java连接zookeeper的3种方式

1、使用zookeeper原始api

public class Demo {

    private static String ip = "192.168.0.101:2181";

    private static int  session_timeout = 40000;

    private static CountDownLatch latch = new CountDownLatch(1);

    public static void main(String[] args) throws Exception {
        ZooKeeper zooKeeper = new ZooKeeper(ip, session_timeout, new Watcher() {
            @Override
            public void process(WatchedEvent watchedEvent) {
                if(watchedEvent.getState() == Event.KeeperState.SyncConnected) {
                    //确认已经连接完毕后再进行操作
                    latch.countDown();
                    System.out.println("已经获得了连接");
                }
            }
        });

        //连接完成之前先等待
        latch.await();
        ZooKeeper.States states = zooKeeper.getState();
        System.out.println(states);
    }
}

  打印：

     如果打印出来的状态为  CONNECTED 则表示连接成功

 2、使用ZkClient客户端连接，这种连接比较简单

public class ZkClientTest {

    private static String ip = "192.168.0.101:2181";

    private static int  session_timeout = 40000;

    public static void main(String[] args) {
        ZkClient zkClient = new ZkClient(ip,session_timeout);
        System.out.println(zkClient.getChildren("/"));
    }
}

    打印：

  

  3、  使用curator连接：

public class CuratorDemo {


    //ZooKeeper服务地址
    private static final String SERVER = "192.168.0.101:2181";

    //会话超时时间
    private static final int SESSION_TIMEOUT = 30000;

    //连接超时时间
    private static final int CONNECTION_TIMEOUT = 5000;

    /**
     * baseSleepTimeMs：初始的重试等待时间
     * maxRetries：最多重试次数
     *
     *
     * ExponentialBackoffRetry：重试一定次数，每次重试时间依次递增
     * RetryNTimes：重试N次
     * RetryOneTime：重试一次
     * RetryUntilElapsed：重试一定时间
     */
    private static final RetryPolicy retryPolicy = new ExponentialBackoffRetry(1000, 3);


    public static void main(String[] args) throws Exception {
        //创建 CuratorFrameworkImpl实例
        CuratorFramework client = CuratorFrameworkFactory.newClient(SERVER, SESSION_TIMEOUT, CONNECTION_TIMEOUT, retryPolicy);

        //启动
        client.start();

        System.out.println("连接成功！");
        Object o = client.getChildren().forPath("/");
        System.out.println(o);
    }

}

    打印：

    以上