Spring Cloud实现微服务调用的负载均衡(详解)

public ShopOrder order(@PathVariable("pid") Long pid) {
        log.info("客户下单，这时候要调用商品微服务查询商品信息。。。");
        //从nacos中获取服务地址
        List<ServiceInstance> instances = discoveryClient.getInstances("shop-product");
        //自定义规则实现随机挑选服务
        int index = new Random().nextInt(instances.size());
        ServiceInstance serviceInstance = instances.get(index);
        String url = serviceInstance.getHost()+":"+serviceInstance.getPort();
        log.info(">>从nacos中获取到的微服务地址为:"+ url);
        //通过restTemplate调用商品微服务
        ShopProduct shopProduct = restTemplate.getForObject("http://"+url+"/product/"+pid, ShopProduct.class);
        log.info("当前用户信息为自己，假设我们设置为1");
        ShopOrder shopOrder = new ShopOrder();
        shopOrder.setUid(1L);
        shopOrder.setUsername("公众号：阿Q说代码");
        shopOrder.setPid(shopProduct.getId());
        shopOrder.setPname(shopProduct.getPname());
        orderService.save(shopOrder);
        //商品扣减库存的逻辑
        ProductReduceDTO productReduceDTO = new ProductReduceDTO();
        productReduceDTO.setProductId(pid);
        productReduceDTO.setReductCount(1);
        Integer count = restTemplate.postForObject("http://"+url+"/product/reduceStock", productReduceDTO, Integer.class);
        return shopOrder;
    }

@Bean
@LoadBalanced
 public RestTemplate getRestTemplate() {
     return new RestTemplate();
 }

//从nacos中获取服务地址
//自定义规则实现随机挑选服务
//List<ServiceInstance> instances = discoveryClient.getInstances("shop-product");
//int index = new Random().nextInt(instances.size());
//ServiceInstance serviceInstance = instances.get(index);
//String url = serviceInstance.getHost()+":"+serviceInstance.getPort();
//直接使用微服务名字，从nacos中获取服务地址
String url="shop-product";

# 负载均衡规则
shop-product:
  ribbon:
    NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RandomRule

 @Bean
 public IRule randomRule(){
     return new RandomRule();
 }

ribbon:
  eager-load:
    clients:
      - shop-product