昆明逆火科技有限公司

 /** 
 * 基于 AsyncContext 支持的 Appender 
 * 
 */ 
 public class WebLogAppender extends WriterAppender { 
     /** 
     * 異步 Servlet 上下文隊列
     */ 
     public static final Queue<AsyncContext> ASYNC_CONTEXT_QUEUE 
     = new ConcurrentLinkedQueue<AsyncContext>(); 

     /** 
     * AsyncContextQueue Writer 
     */ 
     private Writer writer = new AsyncContextQueueWriter(ASYNC_CONTEXT_QUEUE); 

     public WebLogAppender() { 
         setWriter(writer); 
     } 

     public WebLogAppender(Layout layout) { 
         this(); 
         super.layout = layout; 
     } 
 }

 /** 
 * 向一個 Queue<AsyncContext> 中每個 Context 的 Writer 進行輸出
 * 
 */ 
 public class AsyncContextQueueWriter extends Writer { 

     /** 
     * AsyncContext 隊列
     */ 
     private Queue<AsyncContext> queue; 

     /** 
     * 消息隊列
     */ 
     private static final BlockingQueue<String> MESSAGE_QUEUE 
     = new LinkedBlockingQueue<String>(); 

     /** 
     * 發(fā)送消息到異步線程，最終輸出到 http response 流
     * @param cbuf 
     * @param off 
     * @param len 
     * @throws IOException 
     */ 
     private void sendMessage(char[] cbuf, int off, int len) throws IOException { 
         try { 
             MESSAGE_QUEUE.put(new String(cbuf, off, len)); 
         } catch (Exception ex) { 
             IOException t = new IOException(); 
             t.initCause(ex); 
             throw t; 
         } 
     } 

     /** 
     * 異步線程，當(dāng)消息隊列中被放入數(shù)據(jù)，將釋放 take 方法的阻塞，將數(shù)據(jù)發(fā)送到 http response 流上
     */ 
     private Runnable notifierRunnable = new Runnable() { 
        public void run() { 
            boolean done = false; 
            while (!done) { 
                String message = null; 
                try { 
                    message = MESSAGE_QUEUE.take(); 
                    for (AsyncContext ac : queue) { 
                        try { 
                            PrintWriter acWriter = ac.getResponse().getWriter(); 
                            acWriter.println(htmlEscape(message)); 
                            acWriter.flush(); 
                        } catch (IOException ex) { 
                            System.out.println(ex); 
                            queue.remove(ac); 
                        } 
                    } 
                } catch (InterruptedException iex) { 
                    done = true; 
                    System.out.println(iex); 
                } 
            } 
        } 
     }; 

     /** 
     * @param message 
     * @return 
     */ 
     private String htmlEscape(String message) { 
         return "<script type='text/javascript'>nwindow.parent.update(""
         + message.replaceAll("n", "").replaceAll("r", "") + "");</script>n"; 
     } 

     /** 
     * 保持一個默認(rèn)的 writer，輸出至控制臺
     * 這個 writer 是同步輸出，其它輸出到 response 流的 writer 是異步輸出
     */ 
     private static final Writer DEFAULT_WRITER = new OutputStreamWriter(System.out); 

     /** 
     * 構(gòu)造 AsyncContextQueueWriter 
     * @param queue 
     */ 
     AsyncContextQueueWriter(Queue<AsyncContext> queue) { 
         this.queue = queue; 
         Thread notifierThread = new Thread(notifierRunnable); 
         notifierThread.start(); 
     } 

     @Override 
     public void write(char[] cbuf, int off, int len) throws IOException { 
         DEFAULT_WRITER.write(cbuf, off, len); 
         sendMessage(cbuf, off, len); 
     } 

     @Override 
     public void flush() throws IOException { 
         DEFAULT_WRITER.flush(); 
     } 

     @Override 
     public void close() throws IOException { 
         DEFAULT_WRITER.close(); 
         for (AsyncContext ac : queue) { 
             ac.getResponse().getWriter().close(); 
         } 
     } 
 }

   <appender name="CONSOLE" class="org.fenixsoft.log.WebLogAppender"> 
      <param name="Threshold" value="DEBUG"/> 
      <layout class="org.apache.log4j.PatternLayout"> 
         <!-- The default pattern: Date Priority [Category] Messagen --> 
         <param name="ConversionPattern" value="%d %p [%c] %m%n"/> 
      </layout> 
   </appender>

 /** 
 * Servlet implementation class WebLogServlet 
 */ 
 @WebServlet(urlPatterns = { "/WebLogServlet" }, asyncSupported = true) 
 public class WebLogServlet extends HttpServlet { 

    /** 
     * serialVersionUID 
     */ 
    private static final long serialVersionUID = -260157400324419618L; 

    /** 
     * 將客戶端注冊到監(jiān)聽 Logger 的消息隊列中
     */ 
    @Override 
    protected void doGet(HttpServletRequest req, HttpServletResponse res) 
    throws ServletException, IOException { 
        res.setContentType("text/html;charset=UTF-8"); 
        res.setHeader("Cache-Control", "private"); 
        res.setHeader("Pragma", "no-cache"); 
        req.setCharacterEncoding("UTF-8"); 
        PrintWriter writer = res.getWriter(); 
        // for IE 
        writer.println("<!-- Comet is a programming technique that enables web 
        servers to send data to the client without having any need for the client 
        to request it. -->n"); 
        writer.flush(); 

        final AsyncContext ac = req.startAsync(); 
        ac.setTimeout(10 * 60 * 1000); 
        ac.addListener(new AsyncListener() { 
            public void onComplete(AsyncEvent event) throws IOException { 
                WebLogAppender.ASYNC_CONTEXT_QUEUE.remove(ac); 
            } 

            public void onTimeout(AsyncEvent event) throws IOException { 
                WebLogAppender.ASYNC_CONTEXT_QUEUE.remove(ac); 
            } 

            public void onError(AsyncEvent event) throws IOException { 
                WebLogAppender.ASYNC_CONTEXT_QUEUE.remove(ac); 
            } 

            public void onStartAsync(AsyncEvent event) throws IOException { 
            } 
        }); 
        WebLogAppender.ASYNC_CONTEXT_QUEUE.add(ac); 
    } 
 }

 <html> 
 <head></head> 
 <script type="text/javascript" src="js/jquery-1.4.min.js"></script> 
 <script type="text/javascript" src="js/application.js"></script> 
 <style> 
     .consoleFont{font-size:9; color:#DDDDDD; font-family:Fixedsys} 
     .inputStyle{font-size:9; color:#DDDDDD; font-family:Fixedsys; width:100%; 
            height:100%; border:0; background-color:#000000;} 
 </style> 
 <body style="margin:0; overflow:hidden" > 
 <table width="100%" height="100%" border="0" cellpadding="0" 
     cellspacing="0" bgcolor="#000000"> 
  <tr> 
    <td colspan="2"><textarea name="result" id="result" readonly="true" wrap="off" 
         style="padding: 10; overflow:auto" class="inputStyle" ></textarea></td> 
  </tr> 
 </table> 
 <iframe id="comet-frame" style="display: none;"></iframe> 
 </body> 
 </html>

 $(document).ready(function() { 
     var url = '/AsyncServlet/WebLogServlet'; 
     $('#comet-frame')[0].src = url; 
 }); 

 function update(data) { 
     var resultArea = $('#result')[0]; 
     resultArea.value = resultArea.value + data + 'n'; 
 }