如何在插件中访问Maven的依赖关系层次结构

Question

在我的插件中,我需要处理依赖关系层次结构并获取有关每个依赖关系的信息(groupId,artifactId,version等)以及它是否被排除.做这个的最好方式是什么？

Answer 1

依赖插件具有完成大部分工作的树目标.它处理一个MavenProject使用DependencyTreeBuilder,它返回一个DependencyNode关于已解析的依赖关系(及其传递依赖关系)的分层信息.

您可以直接从TreeMojo复制大部分代码.它使用CollectingDependencyNodeVisitor遍历树并生成List所有节点.

您可以Artifact通过调用访问节点getArtifact(),然后根据需要获取工件信息.为了得到排除的原因,DependencyNode有一个getState()方法返回一个int,指示是否已包含依赖项,或者如果没有,省略它的原因是什么(DependencyNode类中有常量来检查返回值)

//All components need this annotation, omitted for brevity

/**
 * @component
 * @required
 * @readonly
 */
private ArtifactFactory artifactFactory;
private ArtifactMetadataSource artifactMetadataSource;
private ArtifactCollector artifactCollector;
private DependencyTreeBuilder treeBuilder;
private ArtifactRepository localRepository;
private MavenProject project;

public void execute() throws MojoExecutionException, MojoFailureException {
    try {
        ArtifactFilter artifactFilter = new ScopeArtifactFilter(null);

        DependencyNode rootNode = treeBuilder.buildDependencyTree(project,
                localRepository, artifactFactory, artifactMetadataSource,
                artifactFilter, artifactCollector);

        CollectingDependencyNodeVisitor visitor = 
            new CollectingDependencyNodeVisitor();

        rootNode.accept(visitor);

        List<DependencyNode> nodes = visitor.getNodes();
        for (DependencyNode dependencyNode : nodes) {
            int state = dependencyNode.getState();
            Artifact artifact = dependencyNode.getArtifact();
            if(state == DependencyNode.INCLUDED) {                    
                //...
            } 
        }
    } catch (DependencyTreeBuilderException e) {
        // TODO handle exception
        e.printStackTrace();
    }
}

Answer 2

您可以使用MavenProject#getDependencyArtifacts()或MavenProject#getDependencies()(后者也返回传递依赖项).

/**
 * Test Mojo
 *
 * @goal test
 * @requiresDependencyResolution compile
 */
public class TestMojo extends AbstractMojo {

    /**
     * The Maven Project.
     *
     * @parameter expression="${project}"
     * @required
     * @readonly
     */
    private MavenProject project = null;

    /**
     * Execute Mojo.
     *
     * @throws MojoExecutionException If an error occurs.
     * @throws MojoFailureException If an error occurs.
     */
    public void execute() throws MojoExecutionException,
MojoFailureException {

        ...

        Set dependencies = project.getDependencies();

       ...
    }

}

我不完全确定,但我认为这两个方法都返回了一个Artifact实现的集合,它们为groupId,artifactId,version等公开getter.

Answer 3

这是一个关于如何获取所有依赖项(包括传递)以及如何访问文件本身的最新Maven3示例(例如,如果您需要将路径添加到类路径中).

// Default phase is not necessarily important.
// Both requiresDependencyCollection and requiresDependencyResolution are extremely important however!
@Mojo(name = "simple", defaultPhase = LifecyclePhase.PROCESS_RESOURCES, requiresDependencyCollection = ResolutionScope.COMPILE_PLUS_RUNTIME, requiresDependencyResolution = ResolutionScope.COMPILE_PLUS_RUNTIME)
public class SimpleMojo extends AbstractMojo {
  @Parameter(defaultValue = "${project}", readonly = true)
  private MavenProject mavenProject;

  @Override
  public void execute() throws MojoExecutionException, MojoFailureException {
    for (final Artifact artifact : mavenProject.getArtifacts()) {
      // Do whatever you need here.
      // If having the actual file (artifact.getFile()) is not important, you do not need requiresDependencyResolution.
    }
  }
}

更改Mojo中的参数是我失踪的一件非常重要的事情.没有它,行如下:

@Parameter(defaultValue = "${project.compileClasspathElements}", readonly = true, required = true)
private List<String> compilePath;

只返回classes目录,而不是您期望的路径.

将requiresDependencyCollection和requiresDependencyResolution更改为不同的值将允许您更改要捕获的范围.该Maven的文档可以提供更多的细节.

Answer 4

尝试使用jcabi-aether中的Aether实用程序类来获取任何工件的所有依赖项的列表:

File repo = this.session.getLocalRepository().getBasedir();
Collection<Artifact> deps = new Aether(this.getProject(), repo).resolve(
  new DefaultArtifact("junit", "junit-dep", "", "jar", "4.10"),
  JavaScopes.RUNTIME
);