限制http接口请求次数

思路：利用aop实现根据ip限制一个接口在一段时间内的请求次数
实现方式用了redis,直接设置key的过期时间

先来个注解：

import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;

import java.lang.annotation.*;

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
@Documented
@Order(Ordered.HIGHEST_PRECEDENCE)
public @interface RequestLimit {

    /**
     * 允许访问的次数，默认值MAX_VALUE
     */
    int count() default Integer.MAX_VALUE;

    /**
     * 时间段，单位为毫秒，默认值一分钟
     */
    long time() default 60000;

}
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接下来是限制逻辑，2种实现方式，hashMap和redis（注释的内容）：

import com.annotation.RequestLimit;
import com.core.websocket.WebSocket;
import com.exception.RequestLimitException;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;

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

@Aspect
public class RequestLimitAop {

    private static final Logger logger = LoggerFactory.getLogger(RequestLimitAop.class);
    @Autowired
    private RedisTemplate redisTemplate;

    @Before("within(@org.springframework.stereotype.Controller *) && @annotation(limit)")
    public void requestLimit(JoinPoint joinPoint, RequestLimit limit) throws RequestLimitException {
        try {
            Object[] args = joinPoint.getArgs();
            HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.currentRequestAttributes()).getRequest();
            String ip = WebSocket.getIpAddress(request);
            String url = request.getRequestURL().toString();
            String key = "req_limit_".concat(url).concat("_").concat(ip);
            boolean checkResult = checkWithRedis(limit, key);
            if (!checkResult) {
                logger.debug("requestLimited," + "[用户ip:{}],[访问地址:{}]超过了限定的次数[{}]次", ip, url, limit.count());
                throw new RequestLimitException();
            }
        } catch (RequestLimitException e) {
            throw e;
        } catch (Exception e) {
            logger.error("RequestLimitAop.requestLimit has some exceptions: ", e);
        }
    }


    /**
     * 以redis实现请求记录
     *
     * @param limit
     * @param key
     * @return
     */
    private boolean checkWithRedis(RequestLimit limit, String key) {
        long count = redisTemplate.opsForValue().increment(key, 1);
        if (count == 1) {
            redisTemplate.expire(key, limit.time(), TimeUnit.MILLISECONDS);
        }
        if (count > limit.count()) {
            return false;
        }
        return true;
    }



}
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最后就是controller了：

    @RequestMapping(value = "limit")
    @RequestLimit(count = 2)
    public String requestLimit(HttpServletRequest request) {
        return "test";
    }
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项目里面还需要开启aop的配置：

@Configuration
@EnableAspectJAutoProxy
@ComponentScan(basePackages = {"com.aop"})
public class AopConfig {

    @Bean
    public RequestLimitAop requestLimitAop() {
        return new RequestLimitAop();
    }

}
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RequestLimitException是自定义的一个RuntimeException子类，在controller层需要处理这个异常：

import com.exception.RequestLimitException;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;

@ControllerAdvice(basePackages = {"com.web.controller"})
public class ExceptionController {

    @ExceptionHandler(RequestLimitException.class)
    public String requestLimitException(Model model) {
        model.addAttribute("errorMsg", "请求过于频繁,超出限制!");
        return "error";
    }

}