以编程方式解析插件之外的Maven依赖关系 - 获取RepositorySystemSession和RepositorySystem

在云计算领域中，解析Maven依赖关系是一个常见的任务。为了实现这个目标，我们可以使用Maven的RepositorySystemSession和RepositorySystem。以下是一个简单的示例，说明如何在编程方式下解析Maven依赖关系。

首先，我们需要创建一个MavenRepositorySystemSession实例，并将其与RepositorySystem实例一起使用。以下是创建这些实例的代码示例：

import org.eclipse.aether.RepositorySystem;
import org.eclipse.aether.RepositorySystemSession;
import org.eclipse.aether.repository.LocalRepository;
import org.eclipse.aether.repository.RemoteRepository;

public RepositorySystemSession createRepositorySystemSession(RepositorySystem system, File localRepoDir) {
    LocalRepository localRepo = new LocalRepository(localRepoDir);
    return MavenRepositorySystemUtils.newSession().setLocalRepositoryManager(system.newLocalRepositoryManager(session, localRepo));
}

public List<RemoteRepository> createRemoteRepositories() {
    return Arrays.asList(
        new RemoteRepository.Builder("central", "default", "https://repo.maven.apache.org/maven2/").build()
    );
}

接下来，我们可以使用RepositorySystem和RepositorySystemSession实例来解析Maven依赖关系。以下是一个示例代码，说明如何使用这些实例解析Maven依赖关系：

import org.eclipse.aether.artifact.Artifact;
import org.eclipse.aether.artifact.DefaultArtifact;
import org.eclipse.aether.collection.CollectRequest;
import org.eclipse.aether.graph.Dependency;
import org.eclipse.aether.graph.DependencyNode;
import org.eclipse.aether.repository.RemoteRepository;
import org.eclipse.aether.resolution.ArtifactResult;
import org.eclipse.aether.resolution.DependencyRequest;
import org.eclipse.aether.resolution.DependencyResolutionException;
import org.eclipse.aether.resolution.DependencyResult;

public List<ArtifactResult> resolveDependencies(RepositorySystem system, RepositorySystemSession session, List<RemoteRepository> remoteRepositories, String groupId, String artifactId, String version) throws DependencyResolutionException {
    Artifact artifact = new DefaultArtifact(groupId + ":" + artifactId + ":" + version);
    CollectRequest collectRequest = new CollectRequest();
    collectRequest.setRoot(new Dependency(artifact, "compile"));
    collectRequest.setRepositories(remoteRepositories);
    DependencyRequest dependencyRequest = new DependencyRequest(collectRequest, null);
    DependencyResult dependencyResult = system.resolveDependencies(session, dependencyRequest);
    List<ArtifactResult> artifactResults = new ArrayList<>();
    for (DependencyNode node : dependencyResult.getArtifactResults()) {
        artifactResults.add(node.getArtifactResult());
    }
    return artifactResults;
}

这个示例代码将解析指定的Maven依赖关系，并返回一个包含所有解析到的依赖关系的列表。

最后，我们可以使用这些方法来解析Maven依赖关系，如下所示：

public static void main(String[] args) throws DependencyResolutionException {
    RepositorySystem system = Booter.newRepositorySystem();
    RepositorySystemSession session = createRepositorySystemSession(system, new File("target/local-repo"));
    List<RemoteRepository> remoteRepositories = createRemoteRepositories();
    List<ArtifactResult> artifactResults = resolveDependencies(system, session, remoteRepositories, "org.apache.maven", "maven-core", "3.8.3");
    for (ArtifactResult artifactResult : artifactResults) {
        System.out.println(artifactResult.getArtifact());
    }
}

这个示例代码将解析Maven核心库（org.apache.maven:maven-core:3.8.3）的依赖关系，并将其打印到控制台上。

请注意，这个示例代码仅用于演示目的，实际应用中可能需要进行错误处理和额外的配置。