Zookeeper实例原生API--异步获取节点数据

import java.util.concurrent.CountDownLatch;
import org.apache.zookeeper.AsyncCallback;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.Watcher.Event.EventType;
import org.apache.zookeeper.Watcher.Event.KeeperState;
import org.apache.zookeeper.ZooDefs.Ids;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.data.Stat;

/**
*
* @ClassName: GetData_API_ASync_Usage
* @Description: TODO(ZooKeeper API 获取节点数据内容，使用异步(async)接口)
* @author RongShu
* @date 2017年6月11日 下午8:36:04
*
*/
public class GetData_API_ASync_Usage implements Watcher {
private static CountDownLatch connectedSemaphore = new CountDownLatch(1);
private static ZooKeeper zk;
public static void main(String[] args) throws Exception {
String path = "/zk-book";
zk = new ZooKeeper("localhost:2181",5000,new GetData_API_ASync_Usage());
connectedSemaphore.await();
zk.create( path, "123".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL );
zk.getData( path, true, new IDataCallback(), null );
zk.setData( path, "123".getBytes(), -1 );
Thread.sleep( Integer.MAX_VALUE );
}
public void process(WatchedEvent event) {
if (KeeperState.SyncConnected == event.getState()) {
if (EventType.None == event.getType() && null == event.getPath()) {
connectedSemaphore.countDown();
} else if (event.getType() == EventType.NodeDataChanged) {
try {
zk.getData( event.getPath(), true, new IDataCallback(), null );
} catch (Exception e) {}
}
}
}
}
class IDataCallback implements AsyncCallback.DataCallback{
public void processResult(int rc, String path, Object ctx, byte[] data, Stat stat) {
System.out.println(rc + ", " + path + ", " + new String(data));
System.out.println(stat.getCzxid()+","+stat.getMzxid()+","+stat.getVersion());
}
}

输出
0, /zk-book, 123
388,388,0
0, /zk-book, 123
388,389,1