RateLimiter简介

RateLimiter是Guava库中的一个限流器，它提供如下功能：
(1)基于PPS进行限流
(2)基于PPS限流的同时提供热启动

springboot集成RateLimiter

pom.xml引入

<!--引入guava依赖-->
<dependency><groupId>com.google.guava</groupId><artifactId>guava</artifactId><version>31.1-jre</version>
</dependency>

RateLimiter常用api

(1)RateLimiter.create(double permitsPerSecond); ===> 指定速率，每秒产生permitsPerSecond个令牌
(2)rateLimiter.acquire(int permits); ===> 返回获取permits个令牌所需的时间
(3)rateLimiter.tryAcquire(1); ===> 获取1个令牌，返回false获取失败，true获取成功
(4)rateLimiter.tryAcquire(1, 2, TimeUnit.SECONDS); ===> 获取1个令牌，最多等待两秒。返回false获取失败，true获取成功

package com.mry.springboottools.controller;import com.google.common.util.concurrent.RateLimiter;import java.util.concurrent.TimeUnit;/*** RateLimiter测试类*/
public class RateLimiterTest {public static void main(String[] args) {//指定速率，每秒产生一个令牌  RateLimiter rateLimiter = RateLimiter.create(1);System.out.println(rateLimiter.getRate());//修改为每秒产生2个令牌rateLimiter.setRate(2);System.out.println(rateLimiter.getRate());//while (true) {  //获取2个令牌所需要的时间  double acquire = rateLimiter.acquire(2);//输出结果， 第一次0秒，后面每次等待接近0.5秒的时间  //0.0  //0.995198  //0.9897  //0.999413  //0.998272  //0.99202  //0.993757  //0.996198  //0.99523  //0.99532  //0.992674  System.out.println(acquire);// }  //获取1个令牌  boolean result = rateLimiter.tryAcquire(1);System.out.println(result);//获取1个令牌,最多等待两秒  boolean result2 = rateLimiter.tryAcquire(1, 2, TimeUnit.SECONDS);System.out.println(result2);}
}

代码实现

自定义注解Limiter

package com.mry.springboottools.annotation;import java.lang.annotation.*;
import java.util.concurrent.TimeUnit;/*** 限流注解** @author* @date*/
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Limiter {/*** 不进行限流*/int NOT_LIMITED = 0;/*** qps (每秒并发量)*/double qps() default NOT_LIMITED;/*** 超时时长,默认不等待*/int timeout() default 0;/*** 超时时间单位,默认毫秒*/TimeUnit timeUnit() default TimeUnit.MILLISECONDS;/*** 返回错误信息*/String msg() default "系统忙，请稍后再试";}

限流切面

package com.mry.springboottools.aspect;import com.google.common.util.concurrent.RateLimiter;
import com.mry.springboottools.annotation.Limiter;
import lombok.extern.slf4j.Slf4j;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.stereotype.Component;
import java.lang.reflect.Method;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;/*** 限流切面* @author* @date*/
@Slf4j
@Aspect
@Component
public class RateLimiterAspect {/*** key: 类全路径+方法名*/private static final ConcurrentMap<String, RateLimiter> RATE_LIMITER_CACHE = new ConcurrentHashMap<>();@Around("@within(limiter) || @annotation(limiter)")public Object pointcut(ProceedingJoinPoint point, Limiter limiter) throws Throwable {MethodSignature signature = (MethodSignature) point.getSignature();Method method = signature.getMethod();if (limiter != null && limiter.qps() > Limiter.NOT_LIMITED) {double qps = limiter.qps();//这个key可以根据具体需求配置,例如根据ip限制,或用户String key = method.getDeclaringClass().getName() + method.getName();if (RATE_LIMITER_CACHE.get(key) == null) {// 初始化 QPSRATE_LIMITER_CACHE.put(key, RateLimiter.create(qps));}// 尝试获取令牌if (RATE_LIMITER_CACHE.get(key) != null && !RATE_LIMITER_CACHE.get(key).tryAcquire(limiter.timeout(), limiter.timeUnit())) {log.error("触发限流操作{}", key);throw new RuntimeException(limiter.msg());}}return point.proceed();}}

验证

package com.mry.springboottools.controller;import com.google.common.util.concurrent.RateLimiter;
import com.mry.springboottools.annotation.Limiter;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.concurrent.TimeUnit;/*** 测试限流* @author* @date*/
@RestController
@RequestMapping("limiter")
@Slf4j
public class RateLimiterController {@GetMapping@Limiter(qps = 1, msg = "您已被限流！")public String getUserName() {String userName = "mry";log.info("userName = {}", userName);return userName;}
}

接口请求：

日志输出：