SpringCloud分布式配置中心(SpringCloud Config)
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。
1：新建一个工程，命名为config-server,同意idea支持创建该类工程
pom如下：
<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>4.0.0modelVersion>
<groupId>com.springcloudgroupId>
<artifactId>config-serverartifactId>
<version>0.0.1-SNAPSHOTversion>
<packaging>jarpackaging>
<name>config-servername>
<description>Demo project for Spring Bootdescription>
<parent>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-parentartifactId>
<version>1.5.2.RELEASEversion>
<relativePath/>
parent>
<properties>
<project.build.sourceEncoding>UTF-8project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8project.reporting.outputEncoding>
<java.version>1.8java.version>
properties>
<dependencies>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-testartifactId>
<scope>testscope>
dependency>
<dependency>
<groupId>org.springframework.cloudgroupId>
<artifactId>spring-cloud-starter-eurekaartifactId>
dependency>
<dependency>
<groupId>org.springframework.cloudgroupId>
<artifactId>spring-cloud-config-serverartifactId>
dependency>
<dependency>
<groupId>org.eclipse.jgitgroupId>
<artifactId>org.eclipse.jgitartifactId>
<version>4.8.0.201706111038-rversion>
dependency>
dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-maven-pluginartifactId>
plugin>
plugins>
build>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloudgroupId>
<artifactId>spring-cloud-dependenciesartifactId>
<version>Camden.SR6version>
<type>pomtype>
<scope>importscope>
dependency>
dependencies>
dependencyManagement>
<repositories>
<repository>
<id>spring-milestonesid>
<name>Spring Milestonesname>
<url>https://repo.spring.io/milestoneurl>
<snapshots>
<enabled>falseenabled>
snapshots>
repository>
repositories>
project>注意，自动新建完的工程 中的版本可能会比较高，我们需要手动改成 1.5.2.RELEASE，这样才能保证下面的操作可用。
启动类加入注解，如下：
@SpringBootApplication
@EnableConfigServer
public class ConfigServerApplication {
public static void main(String[] args) {
SpringApplication.run(ConfigServerApplication.class, args);
}
}修改配置文件，如下：
spring.application.name=config-server
server.port=8888
#配置文件在本地
#spring.profiles.active=native
#配置文件的目录
#spring.cloud.config.server.native.search-locations=D:/workspace/GitHub/spring-config/config-file
#spring.cloud.config.server.git.uri=https://github.com/forezp/SpringcloudConfig/
spring.cloud.config.server.git.uri=https://github.com/iot-wangshuyu/springcloud
#配置仓库路径
spring.cloud.config.server.git.searchPaths=SpringcloudConfig/respo/
#配置仓库的分支
spring.cloud.config.label=master
#访问git仓库的用户名,仓库为public则不用填写
spring.cloud.config.server.git.username=
#访问git仓库的用户密码
spring.cloud.config.server.git.password=如果想使用git仓库就把本地配置注释掉，如果想使用本地配置，就把git仓库注释掉，然后再本地对应目录下新建一个config-client-dev.properties文件，内容为：
foo = foo version 2
我使用的是git远程仓库。
配置完成后启动程序，访问http://localhost:8888/config-client/dev/
返回：
{“name”:”config-client”,”profiles”:[“dev”],”label”:”master”,”version”:”3205652bcac310656b2f00790e7130e7df19a64e”,”state”:null,”propertySources”:[{“name”:”https://github.com/iot-wangshuyu/springcloud/SpringcloudConfig/respo/config-client-dev.properties“,”source”:{“foo”:”foo version 2”}}]}
返回以上结果，说明配置成功了。
2：构建config client
新建一个config client工程，命名为config-client，pom配置如下：
<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>4.0.0modelVersion>
<groupId>com.springcloudgroupId>
<artifactId>config-clientartifactId>
<version>0.0.1-SNAPSHOTversion>
<packaging>jarpackaging>
<name>config-clientname>
<description>Demo project for Spring Bootdescription>
<parent>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-parentartifactId>
<version>1.5.2.RELEASEversion>
<relativePath/>
parent>
<properties>
<project.build.sourceEncoding>UTF-8project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8project.reporting.outputEncoding>
<java.version>1.8java.version>
properties>
<dependencies>
<dependency>
<groupId>org.springframework.cloudgroupId>
<artifactId>spring-cloud-starter-configartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-webartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-testartifactId>
<scope>testscope>
dependency>
dependency>
dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloudgroupId>
<artifactId>spring-cloud-dependenciesartifactId>
<version>Dalston.RC1version>
<type>pomtype>
<scope>importscope>
dependency>
dependencies>
dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-maven-pluginartifactId>
plugin>
plugins>
build>
<repositories>
<repository>
<id>spring-milestonesid>
<name>Spring Milestonesname>
<url>https://repo.spring.io/milestoneurl>
<snapshots>
<enabled>falseenabled>
snapshots>
repository>
repositories>
project>配置文件如下：
#服务名称
spring.application.name=config-client
#仓库分支
spring.cloud.config.label=master
#dev开发环境配置文件
#test测试环境
#pro正式环境
spring.cloud.config.profile=dev
#使用eureka server的时候需要注释掉
spring.cloud.config.uri= http://localhost:8888/在程序中写一个API接口，返回从配置文件中读取的foo变量的值，代码如下：
@SpringBootApplication
@RestController
public class ConfigClientApplication {
public static void main(String[] args) {
SpringApplication.run(ConfigClientApplication.class, args);
}
@Value("${foo}")
String foo;
@RequestMapping(value = "/hi")
public String hi(){
return foo;
}
}在浏览器中访问：http://localhost:8881/hi
返回：
foo version 2
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,如图：
