ZooKeeper共享锁怎么创建

ZooKeeper共享锁是一种分布式锁，它可以让多个客户端在分布式环境中共享一个锁。它的工作原理是，客户端在获取锁之前，首先要向ZooKeeper注册一个临时节点，然后获取锁。如果客户端获取到锁，则表示该客户端可以对共享资源进行操作；如果客户端没有获取到锁，则表示该客户端需要等待。当客户端释放锁之后，临时节点也会被删除。

下面是一个简单的ZooKeeper共享锁的例子：

import org.apache.zookeeper.CreateMode;

import org.apache.zookeeper.WatchedEvent;

import org.apache.zookeeper.Watcher;

import org.apache.zookeeper.ZooDefs.Ids;

import org.apache.zookeeper.ZooKeeper;

public class DistributedLock {

private static final String CONNECTION_STRING = "localhost:2181";

private static final int SESSION_TIMEOUT = 30000;

private static final String LOCK_PATH = "/lock";

private ZooKeeper zk;

private String lockId;

public DistributedLock() throws Exception {

zk = new ZooKeeper(CONNECTION_STRING, SESSION_TIMEOUT, new Watcher() {

public void process(WatchedEvent event) {

// do nothing

}

});

}

public synchronized void lock() throws Exception {

lockId = zk.create(LOCK_PATH, null, Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL);

System.out.println("lock: " + lockId);

}

public synchronized void unlock() throws Exception {

System.out.println("unlock: " + lockId);

zk.delete(lockId, -1);

lockId = null;

}

public static void main(String[] args) throws Exception {

DistributedLock lock = new DistributedLock();

lock.lock();

Thread.sleep(10000);

lock.unlock();

}

}