import org.eclipse.aether.util.graph.selector.ExclusionDependencySelector; //导入依赖的package包/类
private DependencyNode getDependencyTree(Artifact artifact) throws MojoExecutionException {
    try {
        CollectRequest collectRequest = new CollectRequest(new Dependency(artifact, "compile"), null, projectRepositories);
        DefaultRepositorySystemSession session = new DefaultRepositorySystemSession(repositorySystemSession);
        session.setDependencySelector(new AndDependencySelector(new OptionalDependencySelector(),
                new ScopeDependencySelector1(),
                new ExclusionDependencySelector()));
        // between aether-util 0.9.0.M1 and M2, JavaEffectiveScopeCalculator was removed
        // see https://bugs.eclipse.org/bugs/show_bug.cgi?id=397241
        DependencyGraphTransformer transformer = new ChainedDependencyGraphTransformer(new ConflictMarker(),
                new ConflictResolver(new NearestVersionSelector(), new JavaScopeSelector(), new SimpleOptionalitySelector(), new JavaScopeDeriver()),
                new JavaDependencyContextRefiner());
        session.setDependencyGraphTransformer(transformer);
        CollectResult result = repositorySystem.collectDependencies(session, collectRequest);
        return result.getRoot();
    } catch (DependencyCollectionException e) {
        throw new MojoExecutionException("Cannot build project dependency tree", e);
    }
}
 

import org.eclipse.aether.util.graph.selector.ExclusionDependencySelector; //导入依赖的package包/类
/**
 * Set up repository session for maven.
 * 
 * @param system
 *          the repository system
 * @param localDownloadDir
 *          the directory where to put the downloaded artifacts
 * @return the configured repository session
 */
private RepositorySystemSession newSession(RepositorySystem system, final String localDownloadDir) {
  DefaultRepositorySystemSession session = MavenRepositorySystemUtils.newSession();

  LocalRepository localRepo = new LocalRepository(localDownloadDir);
  session.setLocalRepositoryManager(system.newLocalRepositoryManager(session, localRepo));

  DependencySelector depFilter =
      new AndDependencySelector(
      new ScopeDependencySelector(JavaScopes.PROVIDED),
      new OptionalDependencySelector(),
      new ExclusionDependencySelector()
  );
  session.setDependencySelector(depFilter);

  return session;
}
 

import org.eclipse.aether.util.graph.selector.ExclusionDependencySelector; //导入依赖的package包/类
public RepositoryContext ( final Path tmpDir, final String repositoryUrl, final Boolean allOptional )
{
    this.system = Helper.newRepositorySystem ();
    this.session = Helper.newRepositorySystemSession ( tmpDir, this.system );

    if ( allOptional != null )
    {
        final List<DependencySelector> selectors = new LinkedList<> ();

        selectors.add ( new ScopeDependencySelector ( "test", "provided" ) );
        if ( !allOptional )
        {
            selectors.add ( new OptionalDependencySelector () );
        }
        selectors.add ( new ExclusionDependencySelector () );
        this.session.setDependencySelector ( new AndDependencySelector ( selectors ) );
    }

    if ( repositoryUrl == null || repositoryUrl.isEmpty () )
    {
        this.repositories = Collections.singletonList ( Helper.newCentralRepository () );
    }
    else
    {
        this.repositories = Collections.singletonList ( Helper.newRemoteRepository ( "drone.aether.import", repositoryUrl ) );
    }
}
 

import org.eclipse.aether.util.graph.selector.ExclusionDependencySelector; //导入依赖的package包/类
@Bean
public RepositorySystemSession repositorySystemSession(RepositorySystem repositorySystem) {
    // see MavenRepositorySystemUtils.newSession()

    DependencySelector selector = new AndDependencySelector(
            new ScopeDependencySelector("test", "provided"),
            new DepthOneOptionalDependencySelector(),
            new ExclusionDependencySelector());

    DependencyGraphTransformer transformer = new ConflictResolver(
            new NearestVersionSelector(),
            new JavaScopeSelector(),
            new SimpleOptionalitySelector(),
            new JavaScopeDeriver());

    DefaultRepositorySystemSession session = new DefaultRepositorySystemSession();
    session.setLocalRepositoryManager(repositorySystem.newLocalRepositoryManager(session, localRepository()));
    session.setSystemProperties(System.getProperties());
    session.setConfigProperties(System.getProperties());
    session.setArtifactTypeRegistry(artifactTypeRegistry());
    session.setDependencyManager(new ClassicDependencyManager());
    session.setArtifactDescriptorPolicy(new SimpleArtifactDescriptorPolicy(true, true));
    session.setDependencySelector(selector);
    session.setDependencyGraphTransformer(transformer);
    session.setTransferListener(new LogTransferListener());
    session.setRepositoryListener(new LogRepositoryListener());

    if (!session.getConfigProperties().containsKey(ConfigurationProperties.REQUEST_TIMEOUT)) {
        session.setConfigProperty(ConfigurationProperties.REQUEST_TIMEOUT, 3 * 60 * 1000);
    }

    return session;
}