Java Tips - Accessing character data (CDATA) of XML element

Besides elements defined in our DTD, XML has a set of already predefined ones. These are comments, character data (CDATA) etc. Character data is a text directly inserted between start and end tags of the element. It can mix with children tagged-elements.

A concrete implementation of SAX-parser defines whether it will collect all CDATA before passage to handler or it will pass it there by their occurence.


import java.util.Stack;

import javax.xml.parsers.SAXParser;

import javax.xml.parsers.SAXParserFactory;



import org.xml.sax.Attributes;

import org.xml.sax.SAXException;

import org.xml.sax.helpers.DefaultHandler;



/**

 * This example demonstrates how to extract text (CDATA) information

 * from the element in the source XML-document.

 */



public class SampleOfCDataAccess extends DefaultHandler {

  private Stack currentElement = new Stack();



  // we push current element name:

  public void startElement (String uri, String localName,

    String qName, Attributes attrs) throws SAXException {



    currentElement.push(qName);

  }



  public void endElement(String namespaceURI, String localName,

    String qName) throws SAXException {



    currentElement.pop();

  }



  // this method will be called for each character-section occurred;

  // if the element containes several CDATA-sections mixed with

  // child elements the number of calls depends on SAX-implementation:

  public void characters(char[] ch, int start, int length)

    throws SAXException {



    String cdata = new String(ch, start, length);



    System.out.println("Element '" + currentElement.peek()

      + "' contains text: " + cdata);

  }



  public static void main(String[] args) {

    try {

      // creates and returns new instance of SAX-implementation:

      SAXParserFactory factory = SAXParserFactory.newInstance();

      factory.setValidating(true);



      // create SAX-parser...

      SAXParser parser = factory.newSAXParser();





      parser.parse("sample.xml", new SampleOfCDataAccess());



    } catch (Exception ex) {

      ex.printStackTrace(System.out);

    }

  }

}

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