Zookeeper分布式锁（集群环境）

引入 第三方的sdk 

<dependencies>
		<dependency>
			<groupId>com.101tec</groupId>
			<artifactId>zkclient</artifactId>
			<version>0.10</version>
		</dependency>
	</dependencies>

使用模版方法进行分布式锁集成

package com.test.zk;

public interface lock {

    //获取到锁的资源
    void getLock();
    // 释放锁
    void unLock();
}

package com.test.zk;

import org.I0Itec.zkclient.ZkClient;

/**
 * @ClassName ZookeeperAbstractLock
 * @Description TODO
 * @Author moran
 * @Date 2019/12/10 11:29
 **/
public abstract class ZookeeperAbstractLock implements lock{

    // zk连接地址server.2=192.168.2.101:2888:3888
    //server.1=192.168.2.102:2888:3888
    //server.3=192.168.2.148
    private static final String CONNECTSTRING = "192.168.2.101,192.168.2.102,192.168.2.148";
    // 创建zk连接
    protected ZkClient zkClient = new ZkClient(CONNECTSTRING);
    protected static final String PATH = "/lock";
    public void getLock() {
        if (tryLock()) {
            System.out.println("##获取lock锁的资源####");
        } else {
            // 等待
            waitLock();
            // 重新获取锁资源
            getLock();
        }

    }

    // 获取锁资源
    abstract boolean tryLock();

    // 等待
    abstract void waitLock();

    public void unLock() {
        if (zkClient != null) {
            zkClient.close();
            System.out.println("释放锁资源...");
        }
    }
}

package com.test.zk;

import java.text.SimpleDateFormat;
import java.util.Date;

public class OrderNumGenerator {

	// 生成订单号规则
	private static int count = 0;

	public String getNumber() {
		try {
			Thread.sleep(200);
		} catch (Exception e) {

		}
		SimpleDateFormat simpt = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss");
		return simpt.format(new Date()) + "-" + ++count;
	}

}

package com.test.zk;

public class OrderService implements Runnable {
	private OrderNumGenerator orderNumGenerator = new OrderNumGenerator();
	// 使用lock锁
	// private java.util.concurrent.locks.Lock lock = new ReentrantLock();
	private lock lock = new ZookeeperLock();
	public void run() {
		getNumber();
	}
	public void getNumber() {
		try {
			lock.getLock();
			String number = orderNumGenerator.getNumber();
			System.out.println(Thread.currentThread().getName() + ",生成订单ID:" + number);
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			lock.unLock();
		}
	}
	public static void main(String[] args) {
		System.out.println("####生成唯一订单号###");
//		OrderService orderService = new OrderService();
		for (int i = 0; i < 100; i++) {
			new Thread( new OrderService()).start();
		}
	}
}

package com.test.zk;

import org.I0Itec.zkclient.IZkDataListener;

import java.util.concurrent.CountDownLatch;

public class ZookeeperLock extends ZookeeperAbstractLock {
	private CountDownLatch countDownLatch = null;

	@Override
	boolean tryLock() {
		try {
			zkClient.createEphemeral(PATH);
			return true;
		} catch (Exception e) {
//			e.printStackTrace();
			return false;
		}

	}

	@Override
	void waitLock() {
		IZkDataListener izkDataListener = new IZkDataListener() {

			public void handleDataDeleted(String path) throws Exception {
				// 唤醒被等待的线程
				if (countDownLatch != null) {
					countDownLatch.countDown();
				}
			}
			public void handleDataChange(String path, Object data) throws Exception {

			}
		};
		// 注册事件
		zkClient.subscribeDataChanges(PATH, izkDataListener);
		if (zkClient.exists(PATH)) {
			countDownLatch = new CountDownLatch(1);
			try {
				countDownLatch.await();
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
		// 删除监听
		zkClient.unsubscribeDataChanges(PATH, izkDataListener);
	}

}