怎样获取zookeeper集群中leader的IP并应用

Question

现在有一个需求，想调用zookeeper集群中leader的IP,请问应该如何用java实现获取leader的IP？求指教

Answer 1

要获取 Zookeeper 集群中的 Leader IP，可以使用 ZooKeeper 客户端 API，在 Java 中使用 ZooKeeper 客户端 API 可以通过 ZooKeeper 的 Java API 和 Apache Curator API 来实现。

下面是使用 Apache Curator API 获取 ZooKeeper 集群中的 Leader IP 的示例代码

import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.framework.api.ACLProvider;
import org.apache.curator.retry.ExponentialBackoffRetry;
import org.apache.curator.utils.ZookeeperFactory;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.data.ACL;
import org.apache.zookeeper.data.Id;
import org.apache.zookeeper.server.auth.DigestAuthenticationProvider;

import java.security.NoSuchAlgorithmException;
import java.util.ArrayList;
import java.util.List;

public class ZookeeperLeaderIP {
    private static final String ZOOKEEPER_CONNECT_STRING = "zk1:2181,zk2:2181,zk3:2181";
    private static final String ZOOKEEPER_AUTH_TYPE = "digest";
    private static final String ZOOKEEPER_AUTH_USER = "username";
    private static final String ZOOKEEPER_AUTH_PASSWORD = "password";
    private static final int ZOOKEEPER_TIMEOUT = 5000;

    public static void main(String[] args) throws Exception {
        // 创建 Curator 客户端
        CuratorFramework client = CuratorFrameworkFactory.builder()
                .connectString(ZOOKEEPER_CONNECT_STRING)
                .retryPolicy(new ExponentialBackoffRetry(1000, 3))
                .authorization(ZOOKEEPER_AUTH_TYPE, (ZOOKEEPER_AUTH_USER + ":" + ZOOKEEPER_AUTH_PASSWORD).getBytes())
                .build();
        client.start();

        // 获取 ZooKeeper 实例
        ZooKeeper zooKeeper = client.getZookeeperClient().getZooKeeper();

        // 获取 Leader IP
        String leaderIp = zooKeeper.getLeaderElectionAddress();
        System.out.println("Leader IP: " + leaderIp);
        
        // 关闭客户端
        client.close();
    }
}

在上面的代码中，我们使用 CuratorFrameworkFactory 创建了 Curator 客户端，然后通过 getZookeeperClient().getZooKeeper() 方法获取了 ZooKeeper 实例，最后使用 getLeaderElectionAddress() 方法获取 Leader IP。需要注意的是，在创建 Curator 客户端时需要指定连接字符串、重试策略、认证信息等参数，以及在获取 Leader IP 前需要先启动客户端。