将父母POM折叠到孩子身上

Question

给定一个带有父POM的maven项目 - 主要包括插件和依赖版本 - 如何生成一个从父项获取信息的POM,将其放入子项并删除对父项的引用？

理想情况下,这将使用maven-assembly-plugin完成.

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更新:我需要自动完成此操作,因为手动操作很乏味且乏味.

更新2:我正在准备外部的源代码,并且只想提供一个项目,而不是整个系列.

Answer 1

不久前我遇到了类似的问题，您可以通过定义一个新的 Maven 插件来执行以下操作，以避免 Maven 替换属性和解析路径等。

• 使用标准工件工厂解析每个父级
• 使用 MavenXpp3Reader 读取每个 pom 文件（不解析它）
• 合并未解决的项目
• 将合并的项目写入文件

这是我用来证明自己流程的一些测试代码，您显然需要将其包装在 Maven 插件中并将其绑定到流程的某个阶段。默认情况下，解析后的 pom 输出到名称为resolved-pom.xml的输出目录（即目标），可以通过设置“outputDir”和/或“pomfileName”属性，使用通常的Maven插件配置方法覆盖这两个属性。

package name.seller.rich;

import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.Writer;
import java.util.Stack;

import org.apache.maven.artifact.Artifact;
import org.apache.maven.artifact.resolver.ArtifactNotFoundException;
import org.apache.maven.artifact.resolver.ArtifactResolutionException;
import org.apache.maven.model.Model;
import org.apache.maven.model.io.xpp3.MavenXpp3Reader;
import org.apache.maven.plugin.AbstractMojo;
import org.apache.maven.plugin.MojoExecutionException;
import org.apache.maven.plugin.MojoFailureException;
import org.apache.maven.project.MavenProject;
import org.apache.maven.project.inheritance.ModelInheritanceAssembler;
import org.codehaus.plexus.util.xml.pull.XmlPullParserException;

/**
 * @goal output-project
 * @phase process-resources
 * @requiresProject true
 */
public class OutputResolvedProjectMojo extends AbstractMojo {

    /**
     * Used to look up overlay the parent models on the project's model.
     * 
     * @parameter expression=
     *            "${component.org.apache.maven.project.inheritance.ModelInheritanceAssembler}"
     * @required
     * @readonly
     */
    private ModelInheritanceAssembler modelInheritanceAssembler;

    /**
     * Used to look up Artifacts in the remote repository.
     * 
     * @parameter expression=
     *            "${component.org.apache.maven.artifact.factory.ArtifactFactory}"
     * @required
     * @readonly
     */
    protected org.apache.maven.artifact.factory.ArtifactFactory factory;

    /**
     * Used to look up Artifacts in the remote repository.
     * 
     * @parameter expression=
     *            "${component.org.apache.maven.artifact.resolver.ArtifactResolver}"
     * @required
     * @readonly
     */
    protected org.apache.maven.artifact.resolver.ArtifactResolver artifactResolver;

    /**
     * List of Remote Repositories used by the resolver
     * 
     * @parameter expression="${project.remoteArtifactRepositories}"
     * @readonly
     * @required
     */
    protected java.util.List remoteRepos;

    /**
     * Location of the local repository.
     * 
     * @parameter expression="${localRepository}"
     * @readonly
     * @required
     */
    protected org.apache.maven.artifact.repository.ArtifactRepository local;

    /**
     * @parameter expression="${project}"
     * @required
     * @readonly
     */
    private MavenProject mavenProject;

    /**
     * The directory to output the resolved project to.
     * 
     * @parameter expression="${project.build.directory}"
     */
    private File outputDir;

    /**
     * The directory to output the resolved project to.
     * 
     * @parameter expression="resolved-pom.xml"
     */
    private String pomfileName;

    public void execute() throws MojoExecutionException, MojoFailureException {
        MavenProject parentProject = mavenProject.getParent();

        // get the unresolved project by reading the file
        MavenProject bareProject = readBareProject(mavenProject.getFile());

        Stack hierarchy = new Stack();
        hierarchy.push(bareProject);

        try {
            while (parentProject != null) {

                try {
                    // get Maven to resolve the parent artifact (download if
                    // needed)
                    Artifact pomArtifact = this.factory.createArtifact(
                            parentProject.getGroupId(), parentProject
                                    .getArtifactId(), parentProject
                                    .getVersion(), "", "pom");

                    artifactResolver.resolve(pomArtifact, this.remoteRepos,
                            this.local);

                    // get the file from the local repository and read the bare
                    // project
                    File parentPomFile = pomArtifact.getFile();

                    parentProject = readBareProject(parentPomFile);

                    hierarchy.push(parentProject);

                    parentProject = parentProject.getParent();
                } catch (ArtifactResolutionException e) {
                    getLog().error("can't resolve parent pom", e);
                } catch (ArtifactNotFoundException e) {
                    getLog().error("can't resolve parent pom", e);
                }
            }

            // merge each model starting with the oldest ancestors
            MavenProject currentParent = (MavenProject) hierarchy.pop();
            MavenProject currentProject = null;
            while (hierarchy.size() != 0) {
                currentProject = (MavenProject) hierarchy.pop();
                modelInheritanceAssembler.assembleModelInheritance(
                        currentProject.getModel(), currentParent.getModel());
                currentParent = currentProject;
            }

            // spit the merged model to the output file.
            Writer writer = getWriter(outputDir, pomfileName);

            if (writer != null) {
                currentProject.writeModel(writer);
                writer.close();
            }
        } catch (IOException e) {
            getLog().error("can't write resolved pom", e);
        }

    }

    /**
     * Creates and returns a writer for outputting the project to a pom file.
     * 
     * @param logDir
     *            the directory to output the file to.
     * @param logFileName
     *            name of the log file
     * @return the writer.
     * @throws IOException
     *             if the writer cannot be created.
     */
    private Writer getWriter(final File logDir, final String logFileName)
            throws IOException {
        if (!logDir.exists()) {
            logDir.mkdirs();
        }

        File pomLog = new File(logDir, logFileName);

        if (!pomLog.exists()) {
            pomLog.createNewFile();
        }

        return new FileWriter(pomLog);
    }

    /**
     * Read the mavenProject without resolving any inherited settings.
     * 
     * @return the MavenProject for the project's POM
     * @throws MojoExecutionException
     *             if the POM can't be parsed.
     */
    MavenProject readBareProject(final File file) {
        MavenXpp3Reader reader = new MavenXpp3Reader();
        Model model = null;
        try {
            model = reader.read(new FileReader(file));
        } catch (IOException e) {
            getLog().error("can't read pom file", e);
        } catch (XmlPullParserException e) {
            getLog().error("can't read pom file", e);
        }

        return new MavenProject(model);
    }
}