Java拦截器限制IP访问次数

1，pom引入依赖

   com.github.kaligence
   requestLimit
   ${requestLimit.version}

2，定义拦截器

import com.alibaba.fastjson.JSONObject;
import com.github.kaligence.requestLimit.RequestLimit;
import com.sun.java.browser.plugin2.liveconnect.v1.Result;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
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.IOException;
import java.io.PrintWriter;
import java.lang.reflect.Method;
import java.util.concurrent.TimeUnit;


@Slf4j
@Component
public class RequestLimitIntercept extends HandlerInterceptorAdapter {

    @Autowired
    private RedisTemplate redisTemplate;

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        
        if(handler.getClass().isAssignableFrom(HandlerMethod.class)){
            //HandlerMethod 封装方法定义相关的信息,如类,方法,参数等
            HandlerMethod handlerMethod = (HandlerMethod) handler;
            Method method = handlerMethod.getMethod();
            // 获取方法中是否包含注解
            RequestLimit methodAnnotation = method.getAnnotation(RequestLimit.class);
            //获取 类中是否包含注解，也就是controller 是否有注解
            RequestLimit classAnnotation = method.getDeclaringClass().getAnnotation(RequestLimit.class);
            // 如果 方法上有注解就优先选择方法上的参数，否则类上的参数
            RequestLimit requestLimit = methodAnnotation != null?methodAnnotation:classAnnotation;
            if(requestLimit != null){
                if(isLimit(request,requestLimit)){
                    Result result = new Result("訪問次數超過上線",false);
                    resonseOut(response, result);
                    return false;
                }
            }
        }
        return super.preHandle(request, response, handler);
    }
    //判断请求是否受限
    public boolean isLimit(HttpServletRequest request,RequestLimit requestLimit){
        // 受限的redis 缓存key ,用sessionId 来做唯一key,如果是app ,可以使用 用户ID 之类的唯一标识。
        String limitKey = request.getServletPath()+request.getSession().getId();
        // 从缓存中获取，当前这个请求访问了几次
        Integer redisCount = (Integer) redisTemplate.opsForValue().get(limitKey);
        log.info(limitKey + "在"+requestLimit.requestTime()+"S内被点击次数:"+redisCount);
        if(redisCount == null){
            //初始 次数
            redisTemplate.opsForValue().set(limitKey,1,requestLimit.requestTime(), TimeUnit.SECONDS);
        }else{
            if(redisCount.intValue() >= requestLimit.requestCount()){
                return true;
            }
            // 次数自增
            redisTemplate.opsForValue().increment(limitKey,1);
            //RedisUtils.incr(limitKey);
        }
        return false;
    }

    
    private void resonseOut(HttpServletResponse response, Result result) throws IOException {
        response.setCharacterEncoding("UTF-8");
        response.setContentType("application/json; charset=utf-8");
        PrintWriter out = null ;
        String json = JSONObject.toJSON(result).toString();
        out = response.getWriter();
        out.append(json);
    }

3，注册拦截器

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 InterceptorAdapterConfig extends WebMvcConfigurerAdapter {
    @Autowired
    private RequestLimitIntercept authorityInterceptor;
    //private AuthorityInterceptor authorityInterceptor;

    @Override
    public void addInterceptors(InterceptorRegistry registry)
    {
        //注册自己的拦截器并设置拦截的请求路径
        registry.addInterceptor(authorityInterceptor).addPathPatterns("/**");
        super.addInterceptors(registry);
    }
}

4，在controller中的方法上加入注解

@RequestLimit(requestCount = 2L,requestTime = 30L)

30秒内允许2个请求。