Why XPath didnot work with Namespace ?

Question

Dear all,
When I parsing a xml document with Namespace by XPath , it didnot work well , but if I remove the part of Namespace , it worked well , I am not sure if I processed with right steps , any help is appreciated :
My parser : jdom-b9
jdk : 1.4.1
My code is like :
import java.io.*;
import java.util.*;
import org.jdom.*;
import org.jdom.input.*;
import org.jdom.output.*;
import org.jdom.xpath.*;
public class XPathTest {   
    public static void main(String[] args) throws IOException, JDOMException {
        if (args.length != 1) {
            System.err.println("Usage: samples.XPathTest [test.xml]");
            return;
        String filename = args[0];
        PrintStream out = System.out;
        SAXBuilder builder = new SAXBuilder();
        Document doc = builder.build(new File(filename));
        Element root = doc.getRootElement();          
        XPath path = XPath.newInstance("//Worksheet");          
        path.addNamespace("ss","urn:schemas-microsoft-com:office:spreadsheet");
        // or use :
        //Namespace ns = root.getNamespace();
        //path.addNamespace(ns);
        List elementNames = path.selectNodes(doc);
        if (elementNames.size() == 0) {
            out.println("This xml contains no element <Worksheet>");
        } else {
            out.println("This xml contains " + elementNames.size() + " <Worksheet> :");
            Iterator i = elementNames.iterator();
            while (i.hasNext()) {
                out.println("\t" + ((Element)i.next()).getName());
}and test.xml :
<?xml version="1.0"?>
<Workbook xmlns="urn:schemas-microsoft-com:office:spreadsheet"
xmlns:o="urn:schemas-microsoft-com:office:office"
xmlns:x="urn:schemas-microsoft-com:office:excel"
xmlns:ss="urn:schemas-microsoft-com:office:spreadsheet"
xmlns:html="http://www.w3.org/TR/REC-html40">
<Worksheet ss:Name="Sheet2">
  <Table ss:ExpandedColumnCount="12" ss:ExpandedRowCount="38" x:FullColumns="1"
   x:FullRows="1" ss:DefaultColumnWidth="54" ss:DefaultRowHeight="14.25">
   <Column ss:Width="63"/>
   <Column ss:Width="76.5"/>
   <Column ss:Width="103.5"/>
   <Column ss:Width="123"/>
   <Column ss:Width="136.5"/>
   <Column ss:Width="83.25"/>
   <Column ss:Width="39"/>
   <Column ss:Width="76.5"/>
   <Column ss:Width="103.5"/>
   <Column ss:Width="90"/>
   <Column ss:Width="76.5"/>
   <Column ss:Width="90"/>
   <Row>
    <Cell><Data ss:Type="String">PORT_CODE</Data></Cell>
    <Cell><Data ss:Type="String">EFFECT_DATE</Data></Cell>
    <Cell><Data ss:Type="String">END_DATE</Data></Cell>
    <Cell><Data ss:Type="String">ENCODE_SCHEME_PORT</Data></Cell>
    <Cell><Data ss:Type="String">PORT_NAME</Data></Cell>
    <Cell><Data ss:Type="String">COUNTRY_CODE</Data></Cell>
    <Cell><Data ss:Type="String">IS_RT</Data></Cell>
    <Cell><Data ss:Type="String">DATA_SOURCE</Data></Cell>
    <Cell><Data ss:Type="String">LAST_UPD_DATE</Data></Cell>
    <Cell><Data ss:Type="String">LAST_UPD_USER</Data></Cell>
    <Cell><Data ss:Type="String">BP_UPD_DATE</Data></Cell>
    <Cell><Data ss:Type="String">PROVINCE_CODE</Data></Cell>
   </Row>
  </Table>
</Worksheet>
</Workbook>test1.xml
<?xml version="1.0"?>
<Workbook>
<Worksheet Name="Sheet2">
  <Table>
   <Column Width="63"/>
   <Column Width="76.5"/>
   <Column Width="103.5"/>
   <Column Width="123"/>
   <Column Width="136.5"/>
   <Column Width="83.25"/>
   <Column Width="39"/>
   <Column Width="76.5"/>
   <Column Width="103.5"/>
   <Column Width="90"/>
   <Column Width="76.5"/>
   <Column Width="90"/>
   <Row>
    <Cell><Data Type="String">PORT_CODE</Data></Cell>
    <Cell><Data Type="String">EFFECT_DATE</Data></Cell>
    <Cell><Data Type="String">END_DATE</Data></Cell>
    <Cell><Data Type="String">ENCODE_SCHEME_PORT</Data></Cell>
    <Cell><Data Type="String">PORT_NAME</Data></Cell>
    <Cell><Data Type="String">COUNTRY_CODE</Data></Cell>
    <Cell><Data Type="String">IS_RT</Data></Cell>
    <Cell><Data Type="String">DATA_SOURCE</Data></Cell>
    <Cell><Data Type="String">LAST_UPD_DATE</Data></Cell>
    <Cell><Data Type="String">LAST_UPD_USER</Data></Cell>
    <Cell><Data Type="String">BP_UPD_DATE</Data></Cell>
    <Cell><Data Type="String">PROVINCE_CODE</Data></Cell>
   </Row>
  </Table>
</Worksheet>
</Workbook>The output of test.xml is : This xml contains no element <Worksheet>
The output of test1.xml with no namespace part is :
This xml contains 1 <Worksheet> :
Worksheet
WHY ????????????????????????????

Answer 1

I do not use jdom but I had similar problems. You can try "//:worksheet". The prefix for the default namespace might be "". it fixed my problem.
wz