为 MESH 端点执行 SPARQL 查询时出现问题

Question

我在这个网站上执行这段代码MESH Query它returns正确的结果但是当我使用 Jena 执行时，它 returns 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

我编辑了查询，结果不一样，因为“http://id.nlm.nih.gov/mesh/sparql”不知道 meshv:Descriptor，所以我删除了它，现在我正在尝试将查询重新表述为结果相同

Answer 2

您必须使用 QueryEngineHTTP 这样您就可以通过 HTTP 参数启用推理 inference=true:

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);

为 MESH 端点执行 SPARQL 查询时出现问题

Probleme executing SPARQL query for MESH Endpoint

java

ontology

sparql

jena