我无法更新本体模型。

Question

我已经在Protege中制作了一个本体，并在Eclipse.My本体中导入了10个实例，我想在下面的代码中添加更多的instances.The，将实例添加到本体的现有类(名词)中。扩展后不更新本体模型，并显示相同数量的实例。

  public static void main(String[] args) throws OWLException, IOException{
  OWLOntologyManager manager = OWLManager.createOWLOntologyManager();

  File file = new File("D:\\word.owl");{  
      OntModel model=ModelFactory.createOntologyModel(OntModelSpec.OWL_MEM_RULE_INF);
       System.out.println("Model is called successfully");
    OWLOntology ont = manager.loadOntologyFromOntologyDocument(file);
    System.out.println("Loaded ontology: " + ont);

   String SOURCE = ("D:\\word.owl");
   String NS = SOURCE;
   OntModel base = ModelFactory.createOntologyModel(OntModelSpec.OWL_MEM_RULE_INF);
   base.read( SOURCE, "" );

OntModel inf =ModelFactory.createOntologyModel(OntModelSpec.OWL_MEM_RULE_INF, base );

 OntClass Noun = base.getOntClass( NS + "Noun" );
 Individual jack = base.createIndividual( NS + "Jack", Noun );
 Individual Helley = base.createIndividual( NS + "Helley", Noun );  
  manager.saveOntology(ont);

 System.out.println("Number of individuals: " + ont.getIndividualsInSignature().size());

    }
  }
 }

输出

  Model is called successfully
  Loaded ontology: 
 Number of individuals: 10

Answer 1

这样做是可行的：

import java.io.FileWriter;
import java.io.InputStream;

import org.apache.jena.ontology.Individual;
import org.apache.jena.ontology.OntClass;
import org.apache.jena.ontology.OntModel;
import org.apache.jena.ontology.OntModelSpec;
import org.apache.jena.rdf.model.ModelFactory;
import org.apache.jena.util.FileManager;
import org.apache.jena.vocabulary.RDF;

public class Mgt {

    public static void main(String[] args) throws Exception {
        String namespace = "http://www.semanticweb.org/Word#";
        String file = "word.owl";
        OntModel jenaModel = ModelFactory.createOntologyModel(OntModelSpec.OWL_MEM_RULE_INF);

        InputStream in = FileManager.get().open(file);
        jenaModel.read(in, null);
        OntClass Noun = jenaModel.getOntClass(namespace + "Noun");
        Individual Organization = Noun.createIndividual(namespace + "Organization");
        jenaModel.add(Organization, RDF.type, Noun);
        FileWriter out = new FileWriter("word.out.owl");
        jenaModel.getWriter("RDF/XML-ABBREV").write(jenaModel, out, namespace);
        out.close();
    }
}

请注意，命名空间与文件名无关。

Answer 2

我不使用那个API，但我可以看到你的问题。

在代码开始时，您可以创建一个OWLOntology对象：

OWLOntology ont = manager.loadOntologyFromOntologyDocument(file);

问题是，代码中的任何地方都不会更改ont，所以当您调用下面的行时，它将只显示/保存代码开始时从文件中加载的10个个人：

manager.saveOntology(ont);

System.out.println("Number of individuals: " + ont.getIndividualsInSignature().size());

因此，要解决这个问题，您需要在使用上面的行之前以某种方式修改ont以包含新的个体。

Answer 3

更新代码在线程"main“java.lang.NullPointerException at Mgt.main(Mgt.java:29)中给出异常

import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import org.apache.jena.ontology.Individual;
import org.apache.jena.ontology.OntClass;
import org.apache.jena.ontology.OntModel;
import org.apache.jena.ontology.OntModelSpec;
import org.apache.jena.rdf.model.ModelFactory;
import org.apache.jena.util.FileManager;
public class Mgt {
static OntModel jenaModel = null;
public static void main(String[] args) throws Exception{
    String file =("D:\\word.owl");
     jenaModel = ModelFactory.createOntologyModel(OntModelSpec.OWL_MEM_RULE_INF);

            InputStream in = FileManager.get().open(file);
            try 
            {
                jenaModel.read(in, null);
            } 
            catch (Exception e) 
            {
                e.printStackTrace();
            }
            System.out.println("Ontology " + file + " loaded.");
            OntClass Noun = jenaModel.getOntClass( "http://www.semanticweb.org/Word#Noun" );
            Individual Organization = Noun.createIndividual(file + "Organization");
            FileWriter out = null;
            try {
              // XML format - long and verbose
              out = new FileWriter( file);
              jenaModel.write( out, "RDF/XML" );

            }
            finally {
              if (out != null) {
                try {out.close();
                } catch (IOException ignore) {}
              }
            }
          }
         }