Programmatically resolving Maven dependencies outside of a plugin - get RepositorySystemSession and RepositorySystem

Question

Maybe this is going to be a larger task than I had originally thought, but regardless, I\'m trying to load a MavenProject from a file and then resolve its depen

Answer 1

I just whipped up a solution to both your and my problem:

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 * 
 * This file is part of Runway SDK(tm).
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 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 * 
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 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with Runway SDK(tm).  If not, see .
 ******************************************************************************/

package com.test.mavenaether;

import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.Arrays;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;

import org.apache.maven.artifact.repository.ArtifactRepository;
import org.apache.maven.artifact.repository.ArtifactRepositoryPolicy;
import org.apache.maven.artifact.repository.MavenArtifactRepository;
import org.apache.maven.artifact.repository.layout.DefaultRepositoryLayout;
import org.apache.maven.model.Model;
import org.apache.maven.model.io.xpp3.MavenXpp3Reader;
import org.apache.maven.project.MavenProject;
import org.codehaus.plexus.util.xml.pull.XmlPullParserException;
import org.sonatype.aether.artifact.Artifact;
import org.sonatype.aether.resolution.DependencyResolutionException;
import org.sonatype.aether.util.artifact.DefaultArtifact;
import org.sonatype.aether.util.artifact.JavaScopes;

import com.jcabi.aether.Aether;

public class MavenAether
{
  public static void main(String[] args) throws Exception
  {
    String classpath = getClasspathFromMavenProject(new File("/users/terraframe/documents/workspace/MavenSandbox/pom.xml"), new File("/users/terraframe/.m2/repository"));
    System.out.println("classpath = " + classpath);
  }

  public static String getClasspathFromMavenProject(File projectPom, File localRepoFolder) throws DependencyResolutionException, IOException, XmlPullParserException
  {
    MavenProject proj = loadProject(projectPom);

    proj.setRemoteArtifactRepositories(
        Arrays.asList(
            (ArtifactRepository) new MavenArtifactRepository(
                "maven-central", "http://repo1.maven.org/maven2/", new DefaultRepositoryLayout(),
                new ArtifactRepositoryPolicy(), new ArtifactRepositoryPolicy()
            )
        )
    );

    String classpath = "";
    Aether aether = new Aether(proj, localRepoFolder);

    List dependencies = proj.getDependencies();
    Iterator it = dependencies.iterator();

    while (it.hasNext()) {
      org.apache.maven.model.Dependency depend = it.next();

      final Collection deps = aether.resolve(
        new DefaultArtifact(depend.getGroupId(), depend.getArtifactId(), depend.getClassifier(), depend.getType(), depend.getVersion()),
        JavaScopes.RUNTIME
      );

      Iterator artIt = deps.iterator();
      while (artIt.hasNext()) {
        Artifact art = artIt.next();
        classpath = classpath + " " + art.getFile().getAbsolutePath();
      }
    }

    return classpath;
  }

  public static MavenProject loadProject(File pomFile) throws IOException, XmlPullParserException
  {
      MavenProject ret = null;
      MavenXpp3Reader mavenReader = new MavenXpp3Reader();

      if (pomFile != null && pomFile.exists())
      {
          FileReader reader = null;

          try
              {
              reader = new FileReader(pomFile);
              Model model = mavenReader.read(reader);
              model.setPomFile(pomFile);

              ret = new MavenProject(model);
          }
          finally
          {
            reader.close();
          }
      }

      return ret;
  }
}

pom.xml:

  4.0.0
  com.test
  MavenSandbox
  0.0.1-SNAPSHOT

  
    
      com.jcabi
      jcabi-aether
      0.7.19
    
    
      org.apache.maven
      maven-core
      3.0.3
    
  

The code first loads the Maven project (using your function provided in the original question), then uses jcabi-aether to find the artifact in your local repository. You will need to change the two parameters in the main function: the location for the pom.xml of your project, and the location of your local repository.

Enjoy! :)