ZooKeeper Connection Loss 异常

原因:

一般是由于连接还未完成就执行zookeeper的get/create/exsit操作引起的.

解决方法:

利用"CountDownLatch 类 + zookeeper的watcher + zookeeper的getStat" 实现连接完成后再调用.

可防止此错误发生.

示例类如下(为一配置获取类):

 import java.util.concurrent.CountDownLatch;


 import org.apache.zookeeper.WatchedEvent;
 import org.apache.zookeeper.Watcher;
 import org.apache.zookeeper.Watcher.Event.KeeperState;
 import org.apache.zookeeper.ZooKeeper;
 import org.apache.zookeeper.ZooKeeper.States;
 import org.apache.zookeeper.data.Stat;
 public class Conf{
     public static void waitUntilConnected(ZooKeeper zooKeeper, CountDownLatch connectedLatch) {
         if (States.CONNECTING == zooKeeper.getState()) {
             try {
                 connectedLatch.await();
             } catch (InterruptedException e) {
                 throw new IllegalStateException(e);
             }
         }
     }

     static class ConnectedWatcher implements Watcher {

         private CountDownLatch connectedLatch;

         ConnectedWatcher(CountDownLatch connectedLatch) {
             this.connectedLatch = connectedLatch;
         }

         @Override
         public void process(WatchedEvent event) {
            if (event.getState() == KeeperState.SyncConnected) {
                connectedLatch.countDown();
            }
         }
     }
     static public Conf Instance(){
         if(static_ == null){
             static_ = new Conf();
         }
         return static_;
     }
     public boolean Init(String hostports, int times){
         try{
             CountDownLatch connectedLatch = new CountDownLatch(1);
             Watcher watcher = new ConnectedWatcher(connectedLatch);
             zk_ = new ZooKeeper(hostports, times, watcher);
             waitUntilConnected(zk_, connectedLatch);
         }
         catch(Exception e){
             System.out.println(e);
             return false;
         }
         return true;
     }
     public String Get(String keys){
         String re = "";
         String ppath = "/zookeeper";
         int oldpos = -1;
         int pos = 0;
         while(true){
             pos = keys.indexOf(".", oldpos + 1);
             if(pos < 0){
                 ppath += "/";
                 String str = keys.substring(oldpos + 1);
                 ppath += str;
                 break;
             }
             ppath += "/";
             String str = keys.substring(oldpos + 1,  pos);
             ppath += str;
             oldpos = pos;
         }
         Stat stat = new Stat();
         try{
             byte[] b = zk_.getData(ppath, false, stat);    //获取节点的信息及存储的数据
             re = new String(b);
         }
         catch(Exception e){
             System.out.println(e);
         }
         return re;
     }
     private Conf(){

     }
     private ZooKeeper zk_;
     static private Conf static_;
     public static void main(String args[]){
         String hostports = "192.168.1.88:2181,192.168.1.88:2182,192.168.1.88:2183";

         Conf.Instance().Init(hostports, 1000);

         String str = Conf.Instance().Get("conf.logicpoint.subscriberserverip");
         str = Conf.Instance().Get("conf.logicpoint.subscriberserverport");
         System.out.println(str);
         while(true){
             try{Thread.sleep(100);}
             catch(Exception e){

             }
         }

     }
 }