package com.doumee.core.jiandaoyun.util;
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import java.util.Arrays;
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import java.util.List;
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public class LimitUtil {
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private static volatile int seq = 0;
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private static final int bucket = 1000;
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private static volatile List<Long> requestTimeList = Arrays.asList(0L, 0L, 0L, 0L, 0L);
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private LimitUtil() {
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}
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/**
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* 限流实现 用 static synchronized 修饰 表示 对类上锁
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*
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* @throws InterruptedException
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*/
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public static synchronized void tryBeforeRun() throws InterruptedException {
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long now = System.currentTimeMillis();
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// 当前时间 与 前limit个请求的时间 作比较
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long interval = now - requestTimeList.get(seq);
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if (interval < 0) {
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// 执行时间: t[seq]+bucket=now-interval+bucket
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// 等待时间: bucket-interval
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Thread.sleep(bucket - interval);
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// 重新等待
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tryBeforeRun();
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}
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if (interval < bucket) {
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requestTimeList.set(seq, requestTimeList.get(seq) + bucket);
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Thread.sleep(bucket - interval);
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} else {
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requestTimeList.set(seq, now);
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}
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seq = (seq + 1) % requestTimeList.size();
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}
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}
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