Implementing Interface Rate Limiting in Spring Boot with Annotations and Redis

This article demonstrates how to implement interface rate limiting in a Spring Boot application using a custom annotation and Redis.

Technical points covered include basic Spring Boot knowledge and Redis operations.

First, an annotation class AccessLimit is defined with parameters seconds, maxCount, and needLogin to specify the limit configuration.

import java.lang.annotation.Retention;
import java.lang.annotation.Target;

import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**
 * @author yhq
 * @date 2018/9/10 15:52
 */
@Retention(RUNTIME)
@Target(METHOD)
public @interface AccessLimit {
    int seconds();
    int maxCount();
    boolean needLogin() default true;
}

Next, an interceptor FangshuaInterceptor extending HandlerInterceptorAdapter is implemented. It checks whether the handler method carries the @AccessLimit annotation, retrieves the limit parameters, builds a Redis key (optionally including a user identifier), and uses a Redis service to track request counts. If the count exceeds maxCount, it returns an error response.

import com.alibaba.fastjson.JSON;
import com.example.demo.action.AccessLimit;
import com.example.demo.redis.RedisService;
import com.example.demo.result.CodeMsg;
import com.example.demo.result.Result;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.OutputStream;

/**
 * @author yhq
 * @date 2018/9/10 16:05
 */
@Component
public class FangshuaInterceptor extends HandlerInterceptorAdapter {

    @Autowired
    private RedisService redisService;

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        if (handler instanceof HandlerMethod) {
            HandlerMethod hm = (HandlerMethod) handler;
            AccessLimit accessLimit = hm.getMethodAnnotation(AccessLimit.class);
            if (accessLimit == null) {
                return true;
            }
            int seconds = accessLimit.seconds();
            int maxCount = accessLimit.maxCount();
            boolean login = accessLimit.needLogin();
            String key = request.getRequestURI();
            if (login) {
                // Assume user id is 1 for illustration; replace with actual user ID retrieval
                key += "" + "1";
            }
            AccessKey ak = AccessKey.withExpire(seconds);
            Integer count = redisService.get(ak, key, Integer.class);
            if (count == null) {
                redisService.set(ak, key, 1);
            } else if (count < maxCount) {
                redisService.incr(ak, key);
            } else {
                render(response, CodeMsg.ACCESS_LIMIT_REACHED);
                return false;
            }
        }
        return true;
    }

    private void render(HttpServletResponse response, CodeMsg cm) throws Exception {
        response.setContentType("application/json;charset=UTF-8");
        OutputStream out = response.getOutputStream();
        String str = JSON.toJSONString(Result.error(cm));
        out.write(str.getBytes("UTF-8"));
        out.flush();
        out.close();
    }
}

The interceptor is then registered in a Spring Boot configuration class that extends WebMvcConfigurerAdapter.

import com.example.demo.ExceptionHander.FangshuaInterceptor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

/**
 * @author yhq
 * @date 2018/9/10 15:58
 */
@Configuration
public class WebConfig extends WebMvcConfigurerAdapter {

    @Autowired
    private FangshuaInterceptor interceptor;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(interceptor);
    }
}

Finally, the custom annotation is applied to a controller method to enforce the defined rate limit.

import com.example.demo.result.Result;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

/**
 * @author yhq
 * @date 2018/9/10 15:49
 */
@Controller
public class FangshuaController {

    @AccessLimit(seconds = 5, maxCount = 5, needLogin = true)
    @RequestMapping("/fangshua")
    @ResponseBody
    public Result<String> fangshua() {
        return Result.success("请求成功");
    }
}

The article notes that the content references other video tutorials and aims to help IT enthusiasts understand and implement rate‑limiting mechanisms in their projects.