ServletContextListener：這不正確的用法嗎？

Question

我正在閱讀關於「Servlet 3.0中的異步處理支持」（http://www.javaworld.com/javaworld/jw-02-2009/jw-02-servlet3.html?page=2）的專家（？）教程。在這裏面有這個下面的代碼片段：

@WebServlet(name="myServlet", urlPatterns={"/slowprocess"}, asyncSupported=true) 
public class MyServlet extends HttpServlet { 

    public void doGet(HttpServletRequest request, HttpServletResponse response) { 
     AsyncContext aCtx = request.startAsync(request, response); 
     ServletContext appScope = request.getServletContext(); 
     ((Queue<AsyncContext>)appScope.getAttribute("slowWebServiceJobQueue")).add(aCtx); 
    } 
} 

@WebServletContextListener 
public class SlowWebService implements ServletContextListener { 

    public void contextInitialized(ServletContextEvent sce) { 
     Queue<AsyncContext> jobQueue = new ConcurrentLinkedQueue<AsyncContext>(); 
     sce.getServletContext().setAttribute("slowWebServiceJobQueue", jobQueue); 
     // pool size matching Web services capacity 
     Executor executor = Executors.newFixedThreadPool(10); 
     while(true) 
     { 
      if(!jobQueue.isEmpty()) 
      { 
       final AsyncContext aCtx = jobQueue.poll(); 
       executor.execute(new Runnable(){ 
        public void run() { 
         ServletRequest request = aCtx.getRequest(); 
         // get parameteres 
         // invoke a Web service endpoint 
         // set results 
         aCtx.forward("/result.jsp"); 
        } 
       }); 
      } 
     } 
    } 

    public void contextDestroyed(ServletContextEvent sce) { 
    } 

}

因爲，這是專家「這 - 是 - 如何-IT-IS-做」文章中，我假設他們不會是寫一些愚蠢的代碼。 但我無法接受'contextInitialized（）'中有'while（true）'循環。

1. 根據我的理解，此上下文偵聽器線程永遠不會退出'contextInitialized（）'方法。對 ？
2. 我的應用程序中有其他任何Servlet會發生什麼？他們是否可以自由處理請求？或者這是否會導致整個servlet容器？

Answer 1

1）我會改變的代碼如下：

@WebServletContextListener 
public class SlowWebService implements ServletContextListener, Runnable { 
    private volatile boolean running; 
    ExecutorService executor; 
    Thread runner; 
    Queue<AsyncContext> jobQueue; 

    public void contextInitialized(ServletContextEvent sce) { 
     jobQueue = new ConcurrentLinkedQueue<AsyncContext>(); 
     sce.getServletContext().setAttribute("slowWebServiceJobQueue", jobQueue); 
     // pool size matching Web services capacity 
     executor = Executors.newFixedThreadPool(10); 
     runner = new Thread(this); 
     runner.start(); 
    } 

    public void run() { 
     running = true; 
     while(running) 
     { 
      try { 
       if(!jobQueue.isEmpty()) 
       { 
        final AsyncContext aCtx = jobQueue.poll(); 
        executor.execute(new Runnable(){ 
         public void run() { 
          ServletRequest request = aCtx.getRequest(); 
          // get parameteres 
          // invoke a Web service endpoint 
          // set results 
          aCtx.forward("/result.jsp"); 
         } 
        }); 
       } 
      } 
      catch (InterruptException e) { 
      } 
     } 
    } 

    public void contextDestroyed(ServletContextEvent sce) { 
     running = false; 
     runner.interrupt(); 
     executor.shutdown(); 
    } 
} 

2）其他Servlet不應該，只要他們有不同的URL模式的影響。