import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Iterator;
import com.hp.hpl.jena.ontology.*;
import com.hp.hpl.jena.rdf.model.*;

public class OntAccess {

 /**
  * @param filepath
  */
 public String filePath = "sweetdata.owl";
 OntModel model;

 
 /**
  * constructor load ontology
  */
 public OntAccess() {
  
  model = ModelFactory.createOntologyModel();   //create an ontology model
  loadModel();
 }
 
 
 /**
  *  Initialization
  */
 public OntClass getSubClass(String name)  {
  String SOURCE= "file:/C:/Users/Documents/activework/METOC/sweet-data.owl";
  //String SOURCE= "http://sweet.jpl.nasa.gov/ontology/units.owl";
  String NS = SOURCE +"#";
  OntClass r =model.getOntClass( NS + name) ;
  return r;
 }
 
 
 
 /**
  *  return all individuals of class c
  */
 public ArrayList getIndividuals(OntClass c){
  ArrayList individual=new ArrayList();
  if(c !=null){
   for(Iterator j=c.listInstances();j.hasNext();){
    OntResource in = (OntResource) j.next();
    individual.add(in);
   }
  }
  return individual;
 }
 /**
  *
  * Load the OWL file
  */
 private void loadModel() {

  InputStreamReader in;
  try {
   FileInputStream file = new FileInputStream(filePath);
   in = new InputStreamReader(file, "UTF-8");
   model.read(in, null);
   in.close();
  } catch (FileNotFoundException e) {
   System.out.println("can not open");
   System.exit(0);
  } catch (IOException e) {
   e.printStackTrace();
   System.exit(0);
  }

 }
 
 
 public static void main(String[] args) {
  OntAccess onto1=new OntAccess();  
  OntClass c=onto1.getSubClass("Prefix");
  ArrayList a=onto1.getIndividuals(c);
  for(int i=0;i<a.size();i++)
  {
   System.out.println(a.get(i).toString());
  }
  
 }

}

OWL file 里面的import内容是
<rdf:RDF xml:base="file:/C:/Users/Documents/activework/METOC/sweet-data.owl">
−
<owl:Ontology rdf:about="">
<owl:versionInfo>1.0</owl:versionInfo>
<owl:imports rdf:resource="http://sweet.jpl.nasa.gov/ontology/numerics.owl"/>
<owl:imports rdf:resource="http://sweet.jpl.nasa.gov/ontology/space.owl"/>
<owl:imports rdf:resource="http://sweet.jpl.nasa.gov/ontology/time.owl"/>
</owl:Ontology>

现在我查找的是Prefix这个节点,这个节点在 import ../time.owl里面的一个节点,我运行OntClass c=onto1.getSubClass("Prefix"); c返回的是null.

这个节点在第一个import文件的http://sweet.jpl.nasa.gov/ontology/numerics.owl里面的import文件http://sweet.jpl.nasa.gov/ontology/units.owl
能再帮忙看一下吗，谢谢