zookeeper监控znode

package zookeeper;
import java.util.List;


import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.Watcher.Event.EventType;
import org.apache.zookeeper.ZooKeeper;


/**
 * 众所周知，ZooKeeper中的ZNode是树形结构， 现在我需要给/app1结点设置watcher，监听/app1下增减、删除和修改的结点，
 * 并将相应的事件使用log4j记录到日志文件中。ZNode的变化可以直接通过event.getType来获取 使用zk.exists(PATH,
 * wc);来为PATH结点设置watcher，所有结点都可以使用wc做watcher。
 * 
 * @author 小明 2015.5.23
 */
public class WatchClient implements Runnable {
//
private List<String> nodeList;
private static final String path = "/app";
private static ZooKeeper zk;


public static void main(String[] args) throws Exception {
WatchClient client = new WatchClient();
Thread thread = new Thread(client);
thread.start();
}

public WatchClient() throws Exception {
zk = new ZooKeeper("192.168.1.97:2181", 99999, new Watcher() {
public void process(WatchedEvent event) {
System.out.println(event.getPath() + event.getType());
}
});
}


/**
* 设置watch线程
*/
public void run() {
Watcher watcher = new Watcher() {
public void process(WatchedEvent event) {
//System.out.println("__________");
// 结点数据改变前的节点列表
List<String> nodeListBefore = nodeList;


// 主结点的数据发生改变时
if (event.getType() == EventType.NodeDataChanged) {
System.out.println("Node data changed:" + event.getPath());
}


if (event.getType() == EventType.NodeDeleted) {
System.out.println("Node data deleted:" + event.getPath());
}


if (event.getType() == EventType.NodeCreated) {
System.out.println("Node data created:" + event.getPath());
}


// 获取跟新后的nodeList
try {
nodeList=zk.getChildren(event.getPath(), false);
} catch (KeeperException e) {  
                    System.out.println(event.getPath()+" has no child, deleted.");  
                } catch (InterruptedException e) {  
                    e.printStackTrace();  
                }  

// 增加结点 
 List<String> nodeListNow = nodeList;  
                if (nodeListBefore.size() < nodeListNow.size()) {  
                    for (String str : nodeListNow) {  
                        if (!nodeListBefore.contains(str)) { 
                        System.out.println("Node created:" + event.getPath() + "/" + str);
                        }  
                    }  
                } 
                
                // 删除结点 
              if (nodeListBefore.size() > nodeListNow.size()) {  
                  for (String str : nodeListNow) {  
                 if (!nodeListBefore.contains(str)) { 
                      System.out.println("Node deleted:" + event.getPath() + "/" + str);
                      }  
                  }  
              } 
              
              
                
}
};


/**
* 监控Path下的节点
*/
while (true) {
try {
zk.exists(path, watcher);// 所要监控的主结点
} catch (Exception e) {
}


try {
nodeList = zk.getChildren(path, watcher);
} catch (Exception e) {
e.printStackTrace();
}


// 对path下每一个结点都设置一个watcher
for (String nodeName : nodeList) {
try {
zk.exists(path + "/" + nodeName, watcher);
} catch (Exception e) {
e.printStackTrace();
}
}


try {
//System.out.println("hhhh");
Thread.sleep(3000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}


}
}