Google App Engine頻道呈現處理程序拋出異常

Question

我遇到了這種情況，在我的Mac上本地運行SDK。我正在嘗試建立存在處理。我創建了一個簡單的servlet，除了日誌以外什麼也不做。但是，我得到的任何連接和斷開事件以下例外（雖然渠道似乎另有工作）...

Mar 14, 2013 8:04:25 PM com.google.apphosting.utils.jetty.JettyLogger warn 
WARNING: /_ah/channel/disconnected/: javax.servlet.UnavailableException: java.lang.InstantiationException 
Mar 14, 2013 8:04:38 PM com.google.apphosting.utils.jetty.JettyLogger warn 
WARNING: /_ah/channel/connected/: javax.servlet.UnavailableException: java.lang.InstantiationException 

我已經註冊了的servlet的渠道在我的網站都連接和斷開.XML ...

<servlet> 
    <servlet-name>ChannelPresence</servlet-name> 
    <servlet-class>com.readyposition.gaetestbed.ChannelPresenceServlet   
    </servlet-class> 
    </servlet> 

    <servlet-mapping> 
    <servlet-name>ChannelPresence</servlet-name> 
    <url-pattern>/_ah/channel/connected/</url-pattern> 
    </servlet-mapping> 

    <servlet-mapping> 
    <servlet-name>ChannelPresence</servlet-name> 
    <url-pattern>/_ah/channel/disconnected/</url-pattern> 
    </servlet-mapping>                

處理程序（servlet的）本身是很基本的...

package com.readyposition.gaetestbed; 

import java.io.IOException; 

import javax.servlet.ServletException; 
import javax.servlet.http.HttpServlet; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 

import org.slf4j.Logger; 
import org.slf4j.LoggerFactory; 

import com.google.appengine.api.channel.ChannelPresence; 
import com.google.appengine.api.channel.ChannelService; 
import com.google.appengine.api.channel.ChannelServiceFactory; 

@SuppressWarnings("serial") 
public abstract class ChannelPresenceServlet extends HttpServlet { 
    final static Logger logger = 
      LoggerFactory.getLogger(ChannelPresenceServlet.class); 

    @Override 
    public void doGet(final HttpServletRequest req, 
      final HttpServletResponse resp) 
        throws IOException, ServletException 
    { 
     processCommand(req, resp); 
    } 

    @Override 
    public void doPost(final HttpServletRequest req, 
      final HttpServletResponse resp) 
        throws IOException, ServletException 
    { 
     processCommand(req, resp); 
    } 

    public void processCommand(final HttpServletRequest req, 
      final HttpServletResponse resp) 
        throws IOException, ServletException 
    { 
     final ChannelService channelService = 
       ChannelServiceFactory.getChannelService(); 
     final ChannelPresence presence = channelService.parsePresence(req); 

     logger.info("Channel Presence - clientId={}, isConnected={}", 
       presence.clientId(), presence.isConnected()); 
    } 
} 

任何幫助，將不勝感激。

Answer 1

有多尷尬。剪切並粘貼錯誤。我的servlet類錯誤地是抽象的。嘆。固定。

我看到其他幾個人在不同的情況下抱怨同一個例外，至少有一個與頻道的存在有關。如果另外一個人意識到他們錯誤地將servlet類留下了抽象的話，那麼我認爲這會是有益的。

感謝任何試圖追隨我的老鼠洞。