Using xpath and vtd-xml to get sub nodes and text of an element as a string

Question

This is a portion of my XML:

<MAIN>
    <L>
        <D>string1 string2 <b>string3</b> string4</D>
    </L>
    <L>
        <D>string5 string6 <b>string7</b> string8 <i>string9</i></D>
    </L>
</MAIN>

I want to get the content of all the <D> tags as string. So, the example above should return:

1st iteration: 'string1 string2 <b>string3</b> string4'
2nd iteration: 'string5 string6 <b>string7</b> string8 <i>string9</i>'
etc...

In vtd-xml I used an AutoPilot with XPath "//L/D" and "//L/D/text()" but that did not work.

Any advice or alternative approach will be appreciated.

Regards

Can't you just use //L which will return a List of nodes. Then for those nodes loop over the direct children and call whatever method returns the Text. — gshauger, May 14 '11 at 20:15
Good question, +1. See my answer for a complete and short one-liner XPath expression solution. — Dimitre Novatchev, May 15 '11 at 16:46

score 13 · Accepted Answer · answered May 16 '11 at 02:24

13

Below is the code that does what you are looking for.

    VTDGen vg =  new VTDGen();
    if (vg.parseFile("c://xml//alex.txt", true)){
        VTDNav vn = vg.getNav();
        AutoPilot ap = new AutoPilot(vn);
        ap.selectXPath("//L/D");
        int i=-1;
        while((i=ap.evalXPath())!=-1){
            long l = vn.getContentFragment();
            System.out.println(" -==> "+ vn.toString((int )l, (int)(l>>32)));
        }
    }

answered May 16 '11 at 02:24

vtd-xml-author

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I started using this approach, but it seems to spoil escaped chars. For example, if the content has `&`, the printed string only has "&". I ran into a problem with this, and posted it as a separate question [here](http://stackoverflow.com/questions/27823107/vtd-xml-seems-to-be-spoiling-escaped-string-in-xml-document). – Chthonic Project Jan 07 '15 at 16:07
1

Instead of using toString(), use toRawString() the problem should go away. – vtd-xml-author Jan 08 '15 at 03:35
@vtd-xml-author but why ns are ignored? how to specify the namespace ap.selectXPath("//myns:L/otherns:D"); ? – Xelian Aug 16 '16 at 12:27
@Xelian: AutoPilot has a method called declareXPathNameSpace(java.lang.String prefix, java.lang.String URL) This function creates URL ns prefix and is intended to be called prior to selectXPath – vtd-xml-author Aug 16 '16 at 20:35

score 3 · Answer 2 · answered May 15 '11 at 16:45

Use:

/*/L/D/node()

This selects all nodes (elements, text-nodes, processing-instructions and comment-nodes) that are children of any D element that is a child of any L element that is a child of the top element of the XML document.

Alternatively, you could select separately all the node-children of the two /*/L/D elements:

/*/L[1]/D/node()

and

/*/L[2]/D/node()

Verification using XSLT as host of XPath:

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
 <xsl:output omit-xml-declaration="yes" indent="yes"/>

 <xsl:template match="/">
  <xsl:copy-of select="/*/L[1]/D/node()"/>
--------------------
  <xsl:copy-of select="/*/L[2]/D/node()"/>
 </xsl:template>
</xsl:stylesheet>

when applied on the provided XML document:

<MAIN>
    <L>
        <D>string1 string2 
            <b>string3</b> string4
        </D>
    </L>
    <L>
        <D>string5 string6 
            <b>string7</b> string8 
            <i>string9</i>
        </D>
    </L>
</MAIN>

the wanted, correct result is produced:

string1 string2 
            <b>string3</b> string4

--------------------
  string5 string6 
            <b>string7</b> string8 
            <i>string9</i>

Thanks for your reply. This did not work. It iterates through the nodes inside the D tags, so on the first D tag it goes to the b tag and on the second D tag it goes first to the b tag and then to the i tag. — Alex, May 15 '11 at 17:41
@Alex: if this is the case, then you are not using an XPath compliant implementation -- the node-test `node()` must select all children of the current node -- not only the elements. I suspect that you only inspect the elements from the resulting node-list when the right action is to inspect all selected nodes. — Dimitre Novatchev, May 15 '11 at 17:49

Using xpath and vtd-xml to get sub nodes and text of an element as a string

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