SpringCloud: 分布式配置中心(Spring Cloud Config)

简介

在分布式系统中，由于服务数量巨多，为了方便服务配置文件统一管理，实时更新，所以需要分布式配置中心组件。在Spring Cloud中，有分布式配置中心组件spring cloud config ，它支持配置服务放在配置服务的内存中（即本地），也支持放在远程Git仓库中。在spring cloud config 组件中，分两个角色，一是config server，二是config client。

构建Config Server

创建一个spring-boot项目，取名为config-server,其pom.xml:

<?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>cn.easted</groupId><artifactId>com</artifactId><version>0.0.1-SNAPSHOT</version><packaging>jar</packaging><name>com</name><description>Demo project for Spring Boot</description><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>1.5.6.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><spring-cloud.version>Dalston.SR3</spring-cloud.version></properties><dependencies><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><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-eureka</artifactId></dependency></dependencies><dependencyManagement><dependencies><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-dependencies</artifactId><version>${spring-cloud.version}</version><type>pom</type><scope>import</scope></dependency></dependencies></dependencyManagement><build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId></plugin></plugins></build><repositories><repository><id>spring-milestones</id><name>Spring Milestones</name><url>https://repo.spring.io/milestone</url><snapshots><enabled>false</enabled></snapshots></repository></repositories>
</project>

在程序的入口Application类加上@EnableConfigServer注解开启配置服务器的功能，代码如下：

@SpringBootApplication
@EnableConfigServer
public class ConfigServerApplication {
    public static void main(String[] args) {SpringApplication.run(ConfigServerApplication.class, args);}
}

需要在程序的配置文件application.yml文件配置以下：

spring: application: name: config-servercloud: config:label: master       #配置仓库的分支server: git: uri: https://github.com/haogewang/springCloud/ #配置git仓库地址searchPaths: repso     #配置仓库路径username: **********   #访问git仓库的用户名password: **********   #访问git仓库的用户密码
server: port: 8888

远程仓库https://github.com/haogewang/springCloud/repso 中有个文件config-client-dev.properties文件中有一个属性：

fooo=version

启动程序：访问http://localhost:8888/fooo/dev

证明配置服务中心可以从远程程序获取配置信息。

http请求地址和资源文件映射如下:

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

构建一个config client

重新创建一个springboot项目，取名为config-client,其pom文件：

<?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>cn.easted</groupId><artifactId>com</artifactId><version>0.0.1-SNAPSHOT</version><packaging>jar</packaging><name>com</name><description>Demo project for Spring Boot</description><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>1.5.6.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><spring-cloud.version>Dalston.SR3</spring-cloud.version></properties><dependencies><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-config</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency></dependencies><dependencyManagement><dependencies><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-dependencies</artifactId><version>${spring-cloud.version}</version><type>pom</type><scope>import</scope></dependency></dependencies></dependencyManagement><build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId></plugin></plugins></build><repositories><repository><id>spring-milestones</id><name>Spring Milestones</name><url>https://repo.spring.io/milestone</url><snapshots><enabled>false</enabled></snapshots></repository></repositories></project>

其配置文件bootstrap.yml：

spring:application:name: config-clientcloud:  config: label: master   #指明远程仓库的分支profile: dev    #dev开发环境配置文件,test测试环境,pro正式环境uri: http://localhost:8888/ #指明配置服务中心的网址。
server: port: 8881

程序的入口类，写一个API接口“／hi”，返回从配置中心读取的fooo变量的值，代码如下：

@RestController
@SpringBootApplication
public class ConfigClientApplication {
    public static void main(String[] args) {SpringApplication.run(ConfigClientApplication.class, args);}@Value("${fooo}")String fooo;@RequestMapping(value = "/hi")public String hi(){return fooo;}}

打开网址访问：http://localhost:8881/hi，网页显示：

version

这就说明，config-client从config-server获取了foo的属性，而config-server是从git仓库读取的。