Spring Servlet3 扩展模块笔记

Servlet 3.0

AsyncWebRequest.java

• 异步请求接口,继承NativeWebRequest

  接口

         
  /**      * {@inheritDoc}      * <p>In Servlet 3 async processing, the timeout period begins after the      * container processing thread has exited.      */     public void setTimeout(Long timeout) {         Assert.state(!isAsyncStarted(), "Cannot change the timeout with concurrent handling in progress");//断言状态没有启动异步         this.timeout = timeout;     }     public boolean isAsyncStarted() {         return ((this.asyncContext != null) && getRequest().isAsyncStarted());//异步状态不为空，请求是否启动异步处理模式,如果请求被AsyncContext.dispatch()到容器，或 AsynContext.complete ，则返回false.     }     /**      * Whether async request processing has completed.      * <p>It is important to avoid use of request and response objects after async      * processing has completed. Servlet containers often re-use them.      */     public boolean isAsyncComplete() {         return this.asyncCompleted.get();//请求的异步处理是否完成     }     public void startAsync() {         Assert.state(getRequest().isAsyncSupported(),                 "Async support must be enabled on a servlet and for all filters involved " +                 "in async request processing. This is done in Java code using the Servlet API " +                 "or by adding \"<async-supported>true</async-supported>\" to servlet and " +                 "filter declarations in                web.xml.");//判断请求是否支持异步处理         Assert.state(!isAsyncComplete(), "Async processing has already completed");         if (isAsyncStarted()) {//判断状态是否已经启动异步处理模式             return;         }         this.asyncContext = getRequest().startAsync(getRequest(), getResponse());         this.asyncContext.addListener(this);         if (this.timeout != null) {             this.asyncContext.setTimeout(this.timeout);         }     }     public void dispatch() {         Assert.notNull(this.asyncContext, "Cannot dispatch without an AsyncContext");         this.asyncContext.dispatch();     }     // ---------------------------------     // Implementation of AsyncListener methods     // ---------------------------------     public void onStartAsync(AsyncEvent event) throws IOException {     }     public void onError(AsyncEvent event) throws IOException {     }     public void onTimeout(AsyncEvent event) throws IOException {         for (Runnable handler : this.timeoutHandlers) {             handler.run();         }     }     public void onComplete(AsyncEvent event) throws IOException {         for (Runnable handler : this.completionHandlers) {             handler.run();         }         this.asyncContext = null;         this.asyncCompleted.set(true);//设置异步处理已经完成     }
  
  

  NoSupportAsyncWebRequest.java

  • 不支持异步处理模式的web请求

    DeferredResultProcessingInterceptor.java

    • DeferredResult处理过程拦截器
    • 在start async前，超时后/异步处理完成后/网络超时后触发拦截

      DeferredResultProcessingInterceptorAdapter.java

      • 抽象类实现DeferredResultProcessingInterceptor,做空实现

        DeferredResultInterceptorChain.java

        • 调用DeferredResultProcessingInterceptor的辅助类

          DeferredResult.java

          • 递延结果，在两个线程中传递的对象结果
          • 实现Comparable接口以保证加入PriorityQueue队列的正确顺序

            CallableProcessingInterceptor.java

            • Callable拦截器

              CallableProcessingInterceptorAdapter.java

              • 抽象类实现CallableProcessingInterceptor接口，空实现

                CallableInterceptorChain.java

                • 调用CallableProcessingInterceptor的辅助类

                  TimeoutCallableProcessingInterceptor.java

                  • 继承CallableProcessingInterceptorAdapter
                  • 实现超时处理方法

                    TimeoutDeferredResultProcessingInterceptor.java

                    • 继承DeferredResultProcessingInterceptorAdapter
                    • 实现超时处理方法

                      WebAsyncTask.java

                      • web异步任务
                      • 包含一个Callable类，一个超时时间，一个任务执行着或名字

                        WebAsyncUtils.java

                        • 实现getAsyncManager
                        • 实现createAsyncWebRequest

                          WebAsyncManager.java

                          • 对Callables和DeferredResults启动的管理，包括拦截器的注入，Excutor的注入等
                          • 异步处理的入口类