鄂州网站制作哪家好,ps做网站边框,百度指数移动版怎么用,wordpress电子邮件注册本文主要介绍了几种限流方法#xff1a;Guava RateLimiter、简单计数、滑窗计数、信号量、令牌桶#xff0c;漏桶算法和nginx限流等等 1、引入guava集成的工具 pom.xml 文件
dependencygroupIdcom.google.guava/groupIdartifactIdguava…本文主要介绍了几种限流方法Guava RateLimiter、简单计数、滑窗计数、信号量、令牌桶漏桶算法和nginx限流等等 1、引入guava集成的工具 pom.xml 文件
dependencygroupIdcom.google.guava/groupIdartifactIdguava/artifactIdversion23.0/version/dependencydemo代码实现
package com.znkeji.zn_wifi_carck.guava;import com.google.common.util.concurrent.RateLimiter;public class GuavaRateLimiterTest {//比如每秒生产10个令牌相当于每100ms生产1个令牌//RateLimiter是Guava库中的一个限流器// 基于PPS进行限流//基于PPS限流的同时提供热启动private RateLimiter rateLimiterRateLimiter.create(10);/*** 模拟执行业务方法*/public void exeBiz(){if (rateLimiter.tryAcquire(1)){///返回boolean 尝试获取许可如果该许可可以在无延迟下的情况下立即获取得到的话try {Thread.sleep(50);}catch (Exception e){e.printStackTrace();}System.out.println(线程Thread.currentThread().getName()执行业务逻辑);}else {System.out.println(线程Thread.currentThread().getName():被限流了);}}public static void main(String[] args) throws InterruptedException {GuavaRateLimiterTest guavaRateLimiterTest new GuavaRateLimiterTest();System.out.println(线程开始等待);Thread.sleep(500); //等待500ms让limiter生产一些令牌System.out.println(线程睡了0.5秒);//模拟瞬间生产100个线程请求for (int i0;i100;i){new Thread(guavaRateLimiterTest::exeBiz).start();}}}2.令牌桶算法
package com.znkeji.zn_wifi_carck.guava;import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;/*** 令牌桶算法一个存放固定容量令牌的桶按照固定速率往桶里添加令牌如有剩余容量则添加没有则放弃。如果有请求进来则需要先从桶里获取令牌当桶里没有令牌可取时则拒绝任务。** 令牌桶的优点是可以改变添加令牌的速率一旦提高速率则可以处理突发流量。*/
public class TokenBucket {/*** 定义的桶*/public class Bucket {//容量int capacity;//速率每秒放多少int rateCount;//目前token个数AtomicInteger curCount new AtomicInteger(0);public Bucket(int capacity, int rateCount) {this.capacity capacity;this.rateCount rateCount;}public void put() {if (curCount.get() capacity) {System.out.println(目前数量 curCount.get() , 我还可以继续放);curCount.addAndGet(rateCount);}}public boolean get() {if (curCount.get() 1) {curCount.decrementAndGet();return true;}return false;}}// Testpublic void testTokenBucket() throws InterruptedException {Bucket bucket new Bucket(5, 2);//固定线程固定的速率往桶里放数据比如每秒N个ScheduledThreadPoolExecutor scheduledCheck new ScheduledThreadPoolExecutor(1);scheduledCheck.scheduleAtFixedRate(() - {bucket.put();}, 0, 1, TimeUnit.SECONDS);//先等待一会儿让桶里放点tokenThread.sleep(6000);//模拟瞬间10个线程进来拿tokenfor (int i 0; i 10; i) {new Thread(() - {if (bucket.get()) {System.out.println(Thread.currentThread() 获取到了资源);} else {System.out.println(Thread.currentThread() 被拒绝);}}).start();}//等待往桶里放tokenThread.sleep(3000);//继续瞬间10个线程进来拿tokenfor (int i 0; i 10; i) {new Thread(() - {if (bucket.get()) {System.out.println(Thread.currentThread() 获取到了资源);} else {System.out.println(Thread.currentThread() 被拒绝);}}).start();}}
}
3、滑窗计数器
package com.znkeji.zn_wifi_carck.guava;import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;/*** 滑窗计数器 打个比方某接口每秒允许100个请求设置一个滑窗窗口中有10个格子每个格子占100ms每100ms移动一次。滑动窗口的格子划分的越多滑动窗口的滚动就越平滑限流的统计就会越精确。*/
public class SliderWindowRateLimiter implements Runnable {//每秒允许的最大访问数private final long maxVisitPerSecond;//将每秒时间划分N个块private final int block;//每个块存储的数量private final AtomicLong[] countPerBlock;//滑动窗口划到了哪个块儿可以理解为滑动窗口的起始下标位置private volatile int index;//目前总的数量private AtomicLong allCount;/*** 构造函数** param block每秒钟划分N个窗口* param maxVisitPerSecond 每秒最大访问数量*/public SliderWindowRateLimiter(int block,long maxVisitPerSecond){this.blockblock;this.maxVisitPerSecondmaxVisitPerSecond;countPerBlock new AtomicLong[block];for (int i0;iblock;i){countPerBlock[i]new AtomicLong();}allCountnew AtomicLong(0);}/*** 判断是否超过最大允许数量** return*/public boolean isOverLimit() {return currentQPS() maxVisitPerSecond;}/*** 获取目前总的访问数** return*/public long currentQPS() {return allCount.get();}/*** 请求访问进来判断是否可以执行业务逻辑*/public void visit(){countPerBlock[index].incrementAndGet();allCount.incrementAndGet();if (isOverLimit()){System.out.println(Thread.currentThread().getName()被限流了currentQPScurrentQPS());}else {System.out.println(Thread.currentThread().getName()执行业务逻辑currentQPScurrentQPS());}}/*** 定时执行器* 每N毫秒滑块移动一次然后再设置下新滑块的初始化数字0然后新的请求会落到新的滑块上* 同时总数减掉新滑块上的数字并且重置新的滑块上的数量*/Overridepublic void run() {index(index1)%block;long val countPerBlock[block].getAndSet(0);allCount.addAndGet(-val);}public static void main(String[] args) {SliderWindowRateLimiter sliderWindowRateLimiter new SliderWindowRateLimiter(10, 100);//固定的速率移动滑块ScheduledExecutorService scheduledExecutorService Executors.newSingleThreadScheduledExecutor();scheduledExecutorService.scheduleAtFixedRate(sliderWindowRateLimiter, 100, 100, TimeUnit.MILLISECONDS);//模拟不同速度的请求new Thread(() - {while (true) {sliderWindowRateLimiter.visit();try {Thread.sleep(10);} catch (InterruptedException e) {e.printStackTrace();}}}).start();//模拟不同速度的请求new Thread(() - {while (true) {sliderWindowRateLimiter.visit();try {Thread.sleep(50);} catch (InterruptedException e) {e.printStackTrace();}}}).start();}
}
4、信号量
package com.znkeji.zn_wifi_carck.guava;import java.util.Timer;
import java.util.TimerTask;
import java.util.concurrent.Semaphore;/*** 利用Semaphore每隔固定速率释放Semaphore的资源。线程获取到资源则执行业务代码。*/
public class SemaphoreOne {private static Semaphore semaphore new Semaphore(10);public static void bizMethod() throws InterruptedException {if (!semaphore.tryAcquire()) {System.out.println(Thread.currentThread().getName() 被拒绝);return;}System.out.println(Thread.currentThread().getName() 执行业务逻辑);Thread.sleep(500);//模拟处理业务逻辑需要1秒semaphore.release();}public static void main(String[] args) {Timer timer new Timer();timer.scheduleAtFixedRate(new TimerTask() {Overridepublic void run() {semaphore.release(10);System.out.println(释放所有锁);}}, 1000, 1000);for (int i 0; i 10000; i) {try {Thread.sleep(10);//模拟每隔10ms就有1个请求进来} catch (InterruptedException e) {e.printStackTrace();}new Thread(() - {try {SemaphoreOne.bizMethod();} catch (InterruptedException e) {e.printStackTrace();}}).start();}}
}
