class RequestMappingHandlerAdapter extends AbstractHandlerMethodAdapter implements InitializingBean { public void afterPropertiesSet() { // 初始化被@ControllerAdvice标注的类 initControllerAdviceCache();{ List<ControllerAdviceBean> adviceBeans = ControllerAdviceBean.findAnnotatedBeans(getApplicationContext());{ // 保存添加了@ControllerAdvice注解的类信息 List<ControllerAdviceBean> adviceBeans = new ArrayList<>(); // 找到所有的beanName String[] beanNames = BeanFactoryUtils.beanNamesForTypeIncludingAncestors(beanFactory, Object.class); for (String name : beanNames) { // 判断是否是代理的Bean,添加了@Scoped的标识,添加了返回true if (!ScopedProxyUtils.isScopedTarget(name)) { // 找到Bean中带有@ControllerAdvice的类 ControllerAdvice controllerAdvice = beanFactory.findAnnotationOnBean(name, ControllerAdvice.class); if (controllerAdvice != null) { // 将这些信息包装成ControllerAdviceBean对象,避免后续再次找相同的Bean adviceBeans.add(new ControllerAdviceBean(name, beanFactory, controllerAdvice)); } } } // 对这些bean进行排序 OrderComparator.sort(adviceBeans); return adviceBeans; } List<Object> requestResponseBodyAdviceBeans = new ArrayList<>(); Class<?> beanType = adviceBean.getBeanType(); // 获取Bean中带有的ModelAttribute的注解,但不能有RequestMapping // public static final MethodFilter MODEL_ATTRIBUTE_METHODS = method -> { // !AnnotatedElementUtils.hasAnnotation(method, RequestMapping.class) && // AnnotatedElementUtils.hasAnnotation(method, ModelAttribute.class)); Set<Method> attrMethods = MethodIntrospector.selectMethods(beanType, MODEL_ATTRIBUTE_METHODS); if (!attrMethods.isEmpty()) { // 找到了就先缓存起来modelAttributeAdviceCache,防止之后再扫描 this.modelAttributeAdviceCache.put(adviceBean, attrMethods); } // 获取Bean中带有的InitBinder的注解 // public static final MethodFilter INIT_BINDER_METHODS = method -> // AnnotatedElementUtils.hasAnnotation(method, InitBinder.class); Set<Method> binderMethods = MethodIntrospector.selectMethods(beanType, INIT_BINDER_METHODS); if (!binderMethods.isEmpty()) { // 找到了就先缓存起来initBinderAdviceCache,防止之后再扫描 this.initBinderAdviceCache.put(adviceBean, binderMethods); } // 如果bean的类型是RequestBodyAdvice或者ResponseBodyAdvice if (RequestBodyAdvice.class.isAssignableFrom(beanType) || ResponseBodyAdvice.class.isAssignableFrom(beanType)) { // 保存到本地变量requestResponseBodyAdviceBeans中 requestResponseBodyAdviceBeans.add(adviceBean); } } // 如果找到了RequestBodyAdvice或者ResponseBodyAdvice if (!requestResponseBodyAdviceBeans.isEmpty()) { // 缓存起来,防止之后再扫描 this.requestResponseBodyAdvice.addAll(0, requestResponseBodyAdviceBeans); } } // 是否有参数解析器,如果没有设置 if (this.argumentResolvers == null) { // 获取默认的参数解析器 List<HandlerMethodArgumentResolver> resolvers = getDefaultArgumentResolvers();{ List<HandlerMethodArgumentResolver> resolvers = new ArrayList<>(30); // 解析注解参数的解析器 resolvers.add(new RequestParamMethodArgumentResolver(getBeanFactory(), false)); resolvers.add(new RequestParamMapMethodArgumentResolver()); resolvers.add(new PathVariableMethodArgumentResolver()); resolvers.add(new PathVariableMapMethodArgumentResolver()); resolvers.add(new MatrixVariableMethodArgumentResolver()); resolvers.add(new MatrixVariableMapMethodArgumentResolver()); resolvers.add(new ServletModelAttributeMethodProcessor(false)); resolvers.add(new RequestResponseBodyMethodProcessor(getMessageConverters(), this.requestResponseBodyAdvice)); resolvers.add(new RequestPartMethodArgumentResolver(getMessageConverters(), this.requestResponseBodyAdvice)); resolvers.add(new RequestHeaderMethodArgumentResolver(getBeanFactory())); resolvers.add(new RequestHeaderMapMethodArgumentResolver()); resolvers.add(new ServletCookieValueMethodArgumentResolver(getBeanFactory())); resolvers.add(new ExpressionValueMethodArgumentResolver(getBeanFactory())); resolvers.add(new SessionAttributeMethodArgumentResolver()); resolvers.add(new RequestAttributeMethodArgumentResolver()); // 解析特殊类型的解析器 resolvers.add(new ServletRequestMethodArgumentResolver()); resolvers.add(new ServletResponseMethodArgumentResolver()); resolvers.add(new HttpEntityMethodProcessor(getMessageConverters(), this.requestResponseBodyAdvice)); resolvers.add(new RedirectAttributesMethodArgumentResolver()); resolvers.add(new ModelMethodProcessor()); resolvers.add(new MapMethodProcessor()); resolvers.add(new ErrorsMethodArgumentResolver()); resolvers.add(new SessionStatusMethodArgumentResolver()); resolvers.add(new UriComponentsBuilderMethodArgumentResolver()); if (KotlinDetector.isKotlinPresent()) { resolvers.add(new ContinuationHandlerMethodArgumentResolver()); } // 自定义参数解析器 if (getCustomArgumentResolvers() != null) { resolvers.addAll(getCustomArgumentResolvers()); } // 剩下其他类型的参数解析器 resolvers.add(new PrincipalMethodArgumentResolver()); // 后面这个参数为true,是处理参数不包含RequestParam,但是又是基础类型的参数 // Enum.class CharSequence.class Number.class Date.class // Temporal.class URI.class URL.class Locale.class Class.class // 还有八大基本类型 resolvers.add(new RequestParamMethodArgumentResolver(getBeanFactory(), true)); resolvers.add(new ServletModelAttributeMethodProcessor(true)); return resolvers; } // 将所有的参数解析器保存到HandlerMethodArgumentResolverComposite类中,同时保存到argumentResolvers变量中 this.argumentResolvers = new HandlerMethodArgumentResolverComposite().addResolvers(resolvers); } // 判断是否有initBinder的参数解析器 if (this.initBinderArgumentResolvers == null) { // 获取默认的参数解析器,和 List<HandlerMethodArgumentResolver> resolvers = getDefaultInitBinderArgumentResolvers();{ List<HandlerMethodArgumentResolver> resolvers = new ArrayList<>(20); resolvers.add(new RequestParamMethodArgumentResolver(getBeanFactory(), false)); resolvers.add(new RequestParamMapMethodArgumentResolver()); resolvers.add(new PathVariableMethodArgumentResolver()); resolvers.add(new PathVariableMapMethodArgumentResolver()); resolvers.add(new MatrixVariableMethodArgumentResolver()); resolvers.add(new MatrixVariableMapMethodArgumentResolver()); resolvers.add(new ExpressionValueMethodArgumentResolver(getBeanFactory())); resolvers.add(new SessionAttributeMethodArgumentResolver()); resolvers.add(new RequestAttributeMethodArgumentResolver()); resolvers.add(new ServletRequestMethodArgumentResolver()); resolvers.add(new ServletResponseMethodArgumentResolver()); if (getCustomArgumentResolvers() != null) { resolvers.addAll(getCustomArgumentResolvers()); } resolvers.add(new PrincipalMethodArgumentResolver()); resolvers.add(new RequestParamMethodArgumentResolver(getBeanFactory(), true)); return resolvers; } // 将所有的参数解析器保存到HandlerMethodArgumentResolverComposite类中,同时保存到initBinderArgumentResolvers变量中 this.initBinderArgumentResolvers = new HandlerMethodArgumentResolverComposite().addResolvers(resolvers); } // 判断是否有返回值处理器 if (this.returnValueHandlers == null) { // 获取默认的返回值处理器 List<HandlerMethodReturnValueHandler> handlers = getDefaultReturnValueHandlers();{ List<HandlerMethodReturnValueHandler> handlers = new ArrayList<>(20); // 处理某个用途的返回值类型 handlers.add(new ModelAndViewMethodReturnValueHandler()); handlers.add(new ModelMethodProcessor()); handlers.add(new ViewMethodReturnValueHandler()); handlers.add(new ResponseBodyEmitterReturnValueHandler(getMessageConverters(), this.reactiveAdapterRegistry, this.taskExecutor, this.contentNegotiationManager)); handlers.add(new StreamingResponseBodyReturnValueHandler()); handlers.add(new HttpEntityMethodProcessor(getMessageConverters(), this.contentNegotiationManager, this.requestResponseBodyAdvice)); handlers.add(new HttpHeadersReturnValueHandler()); handlers.add(new CallableMethodReturnValueHandler()); handlers.add(new DeferredResultMethodReturnValueHandler()); handlers.add(new AsyncTaskMethodReturnValueHandler(this.beanFactory)); // 处理标注了注解的返回值处理器,例如@ModelAttribute,@ResponseBody handlers.add(new ServletModelAttributeMethodProcessor(false)); handlers.add(new RequestResponseBodyMethodProcessor(getMessageConverters(), this.contentNegotiationManager, this.requestResponseBodyAdvice)); // 处理多用途的返回值类型 handlers.add(new ViewNameMethodReturnValueHandler()); handlers.add(new MapMethodProcessor()); // 自定义的返回值处理器 if (getCustomReturnValueHandlers() != null) { handlers.addAll(getCustomReturnValueHandlers()); } // 处理剩下的返回值处理器 if (!CollectionUtils.isEmpty(getModelAndViewResolvers())) { handlers.add(new ModelAndViewResolverMethodReturnValueHandler(getModelAndViewResolvers())); }else{ handlers.add(new ServletModelAttributeMethodProcessor(true)); } return handlers; } // 将所有的参数解析器保存到HandlerMethodArgumentResolverComposite类中,同时保存到returnValueHandlers变量中 this.returnValueHandlers = new HandlerMethodReturnValueHandlerComposite().addHandlers(handlers); } }