<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
  <groupId>org.springframework.cloud</groupId>
  <artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>

@Service
public class UserService implements UserInterface {

  @Autowired
  protected RestTemplate restTemplate;

  @Override
  public MoRp<List<MoUser>> getUsers(MoRq rq) {
    return null;
  }

  @Override
  public String getMsg() {

    String str = restTemplate.getForObject("http://EUREKA-PROVIDER/msg", String.class);
    return str;
  }
}

@RestController
public class UserController {

  @Autowired
  private UserService userService;

  @GetMapping("/msg")
  public String getMsg(){

    return userService.getMsg();
  }
}

@SpringBootApplication
@EnableDiscoveryClient //消費(fèi)客戶端
public class EurekaConsumerRibbonApplication {

  @Bean 
  @LoadBalanced //負(fù)載均衡
  RestTemplate restTemplate(){
    return new RestTemplate();
  }
  
  public static void main(String[] args) {
    SpringApplication.run(EurekaConsumerRibbonApplication.class, args);
  }
}

/**
 * Created by shenniu on 2018/6
 * <p>
 * rest+eureka+自定義client端
 */
@Component
public class ShenniuBanlance {

  @Autowired
  private RestTemplate restTemplate;

  @Autowired
  private DiscoveryClient discoveryClient;

  /**
   * 服務(wù)真實(shí)地址 ConcurrentHashMap<"服務(wù)應(yīng)用名稱", ("真實(shí)接口ip", 被訪問次數(shù))>
   */
  public static ConcurrentHashMap<String, List<MoService>> sericesMap = new ConcurrentHashMap<>();

  /**
   * 設(shè)置服務(wù)提供者信息到map
   */
  public void setServicesMap() {
    //獲取所有服務(wù)提供者applicationName
    List<String> appNames = discoveryClient.getServices();

    //存儲真實(shí)地址到map
    for (String appName :
        appNames) {
      //獲取某個(gè)服務(wù)提供者信息
      List<ServiceInstance> instanceInfos = discoveryClient.getInstances(appName);
      if (instanceInfos.isEmpty()) {
        continue;
      }

      List<MoService> services = new ArrayList<>();
      instanceInfos.forEach(b -> {
        MoService service = new MoService();
        //被訪問次數(shù)
        service.setWatch(0L);
        //真實(shí)接口地址
        service.setUrl(b.getUri().toString());
        services.add(service);
      });

      //如果存在就更新
      sericesMap.put(appName.toLowerCase(), services);
    }
  }

  /**
   * 根據(jù)app獲取輪詢方式選中后的service
   *
   * @param appName
   * @return
   */
  public MoService choiceServiceByAppName(String appName) throws Exception {
    appName = appName.toLowerCase();
    //某種app的服務(wù)service集合
    List<MoService> serviceMap = sericesMap.get(appName);
    if (serviceMap == null) {
      //初始化所有app服務(wù)
      setServicesMap();
      serviceMap = sericesMap.get(appName);
      if (serviceMap == null) {
        throw new Exception("未能找到" + appName + "相關(guān)服務(wù)");
      }
    }

    //篩選出被訪問量最小的service 輪詢的方式
    MoService moService = serviceMap.stream().min(
        Comparator.comparing(MoService::getWatch)
    ).get();

    //負(fù)載記錄+1
    moService.setWatch(moService.getWatch() + 1);
    return moService;
  }

  /**
   * 自動刷新 服務(wù)提供者信息到map
   */
  @Scheduled(fixedDelay = 1000 * 10)
  public void refreshServicesMap() {
    setServicesMap();
  }

  /**
   * get請求服務(wù)獲取返回?cái)?shù)據(jù)
   *
   * @param appName   應(yīng)用名稱 ApplicationName
   * @param serviceName 服務(wù)名稱 ServiceName
   * @param map     url上請求參數(shù)
   * @param tClass   返回類型
   * @param <T>
   * @return
   */
  public <T> T getServiceData(
      String appName, String serviceName,
      Map<String, ?> map,
      Class<T> tClass) {
    T result = null;
    try {
      //篩選獲取真實(shí)Service
      MoService service = choiceServiceByAppName(appName);

      //請求該service的url
      String apiUrl = service.getUrl() + "/" + serviceName;
      System.out.println(apiUrl);
      result = map != null ?
          restTemplate.getForObject(apiUrl, tClass, map) :
          restTemplate.getForObject(apiUrl, tClass);
    } catch (Exception ex) {
      ex.printStackTrace();
    }
    return result;
  }

  /**
   * Service信息
   */
  public class MoService {
    /**
     * 負(fù)載次數(shù)記錄數(shù)
     */
    private Long watch;
    /**
     * 真實(shí)接口地址： http://xxx.com/api/add
     */
    private String url;

    public Long getWatch() {
      return watch;
    }

    public void setWatch(Long watch) {
      this.watch = watch;
    }

    public String getUrl() {
      return url;
    }

    public void setUrl(String url) {
      this.url = url;
    }
  }
}

@Override
  public String getMsg() {

    String str = banlance.getServiceData(
        "EUREKA-PROVIDER", "msg",
        null,
        String.class
    );
    return str;
  }

/**
   * 自動刷新 服務(wù)提供者信息到map 
   */
  @Scheduled(fixedDelay = 1000 * 10)
  public void refreshServicesMap() {
    setServicesMap();
  }