zookeeper 写入数据的java 程序

以下是使用 Java API 将数据写入 ZooKeeper 的示例代码：

import org.apache.zookeeper.*;
import org.apache.zookeeper.Watcher.Event.KeeperState;
import org.apache.zookeeper.ZooDefs.Ids;
import org.apache.zookeeper.data.Stat;

import java.io.IOException;
import java.util.concurrent.CountDownLatch;

public class ZooKeeperWriter implements Watcher {

    private static final int SESSION_TIMEOUT = 5000;
    private static final String CONNECTION_STRING = "localhost:2181";
    private static final String ZNODE_PATH = "/my_znode";
    private static final String ZNODE_DATA = "Hello, ZooKeeper!";

    private ZooKeeper zooKeeper;
    private CountDownLatch connectedSignal = new CountDownLatch(1);

    public void connect() throws IOException, InterruptedException {
        zooKeeper = new ZooKeeper(CONNECTION_STRING, SESSION_TIMEOUT, this);
        connectedSignal.await();
    }

    public void close() throws InterruptedException {
        zooKeeper.close();
    }

    public void createZNode() throws KeeperException, InterruptedException {
        byte[] data = ZNODE_DATA.getBytes();
        zooKeeper.create(ZNODE_PATH, data, Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
    }

    public void updateZNode() throws KeeperException, InterruptedException {
        byte[] data = "Updated data".getBytes();
        zooKeeper.setData(ZNODE_PATH, data, zooKeeper.exists(ZNODE_PATH, true).getVersion());
    }

    public void deleteZNode() throws KeeperException, InterruptedException {
        zooKeeper.delete(ZNODE_PATH, zooKeeper.exists(ZNODE_PATH, true).getVersion());
    }

    public void process(WatchedEvent event) {
        if (event.getState() == KeeperState.SyncConnected) {
            connectedSignal.countDown();
        }
    }

    public static void main(String[] args) throws IOException, InterruptedException, KeeperException {
        ZooKeeperWriter zooKeeperWriter = new ZooKeeperWriter();
        zooKeeperWriter.connect();
        zooKeeperWriter.createZNode();
        zooKeeperWriter.updateZNode();
        zooKeeperWriter.deleteZNode();
        zooKeeperWriter.close();
    }
}

这个示例程序首先创建了一个 ZooKeeper 实例并在 `connect()` 方法中等待连接建立。然后，它使用 `createZNode()` 方法创建了一个数据节点，并使用 `updateZNode()` 方法更新了该节点的数据，最后使用 `deleteZNode()` 方法删除了该节点。在 `process()` 方法中，我们使用 `CountDownLatch` 来等待连接建立完成。