利用zookeeper实现服务上线（离线）自动感知

package com.itunic.zookeeper.server;

import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooDefs.Ids;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.test.ClientBase;

/**
 * 利用zookeeper实现服务上线功能
 * 
 * @author itunic
 * 
 */
public class Server {
 // zookeeper 服务注册根节点
 static final String SERVER_HOME = "/server";

 public static void main(String[] args) throws Exception {
 // 连接zk
        ZooKeeper zk = new ZooKeeper("zookeeperServer1:2181,zookeeperServer2:2181,zookeeperServer3:2181",
                ClientBase.CONNECTION_TIMEOUT, new Watcher() {
 @Override
 public void process(WatchedEvent arg0) {
                        System.out.println("启动");
                    }
                });
        createNode(zk, args);
        Thread.sleep(Long.MAX_VALUE);
    }

 /**
     * 更新zk节点
     * 
     * @param zk
     * @param args
     * @throws Exception
     */
 public static void createNode(ZooKeeper zk, String[] args) throws Exception {
        zk.create(SERVER_HOME + "/" + args[0], args[0].getBytes(), Ids.OPEN_ACL_UNSAFE,
                CreateMode.EPHEMERAL_SEQUENTIAL);
    }
}
2.2、实现服务上线/离线自动感知
package com.itunic.zookeeper.client;

import java.util.ArrayList;
import java.util.List;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.Watcher.Event.EventType;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.test.ClientBase;

/**
 * 利用zookeeper实现服务上线离线自动感知
 *
 * @author itunic
 *
 */
public class Client {
 static final String SERVER_HOME = "/server";
 private ZooKeeper zk = null;

 // 获取zk连接
 private void getZkClient() throws Exception {
        zk = new ZooKeeper("zookeeperServer1:2181,zookeeperServer2:2181,zookeeperServer3:2181",
                ClientBase.CONNECTION_TIMEOUT, new Watcher() {
 @Override
 public void process(WatchedEvent event) {
 if (event.getType() == EventType.None)
 return;
 try {
 // 获取新的服务器列表,重新注册监听
                            updateServers();
                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                    }
                });
    }

 /**
     * 从zk中获取在线服务器信息
     */
 public void updateServers() throws Exception {
 // 从servers父节点下获取到所有子节点，并注册监听
        List<String> children = zk.getChildren(SERVER_HOME, true);
        ArrayList<String> serverList = new ArrayList<String>();
 for (String child : children) {
 byte[] data = zk.getData(SERVER_HOME + "/" + child, false, null);
            serverList.add(new String(data));
        }
        System.out.println("最新服务器节点");
 for (String server : serverList) {
            System.out.println(server);
        }
    }

 public static void main(String[] args) throws Exception {
        Client client = new Client();
 // 先构造一个zk的连接
        client.getZkClient();
 // 获取服务器列表
        client.updateServers();
        Thread.sleep(Long.MAX_VALUE);
    }
}