java - ServletContextListener : Isn't this incorrect usage?

Question

我正在阅读有关“Servlet 3.0 中的异步处理支持”的专家(？)教程(http://www.javaworld.com/javaworld/jw-02-2009/jw-02-servlet3.html?page=2)。其中有以下代码片段:

@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) {
    }

}

因为这是一篇专家的“这是如何完成的”文章，我假设他们不会编写一些愚蠢的代码。但我无法接受在“contextInitialized()”内有一个“while(true)”循环。

1. 根据我的理解，这个上下文监听器线程永远不会退出“contextInitialized()”方法。对吗？
2. 我的应用程序中的任何其他 Servlet 会发生什么情况？他们可以免费满足请求吗？或者这会导致整个 servlet 容器崩溃吗？

Answer 1

1)我将更改代码如下:

@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 只要具有不同的 urlPattern，就不会受到影响。