Detailed explanation of redis memory lock and PHP preventing concurrent operations

This article mainly shares with you the detailed explanation of redis memory lock and PHP preventing concurrent operations. I hope it can help you.

1、redis锁代码：

   /**
     * 获取锁
     * @param  String  $key    锁标识
     * @param  Int     $expire 锁过期时间
     * @return Boolean
     */
    public function lock($key, $expire=5){
        $is_lock = $this->_redis->setnx($key, time()+$expire);

        // 不能获取锁
        if(!$is_lock){
            // 判断锁是否过期
            $lock_time = $this->_redis->get($key);
            // 锁已过期，删除锁，重新获取
            if(time()>$lock_time){
                $this->unlock($key);
                $is_lock = $this->_redis->setnx($key, time()+$expire);
            }
        }
        return $is_lock? true : false;
    }

    /**
     * 释放锁
     * @param  String  $key 锁标识
     * @return Boolean
     */
    public function unlock($key){
        return $this->_redis->del($key);
    }

2、业务代码（php）
 //设置锁，防止多个用户并发操作连麦超出数量限制
        $lockKey = CacheKeyManage::getLianMaiLockKey($partyId); //缓存key
        $redis = new RedisHelperUtil();
        $lock = $redis->lock($lockKey);
        if(!$lock) {
            for($i=0;$i<3;$i++){ //重试3次，如果3次还未获取倒锁提示繁忙
                $lock = $redis->lock($lockKey);
                if($lock){
                    break;
                }
                sleep(1);
            }
            if(!$lock){
                return self::setAndReturn(ErrorCode::ERR_OTHER_ERR,&#39;服务器获取锁获取不到,$lockKey:&#39;.$lockKey);
            }
        }

        doAction..... //获取到了锁，做自己的业务

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