redis 分布式锁实现

/**
 * 获取锁
 *
 * @param lockKey 锁key
 * @param value 锁值 一般随机生成
 * @param expireTime：单位-秒
 * @return 成功猎取锁返回true
 */
public boolean getLock(String lockKey, String value, int expireTime) {
    try {
        String script = "if redis.call('setNx',KEYS[1],ARGV[1]) then if redis.call('get',KEYS[1])==ARGV[1] then return redis.call('expire',KEYS[1],ARGV[2]) else return 0 end end";
        RedisScript<Long> redisScript = new DefaultRedisScript<>(script, Long.class);
        Object result = this.redisTemplate.execute(redisScript, Collections.singletonList(lockKey), value, expireTime);
        if (SUCCESS.equals(result)) {
            return true;
        }
    } catch (Exception e) {
        e.printStackTrace();
        return false;
    }
    return false;
}

/**
 * 释放锁
 *
 * @param lockKey 锁key
 * @param value 锁值 获取锁时随机生成的串
 * @return
 */
public boolean releaseLock(String lockKey, String value) {
    String script = "if redis.call('get', KEYS[1]) == ARGV[1] then return redis.call('del', KEYS[1]) else return 0 end";
    RedisScript<Long> redisScript = new DefaultRedisScript<>(script, Long.class);
    Object result = this.redisTemplate.execute(redisScript, Collections.singletonList(lockKey), value);
    if (SUCCESS.equals(result)) {
        return true;
    }
    return false;
}

/**
 * 获取查询锁,返回锁标识
 *
 * @param lockName       锁的key
 * @param acquireTimeout 获取锁超时时间 ms
 * @param timeout        锁的超时时间 ms
 * @return 锁标识UUID
 */
public  String lockWithTimeout(String lockName, int acquireTimeout, int timeout) {
    // 随机生成一个value
    String value = UUID.randomUUID().toString();
    if(lockWithTimeout(lockName, value, acquireTimeout, timeout)) {
        return value;
    }
    return null;
}

/**
 * 获取查询锁
 * @param lockName      锁的key
 * @param requestId     请求标识码
 * @param acquireTimeout    获取锁超时时间 ms
 * @param timeout       锁的超时时间 ms
 * @return
 */
public boolean lockWithTimeout(String lockName, String requestId, int acquireTimeout, int timeout) {
    // 超时时间，上锁后超过此时间则自动释放锁
    int lockExpire = timeout / 1000;

    // 获取锁的超时时间，超过这个时间则放弃获取锁
    long end = System.currentTimeMillis() + acquireTimeout;
    while (System.currentTimeMillis() < end) {
        if (getLock(lockName, requestId, lockExpire)) {
            return true;
        }
        try {
            Thread.sleep(10);
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
        }
    }
    return false;
}