SpringCloud Zuul 限流

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/yiyijianxian/article/details/85269349

限流主要是为了防止恶意请求，功能实现放在前置过滤器（Pre）请求被转发之前调用，限流应放在所有的过滤器最前面。

今天介绍的限流方式是令牌桶限流。代码如下

package com.lfv.product.filter;

import org.springframework.stereotype.Component;

import com.google.common.util.concurrent.RateLimiter;
import com.netflix.zuul.ZuulFilter;
import com.netflix.zuul.exception.ZuulException;
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;

/**
 * 限流过滤器
 * @author lf
 *
 */
@Component
public class RateLimterFilter extends ZuulFilter{

	//谷歌令牌桶的实现 100/s 令牌
	private static final RateLimiter RATE_LIMITER = RateLimiter.create(100);
	
	@Override
	public boolean shouldFilter() {
		return true;
	}

	//没有拿到令牌抛出异常
	@Override
	public Object run() throws ZuulException {
		if(!RATE_LIMITER.tryAcquire()) {
			new RuntimeException();
		}
		
		return null;
	}

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

	@Override
	public int filterOrder() {
		return SERVLET_DETECTION_FILTER_ORDER - 1;
	}

}