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update at 2021-07-15 18:35:46 by ehlxr

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ehlxr 2021-07-15 18:35:46 +08:00
parent 0b5acb84ab
commit 2f74ee2c8c
3 changed files with 178 additions and 0 deletions
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35
src/main/java/io/github/ehlxr/ClassLoaderTest.java Normal file
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/*
* The MIT License (MIT)
*
* Copyright © 2021 xrv <xrg@live.com>
*
* 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;
/**
* @author ehlxr
* @since 2021-07-07 22:54.
*/
public class ClassLoaderTest {
public static void main(String[] args) {
System.out.println(ClassLoader.getSystemClassLoader());
}
}

96
src/main/java/io/github/ehlxr/SlideWindow.java Normal file
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/*
* The MIT License (MIT)
*
* Copyright © 2021 xrv <xrg@live.com>
*
* 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<String, List<Long>> 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<Long> 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;
}
}
}

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src/main/java/io/github/ehlxr/jvm/stack/ReturnAddressTest.java Normal file
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/*
* The MIT License (MIT)
*
* Copyright © 2021 xrv <xrg@live.com>
*
* 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.jvm.stack;
/**
* @author ehlxr
* @since 2021-07-11 15:19.
*/
public class ReturnAddressTest {
public void methodA() {
int k = 10;
int l = 20;
methodB();
}
public void methodB() {
int i = 10;
int j = 20;
int a = i + j;
}
}