从Jena ResultSet获取RDFNode

Question

如何从QueryExecution生成的ResultSet中检索Jena RDFNode？我能够在运行查询后看到正确的ResultSet,但结果只提供了节点的URI,任何人都可以告诉我需要做什么才能获取RDF节点的详细信息.这将让我提取每个属性,我以后可以稍后操作.我看到的工作是使用一个查询来显示实例的属性而不是实例本身.

目前的结果:

http://assignment3.stdi.msmsuhail.ead/bpl.owl#Arsenal

预期结果:

<rdf:Description rdf:about="http://assignment3.stdi.msmsuhail.ead/bpl.owl#Arsenal">
    <bpl:hasStadiumLocation rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Holloway</bpl:hasStadiumLocation>
    <rdf:type rdf:resource="http://assignment3.stdi.msmsuhail.ead/bpl.owl#Clubs"/>
    <rdf:type rdf:resource="http://www.w3.org/2002/07/owl#NamedIndividual"/>
    <bpl:hasStadiumName rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Emirates Stadium</bpl:hasStadiumName>
    <bpl:hasPlayer rdf:resource="http://assignment3.stdi.msmsuhail.ead/bpl.owl#TheoWalcott"/>
    <bpl:hasPlayer rdf:resource="http://assignment3.stdi.msmsuhail.ead/bpl.owl#MikelArteta"/>
    <bpl:hasName rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Arsenal</bpl:hasName>
    <bpl:hasNumberSeats rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">60355</bpl:hasNumberSeats>
    <bpl:hasManager rdf:resource="http://assignment3.stdi.msmsuhail.ead/bpl.owl#ArseneWenger"/>
    <bpl:hasPlayer rdf:resource="http://assignment3.stdi.msmsuhail.ead/bpl.owl#AaronRamsey"/>
</rdf:Description>

SPARQL查询:

SELECT DISTINCT  ?clubs ?clubName 
WHERE {
    ?Club bpl:hasPlayer ?players.
    ?Club bpl:hasManager  ?managers.
    ?players bpl:hasClub ?clubs .
    ?players bpl:hasAge ?playerAge.
    ?players bpl:hasName ?playerName.
    ?players bpl:hasNationality ?playerNationality.
    ?players bpl:hasPlayingPosition ?playerPosition.
    ?players bpl:isRetired ?playerIsRetired.
    ?clubs bpl:hasName ?clubName.
    ?clubs bpl:hasNumberSeats ?clubSeats.
    ?clubs bpl:hasStadiumName ?clubStadiumName .
    ?clubs bpl:hasStadiumLocation ?clubStadiumLocation.
    ?managers bpl:hasAge ?managerAge.
    ?managers bpl:hasName ?managerName.
    ?managers bpl:hasNationality ?managerNationality.
    ?managers bpl:isManager ?isManager.
} 
ORDER BY ASC (?clubName)

Java代码:

    while(resultSet!=null && resultSet.hasNext()){
                   QuerySolution querySolution = resultSet.nextSolution();
                   System.out.println(querySolution.get("clubs").toString());                              
    } 

Answer 1

Javadoc for QuerySolution#get(String)表示返回值是 RDFNode,因此您获得的值是RDFNode.如果您正在运行本地查询(即,如果您具有运行查询的模型),那么您可以使用它获取属性值,例如,

RDFNode clubNode = querySolution.get( "club" );
Resource club = clubNode.asResource().inModel( model );
Statement stmt = club.getProperty( BPL.hasStadiumLocation );
System.out.println( stmt.getObject() ); // prints "Holloway"