目的
配置用戶端，使其能夠得到使得其可以從配置伺服器上擷取版本資訊。
改造視圖微服務-feign
直接将前面的一個視圖微服務進行改造。
pom.xml
添加spring-cloud-starter-config 用于通路配置伺服器
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<artifactId>springcloud</artifactId>
<groupId>edu.hpu.springcloud</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>product-view-service-feign</artifactId>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</artifactId> <!--對feign方式的支援-->
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-zipkin</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-config</artifactId>
</dependency>
</dependencies>
</project>
bootstrap.yml
與 Spring Cloud Config （配置）相關的屬性必須配置在 bootstrap.yml 中，config 部分内容才能被正确加載。因為 config 的相關配置會先application.yml，而 bootstrap.yml 的加載也是先于 application.yml。
spring:
cloud:
config:
label: master
profile: dev
discovery:
enabled: true
serviceId: config-server
client:
serviceUrl:
defaultZone: http://localhost:8761/eureka/ application.yml
變化不大，把注冊中心交給了bootstrap.yml,
spring:
application:
name: product-view-service-feign
thymeleaf:
cache: false
prefix: classpath:/templates/
suffix: .html
encoding: UTF-8
content-type: text/html
mode: HTML5
zipkin:
base-url: http://localhost:9411 ProductController
用@Value擷取配置中version的值，并放入Model,
package edu.hpu.springcloud.controller;
import edu.hpu.springcloud.pojo.Product;
import edu.hpu.springcloud.service.ProductService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import java.util.List;
@Controller
public class ProductController {
@Autowired
ProductService productService;
@Value("${version}")
String version;
@RequestMapping("/products")
public Object products(Model m){
List<Product> ps=productService.listProducts();
m.addAttribute("version", version);
m.addAttribute("ps",ps);
return "products";
}
}
product.html
product.html添加對version的顯示，
<!DOCTYPE HTML>
<html xmlns:th="http://www.thymeleaf.org">
<head>
<title>products</title>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<style>
table {
border-collapse:collapse;
width:400px;
margin:20px auto;
}
td,th{
border:1px solid gray;
}
</style>
</head>
<body>
<div class="workingArea">
<table>
<thead>
<tr>
<th>id</th>
<th>産品名稱</th>
<th>價格</th>
</tr>
</thead>
<tbody>
<tr th:each="p: ${ps}">
<td th:text="${p.id}"></td>
<td th:text="${p.name}"></td>
<td th:text="${p.price}"></td>
</tr>
</tbody>
<tr>
<td align="center" colspan="3">
<p th:text="${version}" >LaughterYoung springcloud version unknown</p>
</td>
</tr>
</table>
</div>
</body>
</html> 跑一下，通路
依次運作注冊中心、配置服務、資料服務、視圖服務，通路：
http://localhost:8012/products
錯誤
1、version注入失敗
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'productController': Injection of autowired dependencies failed; nested exception is java.lang.IllegalArgumentException: Could not resolve placeholder 'version' in value "${version}" 1.1、先去看看bootstrap.yml中配置serviceId和注冊的伺服器名字是否一緻，這個沒有問題。
1.2、檢查pom.xml包中是否添加了config jar包，沒有問題。
1.3、修改gitee中項目配置檔案名字，原名product-view-service-dev.properties 改為product-view-service-feign.properties
OK，解決了，懵逼來，懵逼去。
參考：
【1】、
http://how2j.cn/k/springcloud/springcloud-config-client/2048.html【2】、
https://windmt.com/2018/04/19/spring-cloud-7-config-sample/