Resolve prefix programmatically, Jena

I have to parse through xml which contain URI links to dbpedia.org. I have to extract rdf triples from those URI based on a given Ontology using Jena library. How do I resolve the Prefix programmatically in Java based on the ontology give开发者_如何学Gon.

The given ontology says that triples can be extracted by querying dbpedia.org. For all such triples the corresponding dbpedia resource is available to start writing the query. But the problem is how do I write the query with only its resource available. I have the properties to query. But I don't have the PREFIX for those properties

Although this may not answer the question directly, I had a whole load of URIs, some prefixed some not and I wanted them all unprefixed (i.e. written out in full with their prefixes resolved). Searching Google the most useful thing I came across was this question (first) and the JavaDoc so I thought I'd add my experience to this question to help anyone else who might be searching for the same thing.

Jena's PrefixMap interface (which Model implements) has expandPrefix and qnameFor methods. The expandPrefix method is the one which helped me (qnameFor does the reverse i.e. it applies a prefix from a PrefixMap to a string and returns null if no such mapping can be found).

Hence for any resource, to ensure that you have a fully expanded URI you can do

myRes.getModel().expandPrefix(myRes.getURI());

Hope this helps someone.

Your question is not very clear, so if this answer doesn't address your issue please edit your question to say more clearly what your problem is. However, based on what you've asked, once you've read an RDF file into a Jena model, in XML or any other encoding, the prefixes used are available through the methods in the interface com.hp.hpl.jena.shared.PrefixMapping (see javadoc). A Model object implements that interface. To automatically expand prefix "foo", use the method getNsPrefixURI().

Edit

OK, given your revised question, there's a number of things you can do to turn a simple property name into a property URI that you can use in a SPARQL query:

• use the prefix.cc service to look at possible expansions of prefixes and prefix names (e.g. if you are given dbpedia:elevation, you can look it up on prefix.cc (i.e: http://prefix.cc/dbpedia:elevation) to see that one of the possible expansions is http://dbpedia.org/ontology/elevation

• issue a SPARQL describe query on the resource URI to see which properties are returned in the RDF description, then match those to the un-prefixed property names you've been given

• ask your data provider to give you full property names, or otherwise provide the prefix expansions, in order to save you from having to reverse engineer which properties he or she meant in the first place.

Personally I'd advocate the third option if that's at all possible.