Java 使用 Google Guava 实现接口限流

一、引入依赖

<dependency><groupId>com.google.guava</groupId><artifactId>guava</artifactId><version>30.0-jre</version>
</dependency>

二、自定义注解及限流拦截器

自定义注解：@Limiter

package com.haitai.web.device.annotation;import java.lang.annotation.*;
import java.util.concurrent.TimeUnit;/*** 限流注解** @Author xincheng.du* @Date 2023/7/5 17:13*/
@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Limiter {/*** 每秒创建令牌个数，默认:0.5* 代表每秒允许通过的请求数为0.5个，即2秒只能通过一个请求*/double qps() default 0.5D;/*** 获取令牌等待超时时间 默认:500*/long timeout() default 500;/*** 超时时间单位 默认:毫秒*/TimeUnit timeunit() default TimeUnit.MILLISECONDS;/*** 限速提示信息*/String msg() default "访问过于频繁，请稍候再试";
}

限流拦截器：RequestLimitingInterceptor

package com.haitai.web.device.interceptor;import com.google.common.util.concurrent.RateLimiter;
import com.haitai.web.device.annotation.Limiter;
import lombok.extern.slf4j.Slf4j;
import org.jetbrains.annotations.NotNull;
import org.springframework.stereotype.Component;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;/*** 限流拦截器** @Author xincheng.du* @Date 2023/7/5 15:38*/
@Component
@Slf4j
public class RequestLimitingInterceptor implements HandlerInterceptor {private final Map<String, RateLimiter> rateLimiterMap = new ConcurrentHashMap<>();@Overridepublic boolean preHandle(@NotNull HttpServletRequest request, @NotNull HttpServletResponse response, @NotNull Object handler) {if (handler instanceof HandlerMethod) {HandlerMethod handlerMethod = (HandlerMethod) handler;Limiter rateLimit = handlerMethod.getMethodAnnotation(Limiter.class);// 判断是否有注解if (rateLimit != null) {// 获取请求urlString url = request.getRequestURI();// 判断map集合中是否有创建好的令牌桶rateLimiterMap.put(url, rateLimiterMap.computeIfAbsent(url, key -> RateLimiter.create(rateLimit.qps())));RateLimiter rateLimiter = rateLimiterMap.get(url);// 获取令牌boolean acquire = rateLimiter.tryAcquire(rateLimit.timeout(), rateLimit.timeunit());if (!acquire) {log.warn("请求被限流,url:{}", request.getServletPath());throw new RuntimeException(rateLimit.msg());}}}return true;}}

三、测试

package com.haitai.web.controller.device;import com.haitai.common.annotation.Anonymous;
import com.haitai.web.device.annotation.Limiter;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;/*** @Author xincheng.du* @Date 2023/7/24 10:04*/
@RestController
@RequestMapping("/test")
public class LimiterTestController {@Anonymous // 允许匿名访问@Limiter(qps = 0.2D) // 5秒一次@GetMapping("/limiter")public void limiter() {System.out.println("=============正常请求=============");}}