Java 使用 Google Guava 实现接口限流

Bertha 。 2024-03-22 19:57 79阅读 0赞

## 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<>();
    
        @Override
        public 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url
                    String 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=============");
        }
    
    }

5秒内第一次请求：  
![在这里插入图片描述][cdb50b9aa8f040588ffb32419de03f7e.png]  
5秒内第二次请求：  
![在这里插入图片描述][cf7988bd895e45b1a7bc3223725540f1.png]

[cdb50b9aa8f040588ffb32419de03f7e.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/14/1620555f685b440daec6f6a963c5eef0.png
[cf7988bd895e45b1a7bc3223725540f1.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/14/3c4e1af312f14fe990fa04f365f84753.png