Maven 统一管理 jar 包版本

1. 新建一个 Maven 工程作为父工程

2. 父工程只有一个 pom 文件和 .gitignore 文件

3. 在父 pom 统一管理依赖的版本，打包方式为 pom

父项目不包含实际的代码或可执行文件，只是用于管理其他模块或项目的集合。

<?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.study</groupId>
    <artifactId>cloud-alibaba-2021</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>pom</packaging>
 
    <!--子模块-->
    <modules>
        <module>nacos-discovery-consumer</module>
        <module>nacos-discovery-provider</module>
    </modules>
 
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <springboot.version>2.2.0.RELEASE</springboot.version>
        <springcloud.alibaba.version>2.2.0.RELEASE</springcloud.alibaba.version>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
        <lombok.version>1.18.16</lombok.version>
    </properties>
 
    <dependencyManagement>
        <dependencies>
            <!--继承 springboot-->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${springboot.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <!--继承 springcloud alibaba-->
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>${springcloud.alibaba.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <!--lombok-->
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>${lombok.version}</version>
            </dependency>
        </dependencies>
    </dependencyManagement>
 
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-site-plugin</artifactId>
                <configuration>
                    <locales>en,fr</locales>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

4. 新建一个 Maven 工程作为子工程，在 pom 文件引入 dependencyManagement 里包含的依赖，不填写版本，则引入父 pom 相同的版本；填写版本则使用指定版本。

<?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">
    <parent>
        <artifactId>cloud-alibaba-2021</artifactId>
        <groupId>com.study</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
 
    <artifactId>nacos-discovery-consumer</artifactId>
 
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--服务注册与发现-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
    </dependencies>
</project>