redis 分布式锁 使用示例

redis 分布式锁 使用示例

分布式锁

code segment

    private static final String LOCK_SUCCESS = "OK";
    private static final String SET_IF_NOT_EXIST = "NX";
    private static final String SET_WITH_EXPIRE_TIME = "EX";

    private static final String LOCKED = "locked";

    /**
     * 加锁
     *
     * @param key     redis key
     * @param seconds 过期时间
     * @return 如果加锁成功, 返回true, 反之, 返回false
     */
    public boolean lock(String key, Integer seconds) {
        final String newKey = String.format(RedisConstant.PREFIX, key);
        String exist = "";
        try {
            exist = redisTemplate.execute(action -> action.set(newKey,
                    LOCKED,
                    SET_IF_NOT_EXIST,
                    SET_WITH_EXPIRE_TIME,
                    seconds));
        } catch (Exception e) {
            logger.error("lock error", e);
        }
        return exist != null && exist.equals(LOCK_SUCCESS);
    }

设置普通缓存

code segment

redisTemplate.execute(redis -> redis.setex(redisKey, expiredTime,value));

取缓存

code segment

String value = redisTemplate.execute(action -> action.get(key));

取过期时间

code segment

 Long remainSeconds = 0L;
        try {
            remainSeconds = redisTemplate.execute(action -> action.ttl(key));
        } catch (Exception ex) {
            logger.error("redis ttl error", ex);
        }
        if (remainSeconds <= 0L) {
            //some logic
        }