java连接和操作zookeeper 示例代码

好的，以下是一个简单的 Java 连接和操作 Zookeeper 的示例代码：

import org.apache.zookeeper.*;
import java.io.IOException;

public class ZookeeperDemo {
    private static final String ZOOKEEPER_ADDRESS = "localhost:2181";
    private static final int SESSION_TIMEOUT = 5000;
    private static ZooKeeper zooKeeper;

    public static void main(String[] args) throws IOException, KeeperException, InterruptedException {
        connect();

        // 创建节点
        createNode("/test", "hello zookeeper");

        // 获取节点数据
        String data = getNodeData("/test");
        System.out.println(data);

        // 修改节点数据
        setData("/test", "hello world");

        // 重新获取节点数据
        data = getNodeData("/test");
        System.out.println(data);

        // 删除节点
        deleteNode("/test");

        close();
    }

    private static void connect() throws IOException {
        zooKeeper = new ZooKeeper(ZOOKEEPER_ADDRESS, SESSION_TIMEOUT, new Watcher() {
            @Override
            public void process(WatchedEvent event) {
                System.out.println("Watch event: " + event.getType());
            }
        });
    }

    private static void close() throws InterruptedException {
        zooKeeper.close();
    }

    private static void createNode(String path, String data) throws KeeperException, InterruptedException {
        byte[] dataBytes = data.getBytes();
        zooKeeper.create(path, dataBytes, ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
    }

    private static String getNodeData(String path) throws KeeperException, InterruptedException {
        byte[] dataBytes = zooKeeper.getData(path, false, null);
        return new String(dataBytes);
    }

    private static void setData(String path, String data) throws KeeperException, InterruptedException {
        byte[] dataBytes = data.getBytes();
        zooKeeper.setData(path, dataBytes, -1);
    }

    private static void deleteNode(String path) throws KeeperException, InterruptedException {
        zooKeeper.delete(path, -1);
    }
}

这个示例代码中，首先通过 `ZooKeeper` 类的构造函数连接 Zookeeper 服务。然后创建、获取、修改和删除节点的操作分别对应 `createNode`、`getNodeData`、`setData` 和 `deleteNode` 函数。最后通过 `close` 函数关闭连接。

需要注意的是，Zookeeper 的节点类型有持久化节点和临时节点。在创建节点时需要指定节点类型，例如 `CreateMode.PERSISTENT` 表示持久化节点。除此之外还需要指定节点的访问控制列表，例如 `ZooDefs.Ids.OPEN_ACL_UNSAFE` 表示不做访问控制限制。

希望这个示例代码可以帮助您了解如何在 Java 中连接和操作 Zookeeper。