要实现maven的依赖传递：

1.父项目pom文件:节点配置版本号(自定义名称)

<?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>
    <packaging>pom</packaging>
    <modules>
        <module>common</module>
        <module>service</module>
    </modules>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.atguigu</groupId>
    <artifactId>guli_parent</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>guli_parent</name>
    <description>Demo project for Spring Boot</description>

    <properties>
         <java.version>12</java.version>
        <mybatis-plus.version>3.3.1</mybatis-plus.version>
        <velocity.version>2.0</velocity.version>
        <swagger.version>2.7.0</swagger.version>
        <aliyun.oss.version>2.8.3</aliyun.oss.version>
        <jodatime.version>2.10.1</jodatime.version>
        <commons-fileupload.version>1.3.1</commons-fileupload.version>
        <commons-io.version>2.6</commons-io.version>
    </properties>


    <dependencyManagement>
        <dependencies>
             <dependency>
                <groupId>com.baomidou</groupId>
                <artifactId>mybatis-plus-generator</artifactId>
                <version>${mybatis-plus.version}</version>
            </dependency>
			...
			...
     </dependencies>
           
      
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>
<!---->

配置依赖,这样可以达到的效果: 父项目并没有真正导入依赖,只是保存了版本号

2.子项目: 配置依赖不需要再写版本号,达到了需要添加的效果.

 <dependencies>
        <dependency>
            <groupId>com.atguigu</groupId>
            <artifactId>service_base</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!--mybatis-plus-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
        </dependency>
       </dependencies>

3.只写直接的父子关系：这样依赖才会被传递下来
如图是service目录的pom文件示例，
它只要在parent节点中配置父项目

    <parent>
        <artifactId>guli_parent</artifactId>
        <groupId>com.atguigu</groupId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>

在module节点中配置子项目（子项目的子项目不用管）

 <modules>
        <module>service_edu</module>
        <module>service_oss</module>
    </modules>