能够走通本体持久化，但是查询部分就是什么都不输出，现在程序如下，还望达人指教
package jena;
import com.hp.hpl.jena.db.DBConnection;
import com.hp.hpl.jena.db.IDBConnection;
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.ModelMaker;
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.ResultSet;
import com.hp.hpl.jena.query.ResultSetFormatter;
import com.hp.hpl.jena.rdf.model.InfModel;
import com.hp.hpl.jena.reasoner.Reasoner;
import com.hp.hpl.jena.reasoner.rulesys.GenericRuleReasoner;
import com.hp.hpl.jena.reasoner.rulesys.Rule;
public class Sparqlforexpert {
/* 连接数据库 */
public static IDBConnection connectDB(String DB_URL, String DB_USER,
String DB_PASSWD, String DB_NAME) {
return new DBConnection(DB_URL, DB_USER, DB_PASSWD, DB_NAME);
}
/* 从文件读取本体并将其存入数据库 */
public static OntModel createDBModelFromFile(IDBConnection con, String name,
String filePath) {
ModelMaker maker = ModelFactory.createModelRDBMaker(con);
Model base = maker.createModel(name);
OntModel newmodel = ModelFactory.createOntologyModel(
getModelSpec(maker), base);
newmodel.read(filePath);
return newmodel;
}
/* 从数据库中得到已存入本体 */
public static OntModel getModelFromDB(IDBConnection con, String name) {
ModelMaker maker = ModelFactory.createModelRDBMaker(con);
Model base = maker.getModel(name);
OntModel newmodel = ModelFactory.createOntologyModel(
getModelSpec(maker), base);
return newmodel;
}
public static OntModelSpec getModelSpec(ModelMaker maker) {
OntModelSpec spec = new OntModelSpec(OntModelSpec.OWL_MEM);
spec.setImportModelMaker(maker);
return spec;
}
public static void main(String[] args) {
String DB_URL = "jdbc:mysql://localhost:3306/mydb";
String DB_USER = "root";
String DB_PASSWD = "root";
String DB = "MySQL";
String DB_DRIVER = "com.mysql.jdbc.Driver";
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
//String filePath = "file:C://Program Files//Protege_3.3.1//examples//expert//Expert.owl";
IDBConnection con = connectDB(DB_URL,DB_USER, DB_PASSWD, DB);
System.out.println(con);
// createDBModelFromFile(con, "expert",filePath);
OntModel model = getModelFromDB(con, "expert");
}
/*使用sparql对本体进行查询*/
public static void searchOnto1(OntModel model) {
/* 设置规则 */
String rule = "[rule1:(?x http://www.owl-ontologies.com/Expert.owl#research ?y) "
+ "(?y http://www.owl-ontologies.com/Expert.owl#associate ?z) "
+ "->(?x http://www.owl-ontologies.com/Expert.owl#familiar_with ?z)]";
/* 查询语句 */
String queryString = "PREFIX Expert:<http://www.owl-ontologies.com/Expert.owl#> "
+ "SELECT ?expert ?subject "
+ "WHERE {?expert Expert:familiar_with ?subject} ";
/* 创建推理机 */
Reasoner reasoner2 = new GenericRuleReasoner(Rule.parseRules(rule));
InfModel inf = ModelFactory.createInfModel(reasoner2, model);
Query query = QueryFactory.create(queryString);
QueryExecution qe = QueryExecutionFactory.create(query, inf);
ResultSet results = qe.execSelect();
/* 打印结果 */
ResultSetFormatter.out(System.out, results, query);
qe.close();
}
}
[返回] W3CHINA.ORG讨论区 - 语义网·描述逻辑·本体·RDF·OWL →
W3CHINA.ORG讨论区 - Web新技术讨论 → 『 Semantic Web(语义Web)/描述逻辑/本体 』 → 使用Jena对OWL本体进行查询推理
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2010/5/26 10:59:00
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