zookeeper实现HA入门案例

Posted 2021-03-10 leigepython

package com.zhileiedu.zk;

import java.util.Random;

import javax.net.ssl.SSLEngineResult.Status;

import org.apache.zookeeper.CreateMode;
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.ZooDefs.Ids;

public class T {

static String status = "ACTIVE";

public static void main(String[] args) throws Exception {
    String connectString = "192.168.23.157:2181,192.168.23.157:2182,192.168.23.157:2183";
    ZooKeeper zk = new ZooKeeper(connectString, 5000, null);
    String IP = "202.106.29.138";
    String port = new Random().nextInt(500)+"";
    if(zk.exists("/zk01", new MasterWatcher()) != null) { // 节点已经创建
        status = "STANDBY";
    } else {
        zk.create("/zk01", (IP + ":"+port).getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL);
        status = "ACTIVE";
        System.out.println("启动active");
    }
    
    Thread.sleep(Integer.MAX_VALUE);
    
}


static class MasterWatcher implements Watcher {

    public void process(WatchedEvent e ) {
        // TODO Auto-generated method stub
        if (e.getType() == EventType.NodeDeleted) {
            status = "ACTIVE";
            System.out.println("切换为active");
        }
    }
    
}

}