Implementing Rate Limiting in Spring Boot Using a Custom Annotation and Redis

This guide shows how to add request‑rate limiting to a Spring Boot application by defining a custom annotation, implementing an interceptor that consults Redis, and wiring everything together.

1. Define the annotation

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

@Retention(RUNTIME)
@Target(METHOD)
public @interface AccessLimit {
    int seconds();
    int maxCount();
    boolean needLogin() default true;
}

2. Implement the interceptor

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;

@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) {
                // In a real scenario, obtain the user ID from the session
                key += "" + "1"; // placeholder user ID
            }
            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();
    }
}

3. Register the interceptor in Spring Boot

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;

@Configuration
public class WebConfig extends WebMvcConfigurerAdapter {
    @Autowired
    private FangshuaInterceptor interceptor;

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

4. Apply the annotation to a controller method

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;

@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 interceptor uses RedisService to store a counter keyed by the request URI (and optionally the user ID). The counter expires after the configured seconds, and each request increments it until maxCount is reached, after which a predefined error response is returned.

By combining a custom annotation, a Spring MVC interceptor, and Redis as a fast in‑memory store, developers can enforce fine‑grained rate limits on any endpoint with minimal code changes.