企业级 SpringCloud 教程（七）高可用的分布式配置中心(Spring Cloud Config)

一、准备工作

继续使用上一篇文章的工程，创建一个eureka-server工程，用作服务注册中心。

在其pom.xml文件引入Eureka的起步依赖spring-cloud-starter-eureka-server，代码如下 :

<?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.forezp</groupId>
    <artifactId>eureka-server</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>
 
    <name>eureka-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-starter-eureka-server</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>

在配置文件application.yml上，指定服务端口为8889，加上作为服务注册中心的基本配置，代码如下：

server:
  port: 8889
 
eureka:
  instance:
    hostname: localhost
  client:
    registerWithEureka: false
    fetchRegistry: false
    serviceUrl:
      defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/

入口类：

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

二、改造config-server

在其pom.xml文件加上EurekaClient的起步依赖spring-cloud-starter-eureka，代码如下:

<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>

配置文件application.yml，指定服务注册地址为http://localhost:8889/eureka/，其他配置同上一篇文章，完整的配置如下：

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
eureka.client.serviceUrl.defaultZone=http://localhost:8889/eureka/

最后需要在程序的启动类Application加上@EnableEureka的注解。

三、改造config-client

将其注册微到服务注册中心，作为Eureka客户端，需要pom文件加上起步依赖spring-cloud-starter-eureka，代码如下：

<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.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

配置文件bootstrap.properties，注意是bootstrap。加上服务注册地址为http://localhost:8889/eureka/

spring.application.name=config-client
spring.cloud.config.label=master
spring.cloud.config.profile=dev
#spring.cloud.config.uri= http://localhost:8888/
 
eureka.client.serviceUrl.defaultZone=http://localhost:8889/eureka/
spring.cloud.config.discovery.enabled=true
spring.cloud.config.discovery.serviceId=config-server
server.port=8881

spring.cloud.config.discovery.enabled 是从配置中心读取文件。
spring.cloud.config.discovery.serviceId 配置中心的servieId，即服务名。

这时发现，在读取配置文件不再写ip地址，而是服务名，这时如果配置服务部署多份，通过负载均衡，从而高可用。

依次启动eureka-servr,config-server,config-client
访问网址：http://localhost:8889/

访问http://localhost:8881/hi，浏览器显示：

foo version 3

资料和源码来源地址