利用zookeeper实现服务上线（离线）自动感知

文章目录

1、环境说明

1.1、zookeeper环境

运行于centos 6.5 X64系统zookeeper-3.4.8版本，运行于三台节点ha环境，分别对应如下：

[java]zookeeperServer1、zookeeperServer2、zookeeperServer3[/java]

1.2、开发及测试环境

win10系统jdk1.7版本

2、代码实现

2.1、服务上线注册功能开发

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);
}
}