Of course I can access the sparql endpoint at http://dbpedia.org/sparql from my
jvm.
I think the error has relation with PREFIX.
when I access with
"SELECT DISTINCT ?company where {?company a
<http://dbpedia.org/ontology/Company>} LIMIT 20";
I can get result. But when I access with
"PREFIX dbpedia: <http://dbpedia.org/resource/> " +
"PREFIX dbpedia-owl: <http://dbpedia.org/ontology/> " +
"select ?p where {?p dbpedia-owl:country dbpedia:Germany> .} LIMIT 10";
there is not result
log4j:WARN No appenders could be found for logger
(com.hp.hpl.jena.util.FileManager).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more
info.
----------------------------------------------------------------
| company |
================================================================
| <http://dbpedia.org/resource/%C3%9Cstra> |
| <http://dbpedia.org/resource/%C4%8Cesk%C3%A9_dr%C3%A1hy> |
| <http://dbpedia.org/resource/7th_Level> |
| <http://dbpedia.org/resource/A&W_Restaurants> |
| <http://dbpedia.org/resource/A._Lange_&_S%C3%B6hne> |
| <http://dbpedia.org/resource/ABB_Group> |
| <http://dbpedia.org/resource/ABC_Motors> |
| <http://dbpedia.org/resource/AG_Vulcan_Stettin> |
| <http://dbpedia.org/resource/AIDA_Cruises> |
| <http://dbpedia.org/resource/AM_General> |
| <http://dbpedia.org/resource/ARY_Group> |
| <http://dbpedia.org/resource/AVG_Technologies> |
| <http://dbpedia.org/resource/Abbott-Detroit> |
| <http://dbpedia.org/resource/Accenture> |
| <http://dbpedia.org/resource/Adnams_Brewery> |
| <http://dbpedia.org/resource/Aer_Arann> |
| <http://dbpedia.org/resource/Aero_Lloyd> |
| <http://dbpedia.org/resource/Aeropostal_Alas_de_Venezuela> |
| <http://dbpedia.org/resource/Afrinat_International_Airlines> |
| <http://dbpedia.org/resource/Afriqiyah_Airways> |
----------------------------------------------------------------
----------------------------------------------------------------------
发件人： Marco Neumann
发送时间： 2013-09-03 15:04
收件人： users
主题： Re: Re: JENA API question
make sure you can access the sparql endpoint at
http://dbpedia.org/sparqlfrom your
jvm.
QueryExecution qexec = QueryExecutionFactory.sparqlService("
http://dbpedia.org/sparql";, query);
On Mon, Sep 2, 2013 at 9:42 PM, bocai <[email protected]> wrote:
> Oh, I changed Prefix from
> "PREFIX dbpedia: http://dbpedia.org/";
> to
> "PREFIX dbpedia: <http://dbpedia.org/resource/>"
>
> the error also changed as below:
> HttpException: java.net.SocketException: Connection reset:
> java.net.SocketException: Connection reset
> at
> com.hp.hpl.jena.sparql.engine.http.HttpQuery.execCommon(HttpQuery.java:529)
> at com.hp.hpl.jena.sparql.engine.http.HttpQuery.execGet(HttpQuery.java:289)
> at com.hp.hpl.jena.sparql.engine.http.HttpQuery.exec(HttpQuery.java:240)
> at
> com.hp.hpl.jena.sparql.engine.http.QueryEngineHTTP.execSelect(QueryEngineHTTP.java:302)
> at Dbpedia.GetFromSparql.SearchSparql(GetFromSparql.java:42)
> at Dbpedia.GetFromSparql.main(GetFromSparql.java:53)
>
> Caused by: java.net.SocketException: Connection reset
> at java.net.SocketInputStream.read(SocketInputStream.java:168)
> at java.io.BufferedInputStream.fill(BufferedInputStream.java:218)
> at java.io.BufferedInputStream.read1(BufferedInputStream.java:258)
> at java.io.BufferedInputStream.read(BufferedInputStream.java:317)
> at sun.net.www.http.HttpClient.parseHTTPHeader(HttpClient.java:687)
> at sun.net.www.http.HttpClient.parseHTTP(HttpClient.java:632)
> at sun.net.www.http.HttpClient.parseHTTP(HttpClient.java:652)
> at
> sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1064)
> at java.net.HttpURLConnection.getResponseCode(HttpURLConnection.java:373)
> at
> com.hp.hpl.jena.sparql.engine.http.HttpQuery.execCommon(HttpQuery.java:412)
> ... 5 more
>
> How can I do ?
>
>
>
> 发件人： Marco Neumann
> 发送时间： 2013-09-02 18:46
> 收件人： users
> 主题： Re: JENA API question
> change dbpedia prefix to
>
> "PREFIX dbpedia: <http://dbpedia.org/resource/>" +
>
>
> On Mon, Sep 2, 2013 at 5:37 AM, bocai <[email protected]> wrote:
>
> > Hi,
> > I want to access remote sparql endpoint throuth JENA API. My program is
> > below.
> > After I ran the program, There is no record in resultset
> > -----
> > | p |
> > =====
> > -----
> > But I visit http://dbpedia.org/sparql and ran this sparql ( select *
> > where {?p dbpedia-owl:country dbpedia:Germany.} LIMIT 10 ) as same as
> > sparql in my program, I can get the result i want
> >
> > p
> > http://dbpedia.org/resource/%C3%96lsen
> > http://dbpedia.org/resource/%C3%96stringen
> > http://dbpedia.org/resource/%C3%9Cbach-Palenberg
> > http://dbpedia.org/resource/%C3%9Cberherrn
> > http://dbpedia.org/resource/%C3%9Cdersdorf
> > http://dbpedia.org/resource/%C3%9Chlingen-Birkendorf
> > http://dbpedia.org/resource/%C3%9Crzig
> > http://dbpedia.org/resource/16_Blocks
> > http://dbpedia.org/resource/18_%E2%80%93_Allein_unter_M%C3%A4dchen
> > http://dbpedia.org/resource/2011_German_Grand_Prix
> >
> >
> > Can you point out my error? thanks very much!
> >
> > public static void SearchSparql(){
> > try {
> > String queryStr =
> > "PREFIX dbpedia: <http://dbpedia.org/>" +
> > "PREFIX dbpedia-owl: <http://dbpedia.org/ontology/>" +
> > "select * where {?p dbpedia-owl:country dbpedia:Germany.} LIMIT 10";
> >
> > Query query = QueryFactory.create(queryStr);
> > QueryExecution qexec = QueryExecutionFactory.sparqlService("
> > http://dbpedia.org/sparql";, query);
> > ((QueryEngineHTTP)qexec).addParam("timeout", "10000") ;
> > ResultSet rs = qexec.execSelect();
> > ResultSetFormatter.out(System.out, rs, query);
> > qexec.close();
> > } catch (Exception e) {
> > e.printStackTrace();
> > }
> >
> > }
> >
> >
> > -
>
>
> ---
> Marco Neumann
> KONA
--
---
Marco Neumann
KONA
