SpringCloud（三）-应用间通信(慕课网廖师兄SpringCloud微服务实战）

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

 <!--HttpClient-->
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.5.3</version>
        </dependency>

@Configuration
public class RestConfiguration {

   @Autowired
   private RestTemplateBuilder restTemplateBuilder;

   @Bean
   public RestTemplate restTemplate(){
       return restTemplateBuilder.build();
   }
}

 /**
     * 将数据放在缓存中
     * @param uri
     */
    private String saveWeatherData(String uri){
        ResponseEntity<String> respString = restTemplate.getForEntity(uri,String.class);

        String strBody = null;

        if(HttpStatus.OK.equals(respString.getStatusCode())){
            strBody = respString.getBody();
        }

        //TODO 对返回值做校验

        stringRedisTemplate.opsForValue().set(uri,strBody,TIME_OUT, TimeUnit.SECONDS);
        return strBody;
    }

@Component
public class RestTemplateConfig {

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


@RestController
@Slf4j
public class ClientController {

//    @Autowired
//    private LoadBalancerClient loadBalancerClient;

    @Autowired
    private RestTemplate restTemplate;

    @GetMapping("/getProductMsg")
    public String getProductMsg() {
        //1.第一种方式(直接使用restTemplate, url写死)
//        RestTemplate restTemplate = new RestTemplate();
//        String response = restTemplate.getForObject("http://localhost:8080/msg", String.class);

        //2. 第二种方式(利用loadBalancerClient通过应用名获取url, 然后再使用restTemplate)
//        RestTemplate restTemplate = new RestTemplate();
//        ServiceInstance serviceInstance = loadBalancerClient.choose("PRODUCT");
//        String url = String.format("http://%s:%s", serviceInstance.getHost(), serviceInstance.getPort()) + "/msg";
//        String response = restTemplate.getForObject(url, String.class);

        //3. 第三种方式(利用@LoadBalanced, 可在restTemplate里使用应用名字)
        String response = restTemplate.getForObject("http://PRODUCT/msg", String.class);

        log.info("response={}", response);
        return response;
    }
}

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-feign</artifactId>
        </dependency>

/**
 * 启动类
 * @author gaowenfeng
 */
@SpringBootApplication
@EnableScheduling
@EnableDiscoveryClient
@EnableFeignClients
public class MsaWeatherCollectionWeatherApplication {

    public static void main(String[] args) {
        SpringApplication.run(MsaWeatherCollectionWeatherApplication.class, args);
    }
}

import com.gwf.weather.vo.City;
import org.springframework.cloud.netflix.feign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;

import java.util.List;

/**
 * @author gaowenfeng
 * @package com.gwf.weather.service
 * @describe Feign访问城市数据API服务接口
 * @date 2018/2/21
 */
@FeignClient("msa-weather-city-server") // 要访问的微服务名称
public interface CityClient {

    /**
    * GetMapping 的参数是要访问的服务方法名（基于http协议接口）
    * @return 返回值可以自己定义，会自动讲返回字符串做转型，转型失败会抛异常
    */
    @GetMapping("cities")
    List<City> listCitys() throws Exception;
}

...
@Autowired
    private CityClient cityClient;
...
cityList = cityClient.listCitys();

feign:
  client:
    config:
      feignName:
        # 连接超时时间，单位为ms
        connectTimeout: 50000
       # 读取超时时间，单位为ms
        readTimeout: 50000