DCS实践干货：使用Redis实现分布式锁

场景介绍

很多互联网场景（如商品秒杀，论坛回帖盖楼等），需要用加锁的方式，以对某种资源进行顺序访问控制。如果应用服务集群部署，则涉及到对分布式应用加锁。当前分布式加锁主要有三种方式：（磁盘）数据库、缓存数据库、Zookeeper。接下里让我们一起看看加锁实践过程。

 

加锁实现

1  package dcsDemo01;

2   

3  import java.util.UUID;

4   

5  import redis.clients.jedis.Jedis;

6   

7  public class DistributedLock {

8      private final String host = "192.168.0.220";

9      private final int port = 6379;

10   

11      private static final String SUCCESS = "OK";

12      private static final String SET_IF_NOT_EXIST = "NX";

13      private static final String EXPIRE_TIME = "PX";

14   

15      public  DistributedLock(){}

16   

17      /*

18       * @param lockName      锁名

19       * @param timeout       获取锁的超时时间

20       * @param lockTimeout   锁的有效时间

21       * @return              锁的标识

22       */

23      public String getLockWithTimeout(String lockName, long timeout, long lockTimeout) {

24          String ret = null;

25          Jedis jedisClient = new Jedis(host, port);

26   

27          try {

28              String authMsg = jedisClient.auth("Demo@123");

29              if (!SUCCESS.equals(authMsg)) {

30                  System.out.println("AUTH FAILED: " + authMsg);

31              }

32   

33              String identifier = UUID.randomUUID().toString();

34              String lockKey = "DLock:" + lockName;

35              long end = System.currentTimeMillis() + timeout;

36   

37              while(System.currentTimeMillis() < end) {

38                  String result = jedisClient.set(lockKey, identifier, SET_IF_NOT_EXIST, EXPIRE_TIME, lockTimeout);

39