jena sparql rdf java
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2022-03-04 13:09:09
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RDF文件内容:
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:uni="http://www.mydomain.org/uni-ns#"
xmlns:id="http://www.mydomain.org/id-ns#"
>
<rdf:Description rdf:about="id:949352">
<uni:name>Grigoris Antoniou</uni:name>
<uni:title>教授</uni:title>
</rdf:Description>
<rdf:Description rdf:about="id:949318">
<uni:name>David Billington</uni:name>
<uni:title>副教授</uni:title>
</rdf:Description>
<rdf:Description rdf:about="id:949111">
<uni:name>Michael Maher</uni:name>
<uni:title>教授</uni:title>
</rdf:Description>
<rdf:Description rdf:about="id:CIT1111">
<uni:courseName>离散数学</uni:courseName>
<uni:isTaughtBy>David Billington</uni:isTaughtBy>
</rdf:Description>
<rdf:Description rdf:about="id:CIT1112">
<uni:courseName>具体数学</uni:courseName>
<uni:isTaughtBy>Grigoris Antoniou</uni:isTaughtBy>
</rdf:Description>
<rdf:Description rdf:about="id:CIT2112">
<uni:courseName>程序设计</uni:courseName>
<uni:isTaughtBy>Michael Maher</uni:isTaughtBy>
</rdf:Description>
<rdf:Description rdf:about="id:CIT3112">
<uni:courseName>计算理论</uni:courseName>
<uni:isTaughtBy>David Billington</uni:isTaughtBy>
</rdf:Description>
<rdf:Description rdf:about="id:CIT3116">
<uni:courseName>知识表示</uni:courseName>
<uni:isTaughtBy>Grigoris Antoniou</uni:isTaughtBy>
</rdf:Description>
</rdf:RDF>
在官网下载jena包,导入到程序中即可,jena下载地址:http://jena.apache.org/
java源程序:(记得改包名和文件路径名)
package rdf;
import java.io.InputStream;
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.Literal;
import com.hp.hpl.jena.rdf.model.Model;
import com.hp.hpl.jena.rdf.model.ModelFactory;
import com.hp.hpl.jena.rdf.model.RDFNode;
import com.hp.hpl.jena.rdf.model.Resource;
import com.hp.hpl.jena.util.FileManager;
public class jena_sparql_rdf {
public static void main(String[] args) {
//创建模型并读取rdf文件
String inputfileName = "/semanticWeb/src/rdf/files.rdf";
Model model = ModelFactory.createDefaultModel();
InputStream open = FileManager.get().open(inputfileName);
model.read(open, "","RDF/XML");
//编写查询语句
// String select ="SELECT ?sub ?pre WHERE {?sub ?pre \"教授\"}";
// String select ="SELECT ?teacher WHERE {?sub uni:title \"教授\".?sub uni:name ?teacher}";
String select ="SELECT * WHERE {?sub ?pre ?obj}";
String queryString =
"PREFIX uni:<http://www.mydomain.org/uni-ns#>"
+ "PREFIX rdf:<http://www.w3.org/1999/02/22-rdf-syntax-ns#>"
+ "PREFIX id:<http://www.mydomain.org/id-ns#>"+select;
//创建查询
Query query = QueryFactory.create(queryString);
//执行查询
QueryExecution qe = QueryExecutionFactory.create(query, model);
//返回查询结果
ResultSet results = qe.execSelect();
//输出查询结果
System.out.println("遍历结果集依次输出结果:");
while(results.hasNext()){
QuerySolution next = results.next();
Resource resource = next.getResource("sub");
RDFNode rdfNode = next.get("pre");
Literal literal = next.getLiteral("obj");
System.out.println(resource+"\t"+rdfNode+"\t"+literal);
}
// System.out.println("按格式输出结果:");
// ResultSetFormatter.out(System.out, results, query);
//关闭QueryExecution链接
qe.close();
}
}
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