java - Maven `help:effective-pom` 只为单个项目生成，而不是所有项目

Question

我想为多模块构建中的所有子项目生成一个有效的 pom。

help:effective-pom文档 here州

It will iterate over all projects in the current build session, printing the effective POM for each

我在跑 mvn help:effective-pom在this maven project的根目录下并且它只为根而不是为子项目生成。

为什么没有为所有项目生成有效的 pom。注意:我有另一个真实世界的 Maven 项目，其中 mvn help:effective-pom正在正确生成 <projects>带有嵌套 <project> 的标签对于每个子模块。我不确定为什么它不适用于 this maven project

这里是生成的有效pom

<!-- ====================================================================== -->
<!--                                                                        -->
<!-- Generated by Maven Help Plugin on 2017-11-12T09:56:26                  -->
<!-- See: http://maven.apache.org/plugins/maven-help-plugin/                -->
<!--                                                                        -->
<!-- ====================================================================== -->

<!-- ====================================================================== -->
<!--                                                                        -->
<!-- Effective POM for project                                              -->
<!-- 'org.gradle.test.performance:project:pom:1.0'                          -->
<!--                                                                        -->
<!-- ====================================================================== -->

<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>org.gradle.test.performance</groupId>
  <artifactId>project</artifactId>
  <version>1.0</version>
  <packaging>pom</packaging>
  <modules>
    <module>project0</module>
    <module>project1</module>
    <module>project2</module>
    <module>project3</module>
    <module>project4</module>
    <module>project5</module>
    <module>project6</module>
    <module>project7</module>
    <module>project8</module>
    <module>project9</module>
  </modules>
  <repositories>
    <repository>
      <snapshots>
        <enabled>false</enabled>
      </snapshots>
      <id>central</id>
      <name>Central Repository</name>
      <url>https://repo.maven.apache.org/maven2</url>
    </repository>
  </repositories>
  <pluginRepositories>
    <pluginRepository>
      <releases>
        <updatePolicy>never</updatePolicy>
      </releases>
      <snapshots>
        <enabled>false</enabled>
      </snapshots>
      <id>central</id>
      <name>Central Repository</name>
      <url>https://repo.maven.apache.org/maven2</url>
    </pluginRepository>
  </pluginRepositories>
  <build>
    <sourceDirectory>C:\code\gradle-maven-transform\example\smallJavaMultiProject\src\main\java</sourceDirectory>
    <scriptSourceDirectory>C:\code\gradle-maven-transform\example\smallJavaMultiProject\src\main\scripts</scriptSourceDirectory>
    <testSourceDirectory>C:\code\gradle-maven-transform\example\smallJavaMultiProject\src\test\java</testSourceDirectory>
    <outputDirectory>C:\code\gradle-maven-transform\example\smallJavaMultiProject\target\classes</outputDirectory>
    <testOutputDirectory>C:\code\gradle-maven-transform\example\smallJavaMultiProject\target\test-classes</testOutputDirectory>
    <resources>
      <resource>
        <directory>C:\code\gradle-maven-transform\example\smallJavaMultiProject\src\main\resources</directory>
      </resource>
    </resources>
    <testResources>
      <testResource>
        <directory>C:\code\gradle-maven-transform\example\smallJavaMultiProject\src\test\resources</directory>
      </testResource>
    </testResources>
    <directory>C:\code\gradle-maven-transform\example\smallJavaMultiProject\target</directory>
    <finalName>project-1.0</finalName>
    <pluginManagement>
      <plugins>
        <plugin>
          <artifactId>maven-antrun-plugin</artifactId>
          <version>1.3</version>
        </plugin>
        <plugin>
          <artifactId>maven-assembly-plugin</artifactId>
          <version>2.2-beta-5</version>
        </plugin>
        <plugin>
          <artifactId>maven-dependency-plugin</artifactId>
          <version>2.8</version>
        </plugin>
        <plugin>
          <artifactId>maven-release-plugin</artifactId>
          <version>2.3.2</version>
        </plugin>
      </plugins>
    </pluginManagement>
    <plugins>
      <plugin>
        <artifactId>maven-clean-plugin</artifactId>
        <version>2.5</version>
        <executions>
          <execution>
            <id>default-clean</id>
            <phase>clean</phase>
            <goals>
              <goal>clean</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
      <plugin>
        <artifactId>maven-install-plugin</artifactId>
        <version>2.4</version>
        <executions>
          <execution>
            <id>default-install</id>
            <phase>install</phase>
            <goals>
              <goal>install</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
      <plugin>
        <artifactId>maven-deploy-plugin</artifactId>
        <version>2.7</version>
        <executions>
          <execution>
            <id>default-deploy</id>
            <phase>deploy</phase>
            <goals>
              <goal>deploy</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
      <plugin>
        <artifactId>maven-site-plugin</artifactId>
        <version>3.3</version>
        <executions>
          <execution>
            <id>default-site</id>
            <phase>site</phase>
            <goals>
              <goal>site</goal>
            </goals>
            <configuration>
              <outputDirectory>C:\code\gradle-maven-transform\example\smallJavaMultiProject\target\site</outputDirectory>
              <reportPlugins>
                <reportPlugin>
                  <groupId>org.apache.maven.plugins</groupId>
                  <artifactId>maven-project-info-reports-plugin</artifactId>
                </reportPlugin>
              </reportPlugins>
            </configuration>
          </execution>
          <execution>
            <id>default-deploy</id>
            <phase>site-deploy</phase>
            <goals>
              <goal>deploy</goal>
            </goals>
            <configuration>
              <outputDirectory>C:\code\gradle-maven-transform\example\smallJavaMultiProject\target\site</outputDirectory>
              <reportPlugins>
                <reportPlugin>
                  <groupId>org.apache.maven.plugins</groupId>
                  <artifactId>maven-project-info-reports-plugin</artifactId>
                </reportPlugin>
              </reportPlugins>
            </configuration>
          </execution>
        </executions>
        <configuration>
          <outputDirectory>C:\code\gradle-maven-transform\example\smallJavaMultiProject\target\site</outputDirectory>
          <reportPlugins>
            <reportPlugin>
              <groupId>org.apache.maven.plugins</groupId>
              <artifactId>maven-project-info-reports-plugin</artifactId>
            </reportPlugin>
          </reportPlugins>
        </configuration>
      </plugin>
    </plugins>
  </build>
  <reporting>
    <outputDirectory>C:\code\gradle-maven-transform\example\smallJavaMultiProject\target\site</outputDirectory>
  </reporting>
</project>

Answer 1

EffectivePomMojo是聚合器目标。这意味着它只会为您运行它的模块调用。但你是对的，它也应该转储所有子项目。在你的情况下它不这样做的原因是因为这一行:

if ( projects.get( 0 ).equals( project ) && projects.size() > 1 )

在你的例子中，最上面的项目在图中是最后一个(因为没有任何其他模块对它的依赖)。如果您将它作为父项添加到 project0(并且仅针对该模块)，那么它会将您的根 pom 放在图中的第一个位置，一切都会按您预期的那样工作。

我无法为这种行为找到理由。因此，如果您在 bugtracker 中提出问题，每个人都会受益 :) 如果/当您得到答案时请更新我们。

PS:如果你知道如何调试Maven插件，这样的问题很容易解决。为此，您可以使用 mvnDebug 而不是 mvn，然后打开插件的源代码并附加到调试 session 。