Maven 多模块项目（如微服务架构）中，父 POM（最外层） 和 子模块 POM（具体业务模块）的区别和联系

1. 父 POM 的核心职责

父 POM 是项目的 全局配置中心，负责统一管理依赖版本、插件版本和公共配置，确保所有子模块的一致性。

1.1 依赖管理 (dependencyManagement)

• 作用：集中定义依赖的版本和范围，子模块引用时无需重复指定版本。

• 示例：

  <!-- 父 POM -->
  <dependencyManagement>
    <dependencies>
      <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
        <version>3.1.5</version>
      </dependency>
    </dependencies>
  </dependencyManagement>
  

1.2 插件管理 (pluginManagement)

• 作用：统一插件版本和默认配置，子模块按需启用。

• 示例：

  <!-- 父 POM -->
  <build>
    <pluginManagement>
      <plugins>
        <plugin>
          <groupId>org.apache.maven.plugins</groupId>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.11.0</version>
          <configuration>
            <source>17</source>
            <target>17</target>
          </configuration>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>
  

1.3 其他公共配置

• 定义全局属性（如 <properties> 中的 Java 版本）。
• 声明模块聚合（<modules>）。

   <modules>
      <module>auth</module>
      <module>gateway</module>
      <module>modules</module>
      <module>api</module>
      <module>common</module>
  </modules>
  

2. 子模块 POM 的核心职责

子模块 POM 负责 具体模块的实现配置，继承父 POM 的依赖和插件模板，并按需覆盖或扩展。

2.1 依赖声明 (dependencies)

• 规则：

  • 如果依赖在父 POM 的 dependencyManagement 中定义，子模块只需声明 groupId 和 artifactId。
  • 如果依赖未在父 POM 中定义，需在子模块中完整声明（含版本）。

• 示例：

  <!-- 子模块 POM -->
  <dependencies>
    <!-- 继承父 POM 的版本 -->
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <!-- 独立声明新依赖 -->
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>fastjson</artifactId>
      <version>2.0.33</version>
    </dependency>
  </dependencies>
  

2.2 插件启用与覆盖 (plugins)

• 规则：

  • 如果插件在父 POM 的 pluginManagement 中定义，子模块只需声明插件坐标即可继承配置。
  • 子模块可覆盖父 POM 的插件配置（如修改参数、绑定生命周期）。

• 示例：

  <!-- 子模块 POM -->
  <build>
    <plugins>
      <!-- 继承父 POM 的编译插件配置 -->
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
      </plugin>
      <!-- 覆盖父 POM 的配置 -->
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-surefire-plugin</artifactId>
        <configuration>
          <skipTests>true</skipTests> <!-- 禁用测试 -->
        </configuration>
      </plugin>
    </plugins>
  </build>
  

3. 核心对比表

4. 使用场景示例

场景 1：统一管理 Spring Boot 依赖

• 父 POM：

  <dependencyManagement>
    <dependencies>
      <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-dependencies</artifactId>
        <version>3.1.5</version>
        <type>pom</type>
        <scope>import</scope>
      </dependency>
    </dependencies>
  </dependencyManagement>
  

• 子模块：

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

场景 2：覆盖插件配置

• 父 POM：

  <pluginManagement>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-surefire-plugin</artifactId>
        <version>3.2.1</version>
        <configuration>
          <skipTests>false</skipTests>
        </configuration>
      </plugin>
    </plugins>
  </pluginManagement>
  

• 子模块：

  <plugins>
    <plugin>
      <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-surefire-plugin</artifactId>
      <configuration>
        <skipTests>true</skipTests> <!-- 覆盖父 POM 配置 -->
      </configuration>
    </plugin>
  </plugins>
  

5. 最佳实践

1. 父 POM 原则：
   • 仅在 dependencyManagement 和 pluginManagement 中定义版本，不直接使用 <dependencies> 或 <plugins>。
   • 通过 <properties> 统一管理版本号，避免硬编码。
2. 子模块原则：
   • 仅声明需要的依赖和插件，避免冗余配置。
   • 覆盖父 POM 配置时需明确标注（如注释说明）。
3. 版本一致性：
   • 公共依赖（如 Spring Boot、Lombok）应在父 POM 中统一管理。
   • 业务特定依赖（如某个工具类库）可在子模块中独立声明。

6:总结

• 父 POM 是 模板，负责定义“用什么版本”。
• 子模块 POM 是 实例，负责声明“具体用哪些”。
• 通过合理分工，既能保证一致性，又能满足模块个性化需求。

7:完整父子pom实例

1、父pom

<?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.wkl</groupId>
    <artifactId></artifactId>
    <version>3.6.5</version>

    <name></name>
    <url>http://www..vip</url>
    <description>开发系统</description>

    <properties>
        <version>3.6.5</version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <spring-boot.version>2.7.18</spring-boot.version>
        <spring-cloud.version>2021.0.9</spring-cloud.version>
        <spring-cloud-alibaba.version>2021.0.6.1</spring-cloud-alibaba.version>
        <spring-boot-admin.version>2.7.16</spring-boot-admin.version>
        <tobato.version>1.27.2</tobato.version>
        <kaptcha.version>2.3.3</kaptcha.version>
        <pagehelper.boot.version>2.0.0</pagehelper.boot.version>
        <druid.version>1.2.23</druid.version>
        <namic-ds.version>4.3.1</namic-ds.version>
        <commons.io.version>2.13.0</commons.io.version>
        <velocity.version>2.3</velocity.version>
        <fastjson.version>2.0.53</fastjson.version>
        <jjwt.version>0.9.1</jjwt.version>
        <minio.version>8.2.2</minio.version>
        <poi.version>4.1.2</poi.version>
        <springdoc.version>1.6.9</springdoc.version>
        <transmittable-thread-local.version>2.14.4</transmittable-thread-local.version>
        <org.mapstruct.version>1.6.3</org.mapstruct.version>
        <hutool.version>5.8.25</hutool.version>
        <lombok.version>1.18.30</lombok.version>

        <!-- override dependency version -->
        <tomcat.version>9.0.98</tomcat.version>
        <logback.version>1.2.13</logback.version>
        <spring-framework.version>5.3.39</spring-framework.version>
    </properties>

    <!-- 依赖声明 -->
    <dependencyManagement>
        <dependencies>

            <!-- 覆盖SpringFramework的依赖配置-->
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-framework-bom</artifactId>
                <version>${spring-framework.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>

            <!-- SpringCloud 微服务 -->
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>

            <!-- SpringCloud Alibaba 微服务 -->
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>${spring-cloud-alibaba.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>

            <!-- SpringBoot 依赖配置 -->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${spring-boot.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>

            <!-- 覆盖logback的依赖配置-->
            <dependency>
                <groupId>ch.qos.logback</groupId>
                <artifactId>logback-core</artifactId>
                <version>${logback.version}</version>
            </dependency>

            <dependency>
                <groupId>ch.qos.logback</groupId>
                <artifactId>logback-classic</artifactId>
                <version>${logback.version}</version>
            </dependency>

            <!-- 覆盖tomcat的依赖配置-->
            <dependency>
                <groupId>org.apache.tomcat.embed</groupId>
                <artifactId>tomcat-embed-core</artifactId>
                <version>${tomcat.version}</version>
            </dependency>

            <dependency>
                <groupId>org.apache.tomcat.embed</groupId>
                <artifactId>tomcat-embed-el</artifactId>
                <version>${tomcat.version}</version>
            </dependency>

            <dependency>
                <groupId>org.apache.tomcat.embed</groupId>
                <artifactId>tomcat-embed-websocket</artifactId>
                <version>${tomcat.version}</version>
            </dependency>

            <!-- FastDFS 分布式文件系统 -->
            <dependency>
                <groupId>com.github.tobato</groupId>
                <artifactId>fastdfs-client</artifactId>
                <version>${tobato.version}</version>
            </dependency>

            <!-- Springdoc webmvc 依赖配置 -->
            <dependency>
                <groupId>org.springdoc</groupId>
                <artifactId>springdoc-openapi-ui</artifactId>
                <version>${springdoc.version}</version>
            </dependency>

            <!-- 验证码 -->
            <dependency>
                <groupId>pro.fessional</groupId>
                <artifactId>kaptcha</artifactId>
                <version>${kaptcha.version}</version>
            </dependency>

            <!-- pagehelper 分页插件 -->
            <dependency>
                <groupId>com.github.pagehelper</groupId>
                <artifactId>pagehelper-spring-boot-starter</artifactId>
                <version>${pagehelper.boot.version}</version>
            </dependency>

            <!-- io常用工具类 -->
            <dependency>
                <groupId>commons-io</groupId>
                <artifactId>commons-io</artifactId>
                <version>${commons.io.version}</version>
            </dependency>

            <!-- excel工具 -->
            <dependency>
                <groupId>org.apache.poi</groupId>
                <artifactId>poi-ooxml</artifactId>
                <version>${poi.version}</version>
            </dependency>

            <!-- 代码生成使用模板 -->
            <dependency>
                <groupId>org.apache.velocity</groupId>
                <artifactId>velocity-engine-core</artifactId>
                <version>${velocity.version}</version>
            </dependency>

            <!-- JSON 解析器和生成器 -->
            <dependency>
                <groupId>com.alibaba.fastjson2</groupId>
                <artifactId>fastjson2</artifactId>
                <version>${fastjson.version}</version>
            </dependency>

            <!-- JWT -->
            <dependency>
                <groupId>io.jsonwebtoken</groupId>
                <artifactId>jjwt</artifactId>
                <version>${jjwt.version}</version>
            </dependency>

            <!-- 线程传递值 -->
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>transmittable-thread-local</artifactId>
                <version>${transmittable-thread-local.version}</version>
            </dependency>

            <!-- 核心模块 -->
            <dependency>
                <groupId>com.wkl</groupId>
                <artifactId>-common-core</artifactId>
                <version>${.version}</version>
            </dependency>

            <!-- 接口模块 -->
            <dependency>
                <groupId>com.wkl</groupId>
                <artifactId>-common-swagger</artifactId>
                <version>${.version}</version>
            </dependency>

            <!-- 安全模块 -->
            <dependency>
                <groupId>com.wkl</groupId>
                <artifactId>-common-security</artifactId>
                <version>${.version}</version>
            </dependency>



            <!-- 权限范围 -->
            <dependency>
                <groupId>com.wkl</groupId>
                <artifactId>-common-datascope</artifactId>
                <version>${.version}</version>
            </dependency>

            <!-- 多数据源 -->
            <dependency>
                <groupId>com.wkl</groupId>
                <artifactId>-common-datasource</artifactId>
                <version>${.version}</version>
            </dependency>

            <!-- 分布式事务 -->
            <dependency>
                <groupId>com.wkl</groupId>
                <artifactId>-common-seata</artifactId>
                <version>${.version}</version>
            </dependency>

            <!-- 日志记录 -->
            <dependency>
                <groupId>com.wkl</groupId>
                <artifactId>-common-log</artifactId>
                <version>${.version}</version>
            </dependency>

            <!-- 缓存服务 -->
            <dependency>
                <groupId>com.wkl</groupId>
                <artifactId>-common-redis</artifactId>
                <version>${.version}</version>
            </dependency>

            <!-- 系统接口 -->
            <dependency>
                <groupId>com.wkl</groupId>
                <artifactId>-api-system</artifactId>
                <version>${.version}</version>
            </dependency>

            <!-- map转换 -->
            <dependency>
                <groupId>org.mapstruct</groupId>
                <artifactId>mapstruct</artifactId>
                <version>${org.mapstruct.version}</version>
            </dependency>

            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>${lombok.version}</version>
                <scope>provided</scope>
            </dependency>

<!--            <dependency>-->
<!--                <groupId>cn.hutool</groupId>-->
<!--                <artifactId>hutool-all</artifactId>-->
<!--                <version>${hutool.version}</version>-->
<!--            </dependency>-->

        </dependencies>
    </dependencyManagement>

    <modules>
        <module>auth</module>
        <module>gateway</module>
        <module>modules</module>
        <module>api</module>
        <module>common</module>
    </modules>
    <packaging>pom</packaging>

    <dependencies>
        <!-- bootstrap 启动器 -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-bootstrap</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>${java.version}</source>
                    <target>${java.version}</target>
                    <encoding>${project.build.sourceEncoding}</encoding>
                </configuration>
            </plugin>
        </plugins>
        <pluginManagement>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                    <version>${spring-boot.version}</version>
                    <executions>
                        <execution>
                            <goals>
                                <goal>repackage</goal>
                            </goals>
                        </execution>
                    </executions>
                </plugin>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.11.0</version>
                    <configuration>
                        <annotationProcessorPaths>
                            <!-- Lombok 处理器 -->
                            <path>
                                <groupId>org.projectlombok</groupId>
                                <artifactId>lombok</artifactId>
                                <version>1.18.30</version>
                            </path>
                            <!-- MapStruct 处理器 -->
                            <path>
                                <groupId>org.mapstruct</groupId>
                                <artifactId>mapstruct-processor</artifactId>
                                <version>1.5.5.Final</version>
                            </path>
                        </annotationProcessorPaths>
                    </configuration>
                </plugin>

            </plugins>
        </pluginManagement>
    </build>

    <repositories>
        <repository>
            <id>public</id>
            <name>aliyun nexus</name>
            <url>https://maven.aliyun.com/repository/public</url>
            <releases>
                <enabled>true</enabled>
            </releases>
        </repository>
    </repositories>

    <pluginRepositories>
        <pluginRepository>
            <id>public</id>
            <name>aliyun nexus</name>
            <url>https://maven.aliyun.com/repository/public</url>
            <releases>
                <enabled>true</enabled>
            </releases>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </pluginRepository>
    </pluginRepositories>

</project>

2、子pom

<?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>-modules</artifactId>
        <groupId>com.wkl</groupId>
        <version>3.6.5</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>business</artifactId>

    <description>
        modules-bus业务模块
    </description>

    <dependencies>

        <!-- SpringCloud Alibaba Nacos -->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>

        <!-- SpringCloud Alibaba Nacos Config -->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
        </dependency>

        <!-- SpringCloud Alibaba Sentinel -->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
        </dependency>

        <!-- SpringBoot Actuator -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>

        <!-- Mysql Connector -->
        <dependency>
            <groupId>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
        </dependency>

        <!-- RuoYi Common DataSource -->
        <dependency>
            <groupId>com.wkl</groupId>
            <artifactId>-common-datasource</artifactId>
        </dependency>

        <!-- RuoYi Common DataScope -->
        <dependency>
            <groupId>com.wkl</groupId>
            <artifactId>-common-datascope</artifactId>
        </dependency>

        <!-- RuoYi Common Log -->
        <dependency>
            <groupId>com.wkl</groupId>
            <artifactId>-common-log</artifactId>
        </dependency>

        <!-- RuoYi Common Swagger -->
        <dependency>
            <groupId>com.wkl</groupId>
            <artifactId>-common-swagger</artifactId>
        </dependency>


        <dependency>
            <groupId>co.elastic.clients</groupId>
            <artifactId>elasticsearch-java</artifactId>
            <version>8.15.5</version>
            <exclusions>
                <exclusion>
                    <artifactId>elasticsearch-rest-client</artifactId>
                    <groupId>org.elasticsearch.client</groupId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>elasticsearch-rest-client</artifactId>
            <version>8.15.5</version>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.17.0</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>2.17.0</version>
        </dependency>
        <dependency>
            <groupId>jakarta.json</groupId>
            <artifactId>jakarta.json-api</artifactId>
            <version>2.1.1</version>
        </dependency>


        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>

        <!-- starter-test：junit + spring-test + mockito -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.mapstruct</groupId>
            <artifactId>mapstruct</artifactId>
        </dependency>

    </dependencies>

    <build>
        <finalName>${project.artifactId}</finalName>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <executions>
                    <execution>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>

        </plugins>
    </build>

</project>