On 01/14/2012 09:13 PM, Andy Seaborne wrote:
On 14/01/12 12:09, Dave Reynolds wrote:
On 14/01/12 01:58, June wrote:
Dear list,
I got an exception (HttpException: java.net.SocketException: Connection
reset) when I try to query through dbpedia endpoint.
I already set the timeout parameter, and I can access and query in
"http://dbpedia.org/sparql"; through browser. What might be the problem?
------------------Code-----------------------------------------
com.hp.hpl.jena.query.Query query = QueryFactory.create(ask);
QueryExecution qexec = QueryExecutionFactory.sparqlService(
"http://dbpedia.org/sparql";, query);
((QueryEngineHTTP)qexec).addParam("timeout", "60000") ;
boolean rs = qexec.execAsk();
-------------------Exception------------------------------------
Exception in thread "AWT-EventQueue-0" HttpException:
java.net.SocketException: Connection reset: java.net.SocketException:
Connection reset
at
com.hp.hpl.jena.sparql.engine.http.HttpQuery.execCommon(HttpQuery.java:333)
at
com.hp.hpl.jena.sparql.engine.http.HttpQuery.execGet(HttpQuery.java:189)
at
com.hp.hpl.jena.sparql.engine.http.HttpQuery.exec(HttpQuery.java:144)
at
com.hp.hpl.jena.sparql.engine.http.QueryEngineHTTP.execAsk(QueryEngineHTTP.java:169)
Might it be a timeout at the dbpedia end?
Try with a very simple, narrow query.
Dave
This is quite likely - whatever it is "Connection reset" means the
other end has killed the connection for the query abnormally.
http://stackoverflow.com/questions/62929/java-net-socketexception-connection-reset
If the query is wrong (e.g. syntax error) the other end should
returned 400 (and ARQ checks the syntax first anyway although dbpedia
isn't SPARQL 1.1).
As Dave said, start simple, and work upwards including with a SELECT
query.
Also, it may depend on the time of day if it's the timeout.
Andy
Thanks Dave and Andy, I tried a simple SELECT query through the
endpoint, it successfully return the results, but soon it failed again.
I don't think the service is very stable..
Best regards,
June
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