能否创建兼具Spring Boot自定义父POM的多模块项目？及配置咨询

Absolutely! You can absolutely build a multi-module Maven project where the parent POM serves two key roles: managing Spring Boot dependency versions and acting as a container for your custom client/util JARs. Let me break down the correct setup with sample configurations, plus troubleshoot common issues you might be facing.

Step 1: Define Your Project Structure #

First, lay out a clean module hierarchy to keep things organized:

my-shared-parent-project/
├── pom.xml          # Parent POM (packaging: pom)
├── client-jar-1/    # Custom utility/client library (packaging: jar)
├── spring-app-1/    # Independent Spring Boot app (packaging: jar)
└── spring-app-2/    # Another independent Spring Boot app (packaging: jar)

Step 2: Configure the Parent POM #

This POM will inherit Spring Boot's dependency management, declare all child modules, and centralize version control for your custom JARs.

<?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 POM Metadata -->
    <groupId>com.yourcompany</groupId>
    <artifactId>shared-parent</artifactId>
    <version>1.0.0-SNAPSHOT</version>
    <packaging>pom</packaging>
    <name>Shared Parent POM</name>
    <description>Manages Spring Boot dependencies and custom client modules</description>

    <!-- Inherit Spring Boot's official dependency management -->
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.2.0</version> <!-- Use your preferred Spring Boot version -->
        <relativePath/> <!-- Pull from Maven repo instead of local files -->
    </parent>

    <!-- List all child modules so Maven builds them in order -->
    <modules>
        <module>client-jar-1</module>
        <module>spring-app-1</module>
        <module>spring-app-2</module>
    </modules>

    <!-- Centralized dependency management for all child modules -->
    <dependencyManagement>
        <dependencies>
            <!-- Declare your custom client JAR so children can reference it without versions -->
            <dependency>
                <groupId>com.yourcompany</groupId>
                <artifactId>client-jar-1</artifactId>
                <version>${project.version}</version>
            </dependency>

            <!-- Optional: Override Spring Boot's default dependency versions if needed -->
            <dependency>
                <groupId>com.fasterxml.jackson.core</groupId>
                <artifactId>jackson-databind</artifactId>
                <version>2.15.3</version>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <!-- Shared build properties for all modules -->
    <properties>
        <java.version>17</java.version>
        <maven.compiler.source>${java.version}</maven.compiler.source>
        <maven.compiler.target>${java.version}</maven.compiler.target>
    </properties>
</project>

Step 3: Configure the Custom Client JAR Module #

This is a standard JAR (not a Spring Boot app) containing your shared utilities or client code. It only inherits from your parent 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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <groupId>com.yourcompany</groupId>
        <artifactId>shared-parent</artifactId>
        <version>1.0.0-SNAPSHOT</version>
        <relativePath>../pom.xml</relativePath>
    </parent>

    <artifactId>client-jar-1</artifactId>
    <name>Client Utility Jar</name>
    <description>Shared client code/utilities for Spring Boot apps</description>
    <packaging>jar</packaging>

    <!-- Add dependencies specific to this utility module -->
    <dependencies>
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
        </dependency>
    </dependencies>
</project>

Key Note: Don't add the Spring Boot Maven plugin here—this module should be a standard, non-executable JAR.

Step 4: Configure a Spring Boot Child Application #

This module is an independent Spring Boot app that inherits from your parent POM. It can optionally include your custom client JAR.

<?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.yourcompany</groupId>
        <artifactId>shared-parent</artifactId>
        <version>1.0.0-SNAPSHOT</version>
        <relativePath>../pom.xml</relativePath>
    </parent>

    <artifactId>spring-app-1</artifactId>
    <name>Spring Boot App 1</name>
    <description>Independent Spring Boot app using shared parent and client module</description>
    <packaging>jar</packaging>

    <!-- Dependencies: Spring Boot starters + optional custom client JAR -->
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!-- Optional: Only include if this app needs the client library -->
        <dependency>
            <groupId>com.yourcompany</groupId>
            <artifactId>client-jar-1</artifactId>
        </dependency>
    </dependencies>

    <!-- Spring Boot plugin to create an executable JAR -->
    <build>
        <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>

Common Pitfalls & Fixes #

If you're hitting issues, here are the most likely culprits:

1. Child app can't resolve the client JAR

   • Fix: Ensure the client module is listed in the parent's <modules> section. Run mvn clean install on the parent project first to install the client JAR to your local Maven repo.

2. Spring Boot dependency versions aren't being applied

   • Fix: Make sure your parent POM inherits from spring-boot-starter-parent as its direct parent. If you need to override a version, declare it in the parent's <dependencyManagement> section (this takes precedence over Spring Boot's defaults).

3. Client module is packaged as an executable JAR

   • Fix: Remove the Spring Boot Maven plugin from the client module's POM. It should only exist in your Spring Boot application modules.

4. Version conflicts between parent and Spring Boot

   • Fix: If your parent POM needs to inherit from another non-Spring Boot parent, use Spring Boot's dependency BOM instead of inheriting the starter parent:

     <dependencyManagement>
         <dependencies>
             <dependency>
                 <groupId>org.springframework.boot</groupId>
                 <artifactId>spring-boot-dependencies</artifactId>
                 <version>3.2.0</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>
             <!-- Your custom dependencies here -->
         </dependencies>
     </dependencyManagement>
     

内容的提问来源于stack exchange，提问作者sdc