diff --git a/src/main/java/io/github/ehlxr/SlideWindow.java b/src/main/java/io/github/ehlxr/SlideWindow.java deleted file mode 100644 index e060853..0000000 --- a/src/main/java/io/github/ehlxr/SlideWindow.java +++ /dev/null @@ -1,96 +0,0 @@ -/* - * The MIT License (MIT) - * - * Copyright © 2021 xrv - * - * Permission is hereby granted, free of charge, to any person obtaining a copy - * of this software and associated documentation files (the "Software"), to deal - * in the Software without restriction, including without limitation the rights - * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell - * copies of the Software, and to permit persons to whom the Software is - * furnished to do so, subject to the following conditions: - * - * The above copyright notice and this permission notice shall be included in - * all copies or substantial portions of the Software. - * - * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR - * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, - * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE - * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER - * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, - * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN - * THE SOFTWARE. - */ - -package io.github.ehlxr; - -import java.time.LocalTime; -import java.util.LinkedList; -import java.util.List; -import java.util.Map; -import java.util.Random; -import java.util.concurrent.ConcurrentHashMap; - -/** - * 滑动时间窗口限流工具 - * 本限流工具只适用于单机版,如果想要做全局限流,可以按本程序的思想,用redis的List结构去实现 - * - * @author dijia478 - * @date 2020-10-13 10:53 - */ -public class SlideWindow { - - /** - * 队列id和队列的映射关系,队列里面存储的是每一次通过时候的时间戳,这样可以使得程序里有多个限流队列 - */ - private volatile static Map> MAP = new ConcurrentHashMap<>(); - - private SlideWindow() { - } - - public static void main(String[] args) throws InterruptedException { - while (true) { - // 任意10秒内,只允许2次通过 - System.out.println(LocalTime.now().toString() + SlideWindow.isGo("ListId", 5, 1000L)); - // 睡眠0-10秒 - // Thread.sleep(1000 * new Random().nextInt(10)); - } - } - - /** - * 滑动时间窗口限流算法 - * 在指定时间窗口,指定限制次数内,是否允许通过 - * - * @param listId 队列id - * @param count 限制次数 - * @param timeWindow 时间窗口大小 - * @return 是否允许通过 - */ - public static synchronized boolean isGo(String listId, int count, long timeWindow) { - // 获取当前时间 - long nowTime = System.currentTimeMillis(); - // 根据队列id,取出对应的限流队列,若没有则创建 - List list = MAP.computeIfAbsent(listId, k -> new LinkedList<>()); - // 如果队列还没满,则允许通过,并添加当前时间戳到队列开始位置 - if (list.size() < count) { - list.add(0, nowTime); - return true; - } - - // 队列已满(达到限制次数),则获取队列中最早添加的时间戳 - Long farTime = list.get(count - 1); - // 用当前时间戳 减去 最早添加的时间戳 - if (nowTime - farTime <= timeWindow) { - // 若结果小于等于timeWindow,则说明在timeWindow内,通过的次数大于count - // 不允许通过 - return false; - } else { - // 若结果大于timeWindow,则说明在timeWindow内,通过的次数小于等于count - // 允许通过,并删除最早添加的时间戳,将当前时间添加到队列开始位置 - list.remove(count - 1); - list.add(0, nowTime); - return true; - } - } - -} \ No newline at end of file