七、配置中心Config
Spring Cloud Config为分布式系统中的外部化配置提供了服务器端和客户端支持。通过配置服务器，可以很方便的来管理各应用程序的外部属性。本文将实现客户端获取配置参数。
新建config模块，添加pom.xml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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.5.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.mujio</groupId>
<artifactId>config</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>config</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
<!-- spring cloud版本 -->
<spring-cloud.version>Hoxton.SR3</spring-cloud.version>
</properties>
<dependencies>
<!-- config所需要的依赖 -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-config-server</artifactId>
</dependency>
<!-- config需要注册到eureka中，故需要添加eureka依赖 -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
</dependency>
<!-- springboot健康检查 -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</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>
</project>
修改配置文件为application.yml：
server:
port: 9400
eureka:
client:
#是否注册到Eureka服务中
register-with-eureka: true
#是否从Eureka服务中获取注册信息
fetch-registry: false
#Eureka客户端与服务端进行交互的地址
service-url:
defaultZone: http://mujio:123456@localhost:7000/eureka/
#健康检查（需要spring-boot-starter-actuator依赖）
healthcheck:
enabled: true
instance:
#把ip地址注册到Eureka服务中
prefer-ip-address: true
# 续约更新时间间隔（默认30秒）
lease-renewal-interval-in-seconds: 10
# 续约到期时间（默认90秒）
lease-expiration-duration-in-seconds: 10
添加配置文件bootstrap.yml，这里以读取本地文件为例：
spring:
application:
name: config-server #配置服务名称
profiles:
active: native #设置为本地启动的方式，而不是通过git
cloud:
config:
server:
native:
# 配置文件所在目录，classpath（类路径）和（系统文件路径） file两种
searchLocations: classpath:/
给启动类加上eureka注解和config服务端注解：
package com.mujio.config;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.config.server.EnableConfigServer;
@EnableConfigServer
@EnableDiscoveryClient
@SpringBootApplication
public class ConfigApplication {
public static void main(String[] args) {
SpringApplication.run(ConfigApplication.class, args);
}
}
以goods-server为例，pom.xml中加入config的依赖：
<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<!-- springboot版本改为2.1.1.RELEASE -->
<version>2.1.1.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.mujio</groupId>
<artifactId>goods-server</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>goods-server</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
<spring-cloud.version>Greenwich.RC2</spring-cloud.version>
</properties>
<dependencies>
<!-- 添加web服务依赖 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- MySQL数据库依赖 -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.41</version>
</dependency>
<!-- mybatis依赖 -->
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.1.1</version>
</dependency>
<!-- springboot项目需要的依赖，创建项目自动添加 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
<!-- 添加eureka依赖 start -->
<!-- eureka客户端依赖 -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
<exclusions>
<!-- eureka的数据转换，自动将数据结果转为xml格式，我们不需要xml格式的结果所以需要排除 -->
<exclusion>
<groupId>com.fasterxml.jackson.dataformat</groupId>
<artifactId>jackson-dataformat-xml</artifactId>
</exclusion>
</exclusions>
</dependency>
<!-- config客户端所需依赖 -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-config</artifactId>
</dependency>
</dependencies>
<!-- 指定springcloud依赖版本 -->
<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>
<repositories>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
</repository>
</repositories>
<!-- 添加eureka依赖 end -->
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
config的客户端和服务端依赖并不一样，一个是spring-cloud-config-server一个是spring-cloud-starter-config。
添加引导配置bootstrap.yml：
spring:
application:
name: goods-server
cloud:
config:
discovery:
enabled: true
service-id: goods-server
profile: dev
uri: http://localhost:9400/
enabled: true
eureka:
client:
register-with-eureka: true #是否注册到Eureka服务中
fetch-registry: true #是否从Eureka服务中获取注册信息
service-url: #Eureka客户端与服务端进行交互的地址
defaultZone: http://mujio:123456@localhost:7000/eureka/
instance:
prefer-ip-address: true #把ip地址注册到Eureka服务中
ip-address: 127.0.0.1
已经可以进行测试了，启动端口为7000的eureka，启动config，检查eureka管理页面中是否正确获取到config服务：
启动成功，接着启动goods-server，我们原本配置的端口为8000，我读取的是在config模块resources下的配置文件goods-server-dev.yml内容为：
这里读取的配置文件与goods-server模块bootstrap.yml中指定的 service-id: goods-server和 profile: dev一致。
server:
port: 8029
spring:
application:
name: goods-server #指定服务名称
eureka:
client:
register-with-eureka: true #是否注册到Eureka服务中
fetch-registry: false #是否从Eureka服务中获取注册信息
service-url: #Eureka客户端与服务端进行交互的地址
defaultZone: http://mujio:123456@localhost:7000/eureka/
instance:
prefer-ip-address: true #把ip地址注册到Eureka服务中
启动结果：
可以看到，goods-server的application.yml配置文件中指定的端口为8000，但是实际启动的端口是config中读取到的配置8029。说明咱们已经初步配置好了config。