springcloud服务的注册和发现

提供者配置yml：

server:
  port: 3001

eureka:
  instance:
    preferIpAddress: true
  client:
    serviceUrl:
      defaultZone: http://localhost:3000/eureka  ## 注册到 eureka 
spring:
  application:
    name: single-provider  ## 应用程序名称，消费者调用的时候有用

创建一个controller

Slf4j
@RestController
public class ProviderController {

    @Autowired
    private DiscoveryClient discoveryClient;

    @RequestMapping(value = "/hello")
    public String hello(){
        List<String> services = discoveryClient.getServices();
        for(String s : services){
            log.info(s);
        }
        return "hello spring cloud!";
    }
}

消费者配置yml：

server:
  port: 3002
eureka:
  client:
    serviceUrl:
      defaultZone: http://127.0.0.1:3000/eureka  ## 注册到 eureka
  instance:
    preferIpAddress: true
spring:
  application:
    name: single-customer

消费者有2种消费方式：
一种是用 RestTemplate ,另外一种是用 FeignClient

配置类重写RestTemplate 方法：

@Configuration
public class CustomConfiguration {
    @LoadBalanced  // 表示用负载均衡策略请求服务提供者
    @Bean
    public RestTemplate restTemplate() {
        return new RestTemplate();
    }
}

用@FeignClient注解，注入single-provider应用的/hello请求对应的方法作为服务

@FeignClient("single-provider") // 注入single-provider应用的/hello 为服务
public interface IHelloService {
    @RequestMapping(value = "/hello")
    String hello();
}

用这个controller来调用服务：

@RestController
public class ConsumerController {

    @Autowired
    private RestTemplate restTemplate;

    @Autowired
    private IHelloService helloService;
    
    private static final String applicationName = "single-provider";

    @RequestMapping(value = "feignRequest")
    public Object feignRequest(){
        String s = helloService.hello();
        return s;
    }

    @RequestMapping(value = "commonRequest")
    public Object commonRequest(){
        String url = "http://"+ applicationName +"/hello";
        String s = restTemplate.getForObject(url,String.class);
        return s;
    }

}