SpringCloud学习笔记-服务网关-Zuul-限流

 

package com.hx.apigeteway.filter;

import com.google.common.util.concurrent.RateLimiter;
import com.hx.apigeteway.exception.RateLimitException;
import com.netflix.zuul.ZuulFilter;
import com.netflix.zuul.exception.ZuulException;
import org.springframework.stereotype.Component;

import static org.springframework.cloud.netflix.zuul.filters.support.FilterConstants.PRE_TYPE;
import static org.springframework.cloud.netflix.zuul.filters.support.FilterConstants.SERVLET_DETECTION_FILTER_ORDER;


/**限流
 *
 */
@Component
public class RateLimiterFilter  extends ZuulFilter {

    /**每秒中给桶中，放多少令牌，gool的引用*/
   private static final RateLimiter RATE_LIMITER=RateLimiter.create(100);

    @Override
    public String filterType() {
        return PRE_TYPE;
    }

    @Override
    public int filterOrder() {  //优先级最高 -3-1=-4
        return SERVLET_DETECTION_FILTER_ORDER - 1;
    }

    @Override
    public boolean shouldFilter() {
        return true;
    }

    @Override
    public Object run() throws ZuulException {
        //如果没有令牌,抛出异常或者直接返回错误
        if(!RATE_LIMITER.tryAcquire()){
            throw  new RateLimitException();
        }
        return null;
    }
}