SpringBoot 实现流控的操作方法

  <dependency>
            <groupId>com.google.guava</groupId>
            <artifactId>guava</artifactId>
            <version>30.1-jre</version>
        </dependency>

package com.artisan.controller;
import com.artisan.annos.ArtisanLimit;
import com.google.common.util.concurrent.RateLimiter;
import lombok.SneakyThrows;
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.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.concurrent.TimeUnit;
/**
 * @author 小工匠
 * @version 1.0
 * @mark: show me the code , change the world
 */
@Slf4j
@RestController
@RequestMapping("/rateLimit")
public class RateLimitController {
    /**
     * 限流策略 ： 1秒钟1个请求
     */
    private final RateLimiter limiter = RateLimiter.create(1);
    private DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
    @SneakyThrows
    @GetMapping("/test")
    public String testLimiter() {
        //500毫秒内，没拿到令牌，就直接进入服务降级
        boolean tryAcquire = limiter.tryAcquire(500, TimeUnit.MILLISECONDS);
        if (!tryAcquire) {
            log.warn("BOOM 服务降级，时间{}", LocalDateTime.now().format(dtf));
            return "系统繁忙，请稍后再试！";
        }
        log.info("获取令牌成功，时间{}", LocalDateTime.now().format(dtf));
        return "业务处理成功";
    }

 <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>

package com.artisan.annos;
import java.lang.annotation.*;
import java.util.concurrent.TimeUnit;
/**
 * @author 小工匠
 * @version 1.0
 * @mark: show me the code , change the world
 */
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
@Documented
public @interface ArtisanLimit {
    /**
     * 资源的key,唯一
     * 作用：不同的接口，不同的流量控制
     */
    String key() default "";
    /**
     * 最多的访问限制次数
     */
    double permitsPerSecond();
    /**
     * 获取令牌最大等待时间
     */
    long timeout();
    /**
     * 获取令牌最大等待时间,单位(例:分钟/秒/毫秒) 默认:毫秒
     */
    TimeUnit timeunit() default TimeUnit.MILLISECONDS;
    /**
     * 得不到令牌的提示语
     */
    String message() default "系统繁忙,请稍后再试.";
}

package com.artisan.aop;
import com.artisan.annos.ArtisanLimit;
import com.artisan.resp.ResponseCode;
import com.artisan.resp.ResponseData;
import com.artisan.utils.WebUtils;
import com.google.common.collect.Maps;
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.reflect.MethodSignature;
import org.springframework.stereotype.Component;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import javax.servlet.http.HttpServletResponse;
import java.lang.reflect.Method;
import java.util.Map;
/**
 * @author 小工匠
 * @version 1.0
 * @mark: show me the code , change the world
 */
@Slf4j
@Aspect
@Component
public class ArtisanLimitAop {
    /**
     * 不同的接口，不同的流量控制
     * map的key为 ArtisanLimit.key
     */
    private final Map<String, RateLimiter> limitMap = Maps.newConcurrentMap();
    @Around("@annotation(com.artisan.annos.ArtisanLimit)")
    public Object around(ProceedingJoinPoint joinPoint) throws Throwable {
        MethodSignature signature = (MethodSignature) joinPoint.getSignature();
        Method method = signature.getMethod();
        //拿ArtisanLimit的注解
        ArtisanLimit limit = method.getAnnotation(ArtisanLimit.class);
        if (limit != null) {
            //key作用：不同的接口，不同的流量控制
            String key = limit.key();
            RateLimiter rateLimiter = null;
            //验证缓存是否有命中key
            if (!limitMap.containsKey(key)) {
                // 创建令牌桶
                rateLimiter = RateLimiter.create(limit.permitsPerSecond());
                limitMap.put(key, rateLimiter);
                log.info("新建了令牌桶={}，容量={}", key, limit.permitsPerSecond());
            }
            rateLimiter = limitMap.get(key);
            // 拿令牌
            boolean acquire = rateLimiter.tryAcquire(limit.timeout(), limit.timeunit());
            // 拿不到命令，直接返回异常提示
            if (!acquire) {
                log.warn("令牌桶={}，获取令牌失败", key);
                this.responseFail(limit.message());
                return null;
            }
        }
        return joinPoint.proceed();
    }
    /**
     * 直接向前端抛出异常
     *
     * @param msg 提示信息
     */
    private void responseFail(String msg) {
        HttpServletResponse response = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getResponse();
        ResponseData<Object> resultData = ResponseData.fail(ResponseCode.LIMIT_ERROR.getCode(), msg);
        WebUtils.writeJson(response, resultData);
    }
}

   @GetMapping("/test2")
    @ArtisanLimit(key = "testLimit2", permitsPerSecond = 1, timeout = 500, timeunit = TimeUnit.MILLISECONDS, message = "test2 当前排队人数较多，请稍后再试！")
    public String test2() {
        log.info("令牌桶test2获取令牌成功");
        return "test2 ok";
    }