java代码通过redis实现分布式锁

怼烎@ 2021-11-27 02:34 266阅读 0赞

今天有个抢单业务需要需要加锁,所以使用了redis的锁机制,不废话上干货

public int updateTsakSuatusByTaskIdAuthorId() {
      
        try {
            //看当前任务状态----
            boolean isLock = redisRepository.lock(lockKey, "AUTHORID"+authorId, 300L);
            if (!isLock) {//有线程正在使用,请稍后----
                return 7;
            } else {
                业务-----
            }
        } catch (Exception e) {
            log.error("修改抢单状态之前查询状态判断异常", e.getMessage());
        } finally {
            redisRepository.unLock(lockKey);-----必须释放!!!!!
        }
        return updateStatus;
    }

\-------------------------------------------------------

依赖redis的方法

/**
     * 加锁 setNx操作
     */
    public boolean lock(String key, String value, Long second) {
        boolean flag = false;
        List<Object> objList = stringRedisTemplate.executePipelined(new RedisCallback<Object>() {
            public Object doInRedis(RedisConnection connection) throws DataAccessException {
                StringRedisConnection stringRedisConn = (StringRedisConnection) connection;
                return stringRedisConn.setNX(key, value);
            }
        });
        stringRedisTemplate.expire(key, second, TimeUnit.SECONDS);
        if (objList != null && !objList.isEmpty() && (Boolean) objList.get(0) == true)
            flag = true;
        return flag;
    }
    
    /**
     * 释放redis锁
     */
    public void unLock(String key) {
        redisTemplate.delete(key);
    }

\-------------------------------------------------------------

总结个人心得来说,分布式锁,就是让每个线程修改之前先去统一的redis上查当前任务状态,这样既能保证单机也能保证分布式的数据安全.

个人随笔,有错误请指教