博客

前提：具体操作见

https://blog.csdn.net/weixin_41265887/article/details/113974315

1.创建DistributeServer.java类

package cn.tod;

import org.apache.zookeeper.*;

import java.io.IOException;

public class DistributeServer {
    private static String connectString = "hadoop102:2181,hadoop103:2181,hadoop104:2181";
    private static int sessionTimeout = 4000;
    private ZooKeeper zk = null;

    private String parentNode = "/servers";

    public void getConnect() throws IOException {
        zk = new ZooKeeper(connectString, sessionTimeout, new Watcher() {
            public void process(WatchedEvent watchedEvent) {

            }
        });
    }

    public void registServer(String hostname) throws KeeperException, InterruptedException {
        String node = zk.create(parentNode + "/server", hostname.getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL);
        System.out.println(hostname + " is online " + node);
    }

    public void business(String hostname) throws InterruptedException {
        System.out.println(hostname + " is working ...");
        Thread.sleep(Long.MAX_VALUE);
    }

    public void close() throws InterruptedException {
        zk.close();
    }

    public static void main(String[] args) throws IOException, KeeperException, InterruptedException {
        DistributeServer server = new DistributeServer();
        server.getConnect();
        server.registServer(args[0]);
        server.business(args[0]);
        server.close();
    }
}

2.创建DistributeClient.java类

package cn.tod;

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 DistributeClient {
    private static String connectString = "hadoop102:2181,hadoop103:2181,hadoop104:2181";
    private static int sessionTimeout = 4000;
    private ZooKeeper zk = null;

    private String parentNode = "/servers";

    public void getConnect() throws IOException {
        zk = new ZooKeeper(connectString, sessionTimeout, new Watcher() {
            public void process(WatchedEvent watchedEvent) {
                try {
                    getServerList();
                } catch (KeeperException e) {
                    e.printStackTrace();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        });
    }

    public void getServerList() throws KeeperException, InterruptedException {
        List<String> children = zk.getChildren(parentNode, true);
        ArrayList<String> servers = new ArrayList<String>();
        for (String child : children) {
            byte[] data = zk.getData(parentNode + "/" + child, false, null);
            servers.add(new String(data));
        }

        System.out.println(servers);
    }

    public void business() throws InterruptedException {
        System.out.println("Client is working ...");
        Thread.sleep(Long.MAX_VALUE);
    }

    public void close() throws InterruptedException {
        zk.close();
    }

    public static void main(String[] args) throws IOException, KeeperException, InterruptedException {
        DistributeClient client = new DistributeClient();
        client.getConnect();
        client.getServerList();
        client.business();
        client.close();
    }
}

3.在ZooKeeper集群中创建节点servers

[root@hadoop102 bin]# pwd
/opt/module/zookeeper-3.4.10/bin
[root@hadoop102 bin]# zkCli.sh 
[zk: localhost:2181(CONNECTED) 0] create /servers "servers"

4.在IDEA中配置多个程序运行，在DistributeServer程序的Program arguments中添加参数，运行即可模拟。