Spring Servlet3 扩展模块笔记


		Servlet 3.0
AsyncWebRequest.java
 
异步请求接口,继承NativeWebRequest
接口
       
[java] 
        * Set the time required for concurrent handling to complete. 
        * This property should not be set when concurrent handling is in progress, 
        * i.e. when {@link #isAsyncStarted()} is {@code true}. 
        * @param timeout amount of time in milliseconds; {@code null} means no 
        *  timeout, i.e. rely on the default timeout of the container. 
        */  
       //设置超时时间  
       void setTimeout(Long timeout);  
  
       /** 
        * Add a handler to invoke when concurrent handling has timed out. 
        */  
       //增加超时处理类  
       void addTimeoutHandler(Runnable runnable);  
  
       /** 
        * Add a handle to invoke when request processing completes. 
        */  
       //增加请求处理完成处理类  
       void addCompletionHandler(Runnable runnable);  
  
       /** 
        * Mark the start of asynchronous request processing so that when the main 
        * processing thread exits, the response remains open for further processing 
        * in another thread. 
        * @throws IllegalStateException if async processing has completed or is not supported 
        */  
       //标示异步请求开始，返回异步Context  
       void startAsync();  
  
       /** 
        * Whether the request is in async mode following a call to {@link #startAsync()}. 
        * Returns "false" if asynchronous processing never started, has completed, 
        * or the request was dispatched for further processing. 
        */  
       //判断是否是当前线程是否启动异步模式，false表示没有启动异步模式，或者已经完成，否则请求被分发到其他线程处理  
       boolean isAsyncStarted();  
  
       /** 
        * Dispatch the request to the container in order to resume processing after 
        * concurrent execution in an application thread. 
        */  
       //分发请求到容器，唤醒其他线程处理  
       void dispatch();  
  
       /** 
        * Whether asynchronous processing has completed. 
        */  
       //判断异步处理是否完成  
       boolean isAsyncComplete();  
 
StandardServletAsyncWebRequest.java
 
继承ServletWebRequest,实现AsyncWebRequest, AsyncListener，一个标准异步web请求的实现类。
代码
     
[java] view plaincopy
/** 
      * {@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");

补充：软件开发 , Java ,