这是基于一个快速搜索，有一个现有的API称为Aether。它的文档不是很好。
其中的方法称为：getDependencies()，并根据javadoc检索直接依赖关系。
https://maven.apache.org/resolver/maven-resolver-api/apidocs/org/eclipse/aether/resolution/ArtifactDescriptorResult.html
在github上有一个例子：

public class GetDirectDependencies
{

    public static void main( String[] args )
        throws Exception
    {
        System.out.println( "------------------------------------------------------------" );
        System.out.println( GetDirectDependencies.class.getSimpleName() );

        RepositorySystem system = Booter.newRepositorySystem();

        RepositorySystemSession session = Booter.newRepositorySystemSession( system );

        Artifact artifact = new DefaultArtifact( "org.eclipse.aether:aether-impl:1.0.0.v20140518" );

        ArtifactDescriptorRequest descriptorRequest = new ArtifactDescriptorRequest();
        descriptorRequest.setArtifact( artifact );
        descriptorRequest.setRepositories( Booter.newRepositories( system, session ) );

        ArtifactDescriptorResult descriptorResult = system.readArtifactDescriptor( session, descriptorRequest );

        for ( Dependency dependency : descriptorResult.getDependencies() )
        {
            System.out.println( dependency );
        }
    }

}

https://github.com/1984shekhar/fuse-examples-6.2/blob/master/aether-demo-snippets/src/main/java/org/eclipse/aether/examples/GetDirectDependencies.java