[英]converting resultset to RDF/XML in Jena
I'm trying to convert a resultset
in XML/RDF format but with this code:我正在尝试以 XML/RDF 格式转换resultset
,但使用以下代码:
ResultSet result = rmParliament.selectQuery(select);
System.out.println(ResultSetFormatter.asText(result));
ResultSetFormatter.outputAsRDF(System.out, "RDF/XML", result);
The second line of the code is to verify the correct behaviour of the query (it works!), but I get in the console the following output:代码的第二行是为了验证查询的正确行为(它有效!),但我在控制台中得到以下输出:
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:xsd="http://www.w3.org/2001/XMLSchema#"
xmlns:rs="http://www.w3.org/2001/sw/DataAccess/tests/result-set#" >
<rdf:Description rdf:nodeID="A0">
<rs:size rdf:datatype="http://www.w3.org/2001/XMLSchema#int">0</rs:size>
<rs:resultVariable>value</rs:resultVariable>
<rs:resultVariable>property</rs:resultVariable>
<rs:resultVariable>name</rs:resultVariable>
<rdf:type rdf:resource="http://www.w3.org/2001/sw/DataAccess/tests/result-set#ResultSet"/>
</rdf:Description>
</rdf:RDF>
Is doesn't contain my data, what's wrong with my code?不包含我的数据,我的代码有什么问题?
The problem is that your print debugging actually consumes all the results, leaving the ResultSet
at the end.问题是您的打印调试实际上消耗了所有结果,最后留下了ResultSet
。 There are no more results available when you try to output it as RDF/XML.当您尝试将其输出为 RDF/XML 时,没有更多可用的结果。
You can fix it by making the ResultSet
rewindable :您可以通过使ResultSet
rewindable来修复它:
ResultSetRewindable result =
ResultSetFactory.makeRewindable( rmParliament.selectQuery(select) );
System.out.println(ResultSetFormatter.asText(result));
result.reset(); // back to the start
ResultSetFormatter.outputAsRDF(System.out, "RDF/XML", result);
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