利用zookeeper 实现分布式锁

利用Curator(流行的 zk 客户端工具包) 的 InterProcessMute 类

import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.framework.recipes.locks.InterProcessLock;
import org.apache.curator.framework.recipes.locks.InterProcessMutex;
import org.apache.curator.retry.ExponentialBackoffRetry;

import java.util.Random;
import java.util.concurrent.CountDownLatch;

/**
 * 文件功能：zookeeper分布式锁
 * 故事：5个线程（模拟分布式进程）争夺分布式锁
 */
public class CuratorLocksExample {

    private static  InterProcessLock distributeLock=null;
    private static CountDownLatch count=new CountDownLatch(5);

    public static void main(String[] args) {
        CuratorFramework client = CuratorFrameworkFactory.newClient("192.168.64.128:2181", new ExponentialBackoffRetry(1000, 3));
        client.start();
        distributeLock=new InterProcessMutex(client,"/mylock");
        for(int i=0;i<5;i++){
            new Thread(new MyHostThread("线程"+i,client,distributeLock,count)).start();
        }

        try {
            count.await();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }finally {
            System.out.println("释放客户端,断开zk链接");
            client.close();
        }

    }
}


class MyHostThread implements Runnable{

    private String name;
    private CuratorFramework client;
    private InterProcessLock lock;
    private  CountDownLatch count;
    public MyHostThread(String name,CuratorFramework client,InterProcessLock lock,CountDownLatch count){
        this.name=name;
        this.client=client;
        this.lock=lock;
        this.count=count;
    }

    @Override
    public void run() {
        System.out.println(this.name + "开始竞争锁");
        try {
            lock.acquire();//阻塞等待..
            System.out.println(this.name + "获取到锁");
            Thread.sleep(new Random().nextInt(2000));//模拟业务处理2s内
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            try {
                System.out.println(this.name + "业务处理完，释放锁");
                lock.release();//释放锁
                count.countDown();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
}

预期输出：

线程3开始竞争锁
线程0开始竞争锁
线程4开始竞争锁
线程1开始竞争锁
线程2开始竞争锁
线程0获取到锁
线程0业务处理完，释放锁
线程4获取到锁
线程4业务处理完，释放锁
线程1获取到锁
线程1业务处理完，释放锁
线程3获取到锁
线程3业务处理完，释放锁
线程2获取到锁
线程2业务处理完，释放锁
释放客户端,断开zk链接