SPARQL查询异常

Question

我使用APACHE JENA (2.9.4版本)通过SPARQL查询获取结果。下面是我使用的代码。

public class DataGeneratorTest {

public static void main(String[] args) {

    String query = "PREFIX rdfs:<http://www.w3.org/2000/01/rdf-schema#> PREFIX owl:<http://dbpedia.org/ontology/> select ?y where { ?x a owl:Person; rdfs:label ?y. FILTER(LANG(?y) = \"en\") } LIMIT 77";
    ResultSet resultSet = SparqlUtil.generate(query);
    ResultSetFormatter.out(System.out, resultSet);

}
}

我有一个用于执行sparql查询的实用程序类...

public class SparqlUtil {

public static ResultSet generate(String argEndPoint, String argQuery) {
    Precondition.checkNotEmpty(argQuery);
    String endPoint = argEndPoint;
    if (Precondition.checkEmpty(endPoint)) {
        endPoint = SparqlConstants.SPARQL_ENDPOINT;
    }
    QueryExecution queryExecution = null;
    try {
        Query query = QueryFactory.create(argQuery);
        queryExecution = QueryExecutionFactory.sparqlService(endPoint,
                query);
        return queryExecution.execSelect();
    } finally {
        if (Precondition.checkNotNull(queryExecution)) {
            queryExecution.close();
        }
    }
}

public static ResultSet generate(String argQuery) {
    return generate(SparqlConstants.SPARQL_ENDPOINT, argQuery);
}
}

当我运行这段代码时，我得到了以下异常。

javax.xml.stream.XMLStreamException: ParseError at [row,col]:[40,26]
Message: XML document structures must start and end within the same entity.
at com.sun.org.apache.xerces.internal.impl.XMLStreamReaderImpl.next(Unknown Source)
at    com.hp.hpl.jena.sparql.resultset.XMLInputStAX$ResultSetStAX.getOneSolution(XMLInputStAX.java:435)
at com.hp.hpl.jena.sparql.resultset.XMLInputStAX$ResultSetStAX.hasNext(XMLInputStAX.java:232)
at com.hp.hpl.jena.sparql.resultset.ResultSetMem.<init>(ResultSetMem.java:95)
at com.hp.hpl.jena.sparql.resultset.TextOutput.write(TextOutput.java:147)
at com.hp.hpl.jena.sparql.resultset.TextOutput.write(TextOutput.java:130)
at com.hp.hpl.jena.sparql.resultset.TextOutput.write(TextOutput.java:118)
at com.hp.hpl.jena.sparql.resultset.TextOutput.format(TextOutput.java:65)
at com.hp.hpl.jena.query.ResultSetFormatter.out(ResultSetFormatter.java:122)
at com.hp.hpl.jena.query.ResultSetFormatter.out(ResultSetFormatter.java:74)
at com.data.generator.test.DataGeneratorTest.main(DataGeneratorTest.java:17)
Exception in thread "main" com.hp.hpl.jena.sparql.resultset.ResultSetException: XMLStreamException:     ParseError at [row,col]:[40,26]
Message: XML document structures must start and end within the same entity.
at com.hp.hpl.jena.sparql.resultset.XMLInputStAX$ResultSetStAX.staxError(XMLInputStAX.java:539)
at com.hp.hpl.jena.sparql.resultset.XMLInputStAX$ResultSetStAX.hasNext(XMLInputStAX.java:236)
at com.hp.hpl.jena.sparql.resultset.ResultSetMem.<init>(ResultSetMem.java:95)
at com.hp.hpl.jena.sparql.resultset.TextOutput.write(TextOutput.java:147)
at com.hp.hpl.jena.sparql.resultset.TextOutput.write(TextOutput.java:130)
at com.hp.hpl.jena.sparql.resultset.TextOutput.write(TextOutput.java:118)
at com.hp.hpl.jena.sparql.resultset.TextOutput.format(TextOutput.java:65)
at com.hp.hpl.jena.query.ResultSetFormatter.out(ResultSetFormatter.java:122)
at com.hp.hpl.jena.query.ResultSetFormatter.out(ResultSetFormatter.java:74)
at com.data.generator.test.DataGeneratorTest.main(DataGeneratorTest.java:17)
Caused by: javax.xml.stream.XMLStreamException: ParseError at [row,col]:[40,26]
Message: XML document structures must start and end within the same entity.
at com.sun.org.apache.xerces.internal.impl.XMLStreamReaderImpl.next(Unknown Source)
at     com.hp.hpl.jena.sparql.resultset.XMLInputStAX$ResultSetStAX.getOneSolution(XMLInputStAX.java:435)
at com.hp.hpl.jena.sparql.resultset.XMLInputStAX$ResultSetStAX.hasNext(XMLInputStAX.java:232)
... 8 more

我只想检索前77个结果。当我将这个结果集限制为76时，我可以毫无异常地获取结果，但是当我将这个限制增加到77时，我会得到上面的异常。第77条记录有问题。我怎样才能克服这个问题。我被困在这里了。有没有人能帮我...？

提前谢谢你，阿马尔。

Answer 1

什么是SparqlConstants.SPARQL_ENDPOINT？dbpedia.org有时间限制并截断结果，从而导致非法的XML。这可以解释这种情况，但不知道第77个条目是什么，我们不能说。