1.RequestMappingHandlerMapping
1.继承了InitializingBean 加载所有的 Controller.class 和 RequestMapping.class
2. WebMvcAutoConfiguration 初始化时加载interception
3.根据url 获取在RequestMappingHandlerMapping获取handlerMethod，并包装成HandlerExecutionChain，并将RequestMappingHandlerMapping中的intercepters加入到 HandlerExecutionChain
加入规则如下
protected HandlerExecutionChain getHandlerExecutionChain(Object handler, HttpServletRequest request) { HandlerExecutionChain chain = (handler instanceof HandlerExecutionChain ? (HandlerExecutionChain) handler : new HandlerExecutionChain(handler)); String lookupPath = this.urlPathHelper.getLookupPathForRequest(request); for (HandlerInterceptor interceptor : this.adaptedInterceptors) { if (interceptor instanceof MappedInterceptor) { MappedInterceptor mappedInterceptor = (MappedInterceptor) interceptor; if (mappedInterceptor.matches(lookupPath, this.pathMatcher)) { chain.addInterceptor(mappedInterceptor.getInterceptor()); } } else { chain.addInterceptor(interceptor); } } return chain; }
4.使用 handlerMethod 获取handlerAdapter
4.1 RequestMappingHandlerAdapter (初始化时，初始化adviceCache,和参数解析器)
@Override public void afterPropertiesSet() { // Do this first, it may add ResponseBody advice beans initControllerAdviceCache(); if (this.argumentResolvers == null) { List<HandlerMethodArgumentResolver> resolvers = getDefaultArgumentResolvers(); this.argumentResolvers = new HandlerMethodArgumentResolverComposite().addResolvers(resolvers); } if (this.initBinderArgumentResolvers == null) { List<HandlerMethodArgumentResolver> resolvers = getDefaultInitBinderArgumentResolvers(); this.initBinderArgumentResolvers = new HandlerMethodArgumentResolverComposite().addResolvers(resolvers); } if (this.returnValueHandlers == null) { List<HandlerMethodReturnValueHandler> handlers = getDefaultReturnValueHandlers(); this.returnValueHandlers = new HandlerMethodReturnValueHandlerComposite().addHandlers(handlers); } } private void initControllerAdviceCache() { if (getApplicationContext() == null) { return; } List<ControllerAdviceBean> adviceBeans = ControllerAdviceBean.findAnnotatedBeans(getApplicationContext()); AnnotationAwareOrderComparator.sort(adviceBeans); List<Object> requestResponseBodyAdviceBeans = new ArrayList<>(); for (ControllerAdviceBean adviceBean : adviceBeans) { Class<?> beanType = adviceBean.getBeanType(); if (beanType == null) { throw new IllegalStateException("Unresolvable type for ControllerAdviceBean: " + adviceBean); } Set<Method> attrMethods = MethodIntrospector.selectMethods(beanType, MODEL_ATTRIBUTE_METHODS); if (!attrMethods.isEmpty()) { this.modelAttributeAdviceCache.put(adviceBean, attrMethods); } Set<Method> binderMethods = MethodIntrospector.selectMethods(beanType, INIT_BINDER_METHODS); if (!binderMethods.isEmpty()) { this.initBinderAdviceCache.put(adviceBean, binderMethods); } if (RequestBodyAdvice.class.isAssignableFrom(beanType) || ResponseBodyAdvice.class.isAssignableFrom(beanType)) { requestResponseBodyAdviceBeans.add(adviceBean); } } if (!requestResponseBodyAdviceBeans.isEmpty()) { this.requestResponseBodyAdvice.addAll(0, requestResponseBodyAdviceBeans); } if (logger.isDebugEnabled()) { int modelSize = this.modelAttributeAdviceCache.size(); int binderSize = this.initBinderAdviceCache.size(); int reqCount = getBodyAdviceCount(RequestBodyAdvice.class); int resCount = getBodyAdviceCount(ResponseBodyAdvice.class); if (modelSize == 0 && binderSize == 0 && reqCount == 0 && resCount == 0) { logger.debug("ControllerAdvice beans: none"); } else { logger.debug("ControllerAdvice beans: " + modelSize + " @ModelAttribute, " + binderSize + " @InitBinder, " + reqCount + " RequestBodyAdvice, " + resCount + " ResponseBodyAdvice"); } } }
5.使用handlerAdapter handler方法获取ModerAndView
mv = ha.handle(processedRequest, response, mappedHandler.getHandler());
6.
在当前类和ControllerAdvice 中 获取 有InitBinder.class注解的方法全部封装在一起。（InitBinder用法https://blog.csdn.net/qq_38016931/article/details/82080940）
在当前类和ControllerAdvice 中 获取 有ModelAttribute且没有RequestMapping 的注解的方法，全部封装在一起。（ModelAttribute用法https://blog.csdn.net/abc997995674/article/details/80464023）
7.将注解有ModelAttribute的方法，初始化后绑定到sessionAttributes;
8. resolvers解析参数
例：RequestResponseBodyMethodProcessor
8.1 1.使用 binder和 messageConverters 转化 json或xml，或其他的为对象。
8.2 valid 校验参数
9.参数解析正常 则调用代理对象
9.1使用代理对象的拦截器拦截方法，或初始化一些对象
9.2具体的方法调用
10.参数解析异常抛出异常
10.1
0 = {DefaultErrorAttributes@15395}
1 = {HandlerExceptionResolverComposite@12775}
10.2 HandlerExceptionResolverComposite里又含有三个异常
0 = {ExceptionHandlerExceptionResolver@15442} --使用 @ExceptionHandler 解决异常 有些这里抛出的异常会导致 发起/error
1 = {ResponseStatusExceptionResolver@15443} --解决@ResponseStatus或instanceof ResponseStatusException
2 = {DefaultHandlerExceptionResolver@12774} 针对于一些异常，重新发起（/error）请求
@Override @Nullable 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：博客园
作者：阳光11
链接：https://www.cnblogs.com/z-test/p/11550743.html