExceptionResolver handlerExceptionResolver(
@Qualifier("mvcContentNegotiationManager") ContentNegotiationManager contentNegotiationManager) {
List<HandlerExceptionResolver> exceptionResolvers = new ArrayList<>();
//自定义异常解析器
configureHandlerExceptionResolvers(exceptionResolvers);
if (exceptionResolvers.isEmpty()) {
//没有自定义，使用默认的异常解析器
addDefaultHandlerExceptionResolvers(exceptionResolvers, contentNegotiationManager);
}
extendHandlerExceptionResolvers(exceptionResolvers);
HandlerExceptionResolverComposite composite = new HandlerExceptionResolverComposite();
composite.setOrder(0);
composite.setExceptionResolvers(exceptionResolvers);
return composite;
}2、configureHandlerExceptionResolvers( )
获取自定义异常解析器，可以通过自定义实现WebMvcConfigurer接口，重写configureHandlerExceptionResolvers方法
DelegatingWebMvcConfiguration.java
@Override
protected void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> exceptionResolvers) {
this.configurers.configureHandlerExceptionResolvers(exceptionResolvers);
}WebMvcConfigurerComposite.java
@Override
public void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> exceptionResolvers) {
for (WebMvcConfigurer delegate : this.delegates) {
delegate.configureHandlerExceptionResolvers(exceptionResolvers);
}
}3、addDefaultHandlerExceptionResolvers( )
默认的异常解析器，包含 ExceptionHandlerExceptionResolver、ResponseStatusExceptionResolver和DefaultHandlerExceptionResolver
protected final void addDefaultHandlerExceptionResolvers(List<HandlerExceptionResolver> exceptionResolvers,
ContentNegotiationManager mvcContentNegotiationManager) {
//创建 ExceptionHandlerExceptionResolver
ExceptionHandlerExceptionResolver exceptionHandlerResolver = createExceptionHandlerExceptionResolver();
//处理请求的media types
exceptionHandlerResolver.setContentNegotiationManager(mvcContentNegotiationManager);
//设置消息转换器MessageConverters
exceptionHandlerResolver.setMessageConverters(getMessageConverters());
//设置自定义参数解析器ArgumentResolvers()
exceptionHandlerResolver.setCustomArgumentResolvers(getArgumentResolvers());
//设置自定义返回值处理器ReturnValueHandlers()
exceptionHandlerResolver.setCustomReturnValueHandlers(getReturnValueHandlers());
//@JsonView相关
if (jackson2Present) {
exceptionHandlerResolver.setResponseBodyAdvice(
Collections.singletonList(new JsonViewResponseBodyAdvice()));
}
if (this.applicationContext != null) {
exceptionHandlerResolver.setApplicationContext(this.applicationContext);
}
//初始化
exceptionHandlerResolver.afterPropertiesSet();
//添加 ExceptionHandlerExceptionResolver
exceptionResolvers.add(exceptionHandlerResolver);
ResponseStatusExceptionResolver responseStatusResolver = new ResponseStatusExceptionResolver();
responseStatusResolver.setMessageSource(this.applicationContext);
//添加 ResponseStatusExceptionResolver
exceptionResolvers.add(responseStatusResolver);
//添加 DefaultHandlerExceptionResolver
exceptionResolvers.add(new DefaultHandlerExceptionResolver());
}4、 afterPropertiesSet( )
初始化
@Override
public void afterPropertiesSet() {
// Do this first, it may add ResponseBodyAdvice beans
//初始化 @ControllerAdvice 的 bean
initExceptionHandlerAdviceCache();
if (this.argumentResolvers == null) {
//获取 默认的参数解析器 DefaultArgumentResolvers
List<HandlerMethodArgumentResolver> resolvers = getDefaultArgumentResolvers();
this.argumentResolvers = new HandlerMethodArgumentResolverComposite().addResolvers(resolvers);
}
if (this.returnValueHandlers == null) {
//获取 默认的返回值处理器 DefaultReturnValueHandlers
List<HandlerMethodReturnValueHandler> handlers = getDefaultReturnValueHandlers();
this.returnValueHandlers = new HandlerMethodReturnValueHandlerComposite().addHandlers(handlers);
}
}5、initExceptionHandlerAdviceCache( )
初始化 @ControllerAdvice
private void initExceptionHandlerAdviceCache() {
if (getApplicationContext() == null) {
return;
}
//查找出 @ControllerAdvice
List<ControllerAdviceBean> adviceBeans = ControllerAdviceBean.findAnnotatedBeans(getApplicationContext());
for (ControllerAdviceBean adviceBean : adviceBeans) {
Class<?> beanType = adviceBean.getBeanType();
if (beanType == null) {
throw new IllegalStateException("Unresolvable type for ControllerAdviceBean: " + adviceBean);
}
//解析 @ExceptionHandler 方法
ExceptionHandlerMethodResolver resolver = new ExceptionHandlerMethodResolver(beanType);
if (resolver.hasExceptionMappings()) {
//存入 exceptionHandlerAdviceCache
this.exceptionHandlerAdviceCache.put(adviceBean, resolver);
}
if (ResponseBodyAdvice.class.isAssignableFrom(beanType)) {
this.responseBodyAdvice.add(adviceBean);
}
}
if (logger.isDebugEnabled()) {
int handlerSize = this.exceptionHandlerAdviceCache.size();
int adviceSize = this.responseBodyAdvice.size();
if (handlerSize == 0 && adviceSize == 0) {
logger.debug("ControllerAdvice beans: none");
}
else {
logger.debug("ControllerAdvice beans: " +
handlerSize + " @ExceptionHandler, " + adviceSize + " ResponseBodyAdvice");
}
}
}6、ControllerAdviceBean.findAnnotatedBeans( )
public static List<ControllerAdviceBean> findAnnotatedBeans(ApplicationContext context) {
ListableBeanFactory beanFactory = context;
if (context instanceof ConfigurableApplicationContext) {
// Use internal BeanFactory for potential downcast to ConfigurableBeanFactory above
beanFactory = ((ConfigurableApplicationContext) context).getBeanFactory();
}
List<ControllerAdviceBean> adviceBeans = new ArrayList<>();
for (String name : BeanFactoryUtils.beanNamesForTypeIncludingAncestors(beanFactory, Object.class)) {
if (!ScopedProxyUtils.isScopedTarget(name)) {
//查找 @ControllerAdvice
ControllerAdvice controllerAdvice = beanFactory.findAnnotationOnBean(name, ControllerAdvice.class);
if (controllerAdvice != null) {
// Use the @ControllerAdvice annotation found by findAnnotationOnBean()
// in order to avoid a subsequent lookup of the same annotation.
adviceBeans.add(new ControllerAdviceBean(name, beanFactory, controllerAdvice));
}
}
}
//根据order排序
OrderComparator.sort(adviceBeans);
return adviceBeans;
}7、ExceptionHandlerMethodResolver
解析@ExceptionHandler
public static final MethodFilter EXCEPTION_HANDLER_METHODS = method ->
AnnotatedElementUtils.hasAnnotation(method, ExceptionHandler.class);public ExceptionHandlerMethodResolver(Class<?> handlerType) {
//查找含有@ExceptionHandler注解的方法
for (Method method : MethodIntrospector.selectMethods(handlerType, EXCEPTION_HANDLER_METHODS)) {
//获取方法上的异常信息
for (Class<? extends Throwable> exceptionType : detectExceptionMappings(method)) {
//将异常和对应方法存入缓存
addExceptionMapping(exceptionType, method);
}
}
}8、回到第4步
获取默认参数解析器 getDefaultArgumentResolvers()
protected List<HandlerMethodArgumentResolver> getDefaultArgumentResolvers() {
List<HandlerMethodArgumentResolver> resolvers = new ArrayList<>();
// Annotation-based argument resolution
resolvers.add(new SessionAttributeMethodArgumentResolver());
resolvers.add(new RequestAttributeMethodArgumentResolver());
// Type-based argument resolution
resolvers.add(new ServletRequestMethodArgumentResolver());
resolvers.add(new ServletResponseMethodArgumentResolver());
resolvers.add(new RedirectAttributesMethodArgumentResolver());
resolvers.add(new ModelMethodProcessor());
// Custom arguments
//合并了自定义的参数解析器
if (getCustomArgumentResolvers() != null) {
resolvers.addAll(getCustomArgumentResolvers());
}
// Catch-all
resolvers.add(new PrincipalMethodArgumentResolver());
return resolvers;
}获取默认的返回值处理器 getDefaultReturnValueHandlers()
protected List<HandlerMethodReturnValueHandler> getDefaultReturnValueHandlers() {
List<HandlerMethodReturnValueHandler> handlers = new ArrayList<>();
// Single-purpose return value types
handlers.add(new ModelAndViewMethodReturnValueHandler());
handlers.add(new ModelMethodProcessor());
handlers.add(new ViewMethodReturnValueHandler());
handlers.add(new HttpEntityMethodProcessor(
getMessageConverters(), this.contentNegotiationManager, this.responseBodyAdvice));
// Annotation-based return value types
handlers.add(new ServletModelAttributeMethodProcessor(false));
handlers.add(new RequestResponseBodyMethodProcessor(
getMessageConverters(), this.contentNegotiationManager, this.responseBodyAdvice));
// Multi-purpose return value types
handlers.add(new ViewNameMethodReturnValueHandler());
handlers.add(new MapMethodProcessor());
// Custom return value types
//合并了自定义的返回值处理器
if (getCustomReturnValueHandlers() != null) {
handlers.addAll(getCustomReturnValueHandlers());
}
// Catch-all
handlers.add(new ServletModelAttributeMethodProcessor(true));
return handlers;
}9、回到第1步中，afterPropertiesSet()执行结束
extendHandlerExceptionResolvers( )，扩展异常解析器
@Override
protected void extendHandlerExceptionResolvers(List<HandlerExceptionResolver> exceptionResolvers) {
//调用 WebMvcConfigurer 子类的 extendHandlerExceptionResolvers 方法
super.extendHandlerExceptionResolvers(exceptionResolvers);
if (this.mvcProperties.isLogResolvedException()) {
for (HandlerExceptionResolver resolver : exceptionResolvers) {
if (resolver instanceof AbstractHandlerExceptionResolver) {
((AbstractHandlerExceptionResolver) resolver).setWarnLogCategory(resolver.getClass().getName());
}
}
}
}最终生成 HandlerExceptionResolver 的实现类 HandlerExceptionResolverComposite对象。
二、异常的处理流程
从请求进入DispatcherServlet的doDispatch方法之后开始分析
1、doDispatch( )
try {
...
}
catch (Exception ex) {
dispatchException = ex;
}
catch (Throwable err) {
// As of 4.3, we're processing Errors thrown from handler methods as well,
// making them available for @ExceptionHandler methods and other scenarios.
dispatchException = new NestedServletException("Handler dispatch failed", err);
}
processDispatchResult(processedRequest, response, mappedHandler, mv, dispatchException);2、processDispatchResult( )
private void processDispatchResult(HttpServletRequest request, HttpServletResponse response,
@Nullable HandlerExecutionChain mappedHandler, @Nullable ModelAndView mv,
@Nullable Exception exception) throws Exception {
boolean errorView = false;
//存在异常信息
if (exception != null) {
if (exception instanceof ModelAndViewDefiningException) {
logger.debug("ModelAndViewDefiningException encountered", exception);
mv = ((ModelAndViewDefiningException) exception).getModelAndView();
}
else {
Object handler = (mappedHandler != null ? mappedHandler.getHandler() : null);
//处理异常
mv = processHandlerException(request, response, handler, exception);
errorView = (mv != null);
}
}
...3、processHandlerException( )
protected ModelAndView processHandlerException(HttpServletRequest request, HttpServletResponse response,
@Nullable Object handler, Exception ex) throws Exception {
// Success and error responses may use different content types
request.removeAttribute(HandlerMapping.PRODUCIBLE_MEDIA_TYPES_ATTRIBUTE);
// Check registered HandlerExceptionResolvers...
ModelAndView exMv = null;
if (this.handlerExceptionResolvers != null) {
for (HandlerExceptionResolver resolver : this.handlerExceptionResolvers) {
//解析异常
exMv = resolver.resolveException(request, response, handler, ex);
if (exMv != null) {
break;
}
}
}
if (exMv != null) {
if (exMv.isEmpty()) {
//如果model、view是空，设置异常属性，返回null
request.setAttribute(EXCEPTION_ATTRIBUTE, ex);
return null;
}
// We might still need view name translation for a plain error model...
if (!exMv.hasView()) {
String defaultViewName = getDefaultViewName(request);
if (defaultViewName != null) {
exMv.setViewName(defaultViewName);
}
}
if (logger.isTraceEnabled()) {
logger.trace("Using resolved error view: " + exMv, ex);
}
else if (logger.isDebugEnabled()) {
logger.debug("Using resolved error view: " + exMv);
}
WebUtils.exposeErrorRequestAttributes(request, ex, getServletName());
return exMv;
}4、resolveException( )
HandlerExceptionResolverComposite.java
public ModelAndView resolveException(
HttpServletRequest request, HttpServletResponse response, @Nullable Object handler, Exception ex) {
if (this.resolvers != null) {
for (HandlerExceptionResolver handlerExceptionResolver : this.resolvers) {
//解析异常，resolvers 包括 ExceptionHandlerExceptionResolver、ResponseStatusExceptionResolver 和 DefaultHandlerExceptionResolver
ModelAndView mav = handlerExceptionResolver.resolveException(request, response, handler, ex);
if (mav != null) {
return mav;
}
}
}
return null;
}5、ExceptionHandlerExceptionResolver 解析异常的步骤
核心逻辑 ： 解析出能处理异常的@ControllerAdvice中的方法，并请求该方法
（1）resolveException( )
AbstractHandlerExceptionResolver.java
public ModelAndView resolveException(
HttpServletRequest request, HttpServletResponse response, @Nullable Object handler, Exception ex) {
if (shouldApplyTo(request, handler)) {
prepareResponse(ex, response);
//解析异常，返回 ModelAndView
ModelAndView result = doResolveException(request, response, handler, ex);
if (result != null) {
// Print debug message when warn logger is not enabled.
if (logger.isDebugEnabled() && (this.warnLogger == null || !this.warnLogger.isWarnEnabled())) {
logger.debug("Resolved [" + ex + "]" + (result.isEmpty() ? "" : " to " + result));
}
// Explicitly configured warn logger in logException method.
logException(ex, request);
}
return result;
}
else {
return null;
}
}（2）doResolveException( )
protected final ModelAndView doResolveException(
HttpServletRequest request, HttpServletResponse response, @Nullable Object handler, Exception ex) {
HandlerMethod handlerMethod = (handler instanceof HandlerMethod ? (HandlerMethod) handler : null);
//解析异常
return doResolveHandlerMethodException(request, response, handlerMethod, ex);
}（3）doResolveHandlerMethodException( )
protected ModelAndView doResolveHandlerMethodException(HttpServletRequest request,
HttpServletResponse response, @Nullable HandlerMethod handlerMethod, Exception exception) {
//找到能处理该异常的方法
ServletInvocableHandlerMethod exceptionHandlerMethod = getExceptionHandlerMethod(handlerMethod, exception);
if (exceptionHandlerMethod == null) {
return null;
}
if (this.argumentResolvers != null) {
//设置参数解析器
exceptionHandlerMethod.setHandlerMethodArgumentResolvers(this.argumentResolvers);
}
if (this.returnValueHandlers != null) {
//设置返回值处理器
exceptionHandlerMethod.setHandlerMethodReturnValueHandlers(this.returnValueHandlers);
}
//创建新的 ServletWebRequest
ServletWebRequest webRequest = new ServletWebRequest(request, response);
ModelAndViewContainer mavContainer = new ModelAndViewContainer();
ArrayList<Throwable> exceptions = new ArrayList<>();
try {
if (logger.isDebugEnabled()) {
logger.debug("Using @ExceptionHandler " + exceptionHandlerMethod);
}
// Expose causes as provided arguments as well
Throwable exToExpose = exception;
while (exToExpose != null) {
exceptions.add(exToExpose);
Throwable cause = exToExpose.getCause();
exToExpose = (cause != exToExpose ? cause : null);
}
//方法参数
Object[] arguments = new Object[exceptions.size() + 1];
exceptions.toArray(arguments); // efficient arraycopy call in ArrayList
arguments[arguments.length - 1] = handlerMethod;
//调用异常处理方法，如@ControllerAdvice中的某个处理该异常的方法
exceptionHandlerMethod.invokeAndHandle(webRequest, mavContainer, arguments);
}
catch (Throwable invocationEx) {
// Any other than the original exception (or a cause) is unintended here,
// probably an accident (e.g. failed assertion or the like).
if (!exceptions.contains(invocationEx) && logger.isWarnEnabled()) {
logger.warn("Failure in @ExceptionHandler " + exceptionHandlerMethod, invocationEx);
}
// Continue with default processing of the original exception...
return null;
}
//返回 ModelAndView
if (mavContainer.isRequestHandled()) {
return new ModelAndView();
}
else {
ModelMap model = mavContainer.getModel();
HttpStatus status = mavContainer.getStatus();
ModelAndView mav = new ModelAndView(mavContainer.getViewName(), model, status);
mav.setViewName(mavContainer.getViewName());
if (!mavContainer.isViewReference()) {
mav.setView((View) mavContainer.getView());
}
if (model instanceof RedirectAttributes) {
Map<String, ?> flashAttributes = ((RedirectAttributes) model).getFlashAttributes();
RequestContextUtils.getOutputFlashMap(request).putAll(flashAttributes);
}
return mav;
}
}（4）getExceptionHandlerMethod( )
@Nullable
protected ServletInvocableHandlerMethod getExceptionHandlerMethod(
@Nullable HandlerMethod handlerMethod, Exception exception) {
Class<?> handlerType = null;
if (handlerMethod != null) {
// Local exception handler methods on the controller class itself.
// To be invoked through the proxy, even in case of an interface-based proxy.
handlerType = handlerMethod.getBeanType();
ExceptionHandlerMethodResolver resolver = this.exceptionHandlerCache.get(handlerType);
if (resolver == null) {
resolver = new ExceptionHandlerMethodResolver(handlerType);
this.exceptionHandlerCache.put(handlerType, resolver);
}
Method method = resolver.resolveMethod(exception);
if (method != null) {
return new ServletInvocableHandlerMethod(handlerMethod.getBean(), method, this.applicationContext);
}
// For advice applicability check below (involving base packages, assignable types
// and annotation presence), use target class instead of interface-based proxy.
if (Proxy.isProxyClass(handlerType)) {
handlerType = AopUtils.getTargetClass(handlerMethod.getBean());
}
}
//找到@ControllerAdvice 中能处理该异常的方法，封装成 ServletInvocableHandlerMethod
for (Map.Entry<ControllerAdviceBean, ExceptionHandlerMethodResolver> entry : this.exceptionHandlerAdviceCache.entrySet()) {
ControllerAdviceBean advice = entry.getKey();
if (advice.isApplicableToBeanType(handlerType)) {
ExceptionHandlerMethodResolver resolver = entry.getValue();
Method method = resolver.resolveMethod(exception);
if (method != null) {
return new ServletInvocableHandlerMethod(advice.resolveBean(), method, this.applicationContext);
}
}
}
return null;
}（5）resolver.resolveMethod( )
解析出能处理该异常的方法
public Method resolveMethod(Exception exception) {
return resolveMethodByThrowable(exception);
}public Method resolveMethodByThrowable(Throwable exception) {
//根据 exception.getClass() 查找
Method method = resolveMethodByExceptionType(exception.getClass());
if (method == null) {
Throwable cause = exception.getCause();
if (cause != null) {
//找不到时，根据 exception.getCause() 递归查找
method = resolveMethodByThrowable(cause);
}
}
return method;
}public Method resolveMethodByExceptionType(Class<? extends Throwable> exceptionType) {
//先从缓存获取
Method method = this.exceptionLookupCache.get(exceptionType);
if (method == null) {
method = getMappedMethod(exceptionType);
this.exceptionLookupCache.put(exceptionType, method);
}
return (method != NO_MATCHING_EXCEPTION_HANDLER_METHOD ? method : null);
}private Method getMappedMethod(Class<? extends Throwable> exceptionType) {
List<Class<? extends Throwable>> matches = new ArrayList<>();
for (Class<? extends Throwable> mappedException : this.mappedMethods.keySet()) {
//找到能处理该异常的类型或父类
if (mappedException.isAssignableFrom(exceptionType)) {
matches.add(mappedException);
}
}
if (!matches.isEmpty()) {
if (matches.size() > 1) {
//多个时进行排序
matches.sort(new ExceptionDepthComparator(exceptionType));
}
//返回第一个
return this.mappedMethods.get(matches.get(0));
}
else {
return NO_MATCHING_EXCEPTION_HANDLER_METHOD;
}
}6、ResponseStatusExceptionResolver 解析异常的核心步骤
（1）doResolveException( )
ResponseStatusExceptionResolver.java
protected ModelAndView doResolveException(
HttpServletRequest request, HttpServletResponse response, @Nullable Object handler, Exception ex) {
try {
//异常是否是 ResponseStatusException 异常
if (ex instanceof ResponseStatusException) {
return resolveResponseStatusException((ResponseStatusException) ex, request, response, handler);
}
//异常类上是否有 @ResponseStatus 注解
ResponseStatus status = AnnotatedElementUtils.findMergedAnnotation(ex.getClass(), ResponseStatus.class);
if (status != null) {
return resolveResponseStatus(status, request, response, handler, ex);
}
//递归解析异常的 cause
if (ex.getCause() instanceof Exception) {
return doResolveException(request, response, handler, (Exception) ex.getCause());
}
}
catch (Exception resolveEx) {
if (logger.isWarnEnabled()) {
logger.warn("Failure while trying to resolve exception [" + ex.getClass().getName() + "]", resolveEx);
}
}
return null;
}（2）resolveResponseStatusException( )
protected ModelAndView resolveResponseStatusException(ResponseStatusException ex,
HttpServletRequest request, HttpServletResponse response, @Nullable Object handler) throws Exception {
//响应头的设置
ex.getResponseHeaders().forEach((name, values) ->
values.forEach(value -> response.addHeader(name, value)));
//Status 和 Reason 的设置
return applyStatusAndReason(ex.getRawStatusCode(), ex.getReason(), response);
}7、DefaultHandlerExceptionResolver 解析异常的核心步骤
根据异常的具体类型做出相应的处理
protected ModelAndView doResolveException(
HttpServletRequest request, HttpServletResponse response, @Nullable Object handler, Exception ex) {
try {
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 MissingPathVariableException) {
return handleMissingPathVariable(
(MissingPathVariableException) 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);
}
else if (ex instanceof BindException) {
return handleBindException((BindException) ex, request, response, handler);
}
else if (ex instanceof NoHandlerFoundException) {
return handleNoHandlerFoundException(
(NoHandlerFoundException) ex, request, response, handler);
}
else if (ex instanceof AsyncRequestTimeoutException) {
return handleAsyncRequestTimeoutException(
(AsyncRequestTimeoutException) ex, request, response, handler);
}
}
catch (Exception handlerEx) {
if (logger.isWarnEnabled()) {
logger.warn("Failure while trying to resolve exception [" + ex.getClass().getName() + "]", handlerEx);
}
}
return null;
}来源：https://blog.csdn.net/RenshenLi/article/details/122251911