zookeeper实现服务器动态上下线动态感知

package com.mapleleaf.zookeeper.online;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

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

/**
* @author mapleleaf
* 小儿科版本
* 使用zookeeper实现服务器动态上下线动态感知分析：
* 主要思路是利用zookeeper监听节点和它可以创建临时节点的特点
* 客户端：
* 监听父节点
* 服务端
* 启动时向父节点下生成临时子节点，并在子节点里面写入服务器数据信息
*/

public class zkOnlineXiaoErKeClient {
private static ZooKeeper zk;
private static String zkService = "mini1:2181,mini2:2181,mini3:2181";

private static String parentNode = "/servers";
public static void main(String[] args) throws Exception {
　　
}

public static void initZkCli() throws IOException{
zk=new ZooKeeper(zkService, 3000, new Watcher(){
@Override
public void process(WatchedEvent event) {
System.out.println(event.getType() + "----" + event.getPath());
try {
getChildNode();
} catch (KeeperException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
}

});
}

//获取子节点
//getChildren()方法仅仅监控对应节点直接子目录的一次变化，但是只会监控直接子节点的增减情况，不会监控数据变化情况！若要每次对应节点发生增减变化都被监测到，那么每次都得先调用getChildren()方法获取一遍节点的子节点列表！
public static void getChildNode() throws KeeperException, InterruptedException{
//获取子节点并且监听父节点
List<String> childrens = zk.getChildren(parentNode, true);
//获取子节点的数据信息
List<String> childDate = new ArrayList<String>();
for (String children : childrens) {
byte[] data = zk.getData(parentNode+"/"+children, false, null);
childDate.add(new String(data));
}
System.out.println(childDate);
}

private static void handleBussiness() throws InterruptedException {
System.out.println("client start working.....");
Thread.sleep(Long.MAX_VALUE);

}

}

package com.mapleleaf.zookeeper.online;

import java.io.IOException;

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

/**
* @author mapleleaf
* 启动父节点注册带序列的临时子节点，并写入服务器信息即可
*/
public class zkOnlineXiaoErKeServer {
private static ZooKeeper zk;
private static String zkService = "mini1:2181,mini2:2181,mini3:2181";
private static String parentNode = "/servers/";
//利用args出入服务器信息方便
public static void main(String[] args) throws Exception {
initZkCli();
createEphemeralSequentialNode(args[0]);
System.out.println(args[0] + " server start working.....");
//线程睡眠模拟服务在线状态
Thread.sleep(Long.MAX_VALUE);
}

public static void initZkCli() throws IOException{
zk=new ZooKeeper(zkService, 3000, new Watcher(){
@Override
public void process(WatchedEvent event) {

}
});
}

public static void createEphemeralSequentialNode(String args) throws KeeperException, InterruptedException{
zk.create(parentNode, args.getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL);
}

}