<!--guava RateLimiter限流-->
<!-- https://mvnrepository.com/artifact/com.google.guava/guava -->
<dependency>
    <groupId>com.google.guava</groupId>
    <artifactId>guava</artifactId>
    <version>28.2-jre</version>
</dependency>

package com.zjy.knife4j.inte;
import java.lang.annotation.*;
/**
 * 限流注解
 */
@Inherited
@Documented
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface Limit {
    // 默認(rèn)每秒放入桶中的token
    double limitNum() default 20;
    String name() default "";
}

package com.zjy.knife4j.aspect;
import com.google.common.util.concurrent.RateLimiter;
import com.zjy.knife4j.inte.Limit;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.Signature;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;
import java.lang.reflect.Method;
import java.util.concurrent.ConcurrentHashMap;
@Aspect
@Component
public class RateLimitAspect {
    /**日志對(duì)象*/
    private static final Logger logger = LoggerFactory.getLogger(RateLimitAspect.class);
    private ConcurrentHashMap<String, RateLimiter> RATE_LIMITER  = new ConcurrentHashMap<>();
    private RateLimiter rateLimiter;
    @Pointcut("@annotation(com.zjy.knife4j.inte.Limit)")
    public void serviceLimit() {
    }
    @Around("serviceLimit()")
    public Object around(ProceedingJoinPoint point) throws Throwable {
        Object obj = null;
        //獲取攔截的方法名
        Signature sig = point.getSignature();
        //獲取攔截的方法名
        MethodSignature msig = (MethodSignature) sig;
        //返回被織入增加處理目標(biāo)對(duì)象
        Object target = point.getTarget();
        //為了獲取注解信息
        Method currentMethod = target.getClass().getMethod(msig.getName(), msig.getParameterTypes());
        //獲取注解信息
        Limit annotation = currentMethod.getAnnotation(Limit.class);
        double limitNum = annotation.limitNum(); //獲取注解每秒加入桶中的token
        String functionName = msig.getName(); // 注解所在方法名區(qū)分不同的限流策略
        if(RATE_LIMITER.containsKey(functionName)){
            rateLimiter=RATE_LIMITER.get(functionName);
        }else {
            RATE_LIMITER.put(functionName, RateLimiter.create(limitNum));
            rateLimiter=RATE_LIMITER.get(functionName);
        }
        if(rateLimiter.tryAcquire()) {
            logger.info("執(zhí)行成功?。。?..做一些業(yè)務(wù)處理");
            return point.proceed();
        } else {
            logger.info("請(qǐng)求繁忙...做一些業(yè)務(wù)處理");
            return null;
        }
    }
}

package com.zjy.knife4j.controller;
import com.zjy.knife4j.inte.Limit;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@RequestMapping("/ratelimiter")
@RestController
public class RateLimiterController {
    /**
     * 開(kāi)啟限流
     * @return
     */
    @GetMapping("/open")
    @Limit(limitNum = 1, name = "test1")
    public String openRateLimiter1() {
        System.out.println("【限流執(zhí)行了....編寫(xiě)業(yè)務(wù)....】");
        return "限流執(zhí)行了";
    }
    /**
     * 開(kāi)啟限流
     * @return
     */
    @GetMapping("/open2")
    @Limit(limitNum = 1, name = "test2")
    public String openRateLimiter2() {
        System.out.println("【限流執(zhí)行了222】");
        return "限流執(zhí)行了222";
    }
    /**
     * 未開(kāi)啟限流
     * @return
     */
    @GetMapping("/close")
    public String closeRateLimiter() {
        System.out.println("【不限流執(zhí)行了】");
        return "不限流執(zhí)行了";
    }
}