SpringCloud学习成长之路六 cloud配置中心

一、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。

二、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>com.forezp</groupId>

    <artifactId>config-server</artifactId>

    <version>0.0.1-SNAPSHOT</version>

    <packaging>jar</packaging>

    <name>config-server</name>

    <description>Demo project for Spring Boot</description>

    <parent>

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

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

        <version>1.5.2.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.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>Camden.SR6</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.properties文件配置以下：

spring.application.name=config-server

server.port=8888

spring.cloud.config.server.git.uri=https://github.com/forezp/SpringcloudConfig/

spring.cloud.config.server.git.searchPaths=respo

spring.cloud.config.label=master

spring.cloud.config.server.git.username=your username

spring.cloud.config.server.git.password=your password

spring.cloud.config.server.git.uri：配置git仓库地址
spring.cloud.config.server.git.searchPaths：配置仓库路径
spring.cloud.config.label：配置仓库的分支
spring.cloud.config.server.git.username：访问git仓库的用户名
spring.cloud.config.server.git.password：访问git仓库的用户密码

如果Git仓库为公开仓库，可以不填写用户名和密码，如果是私有仓库需要填写，本例子是公开仓库，放心使用。

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

foo = foo version 3

启动程序：访问http://localhost:8888/foo/dev

{"name":"foo","profiles":["dev"],"label":"master",

"version":"792ffc77c03f4b138d28e89b576900ac5e01a44b","state":null,"propertySources":[]}

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

三、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>com.forezp</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>1.5.2.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.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>Dalston.RC1</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.properties：

spring.application.name=config-client

spring.cloud.config.label=master

spring.cloud.config.profile=dev

spring.cloud.config.uri= http://localhost:8888/

server.port=8881

spring.cloud.config.label 指明远程仓库的分支
spring.cloud.config.profile
- dev开发环境配置文件
- test测试环境
- pro正式环境
spring.cloud.config.uri= http://localhost:8888/ 指明配置服务中心的网址。

程序的入口类，写一个API接口“／hi”，返回从配置中心读取的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;

    }

}

打开网址访问：http://localhost:8881/hi，网页显示：

foo version 3

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,如图：