看了Lexxuan回复的帖子，很受启发，刚才刚刚看完《Semantic Web Programming》的第五章，感觉又摸不着头脑了，第五章介绍了推理机的使用，当构建了一个本体以后，针对该本体进行推理，也就是找出这个本体的“语义”，推理的级别有很多种，第一种不使用任何推理，只是对本体中已经存在的陈述进行真实地复述；第二种使用rdfs进行推理，那么则可以得到rdfs语法的推理结果，第三种使用owl语法进行推理，这三种级别推理得到的结果是完全不同。
这些是进行推理的源代码：
package net.semwebprogramming.chapter5.PelletReasoning;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.PrintWriter;
import java.util.Iterator;
import org.mindswap.pellet.jena.PelletReasonerFactory;
import com.hp.hpl.jena.ontology.Individual;
import com.hp.hpl.jena.ontology.OntModel;
import com.hp.hpl.jena.ontology.OntModelSpec;
import com.hp.hpl.jena.rdf.model.Model;
import com.hp.hpl.jena.rdf.model.ModelFactory;
import com.hp.hpl.jena.rdf.model.Statement;
import com.hp.hpl.jena.rdf.model.StmtIterator;
import com.hp.hpl.jena.reasoner.Reasoner;
import com.hp.hpl.jena.reasoner.ValidityReport;
import com.hp.hpl.jena.util.iterator.ExtendedIterator;
public class InferenceExample
{
/**
* This program takes 4 parameters an input file name
* an output file name an input file format a reasoning
* level {RDFS, OWL-DL}
*/
public static void main(String[] args)
{
//validate the program arguments
if(args.length != 4)
{
System.err.println("Usage: java InferenceExample "
+ "<input file> <input format> <output file> "
+ "<none|rdfs|owl>");
return;
}
String inputFileName = args[0];
String inputFileFormat = args[1];
String outputFileName = args[2];
String reasoningLevel = args[3];
//create an input stream for the input file
FileInputStream inputStream = null;
PrintWriter writer = null;
try
{
inputStream = new FileInputStream(inputFileName);
} catch (FileNotFoundException e) {
System.err.println("'" + inputFileName
+ "' is an invalid input file.");
return;
}
//create an output print writer for the results
try
{
writer = new PrintWriter(outputFileName);
} catch (FileNotFoundException e) {
System.err.println("'" + outputFileName
+ "' is an invalid output file.");
return;
}
//create the appropriate jena model
OntModel model = null;
if("none".equals(reasoningLevel.toLowerCase()))
{
/*
* "none" is jena model with OWL_DL
* ontologies loaded and no inference enabled
*/
model = ModelFactory.createOntologyModel(
OntModelSpec.OWL_DL_MEM);
}
else if("rdfs".equals(reasoningLevel.toLowerCase()))
{
/*
* "rdfs" is jena model with OWL_DL
* ontologies loaded and RDFS inference enabled
*/
model = ModelFactory.createOntologyModel(
OntModelSpec.OWL_DL_MEM_RDFS_INF);
}
else if("owl".equals(reasoningLevel.toLowerCase()))
{
/*
* "owl" is jena model with OWL_DL ontologies
* wrapped around a pellet-based inference model
*/
Reasoner reasoner =
PelletReasonerFactory.theInstance().create();
Model infModel = ModelFactory.createInfModel(
reasoner, ModelFactory.createDefaultModel());
model = ModelFactory.createOntologyModel(
OntModelSpec.OWL_DL_MEM, infModel);
}
else
{
//invalid inference setting
System.err.println("Invalid inference setting, "
+ "choose one of <none|rdfs|owl>.");
return;
}
//load the facts into the model
model.read(inputStream, null, inputFileFormat);
//validate the file
ValidityReport validityReport = model.validate();
if(validityReport != null && !validityReport.isValid())
{
Iterator i = validityReport.getReports();
while(i.hasNext())
{
System.err.println(
((ValidityReport.Report)i.next()).getDescription());
}
return;
}
//Iterate over the individuals, print statements about them
ExtendedIterator iIndividuals = model.listIndividuals();
while(iIndividuals.hasNext())
{
Individual i = (Individual)iIndividuals.next();
printIndividual(i, writer);
}
iIndividuals.close();
writer.close();
model.close();
}
/**
* Print information about the individual
* @param i The individual to output
* @param writer The writer to which to output
*/
public static void printIndividual(
Individual i, PrintWriter writer)
{
//print the local name of the individual (to keep it terse)
writer.println("Individual: " + i.getLocalName());
//print the statements about this individual
StmtIterator iProperties = i.listProperties();
while(iProperties.hasNext())
{
Statement s = (Statement)iProperties.next();
writer.println(" " + s.getPredicate().getLocalName()
+ " : " + s.getObject().toString());
}
iProperties.close();
writer.println();
}
}
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[求助]怎样理解这个文件http://www.w3.org/1999/02/22-rdf-syntax-ns
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