zookeeper-05 监听服务器节点动态上下线

public class DistributeServer {

    public static void main(String[] args) throws IOException, KeeperException, InterruptedException {
        DistributeServer server = new DistributeServer();
        // 创建zookeeper集群连接
        server.getConnect();
        // 注册服务器 （创建节点）
        server.regist(args[0]);
        // 业务逻辑 （不让进程退出）
        server.business();
    }

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

    private void regist(String hostname) throws KeeperException, InterruptedException {
        String path = zkClient.create("/servers/server", hostname.getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL);
        System.out.println(hostname + "is online");
    }

    private String connectString = "hadoop001:2181,hadoop002:2181,hadoop003:2181";
    private int sessionTimeout = 2000;
    private ZooKeeper zkClient;

    private void getConnect() throws IOException {
        zkClient = new ZooKeeper(connectString, sessionTimeout, new Watcher() {
            public void process(WatchedEvent event) {

            }
        });
    }
}

public class DistributeClient {

    public static void main(String[] args) throws IOException, KeeperException, InterruptedException {
        DistributeClient server = new DistributeClient();
        // 创建客户端连接
        client.getConnect();
        // 注册监听
        client.getChildren();
        // 业务逻辑
        client.business();
    }

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

    private void getChildren() throws KeeperException, InterruptedException {
        List<String> children = zkClient.getChildren("/servers", true);
        // 存储服务器节点名称集合
        ArrayList<String> hosts = new ArrayList<String>();

        for (String child : children) {
            byte[] data = zkClient.getData("/servers/" + child, false, null);
            hosts.add(new String(data));
        }
        // 将所有在线主机名称打印到控制台
        System.out.println(hosts);
    }

    private String connectString = "hadoop001:2181,hadoop002:2181,hadoop003:2181";
    private int sessionTimeout = 2000;
    private ZooKeeper zkClient;

    private void getConnect() throws IOException {
        zkClient = new ZooKeeper(connectString, sessionTimeout, new Watcher() {
            public void process(WatchedEvent event) {
                try {
                    // 监听响应执行下面函数
                    getChildren();
                } catch (KeeperException e) {
                    e.printStackTrace();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        });
    }
}