假如有一个 ORDER服务,想访问分布式的应用PRODUCT,如下,用eureka注册过
第一种方式,直接RestTemplate ,是把url写死,这种风险在当分布式多台时,无法满足。如下,PRODUCT服务部署两台时
package com.imooc.order.controller;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
@RestController
@Slf4j
public class ClientController {
@GetMapping("/getProductMsg1")
public String getProductMsg1(){
//第一种方式 这种弊端就是当一个服务部署到多台时,多个IP地址问题。
RestTemplate restTemplate = new RestTemplate();
String response = restTemplate.getForObject("http://localhost:8882/msg",String.class);
log.info(response);
return response;
}
}
第二种方式是利用LoadBalancerClient 通过应用名称获取url,然后再使用restTemplate
package com.imooc.order.controller;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
@RestController
@Slf4j
public class ClientController {
@Autowired
private LoadBalancerClient loadBalancerClient;
@GetMapping("/getProductMsg")
public String getProductMsg(){
////第二种方式
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);
log.info(response);
return response;
}
}
第三种方式,直接用注解@LoadBalanced这样就可以在restTemplate使用应用名字
package com.imooc.order.config;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.stereotype.Component;
import org.springframework.web.client.RestTemplate;
@Component
public class RestTemplateConfig {
@Bean
@LoadBalanced
public RestTemplate restTemplate() {
return new RestTemplate();
}
}
package com.imooc.order.controller;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
@RestController
@Slf4j
public class ClientController {
@Autowired
private RestTemplate restTemplate;
@GetMapping("/getProductMsg3")
public String getProductMsg3(){
////第三种方式
String response = restTemplate.getForObject("http://PRODUCT/msg",String.class);
log.info(response);
return response;
}
}