Question

我是使用Apache Jena的新手！以下是我的代码。 exec.execSelect（）的异常，任何人都可以说出原因吗？

public static void main(String [] args){
        ParameterizedSparqlString qs = new ParameterizedSparqlString(""
                + "prefix rdfs:    <http://www.w3.org/2000/01/rdf-schema#>\n"
                + "PREFIX dbo:     <http://dbpedia.org/ontology/>"
                + "\n"
                + "select distinct ?resource ?abstract where {\n"
                + "  ?resource rdfs:label 'Ibuprofen'@en.\n"
                + "  ?resource dbo:abstract ?abstract.\n"
                + "  FILTER (lang(?abstract) = 'en')}");


        QueryExecution exec = QueryExecutionFactory.sparqlService("http://dbpedia.org/sparql", qs.asQuery());

        ResultSet results = exec.execSelect();

        while (results.hasNext()) {

            System.out.println(results.next().get("abstract").toString());
        }

        ResultSetFormatter.out(results);
    }

而且例外是

线程中的异常＆＃34; main＆＃34; java.lang.ClassCastException： java.lang.Long无法强制转换为java.lang.Integer at org.apache.http.params.AbstractHttpParams.getIntParameter（AbstractHttpParams.java:70）在 org.apache.http.client.params.HttpClientParamConfig.getRequestConfig（HttpClientParamConfig.java:54）在 org.apache.http.impl.client.AbstractHttpClient.doExecute（AbstractHttpClient.java:806）在 org.apache.http.impl.client.CloseableHttpClient.execute（CloseableHttpClient.java:72）在 org.apache.http.impl.client.CloseableHttpClient.execute（CloseableHttpClient.java:57）在 org.apache.http.impl.client.DecompressingHttpClient.execute（DecompressingHttpClient.java:158）在 org.apache.http.impl.client.DecompressingHttpClient.execute（DecompressingHttpClient.java:139）在org.apache.jena.riot.web.HttpOp.exec（HttpOp.java:1097）at org.apache.jena.riot.web.HttpOp.execHttpGet（HttpOp.java:378）at at org.apache.jena.riot.web.HttpOp.execHttpGet（HttpOp.java:440）at org.apache.jena.sparql.engine.http.HttpQuery.execGet（HttpQuery.java:343）在 org.apache.jena.sparql.engine.http.HttpQuery.exec（HttpQuery.java:292）在 org.apache.jena.sparql.engine.http.QueryEngineHTTP.execResultSetInner（QueryEngineHTTP.java:345）在 org.apache.jena.sparql.engine.http.QueryEngineHTTP.execSelect（QueryEngineHTTP.java:337）在trial.SecondAttempt.main（SecondAttempt.java:32）

在Apache Jena中执行SPARQL查询时获取ClassCastException。

0 个答案: