zookeeper 使用zkclient的回调

public class ZKDataListener implements IZkDataListener {

	public void handleDataChange(String dataPath, Object data) throws Exception {  
        
        System.out.println(dataPath+":"+data.toString());  
    }  

    public void handleDataDeleted(String dataPath) throws Exception {  
          
        System.out.println(dataPath);  
          
    }  

}

public class ZkTest {

	public static void main(String[] args) throws InterruptedException {
		ZkClient zkClient = new ZkClient("127.0.0.1:2181");		
		zkClient.setZkSerializer(new MyZkSerializer());
		zkClient.subscribeDataChanges("/test", new ZKDataListener());
		zkClient.writeData("/test", 1);
		Thread.sleep(3000);
		zkClient.writeData("/test", 2);
		Thread.sleep(3000);
		zkClient.writeData("/test", 3);
		while(true) {}
	}

}

setdata以后不休眠的话，只会有一次回调，休眠正常回调三次。
大佬知道神马原因吗？