接口访问限流器（频率限制）

某个接口有访问频率限制，限制一分钟最多可以访问XX次，在访问代码中增加限流器，如下

    // 限制每分钟访问次数
        int tpm = SystemConfigs.getInt(SysConfigKeys.XXX_TPM);
        
        int count = 0, round = 0;
        List<XXX> list = new ArrayList<XXX>();
        
        long startMillis = System.currentTimeMillis();
        while (start.before(end)) {//按时间段不停的访问接口
            // 预计时间开销
            long predict = round * 60000 / tpm;
            long duration = System.currentTimeMillis() - startMillis;
            if(predict > duration) {
                // 实际耗时小于预计耗时，sleep
                long waitting = predict - duration;
                try {
                    Thread.sleep(waitting);
                    LOG.debug("XXX同步休眠{}ms. ", waitting);
                } catch (InterruptedException e) {
                    LOG.error("XXX访问频率限制失败：", e);
                }
            }
            round ++;         
            count += this.syncData(start);
            
            start = DateUtils.addDay(start, 1);
        }
     
        LOG.info("总共同步了{}条数据！", count);
        return "XXX同步了" + count + "条数据！";