欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识!
您现在的位置是: 首页

限流实战:guava的RateLimiter实现令牌桶算法限流

程序员文章站 2024-01-20 13:40:04
...

目录

1 引入依赖

2 限流实现

3 自定义拦截器,在拦截器中实现限流

4 实现 WebMvcConfigurer 添加自定义拦截器

5 RateLimiterAnnotation 实现

6 Controller 类实现

7 通过 jmeter 进行限流测试


       限流和限流算法已经介绍了常见的限流算法。guava 的 RateLimiter 使用的是令牌桶算法。本次实战,我们用的是 guava 的RateLimiter,springboot 在处理请求时候,从桶中申请令牌,申请到了就成功响应,申请不到时直接返回失败。

1 引入依赖

<dependency>
    <groupId>com.google.guava</groupId>
    <artifactId>guava</artifactId>
    <version>18.0</version>
</dependency>

2 限流实现

package com.sb.rateLimiter.service;

import com.google.common.util.concurrent.RateLimiter;
import org.springframework.stereotype.Service;

@Service
public class RateLimiterService {
    /**
     * 每秒只发出5个令牌
     */
    RateLimiter rateLimiter = RateLimiter.create(5.0);

    /**
     * 尝试获取令牌
     * @return
     */
    public boolean tryAcquire(){
        return rateLimiter.tryAcquire();
    }
}

自定义拦截器,在拦截器中实现限流

package com.sb.rateLimiter.interceptor;
import com.sb.rateLimiter.annotation.RateLimiterAnnotation;
import com.sb.rateLimiter.service.RateLimiterService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@Component
public class RateLimiterInterceptor implements HandlerInterceptor {
    @Resource
    private RateLimiterService accessLimitService;

    private Logger logger = LoggerFactory.getLogger(RateLimiterInterceptor.class);

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        if (!(handler instanceof HandlerMethod)) {
            return true;
        }

        HandlerMethod handlerMethod = (HandlerMethod) handler;
        RateLimiterAnnotation rateLimiterAnnotation = handlerMethod.getMethod().getAnnotation(RateLimiterAnnotation.class);
        if(rateLimiterAnnotation == null) {
            return true;
        }

        if (!accessLimitService.tryAcquire()) {
            logger.info("限流中......");
            return false;
        }
        logger.info("请求成功");
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {

    }
}

4 实现 WebMvcConfigurer 添加自定义拦截器

package com.sb.rateLimiter.config;
import com.sb.rateLimiter.interceptor.RateLimiterInterceptor;
import org.springframework.boot.SpringBootConfiguration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import javax.annotation.Resource;

@SpringBootConfiguration
public class WebConfiguration implements WebMvcConfigurer {

    @Resource
    private RateLimiterInterceptor rateLimiterInterceptor;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(rateLimiterInterceptor).addPathPatterns("/**");
    }
}

5 RateLimiterAnnotation 实现

package com.sb.rateLimiter.annotation;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface RateLimiterAnnotation {
    int rateLimiterNumber() default 1;
}

6 Controller 类实现

package com.sb.rateLimiter.controller;
import com.sb.rateLimiter.Enum.ResponseEnum;
import com.sb.rateLimiter.annotation.RateLimiterAnnotation;
import com.sb.rateLimiter.dto.RetDTO;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/api")
public class RateLimiterController {

    @RateLimiterAnnotation
    @RequestMapping(value = "/rateLimiterTest", method = RequestMethod.GET)
    public RetDTO rateLimiterTest() throws Exception {
        return RetDTO.getReturnJson(ResponseEnum.OK);
    }
}

7 通过 jmeter 进行限流测试

限流实战:guava的RateLimiter实现令牌桶算法限流

 

相关标签: 数据通信