ZooKeeper(String connectionString, int sessionTimeout, Watcher watcher)

• connectionString - zooKeeper集合主机。

• sessionTimeout - 会话超时（以毫秒为单位）。

• watcher - 实现“监视器”界面的对象。ZooKeeper集合通过监视器对象返回连接状态。

案例：

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

import java.util.concurrent.CountDownLatch;

public class ZookeeperConnection {
    public static void main(String[] args) {
        try {
            // 计数器对象
            CountDownLatch countDownLatch = new CountDownLatch(1);
            // arg1:服务器的ip和端口
            // arg2:客户端与服务器之间的会话超时时间  以毫秒为单位的
            // arg3:监视器对象
            ZooKeeper zooKeeper = new
                    ZooKeeper("192.168.60.130:2181,192.168.60.130:2182,192.168.60.130:2183",
                    5000, new Watcher() {
                @Override
                public void process(WatchedEvent event) {
                    if (event.getState() == Event.KeeperState.SyncConnected) {
                        System.out.println("连接创建成功!");
                        countDownLatch.countDown();
                    }
                }
            });
            // 主线程阻塞等待连接对象的创建成功
            countDownLatch.await();
            // 会话编号
            System.out.println(zooKeeper.getSessionId());
            zooKeeper.close();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}