java简单操作zookeeper

首先创建一个maven工程，然后导入基础的需要的，导入zookeeper依赖 org.apache.zookeeper zookeeper 3.6.3

首先先创建一个服务器端

package com.zookeeper;

import jdk.nashorn.internal.ir.debug.ClassHistogramElement;
import org.apache.zookeeper.*;

import java.io.IOException;

public class FirstServer {
    String connectionString = "";  //连接到的主机
    Integer sessionTimeOut = 2000;
    ZooKeeper zk = null;

    public static void main(String[] args) throws IOException, KeeperException, InterruptedException {
        FirstServer server = new FirstServer();

        //1.获取zookeeper 连接
        server.getConnection();
        //2.绑定对应的节点  ---注册服务器到对应的集群
        server.register(args[0]);
        //3.节点的具体业务
        server.business();
    }

    private void business() throws InterruptedException {
        Thread.sleep(100);
    }

    private void register(String hostName) throws KeeperException, InterruptedException {
        //向server下创建节点
        String s = zk.create("/servers/" + hostName, hostName.getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL);

        System.out.println(hostName + "is online");
    }

    private void getConnection() throws IOException {
        zk = new ZooKeeper(connectionString, sessionTimeOut, new Watcher() {
            @Override
            public void process(WatchedEvent watchedEvent) {

            }
        });
    }
}

创建一个客户端

package com.zookeeper;

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

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

public class ZkClient {
    private String connectionString = "client1:1001,client2:1002,client3:1003";
    private int connectionTimeOut = 2000;
    ZooKeeper zk = null;

    public static void main(String[] args) throws IOException, KeeperException, InterruptedException {
        ZkClient client = new ZkClient();
        //1.获取zk连接
        client.getConnection();
        //2.监听节点 server下节点的增删
        client.getServerList();
        //3.业务逻辑
        client.business();
    }

    private void business() throws InterruptedException {
        Thread.sleep(100);
    }

    private void getServerList() throws KeeperException, InterruptedException {
        //获取节点下的所有连接数据
        List children = zk.getChildren("/server", true);//监听path  true走初始化的节点
        ArrayList servers = new ArrayList<>();
        for (String child : children) {
            byte[] data = zk.getData("/server/" + child, false, null);//获取对应的数据 具体节点的路径，是否监听节点数据的变化，状态
            servers.add(new String(data));
        }
        //打印
        System.out.println(servers.size());
    }

    private void getConnection() throws IOException {

        zk = new ZooKeeper(connectionString, connectionTimeOut, new Watcher() {
            @Override
            public void process(WatchedEvent watchedEvent) {
                try {
                    //保证时刻监听，若不调用为初始则只监听第一次
                    getServerList();
                } catch (KeeperException e) {
                    e.printStackTrace();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        });
    }

}

然后用可视化工具增删对应服务器节点即可