分布式锁（Redis）

加锁

public class RedisTool {

 

    private static final String LOCK_SUCCESS = "OK";

    private static final String SET_IF_NOT_EXIST = "NX";

    private static final String SET_WITH_EXPIRE_TIME = "PX";

 

    /**

     * 尝试获取分布式锁

     * @param jedis Redis客户端

     * @param lockKey 锁

     * @param requestId 请求标识

     * @param expireTime 超期时间

     * @return 是否获取成功

     */

    public static boolean tryGetDistributedLock(Jedis jedis, String lockKey, String requestId, int expireTime) {

 

        String result = jedis.set(lockKey, requestId, SET_IF_NOT_EXIST, SET_WITH_EXPIRE_TIME, expireTime);

 

        if (LOCK_SUCCESS.equals(result)) {

            return true;

        }

        return false;

 

    }

 

}

 

解锁

 

public class RedisTool {

 

    private static final Long RELEASE_SUCCESS = 1L;

 

    /**

     * 释放分布式锁

     * @param jedis Redis客户端

     * @param lockKey 锁

     * @param requestId 请求标识

     * @return 是否释放成功

     */

    public static boolean releaseDistributedLock(Jedis jedis, String lockKey, String requestId) {

 

        String script = "if redis.call('get', KEYS[1]) == ARGV[1] then return redis.call('del', KEYS[1]) else return 0 end";

        Object result = jedis.eval(script, Collections.singletonList(lockKey), Collections.singletonList(requestId));

 

        if (RELEASE_SUCCESS.equals(result)) {

            return true;

        }

        return false;

 

    }

 

}