ZooKeeper（八）-- Curator实现分布式锁

1.pom.xml

  <dependencies>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.10</version>
        <scope>test</scope>
   </dependency>
   <dependency>
        <groupId>org.apache.zookeeper</groupId>
        <artifactId>zookeeper</artifactId>
        <version>3.4.6</version>
   </dependency>
   <dependency>
       <groupId>org.apache.curator</groupId>
       <artifactId>curator-recipes</artifactId>
       <version>2.5.0</version>
   </dependency>
  </dependencies>

2.JAVA代码

package com.xbq.zookeeper.curator;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Semaphore;
import java.util.concurrent.TimeUnit;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.framework.recipes.locks.InterProcessMutex;
import org.apache.curator.retry.RetryNTimes;

/**
 * 使用Curator来实现分布式锁
 * @author xbq
 */
public class LockByCurator {

    // 此demo使用的集群，所以有多个ip和端口
    private static String CONNECT_SERVER = "192.168.242.129:2181,192.168.242.129:2182,192.168.242.129:2183";
    // session过期时间
    private static int SESSION_TIMEOUT = 3000;
    // 连接超时时间
    private static int CONNECTION_TIMEOUT = 3000; 
    
    // 锁节点
    private static final String CURATOR_LOCK = "/curatorLock";
    
    /**
     * 获取锁操作
     * @param cf
     */
    public static void doLock(CuratorFramework cf){
        System.out.println(Thread.currentThread().getName() + " 尝试获取锁！");
        // 实例化 zk分布式锁  
        InterProcessMutex mutex = new InterProcessMutex(cf, CURATOR_LOCK);
        try {
            // 判断是否获取到了zk分布式锁
            if(mutex.acquire(5, TimeUnit.SECONDS)){
                System.out.println(Thread.currentThread().getName() + " 获取到了锁！-------");
                // 业务操作
                Thread.sleep(5000);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                // 释放锁
                mutex.release();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
    
    /**
     * 测试
     * @param args
     */
    public static void main(String[] args) {
        // 定义线程池
        ExecutorService service = Executors.newCachedThreadPool();
        // 定义信号灯，只能允许10个线程并发操作
        final Semaphore semaphore = new Semaphore(10);
        // 模拟10个客户端
        for(int i=0; i < 10 ;i++){
            Runnable runnable = new Runnable() {
                @Override
                public void run() {
                    try {
                        semaphore.acquire();
                         // 连接 ZooKeeper 
                        CuratorFramework framework = CuratorFrameworkFactory.
                                newClient(CONNECT_SERVER, SESSION_TIMEOUT, CONNECTION_TIMEOUT, new RetryNTimes(10,5000));
                        // 启动
                        framework.start();
                        doLock(framework);
                        
                        semaphore.release();
                    } catch (Exception e) {
                    
                    }
                }
            };
            service.execute(runnable);
        }
        service.shutdown();
    }
}

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