获取所有注册的服务，从注册的服务中选取一个，服务调用

package com.xyz.comsumer.controller;

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

@RestController
public class HelloController {
 @Autowired
 private LoadBalancerClient loadBalancer;
 @Autowired
 private DiscoveryClient discoveryClient;
 private String serviceName = "service-provider";

 @RequestMapping("/services")
 public Object services() {
  return discoveryClient.getInstances(serviceName);
 }

 @RequestMapping("/discover")
 public Object discover() {
  return loadBalancer.choose(serviceName).getUri().toString();
 }

 @RequestMapping("/hello")
 public String hello() {
  ServiceInstance serviceInstance = loadBalancer.choose(serviceName);
  String callServiceResult = new RestTemplate().getForObject(serviceInstance.getUri().toString() + "/hello", String.class);
  return callServiceResult;
 }
}

注：

客户端调用的服务名，是在服务端指定的，在服务端配置里使用 spring.cloud.consul.discovery.service-name指注册到 Consul 的服务名称

测试

启动Consul

启动provider和provider1

启动comsumer

测试地址 http://localhost:8015/services

返回结果

[
 {
  "instanceId": "provider-8010",
  "serviceId": "service-provider",
  "host": "hkgi-PC",
  "port": 8010,
  "secure": false,
  "metadata": {
   "secure": "false"
  },
  "uri": "http://hkgi-PC:8010",
  "scheme": null
 },
 {
  "instanceId": "provider-8011",
  "serviceId": "service-provider",
  "host": "hkgi-PC",
  "port": 8011,
  "secure": false,
  "metadata": {
   "secure": "false"
  },
  "uri": "http://hkgi-PC:8011",
  "scheme": null
 }
]

测试地址 http://localhost:8015/discover

返回结果

　　http://hkgi-PC:8011 或 http://hkgi-PC:8011 　　测试地址 http://localhost:8015/hello 　　返回结果 　　hello,provider 或 hello,another provider

注：

结果交替出现的，这是因为负载均衡器是采用的是轮询的方式

说明：

调用的过程：

A.通过LoadBalancerClient查询服务

B.通过RestTemplate调用远程服务

Ribbon负载均衡策略

　　BestAvailableRule 　　AvailabilityFilteringRule 　　WeightedResponseTimeRule 　　RetryRule 　　RoundRobinRule 　　RandomRule 　　ZoneAvoidanceRule

自定义Ribbon负载均衡——使用随机访问策略

修改启动类

package com.xyz.comsumer;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;
@SpringBootApplication
public class ComsumerApplication {
 public static void main(String[] args) {
  SpringApplication.run(ComsumerApplication.class, args);
 }

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