Maven版本-maven-plugin版本plugin2.2--Maven叔叔情况

Question

Maven是3.1.0。

<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>

    <artifactId>tools-parent</artifactId>
    <version>0.0.7-SNAPSHOT</version>
    <packaging>pom</packaging>

    <description>
        Infrastructure related to the &quot;vapp&quot; and
        &quot;deployer&quot; utilities.
    </description>

    <parent>
        <groupId>com.company.product</groupId>
        <artifactId>deploy-parent</artifactId>
        <version>0.0.6-SNAPSHOT</version>
    </parent>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-scm-plugin</artifactId>
                <version>1.9.4</version>
                <configuration>
                    <connectionType>connection</connectionType>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>versions-maven-plugin</artifactId>
                <version>2.2</version>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-enforcer-plugin</artifactId>
                <version>1.4</version>
                <executions>
                    <execution>
                        <!-- Make sure that only non-snapshot versions are used for the dependencies. Only active when property 'snapshotDependencyAllowed' is false. -->
                        <id>enforce-no-snapshots</id>
                        <goals>
                            <goal>enforce</goal>
                        </goals>
                        <configuration>
                            <skip>${snapshotDependencyAllowed}</skip>
                            <rules>
                                <requireReleaseDeps>
                                    <message>No Snapshots Allowed!</message>
                                </requireReleaseDeps>
                                <requireReleaseVersion>
                                    <message>No Snapshots Allowed!</message>
                                </requireReleaseVersion>
                            </rules>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

[INFO] ------------------------------------------------------------------------
[INFO] Building tools-parent 0.0.7-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- versions-maven-plugin:2.2:set (default-cli) @ tools-parent ---
[INFO] Searching for local aggregator root...
[INFO] Local aggregation root: /user/home/u100123/giga/tools
[INFO] Processing change of com.company.product:tools-parent:0.0.7-SNAPSHOT -> 0.0.7
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary:
[INFO]
[INFO] tools-parent .................................... FAILURE [1.093s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2.404s
[INFO] Finished at: Fri May 01 20:44:22 GMT-00:00 2015
[INFO] Final Memory: 12M/246M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.codehaus.mojo:versions-maven-plugin:2.2:set (default-cli) on project tools-parent: Execution default-cli of goal org.codehaus.mojo:versions-maven-plugin:2.2:set failed. NullPointerException -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/PluginExecutionException

1. 2.2失败的原因是什么？如何解决这个问题？

Answer 1

好像是什么虫子。

html" target="_blank">解决方案:1。我还必须在...部分之外添加 com.company.product 属性，即对于tools-parent，现在version-maven-plugin:2.2工作正常，即我添加了顶部的行（如下所示）。唯一的问题是，那么parent节有什么用（除了继承deploy-parent的主代码外，还继承了tools-parent项目）。为什么groupId需要被定义为artifactId工具的父部分的输出-parent当它已经在版本的父部分中时-maven-plugin:2.2才能成功工作。

最重要的是：只有当pom.xml for a project/module有 节，而父节的artifactId不是项目本身的父节时（典型的-Maven叔叔情况），即如果tools-parent工件是在另一个模块的父节中定义的（比方说tools-child)，那么版本2.2将成功工作。但是，如果tools-child的父节不包含作为“tools-parent”的artifactId，并且对于ex：deploy-parent/some-diversity-project-artifact（它驻留在源代码管理工具中的不同项目中）来说，则对于tools-child artifactId，我们也需要在父节之外设置groupId值（即使父节artifactId的groupId与tools-child的groupId相同/不同）。

<groupId>com.company.product</groupId>
<artifactId>tools-parent</artifactId>
<version>0.0.7-SNAPSHOT</version>
<packaging>pom</packaging>

<description>
    Infrastructure related to the &quot;vapp&quot; and
    &quot;deployer&quot; utilities.
</description>

<parent>
    <groupId>com.company.product</groupId>
    <artifactId>deploy-parent</artifactId>
    <version>0.0.6-SNAPSHOT</version>
</parent>

--或者

2.切换回版本-maven-plugin:2.1