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XML Namespace handling?

843834Jul 18 2001 — edited Jul 25 2001
Hi,
I am having a typical problem here. Is there any way I can set a namespace to an XML string before I convert it into a Document. The problem is I have this XML string and I am trying to parse it, but I get a java.io.Nullpointer Exception because one of the tags in the XML string has a name space and I need to assign a name space to it here.

here's an example...

Following is my XML string say....

<metadata>
<schema>Schema 1</schema>
<schemaversion>DX:MD1.0 S:1.0</schemaversion>
<dlmd:record>Record</dlmd:record>
</metadata>

I need to parse this string, but I can not do it without setting a namespace for dlmd:record! Or is there a way I can do it without the namespace...I tried using the setNamespaceaware() option but it does not seem to work.

It's sort of strange as to why I need to assign a name space to it here...but thats the problem I have to deal with...

any help would be very much appreciated.

Thanks in advance
Prashanth

Comments

843834
I agree with your hunch. The parser should treat dlmd:record as just another element (colons are allowed in XML element names when namspace feature is turned off). Maybe you could elaborate a bit on what parser you're using, what Document (JDOM or DOM) you're building and where the exception comes from (io exception is kind of strange, too).
843834
Hi
I am using JAXP 1.1 and I am builidng a DOM document. The exception I get is a SAX Exception and the following is the stack trace

java.lang.NullPointerException
at org.apache.crimson.parser.Parser2.parseInternal(Parser2.java:523)
at org.apache.crimson.parser.Parser2.parse(Parser2.java:304)
at org.apache.crimson.parser.XMLReaderImpl.parse(XMLReaderImpl.java:433)
at org.apache.crimson.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:179)

at javax.xml.parsers.DocumentBuilder.parse(DocumentBuilder.java:161)
at dlnet.DLXMLParse.dlDocumentBuild(DLXMLParse.java:282)
at dlnet.DLXMLParse.dlStart_Parse(DLXMLParse.java:50)
at dlnet.DLTrigger.main(DLTrigger.java:40)

Hope you can suggest a solution.....
843834
I see. I only tried xerces with your example and it was just fine. You're using Crimson, though and there seems to be a bug in crimson1.1. Go, get crimson1.1.1 from http://xml.apache.org and it'll parse fine.

Good luck,
Leo.
843834
Using the new version of Crimson does not help either. After I build the new Document Factory I set the namespace awareness to false and yet it gives me a sax exception......Could something else be wrong too!??

Thanks for your help....
Prashanth
843834
Prashanth,
this is what I'm doing. First, the parser test code:
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;

public class JAXPDOMTest {

    public void domParse(String url) {
        DocumentBuilder parser;
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        factory.setValidating(false);
        factory.setNamespaceAware(false);

        try {
            parser = factory.newDocumentBuilder();
            Document doc = parser.parse(url);

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    static public void main(String[] args)
    {
       JAXPDOMTest x=new JAXPDOMTest();
       x.domParse("test.xml");
    }
}
and here's test.xml: 
<?xml version="1.0"?>

<metadata>
   <schema>Schema 1</schema>
   <schemaversion>DX:MD1.0 S:1.0</schemaversion>
   <dlmd:record>Record</dlmd:record>
</metadata>
jaxp-1.1 is my directory containing the official 1.1 release and my complete classpath look like this:
CLASSPATH=d:\xml_tools\jaxp-1.1\crimson.jar;d:\xml_tools\jaxp-1.1\jaxp.jar;.

I run the above (java JAXPDOMTest), I get:
java.lang.NullPointerException
at org.apache.crimson.parser.Parser2.parseInternal(Parser2.java:523)
at org.apache.crimson.parser.Parser2.parse(Parser2.java:304)
at org.apache.crimson.parser.XMLReaderImpl.parse(XMLReaderImpl.java:433)

at org.apache.crimson.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:179)
at javax.xml.parsers.DocumentBuilder.parse(DocumentBuilder.java:134)
at JAXPDOMTest.domParse(JAXPDOMTest.java:15)
at JAXPDOMTest.main(JAXPDOMTest.java:24)

I set the class path to:
CLASSPATH=d:\xml_tools\crimson-1.1.1\crimson.jar;d:\xml_tools\crimson-1.1.1\jaxp.jar;.

and, voila, no exception.

Hope that helps,
Leo.
843834
Hi

This is what I did just now....I created a file out of the pseudo string and passed it to be parsed with crimson.....it gives me an error irrespective of whether I turn Namespace awareness true or not!

What could the reason be?

Thanks
Prashanth
843834
Well, that seems to be classic dilemma. The same code works fine on my machine, but has trouble on yours. I'm running on 95 with JSDK 1.3 (build 1.3.0-C).
I'm afraid I can't help you any further, since I can't reproduce this behaviour.

Leo.
843834
Thanks anyways....guess I have to figure it out myself.
Prashanth
843834
It finally worked!!!! This is what I did. I had to delete the jar files in the \lib\ext directory of Java Runtime Environment and it started working. Thanks Leo you have been of great help.......

Prashanth
843834
Yeah, that's a valuable lesson. jar files in lib/ext, I believe, are accessed before stuff in the class path. Glad to hear it's working.
843834
P.S.
check out http://forums.java.sun.com/rewardFaq.jsp#assign

;-)
843834
Yup! I did....It would be helpful if yo could throw some light one one other question i've posted!

http://forum.java.sun.com/thread.jsp?forum=34&thread=150639

Thanks
843834
Thx for the DDs. I saw this question before, but haven't done anything like this and I'm afraid, I can't give you advice on that one, but my instincts tell me, you'd be better off with the database solution.

Good luck.
843834
Thanks for the info.
I had the same problem, I have it no more

Small note: I had to put the XALAN.jar file AFTER the crimson.jar and jaxp.jar in order to make it work.


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Locked on Aug 22 2001
Added on Jul 18 2001
#java-technology-xml
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