Spring3.2 Http 请求处理过程笔记

Spring3.2请求处理大致过程

处理过程

• 初始化:

  • DispatcherServlet.onRefresh()
  • DispatcherServlet.initStrategies()
  • DispatcherServlet.initHandlerMappings()

• 处理请求:

  • DispatcherServlet.doDispatch()
  • RequestMappingHandlerAdapter.handle()
  • RequestMappingHandlerAdapter.handleInternal()
  • RequestMappingHandlerAdapter.invokeHandleMethod()

    • WebAsyncManager.setTaskExecutor()
    • WebAsyncManager.setAsyncWebRequest()
    • WebAsyncManager.registerCallableInterceptors()
    • WebAsyncManager.registerDeferredResultInterceptors()

    • ServletInvocableHandlerMethod.invokeAndHandle()
    • CallableMethodReturnValueHandler/DeferredResultMethodReturnValueHandler.handleReturnValue()
    • WebAsyncManager.startCallableProcessing()/WebAsyncManager.startDeferredResultProcessing()

  代码详述

  DispatcherServlet.java

  在onRefresh时，初始化

         
  /**         * Start concurrent request processing and initialize the given         * {@link DeferredResult} with a {@link DeferredResultHandler} that saves         * the result and dispatches the request to resume processing of that         * result. The {@code AsyncWebRequest} is also updated with a completion         * handler that expires the {@code DeferredResult} and a timeout handler         * assuming the {@code DeferredResult} has a default timeout result.         *         * @param deferredResult the DeferredResult instance to initialize         * @param processingContext additional context to save that can be accessed         * via {@link #getConcurrentResultContext()}         * @throws Exception If concurrent processing failed to start         *         * @see #getConcurrentResult()         * @see #getConcurrentResultContext()         */        public void startDeferredResultProcessing(                final DeferredResult<?> deferredResult, Object... processingContext) throws Exception {            Assert.notNull(deferredResult, "DeferredResult must not be null");            Assert.state(this.asyncWebRequest != null, "AsyncWebRequest must not be null");            Long timeout = deferredResult.getTimeoutValue();            if (timeout != null) {                this.asyncWebRequest.setTimeout(timeout);            }            List<DeferredResultProcessingInterceptor> interceptors = new ArrayList<DeferredResultProcessingInterceptor>();            interceptors.add(deferredResult.getInterceptor());            interceptors.addAll(this.deferredResultInterceptors.values());            interceptors.add(timeoutDeferredResultInterceptor);            final DeferredResultInterceptorChain interceptorChain = new DeferredResultInterceptorChain(interceptors);            this.asyncWebRequest.addTimeoutHandler(new Runnable() {                public void run() {                    try {                        interceptorChain.triggerAfterTimeout(asyncWebRequest, deferredResult);                    }                    catch (Throwable t) {                        setConcurrentResultAndDispatch(t);                    }                }            });            this.asyncWebRequest.addCompletionHandler(new Runnable() {                public void run() {                    interceptorChain.triggerAfterCompletion(asyncWebRequest, deferredResult);                }            });            interceptorChain.applyBeforeConcurrentHandling(asyncWebRequest, deferredResult);            startAsyncProcessing(processingContext);            try {                interceptorChain.applyPreProcess(this.asyncWebRequest, deferredResult);                deferredResult.setResultHandler(new DeferredResultHandler() {                    public void handleResult(Object result) {                        result = interceptorChain.applyPostProcess(asyncWebRequest, deferredResult, result);                        setConcurrentResultAndDispatch(result);                    }                });            }            catch (Throwable t) {                setConcurrentResultAndDispatch(t);            }        }