How to use Xpath to extract child nodes

smilysuresh · February 23rd, 2007, 04:34 AM

Hi,

I need to extract the value of the Document_Body_content from below xhtml content. I used something similar to

String xpq="//div[div/div/div/h2/a[@name='Document_Body_content']]/self::div";

I tried like this but its not returning me the exact output....

My Sample xhtml :

-------------------------------------

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta name="generator" content="HTML Tidy, see www.w3.org" />
<title></title>
</head>
<body>
<div class="article" lang="en">
<div class="titlepage">
<div>
<div>
<h2 class="title"><a id="ID" name="ID"></a></h2>
</div>
</div>

</div>

<div class="section" lang="en">
<div class="titlepage">
<div>
<div>
<h2 class="title" style="clear: both"><a id="Description_content"
name="Description_content"></a> <span
class="underline">Description</span></h2>
</div>
</div>
</div>
</div>

<div class="section" lang="en">
<div class="titlepage">
<div>
<div>
<h2 class="title" style="clear: both"><a id="Document_Body_content"
name="Document_Body_content"></a> <span class="underline">Document
Body</span></h2>
</div>
</div>
</div>

<p>To check the mount options on your NFS mounted filesystems, use
the <span class="italic">nfsstat -m</span> command. This will
display all the current settings.</p>

<p></p>

<p><span class="italic">Example:</span></p>

<p><span class="italic">% nfsstat -m</span></p>

<p><span class="italic">/home/<username> from
<NFS_Server>:/global/export/home1/<username> Flags:
vers=3,proto=tcp,sec=sys,hard,intr,link,symlink,ac l,rsize=32768,wsize=32768,retrans=5</span></p>

<p><span class="italic">/usr/dist from <NFS_Server>:/usr/dist
Flags:
vers=3,proto=tcp,sec=sys,soft,intr,link,symlink,ac l,rsize=32768,wsize=32768,retrans=5</span></p>

<p><span class="italic">/net/share/ from
<NFS_Server>:/share/export Flags:
vers=3,proto=tcp,sec=sys,hard,intr,link,symlink,ac l,rsize=32768,wsize=32768,retrans=5</span></p>

<p><span class="bold"><b>If any of the mount options are changed,
you must umount and remount the filesystem for the changes to take
effect. Only then will the changes be displayed with the <span
class="italic">nfsstat -m</span> command.</b></span></p>

<p>Note: the <username> and <NFS_Server> are
"placeholders" which represent the actual user and server names. Of
course, the server noted in each mount point could easily be
different (or not).</p>

<p></p>
</div>

<div class="section" lang="en">
<div class="titlepage">
<div>
<div>
<h2 class="title" style="clear: both"><a
id="_________Internal_Only_______content"
name="_________Internal_Only_______content"></a> <span
class="underline">Internal Only</span></h2>
</div>
</div>
</div>

<p>[email protected]</p>

<p></p>
</div>
</div>
</body>
</html>

For Document_Body_content, I expect my output as below

<p>To check the mount options on your NFS mounted filesystems, use
the <span class="italic">nfsstat -m</span> command. This will
display all the current settings.</p>

<p></p>

<p><span class="italic">Example:</span></p>

<p><span class="italic">% nfsstat -m</span></p>

<p><span class="italic">/home/<username> from
<NFS_Server>:/global/export/home1/<username> Flags:
vers=3,proto=tcp,sec=sys,hard,intr,link,symlink,ac l,rsize=32768,wsize=32768,retrans=5</span></p>

<p><span class="italic">/usr/dist from <NFS_Server>:/usr/dist
Flags:
vers=3,proto=tcp,sec=sys,soft,intr,link,symlink,ac l,rsize=32768,wsize=32768,retrans=5</span></p>

<p><span class="italic">/net/share/ from
<NFS_Server>:/share/export Flags:
vers=3,proto=tcp,sec=sys,hard,intr,link,symlink,ac l,rsize=32768,wsize=32768,retrans=5</span></p>

<p><span class="bold"><b>If any of the mount options are changed,
you must umount and remount the filesystem for the changes to take
effect. Only then will the changes be displayed with the <span
class="italic">nfsstat -m</span> command.</b></span></p>

<p>Note: the <username> and <NFS_Server> are
"placeholders" which represent the actual user and server names. Of
course, the server noted in each mount point could easily be
different (or not).</p>

<p></p>

Please let me know how to incorporate xpath for this scenario.

Thanks
Suresh

mhkay · February 23rd, 2007, 05:26 AM

All your input elements are in the XHTML namespace, so in a path expression the names need to be prefixed, for example

<xsl:copy-of select="h:dv/h:div[h:a='...']">

with xmlns:h="http://www.w3.org/1999/xhtml"

declared at the top level of your stylesheet.

I would use something like

<xsl:copy-of select="//h:div[@class='section']
[.//h:a/@id='Document_Body_content']/h:p"/>

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference

smilysuresh · February 23rd, 2007, 06:04 AM

Michael,

Thanks a lot for your immediate response...

I am using this xpath with java...I m passing this xpath to a XpathFactory but still its not returning me required output..

            DocumentBuilderFactory domBuilderFactory = DocumentBuilderFactory.newInstance();
            DocumentBuilder domBuilder = domBuilderFactory.newDocumentBuilder();
            Document dom = domBuilder.parse(new InputSource(new FileReader(args[0])));

            XPathFactory xpathFactory = XPathFactory.newInstance();
            XPath xpath = xpathFactory.newXPath();
            String xpq = "//h:div[@class='section'][.//h:a/@id='Document_Body_content']/h:p";
            Node node = (Node) xpath.evaluate(xpq, dom, XPathConstants.NODE);
            transformer.transform(new DOMSource(node), new StreamResult(System.out));

So could you please let me know how to directly incorporate xpath query in this case ?

Sorry for pasting my whole xhtml content
--------------------------------------------------
<html xmlns="http://www.w3.org/1999/xhtml">
<xsl:copy-of select="h:div/h:div[h:a='...']"></xsl:copy-of>
<head>
<meta name="generator" content="HTML Tidy, see www.w3.org" />
<title></title>
</head>
<body>
<div class="article" lang="en">
<div class="titlepage">
<div>
<div>
<h2 class="title"><a id="ID" name="ID"></a></h2>
</div>
</div>

</div>

<div class="section" lang="en">
<div class="titlepage">
<div>
<div>
<h2 class="title" style="clear: both"><a id="Description_content"
name="Description_content"></a> <span
class="underline">Description</span></h2>
</div>
</div>
</div>
</div>

<div class="section" lang="en">
<div class="titlepage">
<div>
<div>
<h2 class="title" style="clear: both"><a id="Document_Body_content"
name="Document_Body_content"></a> <span class="underline">Document
Body</span></h2>
</div>
</div>
</div>

<p><span class="bold"><b>How to have a secured nfs without nis or
nis+.</b></span></p>

<p><span class="bold"><b>On Server :</b></span></p>

<p>1. Make sure that the /etc/publickey does not have keys other
than <span class="italic">nobody</span>.</p>

<p>2. vi /etc/defaultdomain (needed for netname)</p>

<p>Enter any domain name</p>

<p>reboot</p>

<p>3. newkey -h <machinename which is servername> -s
files</p>

<p>Adding new key for
unix.<machinename>@<domainname></p>

<p>Enter local root login password: (enter root passwd for that
machine)</p>

<p>Enter <machinename's> root login password: (enter rpc
passwd you want)</p>

<p>4. newkey -h <machinename which are clients> -s files</p>

<p><span class="italic">Same procedure as 3</span></p>

<p>5. keylogin -r</p>

<p>Enter rpc passwd.</p>

<p>Wrote secret key in .rootkey</p>

<p>6. vi /etc/dfs/dfstab</p>

<p>share -F nfs -o sec=dh /<filesystem to be shared></p>

<p>shareall</p>

<p></p>

<p><span class="bold"><b>On Client</b></span>:</p>

<p>1. vi /etc/defaultdomain (needed for netname)</p>

<p>Enter the same domainname as the server</p>

<p>reboot</p>

<p>2. copy file /etc/publickey from server to the client.</p>

<p>3. Make sure that /etc/publickey on server and client are the
same.</p>

<p>4. keylogin -r</p>

<p>Enter the rpc passwd for client.</p>

<p>5. mount -F nfs -o sec=dh <server>:/<filesystem it is
sharing> <mount point></p>

<p>You should be able to mount .</p>
</div>

<div class="section" lang="en">
<div class="titlepage">
<div>
<div>
<h2 class="title" style="clear: both"><a
id="_________Internal_Only_______content"
name="_________Internal_Only_______content"></a> <span
class="underline">Internal Only</span></h2>
</div>
</div>
</div>

<p>None.</p>
</div>
</div>
</body>
</html>
------------------------------------------------------------

mhkay · February 23rd, 2007, 06:32 AM

You need to set the namespace mapping in the XPath object.

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference