思路：利用aop實現根據ip限制一個介面在一段時間內的請求次數
實現方式用了redis,直接設定key的過期時間

先來個註解：

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 {

    /**
     * 允許訪問的次數，預設值MAX_VALUE
     */
    int count() default Integer.MAX_VALUE;

    /**
     * 時間段，單位為毫秒，預設值一分鐘
     */
    long time() default 60000;

}

接下來是限制邏輯，2種實現方式，hashMap和redis（註釋的內容）：

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," + "[使用者ip:{}],[訪問地址:{}]超過了限定的次數[{}]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實現請求記錄
     *
     * @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;
    }



}

最後就是controller了：

    @RequestMapping(value = "limit")
    @RequestLimit(count = 2)
    public String requestLimit(HttpServletRequest request) {
        return "test";
    }

專案裡面還需要開啟aop的配置：

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

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

}

RequestLimitException是自定義的一個RuntimeException子類，在controller層需要處理這個異常：

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", "請求過於頻繁,超出限制!");
        return "error";
    }

}