Question

我在此网站MESH Query上执行此代码，它会返回正确的结果但是当我使用Jena执行时，它返回null。在耶拿

String s = "PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> 
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> 
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#> 
PREFIX owl: <http://www.w3.org/2002/07/owl#> 
PREFIX meshv: <http://id.nlm.nih.gov/mesh/vocab#> 
PREFIX mesh: <http://id.nlm.nih.gov/mesh/> 
PREFIX mesh2015: <http://id.nlm.nih.gov/mesh/2015/> 
PREFIX mesh2016: <http://id.nlm.nih.gov/mesh/2016/> 
PREFIX mesh2017: <http://id.nlm.nih.gov/mesh/2017/> 
SELECT ?d ?dName ?c ?cName 
FROM <http://id.nlm.nih.gov/mesh> 
WHERE { 
  ?d a meshv:Descriptor .
  ?d meshv:concept ?c . 
  ?d rdfs:label ?dName .
  ?c rdfs:label ?cName 
  FILTER(REGEX(?dName,'infection','i') || REGEX(?cName,'infection','i'))
}
ORDER BY ?d ";
Query query = QueryFactory.create(s);
            QueryExecution qe = QueryExecutionFactory.sparqlService("http://id.nlm.nih.gov/mesh/sparql", query );
            ResultSet results = qe.execSelect();
            ResultSetFormatter.out(System.out, results, query);

Answer 1

您必须使用QueryEngineHTTP，以便通过HTTP参数inference=true启用推理：

Query query = QueryFactory.create(s);
QueryEngineHTTP qe = new QueryEngineHTTP("http://id.nlm.nih.gov/mesh/sparql", query );
qe.addPAram("inference", "true")
ResultSet results = qe.execSelect();
ResultSetFormatter.out(System.out, results, query);

Answer 2

我编辑了查询，但我有一个不同的结果，因为＆＃34; http://id.nlm.nih.gov/mesh/sparql＆＃34;不知道meshv：Descriptor所以我删除了它，现在我试图重新构造查询以获得相同的结果

有问题执行MESH端点的SPARQL查询

2 个答案: