Example: Regular Expressions in Java

CIT 597 First SAX Example
Fall 2002, David Matuszek

Here is a trivial example of using SAX, taken from CodeNotes® for XML, by Gregory Brill. This code is available as a zip file containing a BlueJ package. Note that you must either run the program from the command line, or move the hello.xml file into whatever directory your IDE uses as its default directory.

Sample.java

import org.xml.sax.*;
import org.xml.sax.helpers.*;
import javax.xml.parsers.*;


/**
 * This is from CodeNotes for XML, by Gregory Brill, page 159.
 * I have made a few changes.
 */
public class Sample {

    public static void main(String args[]) throws Exception {

        // create a parser
        SAXParserFactory spf = SAXParserFactory.newInstance();
        spf.setNamespaceAware(true);
        SAXParser saxParser = spf.newSAXParser();
        XMLReader parser = saxParser.getXMLReader();

        // create a handler
        Handler handler = new Handler();

        // assign the handler to the parser
        parser.setContentHandler(handler);

        // parse the document
        parser.parse("hello.xml");
    }
}

Handler.java

import org.xml.sax.*;
import org.xml.sax.helpers.*;


/**
 * This is from CodeNotes for XML, by Gregory Brill, page 158.
 * I have made some minor cosmetic changes.
 */
public class Handler extends DefaultHandler {
    
    // SAX calls this method when it encounters an element
    public void startElement(String namespaceURI,
                             String localName,
                             String qualifiedName,
                             Attributes att)
            throws SAXException {
        System.out.println("startElement: " + qualifiedName);
    }
    
    // SAX calls this method to pass in character data
    public void characters(char ch[], int start, int length)
            throws SAXException {
        System.out.println("characters " + start + " to " +
                           (start + length - 1) +  ": " +
                           new String(ch, start, length));
    }
    
    // SAX call this method when it encounters an end tag
    public void endElement(String namespaceURI,
                           String localName,
                           String qualifiedName)
            throws SAXException {
        System.out.println("Element: /" + qualifiedName);
    }
}

hello.xml

<?xml version="1.0"?>
<display>
    Hello World!
</display>

Example output

startElement: display
characters 32 to 31: 
characters 0 to 0: 

characters 34 to 49:     Hello World!
characters 0 to 0: 

endElement: /display