详解RestTemplate的三种使用方式

@RestController
public class ServerController {

 @GetMapping("/msg")
 public String msg(){
  return "this is product' msg";
 }

}

@Slf4j
@RestController
public class ClientController {

 @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:9082/msg",String.class);
  log.info("response={}",response);
  return response;
 }

}

@Slf4j
@RestController
public class ClientController {

 @Autowired
 private LoadBalancerClient loadBalancerClient;

 @GetMapping("/getProductMsg")
 public String getProductMsg(){

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

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

}

@Component
public class RestTemplateConfig {

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

}
@Slf4j
@RestController
public class ClientController {

 @Autowired
 private RestTemplate restTemplate;

 @GetMapping("/getProductMsg")
 public String getProductMsg(){

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

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

}