I have been working on solutions to this problem for the last month. In my case, I convert a resultset to a document using a simple method: I don't have the person I received this code from referenced (oops!). If you need the imports for this, just let me know.
private static Document toDocument(ResultSet rs) throws ParserConfigurationException, SQLException {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.newDocument();
Element results = doc.createElement("Results");
doc.appendChild(results);
ResultSetMetaData rsmd = rs.getMetaData();
int colCount = rsmd.getColumnCount();
/* System.out.println("Starting to build Document"); */
while (rs.next()) {
Element row = doc.createElement("Row");
results.appendChild(row);
for (int i = 1; i <= colCount; i++) {
String columnName = rsmd.getColumnName(i);
String value = rs.getString(i);
Element node = doc.createElement(columnName);
node.appendChild(doc.createTextNode(value.trim()));
row.appendChild(node);
}
}
/* System.out.println("Document created"); */
return doc;
}
To get around memory problems, I did two things, added memory to the web server, and changed the memory settings to use quite a bit of memory on the jvm. In tomcat, I use the following JAVA_OPTS setting: "-Xms256m -Xmx256m -DentityExpansionLimit=1000000" The -DentityExpansionLimit change came from a comment by Nelson Minar on this forum.
I still don't have an answer that would send the document back compressed, and using DIME or some other chunking mechanism. I just haven't figured it out yet.
I hope some of this may help. I am not sure Web services is the right answer for sending large amounts of data. I have also been looking at using SSH tunnels to access the data directly in a secure manner. The speed has actually been better than all of the hoops that SOAP has be jumping through.
For smaller datasets, SOAP is working great!
Hope this helps. I also hope that someone else with knowledge working with large output objects will provide more enlightenment!
Ken
> -----Original Message-----
> From: Vinod Patil [mailto:[EMAIL PROTECTED]]
> Sent: Tuesday, May 18, 2004 10:40 PM
> To: [EMAIL PROTECTED]
> Subject: Passing large data in SOAP Message
>
> Hi All,
>
> A type java:MSG service should have the signatures as
> --public Element [] method(Element [] bodies)
> --public SOAPBodyElement [] method (SOAPBodyElement [] bodies)
> --public Document method(Document body)
> --public void method(SOAPEnvelope req, SOAPEnvelope resp)
>
> Now if the XML that i am going to embed in the body of the
> message is very large (say abt 3+ Mb) then the output objects
> of the service methods will be also be large in size.
> And this will lead to memory problems.
>
> What i want to ask is that how do we pass very large XML's in
> the SOAP messages...What approach should be taken if one
> wants to pass very large XML data in the SOAP message body?
>
> I am currently using the messaging style service ( with
> signature public SOAPBodyElement [] method (SOAPBodyElement
> [] bodies) ) but i am running into OutOfMemory problems...
> This is because the Document object that we use to construct
> the SOAPBodyElement is very large.
>
> Can anyone please guide me regarding the approcah that needs
> to be taken in case of passing back huge XML data from a
> webservice using Axis or any SOAP Implementation?
>
> Regards,
> Vinod
