How to extract RDF triples from XML file using an existing ontology?

Question

I am trying to extract RDF triples from XML files by using an existing ontology. I am using Java, and can use XPath to extract data from XML and Jena to read and write RDF documents and ontologies. How can I extract the relevant triples from the XML according to the existing ontology?

Manuel Salvadores Manuel Salvadores · Accepted Answer · 2011-04-14T20:58:15

Forget about XPath to extract triples, it way easier and less problematic with Jena.

You can use the interface SimpleSelector together with model.listStatements from Jena.

In this example I am using SimpleSelector to find all the triples with a single property but you can implement the any search you need by customizing the method selects.

FileManager fManager = FileManager.get();
Model model = fManager.loadModel("some_file.rdf");

Property someRelevantProperty = 
    model. createProperty("http://your.data.org/ontology/",
                          "someRelevantProperty");

SimpleSelector selector = new SimpleSelector(null, null, (RDFNode)null) {
    public boolean selects(Statement s)
        { return s.getPredicate().equals(someRelevantProperty);}
}

StmtIterator iter = model.listStatements(selector);
while(it.hasNext()) {
   Statement stmt = iter.nextStatement();
   System.out.print(stmt.getSubject().toString());
   System.out.print(stmt.getPredicate().toString());
   System.out.println(stmt.getObject().toString());
}

You'll find more information here.

If you describe a bit more the ontology you are using and the type of search you need we might be able to help more.

How to extract RDF triples from XML file using an existing ontology?

1 Answers