如何从已导入的Maven依赖管理POM中访问属性？

问题背景 #

我通过<scope>import</scope>将一个dependency-management POM导入到另一个Maven项目中，但无法直接访问该POM里定义的属性。尝试过将其设为父POM，但目标项目已有父POM，此方案不可行；也试过properties-maven-plugin，但不清楚如何用它从外部POM读取属性。

项目结构 #

dependency-management POM (artifact1-0.1.pom):

<project>
    <packaging>pom</packaging>
    <groupId>group1</groupId>
    <artifactId>artifact1</artifactId>
    <name>management-pom</name>
    <version>0.1</version>

    <properties>
        <test.version>0.2</test.version>
    </properties>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>group2</groupId>
                <artifactId>artifact2</artifactId>
                <version>${test.version}</version>
            </dependency>
        </dependencies>
    </dependencyManagement>
</project>

导入该POM的目标项目POM (artifact3-0.1.pom):

<project>
    <packaging>war</packaging>
    <groupId>group3</groupId>
    <artifactId>artifact3</artifactId>
    <name>war-pom</name>
    <version>0.1</version>
    <properties>
        <!-- 如何访问dependency-management POM中的${test.version}？ -->
        <maven.test.version>${test.version}</maven.test.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>group2</groupId>
            <artifactId>artifact2</artifactId>
            <scope>compile</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>group1</groupId>
                <artifactId>artifact1</artifactId>
                <version>0.1</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
</project>

解决方案 #

方法1：用properties-maven-plugin读取外部POM属性

通过maven-dependency-plugin先将dependency-management POM复制到本地构建目录，再用properties-maven-plugin读取其中的属性：

<build>
    <plugins>
        <!-- 复制dependency-management POM到构建目录 -->
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-dependency-plugin</artifactId>
            <executions>
                <execution>
                    <id>copy-management-pom</id>
                    <phase>initialize</phase>
                    <goals>
                        <goal>copy</goal>
                    </goals>
                    <configuration>
                        <artifactItems>
                            <artifactItem>
                                <groupId>group1</groupId>
                                <artifactId>artifact1</artifactId>
                                <version>0.1</version>
                                <type>pom</type>
                                <outputDirectory>${project.build.directory}</outputDirectory>
                            </artifactItem>
                        </artifactItems>
                    </configuration>
                </execution>
            </executions>
        </plugin>
        <!-- 读取复制后的POM属性 -->
        <plugin>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>properties-maven-plugin</artifactId>
            <executions>
                <execution>
                    <id>load-management-properties</id>
                    <phase>initialize</phase>
                    <goals>
                        <goal>read-project-properties</goal>
                    </goals>
                    <configuration>
                        <files>
                            <file>${project.build.directory}/artifact1-0.1.pom</file>
                        </files>
                    </configuration>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

配置完成后，目标项目就能直接使用${test.version}属性。

方法2：提取属性到共享配置文件

将dependency-management POM中的属性移到单独的shared.properties文件，在两个POM中都通过properties-maven-plugin读取该文件：

1. 在dependency-management POM的资源目录下创建shared.properties：

test.version=0.2

2. 修改dependency-management POM，添加插件读取该文件并打包资源：

<build>
    <plugins>
        <plugin>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>properties-maven-plugin</artifactId>
            <executions>
                <execution>
                    <id>load-shared-props</id>
                    <phase>initialize</phase>
                    <goals>
                        <goal>read-project-properties</goal>
                    </goals>
                    <configuration>
                        <files>
                            <file>src/main/resources/shared.properties</file>
                        </files>
                    </configuration>
                </execution>
            </executions>
        </plugin>
    </plugins>
    <resources>
        <resource>
            <directory>src/main/resources</directory>
        </resource>
    </resources>
</build>

3. 在目标项目中同样配置读取该文件（需确保能访问到shared.properties，可通过依赖引入或直接复制）：

<build>
    <plugins>
        <plugin>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>properties-maven-plugin</artifactId>
            <executions>
                <execution>
                    <id>load-shared-props</id>
                    <phase>initialize</phase>
                    <goals>
                        <goal>read-project-properties</goal>
                    </goals>
                    <configuration>
                        <files>
                            <file>path/to/shared.properties</file>
                        </files>
                    </configuration>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

方法3：调整继承链（需修改现有父POM）

如果有权限修改目标项目的现有父POM，可以将dependency-management POM设为现有父POM的父POM，形成目标项目 -> 现有父POM -> dependency-management POM的继承链。这样目标项目就能直接继承到dependency-management POM中的属性。

关键说明 #

Maven的import scope仅会导入dependency-management节点的内容，不会继承properties、build等其他配置，因此必须通过上述方法间接获取属性。

内容的提问来源于stack exchange，提问作者John