用Jena通过SPARQL读取RDF内容
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2022-03-04 13:07:51
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package sh.pl;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import com.hp.hpl.jena.ontology.OntModel;
import com.hp.hpl.jena.ontology.OntModelSpec;
import com.hp.hpl.jena.query.Query;
import com.hp.hpl.jena.query.QueryExecution;
import com.hp.hpl.jena.query.QueryExecutionFactory;
import com.hp.hpl.jena.query.QueryFactory;
import com.hp.hpl.jena.query.QuerySolution;
import com.hp.hpl.jena.query.ResultSet;
import com.hp.hpl.jena.rdf.model.ModelFactory;
public class TestJena {
public static void main(String args[]) throws IOException {
OntModel ontModel = ModelFactory.createOntologyModel(OntModelSpec.OWL_MEM);
URL url = new URL("http://jvn.jp/rss/jvn.rdf");
HttpURLConnection connect = (HttpURLConnection) url.openConnection();
InputStream in = url.openStream();
ontModel.read(in, "");
String queryString = "PREFIX rss: <http://purl.org/rss/1.0/> SELECT ?item_title ?item_link"
+
" WHERE " + "{ ?item rss:title ?item_title " +
"FILTER regex(?item_title, \"MAC\", \"i\" ) ." +
"?item rss:link ?item_link }";
Query query = QueryFactory.create(queryString);
QueryExecution qe = QueryExecutionFactory.create(query, ontModel);
ResultSet results = qe.execSelect();
while (results.hasNext()) {
QuerySolution qs = results.next();
System.out.println(qs.get("item_title"));
System.out.println(qs.get("item_link"));
}
// ResultSetFormatter.out(System.out, results, query);
qe.close();
}
}
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