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以及是否被排除的信息（groupId，artifactId，version等）。这样做的最佳方式是什么？
答案 0 :(得分：29)
依赖插件具有执行大部分工作的tree goal。它使用MavenProject处理DependencyTreeBuilder，这将返回DependencyNode，其中包含有关已解析的依赖项（及其传递依赖项）的层次结构信息。
您可以直接从TreeMojo复制大部分代码。它使用CollectingDependencyNodeVisitor遍历树并生成所有节点的List。
您可以通过调用Artifact来访问节点的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，表明是否包含了依赖项，或者如果没有，省略它的原因是什么（DependencyNode类中有常量检查返回值）
//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();
}
}
答案 1 :(得分：19)
您可以使用MavenProject#getDependencyArtifacts()或MavenProject#getDependencies()（后者也会返回传递依赖项）。
/**
* Test Mojo
*
* @goal test
* @requiresDependencyResolution compile
*/
public class TestMojo extends AbstractMojo {
/**
* The Maven Project.
*
* @parameter expression="${project}"
* @required
* @readonly
*/
private MavenProject project = null;
/**
* Execute Mojo.
*
* @throws MojoExecutionException If an error occurs.
* @throws MojoFailureException If an error occurs.
*/
public void execute() throws MojoExecutionException,
MojoFailureException {
...
Set dependencies = project.getDependencies();
...
}
}
我不完全确定，但我认为这两个方法都返回了Artifact个实现的集合，这些实现为groupId，artifactId，version等公开了getter。
答案 2 :(得分：11)
这是一个关于如何获取所有依赖项（包括传递）以及如何访问文件本身的最新Maven3示例（例如，如果您需要将路径添加到类路径中）。
// Default phase is not necessarily important.
// Both requiresDependencyCollection and requiresDependencyResolution are extremely important however!
@Mojo(name = "simple", defaultPhase = LifecyclePhase.PROCESS_RESOURCES, requiresDependencyCollection = ResolutionScope.COMPILE_PLUS_RUNTIME, requiresDependencyResolution = ResolutionScope.COMPILE_PLUS_RUNTIME)
public class SimpleMojo extends AbstractMojo {
@Parameter(defaultValue = "${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 = "${project.compileClasspathElements}", readonly = true, required = true)
private List<String> compilePath;
只会返回classes目录，而不是您期望的路径。
将requiresDependencyCollection和requiresDependencyResolution更改为不同的值将允许您更改要捕获的范围。 maven documentation可以提供更多详细信息。
答案 3 :(得分：5)
尝试使用Aether中的jcabi-aether实用程序类来获取任何工件的所有依赖项列表：
File repo = this.session.getLocalRepository().getBasedir();
Collection<Artifact> deps = new Aether(this.getProject(), repo).resolve(
new DefaultArtifact("junit", "junit-dep", "", "jar", "4.10"),
JavaScopes.RUNTIME
);
答案 4 :(得分：3)
为什么不回退所有依赖项（直接和传递依赖项）并检查排除？
@Parameter(property = "project", required = true, readonly = true)
private MavenProject project;
public void execute() throws MojoExecutionException
{
for (Artifact a : project.getArtifacts()) {
if( a.getScope().equals(Artifact.SCOPE_TEST) ) { ... }
if( a.getScope().equals(Artifact.SCOPE_PROVIDED) ) { ... }
if( a.getScope().equals(Artifact.SCOPE_RUNTIME) ) { ... }
}
}
答案 5 :(得分：2)
Maven 3使用以太，这里有样本： https://docs.sonatype.org/display/AETHER/Home
答案 6 :(得分：1)
对于Maven 3，您可以使用DependencyGraphBuilder。它与DependencyTreeBuilder几乎完全相同。
以下是示例
import org.apache.maven.artifact.resolver.filter.ArtifactFilter;
import org.apache.maven.artifact.resolver.filter.IncludesArtifactFilter;
import org.apache.maven.execution.MavenSession;
import org.apache.maven.model.Dependency;
import org.apache.maven.plugins.annotations.ResolutionScope;
import org.apache.maven.plugins.annotations.LifecyclePhase;
import org.apache.maven.shared.dependency.graph.DependencyGraphBuilder;
import org.apache.maven.shared.dependency.graph.DependencyNode;
import org.apache.maven.shared.dependency.graph.traversal.CollectingDependencyNodeVisitor;
public class AnanlyzeTransitiveDependencyMojo extends AbstractMojo{
@Parameter(defaultValue = "${project}", readonly = true, required = true)
private MavenProject project;
@Parameter(defaultValue = "${session}", readonly = true, required = true)
private MavenSession session;
@Component(hint="maven3")
private DependencyGraphBuilder dependencyGraphBuilder;
@Override
public void execute() throws MojoExecutionException, MojoFailureException {
// If you want to filter out certain dependencies.
ArtifactFilter artifactFilter = new IncludesArtifactFilter("groupId:artifactId:version");
ProjectBuildingRequest buildingRequest = new DefaultProjectBuildingRequest(session.getProjectBuildingRequest());
buildingRequest.setProject(project);
try{
DependencyNode depenGraphRootNode = dependencyGraphBuilder.buildDependencyGraph(buildingRequest, artifactFilter);
CollectingDependencyNodeVisitor visitor = new CollectingDependencyNodeVisitor();
depenGraphRootNode.accept(visitor);
List<DependencyNode> children = visitor.getNodes();
getLog().info("CHILDREN ARE :");
for(DependencyNode node : children) {
Artifact atf = node.getArtifact();
}
}catch(Exception e) {
e.printStackTrace();
}