Java利用zookeeper实现服务器动态上下线感知

package com.pactera.client; import java.io.IOException; import java.util.List; import org.apache.zookeeper.KeeperException; import org.apache.zookeeper.WatchedEvent; import org.apache.zookeeper.Watcher; import org.apache.zookeeper.ZooKeeper; public class Client { private static final String connection = "mini0:2181,mini1:2181,mini2:2181"; private static final int timeout = 2000; private static final String parentNode = "/serverList"; private ZooKeeper zk; private Watcher wc; public Client(){ try { this.zk = new ZooKeeper(connection,timeout,null); this.wc = new Watcher(){ @Override public void process(WatchedEvent event) { List<String> zNode; try { zNode = zk.getChildren(parentNode, this); showServerList(zNode,zk); } catch (Exception e) { e.printStackTrace(); } } }; } catch (IOException e) { e.printStackTrace(); } } public void listener() throws Exception{ List<String> zNode = this.zk.getChildren(parentNode, this.wc); showServerList(zNode,zk); } public static void showServerList(List<String> zNode, ZooKeeper zk){ System.out.println("当前在线服务器列表:"); for(String zNodeTemp:zNode){ try { System.out.println("zNode:"+zNodeTemp+"--data:"+zk.getData(parentNode+"/"+zNodeTemp, false, null)); } catch (Exception e) { e.printStackTrace(); } } } public static void main(String args[]) throws Exception{ Client cli = new Client(); cli.listener(); Thread.sleep(Long.MAX_VALUE); } }