Spring Cloud (5) 分布式配置中心
Spring Cloud Config
在分布式系统中，由于服务数量很多，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，使用Spring Cloud Config来实现分布式配置中心，它支持配置服务放在配置服务的内存中（本地），也支持放在远程git仓库中，在spring cloud config组件中，分为两个角色，一个是config server，一个是config client。
准备配置仓库
https://gitee.com/baidawei/SpringCloudConfig.git
构建配置中心（config server）
新建一个spring boot项目，名为com.david.configserver , pom.xml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.david</groupId> <artifactId>configserver</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>configserver</name> <description>Demo project for Spring Boot</description> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.5.9.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> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-config-server</artifactId> </dependency> </dependencies> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-dependencies</artifactId> <version>Edgware.SR2</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> </project>
在启动类中加上@EnableConfigServer注解开启配置服务器的功能：
@EnableConfigServer @SpringBootApplication public class ConfigserverApplication { public static void main(String[] args) { SpringApplication.run(ConfigserverApplication.class, args); } }
在application.yml中添加配置服务的基本信息以及git仓库的相关信息：
spring: application: name: david-config-server cloud: config: server: git: uri: https://gitee.com/baidawei/SpringCloudConfig.git
search-paths: repo username: #如果需要权限username password: #password server: port: 8888
如果项目公开可以不使用账号密码，searchPaths 是文件的路径.
假设我们读取配置中心的应用名为david-config-client，那么我们可以在git仓库中创建如下两个配置文件：
david-config-client.yml
info:
profile: default
form: git-repo
david-config-client-dev.yml dev环境
info:
profile: dev
form: git-repo
到现在，使用git管理的分布式配置中心就完成了，可以通过浏览器、postman等工具来访问配置的内容了。访问配置信息的url与配置文件的映射关系如下：
/{application}/{profile}[/{label}]
/{application}-{profile}.yml
/{label}/{application}-{profile}.yml
/{application}-{profile}.properties
/{label}/{application}-{profile}.properties
其中，{label}对应git上不同的分支，默认为master。
访问david-config-client.yml 路径为：http://localhost:8888/david-config-client/master
{"name":"david-config-client","profiles":["master"],"label":null,"version":"b5fdf45844bf09c30e403e7b069f1c243fb1d4a7","state":null,"propertySources":[{"name":"https://gitee.com/baidawei/SpringCloudConfig.git/repo/david-config-client.yml","source":{"info.profile":"default","info.form":"git-repo"}}]}
dev: http://localhost:8888/david-config-client/dev
{"name":"david-config-client","profiles":["dev"],"label":null,"version":"b5fdf45844bf09c30e403e7b069f1c243fb1d4a7","state":null,"propertySources":[{"name":"https://gitee.com/baidawei/SpringCloudConfig.git/repo/david-config-client-dev.yml","source":{"info.profile":"dev","info.from":"git-repo"}},{"name":"https://gitee.com/baidawei/SpringCloudConfig.git/repo/david-config-client.yml","source":{"info.profile":"default","info.form":"git-repo"}}]}
构建客户端
完成了分布式配置中心后，构建一个david-config-client，获取上述配置信息，在pom.xml中添加依赖：
<?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.david</groupId> <artifactId>config-client</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>config-client</name> <description>Demo project for Spring Boot</description> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.5.9.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> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-config</artifactId> </dependency> </dependencies> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-dependencies</artifactId> <version>Edgware.SR2</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> </project>
配置文件bootstrap.yml，来指定获取配置中心的配置文件
spring:
application:
name: david-config-client #对应{application}位置
cloud:
config:
uri: http://localhost:8888/ #配置中心网址
profile: default #对应{profile}位置 dev等
label: master #对应{label}位置 分支
server:
port: 8881
名字必须是bootstrap.yml或properties才能被正确加载，
新建TestController
@RestController public class TestController { @Value("${info.profile}") String info; @GetMapping("/test") public String test(){ return info; } }
把server和client都启动起来
http://localhost:8881/test 输出default 切换配置文件中的profile为dev 输出为dev
这说明，config-client是从config-server中获取了info.profile属性,而config-server是从git仓库读取的
