带有命名空间的GPX文件的XPath查询？

Question

当GPX文件具有以下简单结构时,我能够<trkpt></trkpt>通过xpath表达式访问节点<xsl:for-each select='gpx/trk/trkseg/trkpt'>:

<gpx>
  <trk>
    <trkseg>
      <trkpt lat="50.5324906" lon="7.0842605">
        <ele>105.8824463</ele>
        <time>2010-07-11T08:50:16Z</time>
      </trkpt>
      <trkpt lat="50.5323745" lon="7.0843524">
        <ele>108.7662354</ele>
        <time>2010-07-11T08:50:44Z</time>
      </trkpt>
      ...
    </trkseg>
  </trk>
</gpx>

如何在涉及名称空间时实现相同的效果,例如:

<gpx xmlns="http://www.topografix.com/GPX/1/1" 
     creator="MapSource 6.15.11" 
     version="1.1" 
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://www.topografix.com/GPX/1/1 
                         http://www.topografix.com/GPX/1/1/gpx.xsd">

Answer 1

In XSLT 1.0:

<xsl:apply-templates 
    select="/g:gpx/g:trk/g:trkseg/g:trkpt"
    xmlns:g="http://www.topografix.com/GPX/1/1"/> 

In XSLT 2.0:

<xsl:apply-templates 
    select="/gpx/trk/trkseg/trkpt" 
    xpath-default-namespace="http://www.topografix.com/GPX/1/1"/> 

So, you need to declare the namespace (prefix, URI) in your stylesheet and add this namespace in your QName test of XPath expression.

As example, this XSLT 1.0 stylesheet:

<xsl:stylesheet version="1.0" 
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
 xmlns:g="http://www.topografix.com/GPX/1/1">
    <xsl:output method="text"/>
    <xsl:template match="g:trkpt">
       <xsl:text>Found 'trkseg' element&#xA;</xsl:text>
    </xsl:template>
</xsl:stylesheet>

And this XSLT 2.0 stylesheet:

<xsl:stylesheet version="2.0" 
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xpath-default-namespace="http://www.topografix.com/GPX/1/1">
    <xsl:output method="text"/>
    <xsl:strip-space elements="*"/>
    <xsl:template match="trkpt">
        <xsl:text>Found 'trkseg' element&#xA;</xsl:text>
    </xsl:template>
</xsl:stylesheet>

With this input:

<gpx xmlns="http://www.topografix.com/GPX/1/1"
     creator="MapSource 6.15.11"
     version="1.1"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://www.topografix.com/GPX/1/1
                         http://www.topografix.com/GPX/1/1/gpx.xsd">
    <trk>
        <trkseg>
            <trkpt lat="50.5324906" lon="7.0842605">
                <ele>105.8824463</ele>
                <time>2010-07-11T08:50:16Z</time>
            </trkpt>
            <trkpt lat="50.5323745" lon="7.0843524">
                <ele>108.7662354</ele>
                <time>2010-07-11T08:50:44Z</time>
            </trkpt>
        </trkseg>
    </trk>
</gpx>

Both output:

Found 'trkseg' element
Found 'trkseg' element