springcloud ribbon 的简单使用

RestTemplate

对http请求通信的封装，封装了http请求，方便的请求http接口。

Ribbon

ribbon是一个http的负载均衡工具

maven

<dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
            <version>2.2.3.RELEASE</version>
        </dependency>

注意要加上starter。
application.yml

order-service:
  ribbon:
    listOfServers: localhost:8081,localhost:8082

这里的order-service是order程序的application name
listOfServers是2个服务地址，负载均衡
controller

@RestController
public class UserController {

    @Autowired
    RestTemplate restTemplate;

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

    @Autowired
    LoadBalancerClient loadBalancerClient;

    @GetMapping("/user")
    public String user() {
        ServiceInstance serviceInstance = loadBalancerClient.choose("order-service");
        String url = String.format("http://%s:%s",serviceInstance.getHost(),serviceInstance.getPort()+"/order");
        System.out.println(url);
        String forObject = restTemplate.getForObject(url, String.class);
        return forObject;
    }
}