令牌桶算法实现API限流

https://www.cnblogs.com/wangxiayun/p/9300556.html

令牌桶算法( Token Bucket )和 Leaky Bucket 效果一样但方向相反的算法,更加容易理解.随着时间流逝,系统会按恒定 1/QPS 时间间隔(如果 QPS=100 ,则间隔是 10ms )往桶里加入 Token(想象和漏洞漏水相反,有个水龙头在不断的加水),如果桶已经满了就不再加了.新请求来临时,会各自拿走一个 Token ,如果没有 Token 可拿了就阻塞或者拒绝服务.

 

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@Autowired    private JedisClientService jedisClient;      public boolean acquire(String key, Integer permits, long currMillSecond) {        try  {              //针对新用户创建令牌桶            if (!jedisClient.exists(key)) {                jedisClient.hset(key, "last_mill_second", String.valueOf(currMillSecond));                jedisClient.hset(key, "curr_permits", "0");                jedisClient.hset(key, "max_permits", "50");                jedisClient.hset(key, "rate", "400");                return true;            }            //获取令牌桶信息，上一个令牌时间，当前可用令牌数，最大令牌数，令牌消耗速率            List<String> limitInfo = jedisClient.hmget(key, "last_mill_second", "curr_permits", "max_permits", "rate");            long lastMillSecond = Long.parseLong(limitInfo.get(0));            Integer currPermits = Integer.valueOf(limitInfo.get(1));            Integer maxPermits = Integer.valueOf(limitInfo.get(2));            Double rate = Double.valueOf(limitInfo.get(3));            //向桶里面添加令牌            Double reversePermitsDouble = ((currMillSecond - lastMillSecond) / 1000) * rate;              Integer reversePermits = reversePermitsDouble.intValue();            Integer expectCurrPermits = reversePermits + currPermits;            Integer localCurrPermits = Math.min(expectCurrPermits, maxPermits);            //添加令牌之后更新时间            if (reversePermits > 0) {                jedisClient.hset(key, "last_mill_second", String.valueOf(currMillSecond));            }            //判断桶里面剩余的令牌数目            if (localCurrPermits - permits >= 0) {                jedisClient.hset(key, "curr_permits", String.valueOf(localCurrPermits - permits));                return true;            } else {                jedisClient.hset(key, "curr_permits", String.valueOf(localCurrPermits));                return false;            }        } catch (Exception e) {            e.printStackTrace();            return false;        }    }

　　

 

参考文章: https://blog.youkuaiyun.com/tianyaleixiaowu/article/details/74942405