SpringCloud - RestTemplate的三种使用方式_RestTemplate

SpringCloud - RestTemplate的三种使用方式_微服务_02

三种方式访问服务

  1. URL 写死,用new RestTemplate()访问url来获取消息。(在服务有多个节点,地址多个的情况下,该方法不适用)
  2. 使用loadBlancerClient获取到url,然后使用new RestTemplate()访问url来获取消息。(太繁琐了)
  3. 利用@LoadBlanced 注解restTemplate,然后restTemplate 就可以使用应用名称来访问。
# product.yml

spring:
application:
name: product
datasource:
driver-class-name: com.mysql.jdbc.Driver
username: root
password: 123456
url: jdbc:mysql://127.0.0.1:3306/SpringCloud_Sell?characterEncoding=utf-8&useSSL=false
jpa:
show-sql: true
eureka:
client:
service-url:
defaultZone: http://localhost:8761/eureka/
package com.imooc.product.controller;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class ServerController {

@GetMapping("/msg")
public String msg() {
return "this is product' msg";
}
}
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 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;
}
}
// 第三种情况

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();
}
}