springcloud Ribbon本地客户端负载均衡底层实现算法代码模拟

ribbon本地负载均衡算法： 某个接口的总请求数%服务器集群总数 = 实际调用的服务器的下标

具体模拟代码如下

package com.wangcj.api.controller;

import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.util.CollectionUtils;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
public class SimulateRibbonController {

	@Autowired
	private RestTemplate restTemplate;
	@Autowired
	private DiscoveryClient discoveryClient;
	
	//总请求数
	private AtomicInteger reqCount = new AtomicInteger(1);
	
	//订单服务调用会员服务
	@RequestMapping("/getSimulateOrder")
	public String getOrder() {
		List<ServiceInstance> instances = discoveryClient.getInstances("app-member");
		if(!CollectionUtils.isEmpty(instances)) {
			//集群总数
			int totalCount = instances.size();
			//获取调用的服务器的下标数
			int index = reqCount.get() % totalCount;
			String result = restTemplate.getForObject(instances.get(index).getUri().toString()+"/getMember", String.class);
			//请求数+1
			reqCount.getAndIncrement();
			return result;
		}
		return null;
	}
}