SpringMVC源码阅读HandlerAdapter初始化-RequestMappingHandlerAdapter(七)
接口
public interface HandlerAdapter { /** * 是否能处理指定Handler * @param var1 * @return */ boolean supports(Object var1); /** * 处理Handler * @param var1 * @param var2 * @param var3 * @return * @throws Exception */ @Nullable ModelAndView handle(HttpServletRequest var1, HttpServletResponse var2, Object var3) throws Exception; /** * 获取资源最后一次更新时间 * @param var1 * @param var2 * @return */ long getLastModified(HttpServletRequest var1, Object var2); }
类图
我们注解方式 都是走RequestMappingHandlerAdapter
RequestMappingHandlerAdapter
afterPropertiesSet
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter#afterPropertiesSet
public void afterPropertiesSet() { //<1>对打上了@ControllerAdvice的注解进行加载 this.initControllerAdviceCache(); List handlers; if (this.argumentResolvers == null) { //<2>初始化参数绑定器 handlers = this.getDefaultArgumentResolvers(); this.argumentResolvers = (new HandlerMethodArgumentResolverComposite()).addResolvers(handlers); } if (this.initBinderArgumentResolvers == null) { //<3>暂时不造干嘛 handlers = this.getDefaultInitBinderArgumentResolvers(); this.initBinderArgumentResolvers = (new HandlerMethodArgumentResolverComposite()).addResolvers(handlers); } if (this.returnValueHandlers == null) { //<4>初始化响应值处理器 handlers = this.getDefaultReturnValueHandlers(); this.returnValueHandlers = (new HandlerMethodReturnValueHandlerComposite()).addHandlers(handlers); } }
RequestMappingHandlerAdapter
<1>initControllerAdviceCache
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter#afterPropertiesSet
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org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter#initControllerAdviceCache
private void initControllerAdviceCache() { //判断spring容器是否为空 正常都不会为空 if (this.getApplicationContext() != null) { /** * 扫描如有bean返回打上了@ControllerAdvice的Controlle 封装成ControllerAdviceBean返回 * @ControllerAdvice可以做全局异常 全局绑定处理 具体百度搜关键字 */ List<ControllerAdviceBean> adviceBeans = ControllerAdviceBean.findAnnotatedBeans(this.getApplicationContext()); /** * 如果根据@Order注解排序 */ AnnotationAwareOrderComparator.sort(adviceBeans); List<Object> requestResponseBodyAdviceBeans = new ArrayList(); Iterator var3 = adviceBeans.iterator(); while(var3.hasNext()) { ControllerAdviceBean adviceBean = (ControllerAdviceBean)var3.next(); Class<?> beanType = adviceBean.getBeanType(); if (beanType == null) { throw new IllegalStateException("Unresolvable type for ControllerAdviceBean: " + adviceBean); } /** * 找到所有打上了@ModelAttribute的方法 并加入到modelAttributeAdviceCache * 执行所有方法之前都会先执行打上了@ModelAttribute的方法 * 具体使用方法可以百度关键字 * */ Set<Method> attrMethods = MethodIntrospector.selectMethods(beanType, MODEL_ATTRIBUTE_METHODS); if (!attrMethods.isEmpty()) { this.modelAttributeAdviceCache.put(adviceBean, attrMethods); } /** * 找到所有打上了了@InitBind方法 * 执行参数绑定之前都会先调用@IinitBind 进行自定义绑定器绑定 * 具体使用可以百度关键字 */ Set<Method> binderMethods = MethodIntrospector.selectMethods(beanType, INIT_BINDER_METHODS); if (!binderMethods.isEmpty()) { this.initBinderAdviceCache.put(adviceBean, binderMethods); } /** * 是否是实现了RequestBodyAdvice接口 * 可以统一返回结果之前做自定义处理 比如加响应公参 比如 我业务中需求，增加在响应统一加上traceId */ if (RequestBodyAdvice.class.isAssignableFrom(beanType)) { requestResponseBodyAdviceBeans.add(adviceBean); } if (ResponseBodyAdvice.class.isAssignableFrom(beanType)) { requestResponseBodyAdviceBeans.add(adviceBean); } } /** * 将requestResponseBodyAdviceBeans 加入到requestResponseBodyAdvice */ if (!requestResponseBodyAdviceBeans.isEmpty()) { this.requestResponseBodyAdvice.addAll(0, requestResponseBodyAdviceBeans); } if (this.logger.isDebugEnabled()) { int modelSize = this.modelAttributeAdviceCache.size(); int binderSize = this.initBinderAdviceCache.size(); int reqCount = this.getBodyAdviceCount(RequestBodyAdvice.class); int resCount = this.getBodyAdviceCount(ResponseBodyAdvice.class); if (modelSize == 0 && binderSize == 0 && reqCount == 0 && resCount == 0) { this.logger.debug("ControllerAdvice beans: none"); } else { this.logger.debug("ControllerAdvice beans: " + modelSize + " @ModelAttribute, " + binderSize + " @InitBinder, " + reqCount + " RequestBodyAdvice, " + resCount + ", ResponseBodyAdvice"); } } } }
<2>getDefaultArgumentResolvers
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter#afterPropertiesSet
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org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter#getDefaultArgumentResolvers
private List<HandlerMethodArgumentResolver> getDefaultArgumentResolvers() { List<HandlerMethodArgumentResolver> resolvers = new ArrayList(); resolvers.add(new RequestParamMethodArgumentResolver(this.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(this.getMessageConverters(), this.requestResponseBodyAdvice)); resolvers.add(new RequestPartMethodArgumentResolver(this.getMessageConverters(), this.requestResponseBodyAdvice)); resolvers.add(new RequestHeaderMethodArgumentResolver(this.getBeanFactory())); resolvers.add(new RequestHeaderMapMethodArgumentResolver()); resolvers.add(new ServletCookieValueMethodArgumentResolver(this.getBeanFactory())); resolvers.add(new ExpressionValueMethodArgumentResolver(this.getBeanFactory())); resolvers.add(new SessionAttributeMethodArgumentResolver()); resolvers.add(new RequestAttributeMethodArgumentResolver()); resolvers.add(new ServletRequestMethodArgumentResolver()); resolvers.add(new ServletResponseMethodArgumentResolver()); resolvers.add(new HttpEntityMethodProcessor(this.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()); //我们自定义的转换器 可以通过构造函数初始化到到这里面 if (this.getCustomArgumentResolvers() != null) { resolvers.addAll(this.getCustomArgumentResolvers()); } resolvers.add(new RequestParamMethodArgumentResolver(this.getBeanFactory(), true)); resolvers.add(new ServletModelAttributeMethodProcessor(true)); return resolvers; }
<3>getDefaultInitBinderArgumentResolvers
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter#afterPropertiesSet
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org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter#getDefaultInitBinderArgumentResolvers
private List<HandlerMethodArgumentResolver> getDefaultInitBinderArgumentResolvers() { List<HandlerMethodArgumentResolver> resolvers = new ArrayList(); resolvers.add(new RequestParamMethodArgumentResolver(this.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(this.getBeanFactory())); resolvers.add(new SessionAttributeMethodArgumentResolver()); resolvers.add(new RequestAttributeMethodArgumentResolver()); resolvers.add(new ServletRequestMethodArgumentResolver()); resolvers.add(new ServletResponseMethodArgumentResolver()); //加入我们自定义的绑定器 if (this.getCustomArgumentResolvers() != null) { resolvers.addAll(this.getCustomArgumentResolvers()); } resolvers.add(new RequestParamMethodArgumentResolver(this.getBeanFactory(), true)); return resolvers; }
<4>getDefaultReturnValueHandlers
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter#afterPropertiesSet
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org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter#getDefaultReturnValueHandlers
private List<HandlerMethodReturnValueHandler> getDefaultReturnValueHandlers() { List<HandlerMethodReturnValueHandler> handlers = new ArrayList(); handlers.add(new ModelAndViewMethodReturnValueHandler()); handlers.add(new ModelMethodProcessor()); handlers.add(new ViewMethodReturnValueHandler()); handlers.add(new ResponseBodyEmitterReturnValueHandler(this.getMessageConverters(), this.reactiveAdapterRegistry, this.taskExecutor, this.contentNegotiationManager)); handlers.add(new StreamingResponseBodyReturnValueHandler()); handlers.add(new HttpEntityMethodProcessor(this.getMessageConverters(), this.contentNegotiationManager, this.requestResponseBodyAdvice)); handlers.add(new HttpHeadersReturnValueHandler()); handlers.add(new CallableMethodReturnValueHandler()); handlers.add(new DeferredResultMethodReturnValueHandler()); handlers.add(new AsyncTaskMethodReturnValueHandler(this.beanFactory)); handlers.add(new ModelAttributeMethodProcessor(false)); handlers.add(new RequestResponseBodyMethodProcessor(this.getMessageConverters(), this.contentNegotiationManager, this.requestResponseBodyAdvice)); handlers.add(new ViewNameMethodReturnValueHandler()); handlers.add(new MapMethodProcessor());
if (this.getCustomReturnValueHandlers() != null) { handlers.addAll(this.getCustomReturnValueHandlers()); } if (!CollectionUtils.isEmpty(this.getModelAndViewResolvers())) { handlers.add(new ModelAndViewResolverMethodReturnValueHandler(this.getModelAndViewResolvers())); } else { handlers.add(new ModelAttributeMethodProcessor(true)); } return handlers; }
总结
1.通过请求适配对应的Handle
2.通过Handle再适配对应的处理器，因为Handle会有多种形式存在，比如我们常用的就是存储了处理类 和处理方法 对应的处理器可以通过反射执行
3.RequestMappingHandlerAdapter通过实现spring InitializingBean来实现初始化入参绑定器 返回值绑定器 ControllerAdvice 的初始化 供后续使用
