java 实现接口频次限制

1、添加依赖

        <dependency>
            <groupId>net.jodah</groupId>
            <artifactId>expiringmap</artifactId>
            <version>0.5.10</version>
        </dependency>

2、新建注解

package com.qax.situation.transmission.application.annoation;

import java.lang.annotation.*;

@Documented
@Target(ElementType.METHOD) // 说明该注解只能放在方法上面
@Retention(RetentionPolicy.RUNTIME)
public @interface LimitRequest {
    long time() default 60000; // 限制时间 单位：毫秒

    int count() default Integer.MAX_VALUE; // 允许请求的次数
}

3、自定义AOP切面

package com.qax.situation.transmission.application.annoation;

import com.qax.needle.common.constant.HttpStatus;
import com.qax.needle.framework.boot.exception.BaseException;
import net.jodah.expiringmap.ExpirationPolicy;
import net.jodah.expiringmap.ExpiringMap;
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.stereotype.Component;
import org.springframework.web.context.request.RequestAttributes;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

import javax.servlet.http.HttpServletRequest;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.TimeUnit;


@Aspect
@Component
public class LimitRequestAspect {
    private static ConcurrentHashMap<String, ExpiringMap<String, Integer>> book = new ConcurrentHashMap<>();

    // 定义切点
    // 让所有有@LimitRequest注解的方法都执行切面方法
    @Pointcut("@annotation(limitRequest)")
    public void excudeService(LimitRequest limitRequest) {
    }

    @Around("excudeService(limitRequest)")
    public Object doAround(ProceedingJoinPoint pjp, LimitRequest limitRequest) throws Throwable {

        // 获得request对象
        RequestAttributes ra = RequestContextHolder.getRequestAttributes();
        ServletRequestAttributes sra = (ServletRequestAttributes) ra;
        HttpServletRequest request = sra.getRequest();

        // 获取Map对象， 如果没有则返回默认值
        // 第一个参数是key， 第二个参数是默认值
        ExpiringMap<String, Integer> uc = book.getOrDefault(request.getRequestURI(), ExpiringMap.builder().variableExpiration().build());
        Integer nowCount = uc.getOrDefault(request.getRemoteAddr(), 0);


        if (nowCount >= limitRequest.count()) { // 超过次数，不执行目标方法
            throw new BaseException(HttpStatus.PERMISSION_DENIED, "", "接口请求超过次数");
            //return JsonResult.error("请求次数过多，已经限制");
        } else if (nowCount == 0) { // 第一次请求时，设置有效时间
//            /** Expires entries based on when they were last accessed */
//            ACCESSED,
//            /** Expires entries based on when they were created */
//            CREATED;
            uc.put(request.getRemoteAddr(), nowCount + 1, ExpirationPolicy.CREATED, limitRequest.time(), TimeUnit.MILLISECONDS);
        } else { // 未超过次数， 记录加一
            uc.put(request.getRemoteAddr(), nowCount + 1);
        }
        book.put(request.getRequestURI(), uc);

        // result的值就是被拦截方法的返回值
        return pjp.proceed();
    }
}

4、在函数上添加注解

@LimitRequest(count = 10)