最近学习了LongAdder和Striped64，打算写一个qps统计工具，刚好项目上也需要。

借鉴了一下前人的文章：https://www.cnblogs.com/ganRegister/p/9369131.html

 

优化点：

1、增加了一个最大qps的统计

2、最上锁部分的代码进行了一些简化

/**
* 最大qps
*/
private volatile long maxSummary;

　　　　　　　　　　　　try {
                        enterNextBucketLock.lock(); //可以尝试用tryLock
                        //其他线程出来
                        if (passTime - lastPassTimeCloseToTargetBucket >= bucketTimeSlice) {
                            int nextTargetBucketPosition = (int) (passTime / bucketTimeSlice) % bucketNum;
                            Bucket nextBucket = buckets[nextTargetBucketPosition];
                            if (!nextBucket.equals(currentBucket)) {
                                //跨槽
                                long summary = buckets[targetBucketPosition].sum();
                                if (summary > maxSummary) {
                                    //增加了最大qps的统计
                                    maxSummary = summary;
                                }
                                nextBucket.reset(passTime);
                                //目标槽位变动
                                targetBucketPosition = nextTargetBucketPosition;
                            }
                            lastPassTimeCloseToTargetBucket = passTime;
                            nextBucket.incr();
                            return;
                        } else {
                            currentBucket = buckets[targetBucketPosition];
                        }
                    } finally {
                        enterNextBucketLock.unlock();
                    }