Spring Cloud Config是什麼，能做什麼？

Spring Cloud Config構建

1. Server端構建

   先去github建立個repository（當然可以使用預設的，需要配置spring.config.name=configserver，因為Spring-cloud-config-server-*.jar包中已經給出了預設的伺服器配置資訊和測試地址，Spring-cloud-config-server-2.0.2.jar的檔案中叫configserver.yml），然後建立一個建立一個目錄和一個檔案，用來做伺服器同步資料測試。比如我已經建立好的https://github.com/poetLoo/gitRepository

   建立一個SpringBoot專案，然後配置Spring Cloud config依賴，啟動類中加入註解：@EnableConfigServer

   。我這裡使用maven來構建專案，具體的pom如下：

   <?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">
   	<modelVersion>4.0.0</modelVersion>
   
   	<groupId>com.example</groupId>
   	<artifactId>springCloud</artifactId>
   	<version>0.0.1-SNAPSHOT</version>
   	<packaging>jar</packaging>
   
   	<name>springCloudConfig</name>
   	<description>Demo project for Spring Boot</description>
   
   	<parent>
   		<groupId>org.springframework.boot</groupId>
   		<artifactId>spring-boot-starter-parent</artifactId>
   		<version>2.1.0.RELEASE</version>
   		<relativePath/> <!-- lookup parent from repository -->
   	</parent>
   
   	<properties>
   		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
   		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
   		<java.version>1.8</java.version>
   	</properties>
   
   	<dependencyManagement>
   	    <dependencies>
   	        <dependency>
   	            <groupId>org.springframework.cloud</groupId>
   	            <artifactId>spring-cloud-dependencies</artifactId>
   	            <version>Finchley.SR2</version>
   	            <type>pom</type>
   	            <scope>import</scope>
   	        </dependency>
   	    </dependencies>
   	</dependencyManagement>
   	
   	<dependencies>
   		
   		<dependency>
   	        <groupId>org.springframework.cloud</groupId>
   	        <artifactId>spring-cloud-starter-config</artifactId>
   	    </dependency>
   	    <dependency>
               <groupId>org.springframework.cloud</groupId>
               <artifactId>spring-cloud-config-server</artifactId>
           </dependency>
           
   		<dependency>
   			<groupId>org.springframework.boot</groupId>
   			<artifactId>spring-boot-starter-test</artifactId>
   			<scope>test</scope>
   		</dependency>
   		
   	</dependencies>
   
   	<build>
   		<plugins>
   			<plugin>
   				<groupId>org.springframework.boot</groupId>
   				<artifactId>spring-boot-maven-plugin</artifactId>
   			</plugin>
   		</plugins>
   	</build>
   
   
   </project>
    
   

   需要注意的是，Spring boot和Spring cloud的版本要能對應起來，否則專案啟動會報錯.版本對應關係：

   Spring Cloud	Spring Boot
   Finchley	相容Spring Boot 2.0.x，不相容Spring Boot 1.5.x
   Dalston和Edgware	相容Spring Boot 1.5.x，不相容Spring Boot 2.0.x
   Camden	相容Spring Boot 1.4.x，也相容Spring Boot 1.5.x
   Brixton	相容Spring Boot 1.3.x，也相容Spring Boot 1.4.x
   Angel	相容Spring Boot 1.2.x

   如果使用我們自己的repository,那麼application.yml配置如下：

   server:
     port: 8888
   
   spring:
     cloud:
       config:
         server:
           git:
             #指定配置中心地址
             uri: https://github.com/poetLoo/cloudConfig
             #設定搜尋目錄，如果不設定，預設只搜尋根目錄
             search-paths:
             - myConfig
     name: server
     application:
       name: configServer

   返回資訊如下：

   {
       "name": "config-sample",
       "profiles": [
           "master"
       ],
       "label": null,
       "version": "168139978ce7b76e646f222cc6fb1ff8f2203366",
       "state": null,
       "propertySources": [
           {
               "name": "https://github.com/poetLoo/cloudConfig/myConfig/config-sample.yml",
               "source": {
                   "appName": "poetLav",
                   "version": "1.0.0"
               }
           }
       ]
   }

   /{application}/{profile}[/{label}]
   /{application}-{profile}.yml
   /{label}/{application}-{profile}.yml
   /{application}-{profile}.properties
   /{label}/{application}-{profile}.properties

2. Client端構建

   新建一個專案，作為客戶端構建和服務端基本一致，在pom中多加一個依賴，表示是一個web服務

   <dependency>

   <groupId>org.springframework.boot</groupId>

   <artifactId>spring-boot-starter-web</artifactId>

   </dependency>

   主要是在resource目錄下新增一個bootstrap.yml檔案，基本配置如下：

   spring:
     application:
       name: config-sample
     cloud:
       config:
         uri:
         - http://localhost:8888
         

   新增一個簡單的controller：  

   import org.springframework.beans.factory.annotation.Value;
   import org.springframework.web.bind.annotation.RequestMapping;
   import org.springframework.web.bind.annotation.RestController;
   
   @RestController
   public class HelloConfigController {
   
   	@Value("${appName}") String name;
   	@Value("${version}") String version;
   
   	@RequestMapping("/helloConfig")
   	public Object hello() {
   		return "hello " + name
   				+" version："+ version;
   	}
   }

總結