Zookeeper org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = Connection

zk版本3.4.13 ，虚拟机版本CentOs7 

在虚拟机做了集群，测试抛异常

Exception in thread "main" org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = ConnectionLoss for /test
	at org.apache.zookeeper.KeeperException.create(KeeperException.java:102)
	at org.apache.zookeeper.KeeperException.create(KeeperException.java:54)
	at org.apache.zookeeper.ZooKeeper.getData(ZooKeeper.java:1221)
	at com.along.client.zookeeper.ZookeeperClient.main(ZookeeperClient.java:21)

上面的代码对于避免连接建立完成之前就发出ZooKeeper操作命令出现ConnectionLoss是有用的。

因为new出ZooKeeper实例时只是建立了与服务端之间的会话，此时TCP连接可能还未建立完成，如果这时发出ZooKeeper操作命令的确会出现连接丢失异常，虽然这种概率相对较小。

当客户端与服务端连接建立之后客户端会收到一个SyncConnected事件，此时将CountDownLatch减到零就可以让阻塞的主线程继续运行，再来发出ZooKeeper操作命令就不会出现连接丢失的异常了。

package com.along.client.zookeeper;
 
import org.apache.zookeeper.KeeperException;
import org.apache.zook