Re: looking for simple example to access XML node

From:

=?ISO-8859-1?Q?Arne_Vajh=F8j?= <arne@vajhoej.dk>

Newsgroups:

comp.lang.java.programmer

Date:

Sun, 08 Apr 2007 12:35:25 -0400

Message-ID:

<461919b4$0$90270$14726298@news.sunsite.dk>

Mich wrote:

I have a small XML document and I need to locate an 'led' node according to
the unique 'skew'. I would really appreciate if someone can point me to an
online example of how to do this.

<catalog>
   <led color="Blue" skew='LB1' circumference='5' nm='470' ma='20'
voltage='3.2 ~ 3.8' mcd='6000' angle='10 ~ 20'/>
   <led color="Turquoise" skew='LB1' circumference='5' nm='510' ma='20'
voltage='3.2 ~ 3.8' mcd='6000+' angle='25 to 30'/>
   <led color="Green" skew='LG1' circumference='5' nm='520' ma='20'
voltage='3.2 ~ 3.6' mcd='5000' angle='10 ~ 20'/>
   <led color="Yellow" skew='LY1' circumference='5' nm='585 ~ 595' ma='20'
voltage='1.8 ~ 2.2' mcd='5000' angle='10 ~ 20'/>
   <led color="Red" skew='LR1' circumference='5' nm='640 ~ 645' ma='20'
voltage='1.8 ~ 2.2' mcd='8000' angle='10 ~ 20'/>
   <led color="Red" skew='LR2' circumference='P4' nm='624' ma='70'
voltage='1.8 ~ 2.2' mcd='4500' angle='80'/>
   <led color="Red" skew='LR3' circumference='10' nm='660' ma='20'
voltage='1.8 ~ 2.2' mcd='5000' angle='20'/>
</catalog>

You can use XPath.

Here are an example illustrating the technique:

package april;

import java.io.File;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.apache.xml.serialize.OutputFormat;
import org.apache.xml.serialize.XMLSerializer;
import org.apache.xpath.XPathAPI;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

public class SelextXPath {
     public static void main(String[] args) throws Exception {
         DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
         DocumentBuilder db = dbf.newDocumentBuilder();
         Document doc = db.parse(new File("C:\\catalog.xml"));
         Element led =
(Element)XPathAPI.selectSingleNode(doc.getDocumentElement(),
"led[@skew='LY1']");
         OutputFormat fmt = new OutputFormat();
         fmt.setIndenting(true);
         XMLSerializer ser = new XMLSerializer(System.out, fmt);
         ser.serialize(led);
     }
}

Arne