java - 从查询中选择多个结果

例如，我有此查询返回四个结果。我在用此代码执行的操作是通过整数选择这些结果之一，以便稍后可以对其进行另一个查询。我一直想做但还没有做的就是选择多个结果，以便我可以分别重用它们。例如，此查询将返回：


结果A
结果B
结果C
结果D


例如，我可以在控制台中键入1并以字符串形式获取该值并重新使用它。例如，键入1,2,3并将这些值添加到String数组的便捷方法是什么？

public static String[] path = new String[30];

String queryString =
    "PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> " +
    "PREFIX owl: <http://www.w3.org/2002/07/owl#> " +
    "PREFIX xsd: <http://www.w3.org/2001/XMLSchema#> " +
    "PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> " +
    "PREFIX bio: <http://www.semanticweb.org/vassilis/ontologies/2013/5/Onto#> " +

    " SELECT DISTINCT ?Animal " +
    " WHERE { ?Animal rdf:type bio:Animal } " ;

Query query = QueryFactory.create(queryString);
QueryExecution qe= QueryExecutionFactory.create(query, model);
ResultSet resultset = qe.execSelect();
ResultSet results = ResultSetFactory.copyResults(resultset);
ResultSet results2 = ResultSetFactory.copyResults(results);
ResultSetFormatter.out(System.out, results, query);

List<QuerySolution> e = ResultSetFormatter.toList(results2);
String next;
System.out.println("Select Animal: ");

next = user_input.next( );

int i = Integer.parseInt(next);
QuerySolution e1 = e.get(i);
RDFNode rd = e1.get("");
String rds = rd.toString();
String phrase = rds;
String delims = "[#]";
String[] tokens = phrase.split(delims);
newStr = tokens[1].replaceAll("_","");
path[1] = newStr;

编辑，更新代码：

final Scanner input = new Scanner( System.in );
String selec2;
selec2 = input.next();

final String[] indices = selec2.split("\\s*,\\s*");

final List<QuerySolution> selectedSolutions = new ArrayList<QuerySolution>( indices.length ) {{
        final List<QuerySolution> solutions = ResultSetFormatter.toList( results2 );
        for ( final String index : indices ) {
            add( solutions.get( Integer.valueOf( index )));
        }
    }};

System.out.println( "== Selected Solutions ==" );
System.out.println(selectedSolutions);

int k = 0;
while (input.hasNext()) {
    int i = Integer.parseInt(selec2);
    QuerySolution e1 = selectedSolutions.get(i);

    RDFNode rd = e1.get("Ani");
    String rds = rd.toString();
    String phrase = rds;
    String delims = "[#]";
    String[] tokens = phrase.split(delims);
    newStr = tokens[1].replaceAll("_", "");
    path[k]= newStr;
    k++;
}
System.out.println(path);

最佳答案

获得ResultSet时，只能使用其解决方案一次，然后使用它们。因此，为了多次遍历解决方案，您需要使用例如ResultSetFactory.copyResults复制结果。然后，您可以多次访问查询解决方案。您可以使用诸如"1,2,3"之类的输入字符串并使用类似于以下内容的答案获得字符串数组["1", "2", "3"]


how to get numbers separated by comma entered in a line into an array in Java


然后，您可以遍历索引并仅选择所需的查询解决方案并将其添加到列表中。例如：

import java.io.ByteArrayInputStream;
import java.util.ArrayList;
import java.util.List;

import com.hp.hpl.jena.query.QueryExecutionFactory;
import com.hp.hpl.jena.query.QuerySolution;
import com.hp.hpl.jena.query.ResultSet;
import com.hp.hpl.jena.query.ResultSetFactory;
import com.hp.hpl.jena.query.ResultSetFormatter;
import com.hp.hpl.jena.rdf.model.Model;
import com.hp.hpl.jena.rdf.model.ModelFactory;

public class QuerySolutionsFromIndicesExample {

    final static String modelText = "" +
            "@prefix bio: <http://www.semanticweb.org/vassilis/ontologies/2013/5/Onto#>.\n" +
            "@prefix ex: <http://example.org/>.\n" +
            "\n" +
            "ex:Giraffe a bio:Animal .\n" +
            "ex:Dog a bio:Animal .\n" +
            "ex:Cat a bio:Animal . \n" +
            "ex:WoollyMammoth a bio:Animal.\n" +
            "";

    final static String sparqlQuery = "" +
            "prefix bio: <http://www.semanticweb.org/vassilis/ontologies/2013/5/Onto#>\n" +
            "\n" +
            "select ?animal where {\n" +
            "  ?animal a bio:Animal\n" +
            "}\n" +
            "";

    public static void main(String[] args) {
        final Model model = ModelFactory.createDefaultModel();
        model.read( new ByteArrayInputStream( modelText.getBytes()), null, "TTL" );

        final ResultSet results = ResultSetFactory.copyResults( QueryExecutionFactory.create( sparqlQuery, model ).execSelect() );

        System.out.println( "== All Solutions ==" );
        ResultSetFormatter.out( results );

        // based on https://stackoverflow.com/q/10565335/1281433
        final String input = "0,3";
        final String[] indices = input.split("\\s*,\\s*");

        final List<QuerySolution> selectedSolutions = new ArrayList<QuerySolution>( indices.length ) {{
            final List<QuerySolution> solutions = ResultSetFormatter.toList( results );
            for ( final String index : indices ) {
                add( solutions.get( Integer.valueOf( index )));
            }
        }};

        System.out.println( "== Selected Solutions ==" );
        System.out.println( selectedSolutions );
    }
}