SpringBoot利用Guava实现单机app限流访问-Toy模板网

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SpringBoot利用Guava实现单机app限流访问

物料准备：
1.引入Guava依赖
2.定义一个限流注解作用于api接口的方法上
3.定义一个切面，对注解标注的方法实现一个限流访问

引入Guava依赖

<dependency>
            <groupId>com.google.guava</groupId>
            <artifactId>guava</artifactId>
            <version>28.2-jre</version>
        </dependency>

定义注解@RateLimitAspect

package com.example.demo.service.guava;

import java.lang.annotation.*;


@Inherited
@Documented
@Target({ElementType.METHOD, ElementType.FIELD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface RateLimitAspect {
}

定义对应的处理的AOP逻辑

package com.example.demo.service.guava;

import com.alibaba.fastjson.JSON;
import com.example.demo.web.AjaxPubResponse;
import com.google.common.util.concurrent.RateLimiter;
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.annotation.Pointcut;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;



@Component
@Scope
@Aspect
@Slf4j
public class RateLimitAop {

    @Autowired
    private HttpServletResponse response;
    @Pointcut("@annotation(com.example.demo.service.guava.RateLimitAspect)")
    public void serviceLimit() {
    }
    private RateLimiter rateLimiter = RateLimiter.create(5.0); //比如说，我这里设置"并发数"为5
    @Around("serviceLimit()")
    public Object around(ProceedingJoinPoint joinPoint) {
        Boolean flag = rateLimiter.tryAcquire();
        Object obj = null;
        try {
            if (flag) {
                obj = joinPoint.proceed();
            }else{
                String result = JSON.toJSONString(AjaxPubResponse.error("2003", "未获取到许可"));
//                String result = JSONObject.fromObject(AjaxPubResponse.error("100", "failure")).toString();
                output(response, result);
            }
        } catch (Throwable e) {
            e.printStackTrace();
        }
        log.info("flag={},obj={}",flag,obj);
//        System.out.println("flag=" + flag + ",obj=" + obj);
        return obj;
    }


    public void output(HttpServletResponse response, String msg) throws IOException {
        response.setContentType("application/json;charset=UTF-8");
        ServletOutputStream outputStream = null;
        try {
            outputStream = response.getOutputStream();
            outputStream.write(msg.getBytes("UTF-8"));
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            outputStream.flush();
            outputStream.close();
        }
    }

}