zookeeper错误KeeperErrorCode = ConnectionLoss解决-白红宇

zookeeper错误KeeperErrorCode = ConnectionLoss解决

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发布时间：2019-05-25

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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):

[java]
 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){  
                   
             }  
         }  
           
     }  
 }  