Maven - 父模块 vs 子模块 与 <dependencyManagement> vs <dependencies>

父模块 vs 子模块

多模块开发中，使用父模块对子模块的管理非常方便。

1. 父模块pom中的<properties>属性会被子模块继承
2. 父模块pom中，在<dependencyManagement>中可以进行子模块依赖的版本管理，子模块继承父模块之后，提供作用：锁定版本 + 子模块不用再写 version(但还需要显示声明)。

3. 此外，父模块中可以添加依赖作为全局依赖，子模块自动继承。<dependencyManagement>外的<dependencies>中定义全局依赖。

 

目录结构

 

父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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.zsy</groupId>
    <artifactId>guli-mall</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>pom</packaging>

    <modules>
        <module>mall-coupon</module>
        <module>mall-member</module>
        <module>mall-order</module>
        <module>mall-product</module>
        <module>mall-ware</module>
    </modules>
    <name>guli-mall</name>
    <description>parent</description>

    <!--  这里的属性会被子模块继承  -->
    <properties>
        <java.version>1.8</java.version>
        <spring.boot.version>2.4.3</spring.boot.version>
        <spring-cloud.version>2020.0.1</spring-cloud.version>
    </properties>
<!--  dependencyManagement里的dependencies，只会帮助子模块显示声明同样依赖时，免去再写一遍版本。并不是直接被子模块继承  -->
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${spring.boot.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <!--  这里的依赖会被子模块继承  -->
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>

 

 

子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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>com.zsy</groupId>
        <artifactId>guli-mall</artifactId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    <groupId>com.zsy</groupId>
    <artifactId>mall-product</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>mall-product</name>
    <description>商品服务</description>

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

</project>