saxdemo.java

java核心编程的部分源码

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


/**
* SAXDemo uses JAXP to acquire a SAX parser to parse an XML file.
* The example XML file represents a shopping cart.
*
* The following JARs must be in your CLASSPATH:
* - jaxp.jar
* - xerces.jar (for SAX parser implementation)
*
* Download JAXP (which includes these JARs) here: http://java.sun.com/xml/
* Find additional Xerces info here: http://xml.apache.org/
*
* Note: Unlike DOM, SAX parsing does not load the XML file into memory.
* SAX parsers traverse the XML file and report parse "events" to an event handler.
**/

public class SAXDemo
extends org.xml.sax.HandlerBase
{

/**
* main creates and runs a SaxTest instance.
**/
public static void main( String[] args )
{
SAXDemo me = new SAXDemo();
me.run();
}


public void run()
{
try
{
SAXParserFactory factory = SAXParserFactory.newInstance();
log( "SAXParserFactory classname: " + factory.getClass().getName() );

SAXParser saxParser = factory.newSAXParser();
log( "SAXParser classname: " + saxParser.getClass().getName() );

/*
The SAXParser.parse method initiates parsing of the XML file.
The second parameter specifies which class will handle parse events.
This class must extend org.xml.sax.HandlerBase
**/
saxParser.parse( "cart.xml", this );
}
catch( Exception e )
{
e.printStackTrace();
}
}

/**
* log simply prints the specified message to System.out
**/
public void log( String message )
{
System.out.println( message );
}


/**
* SAXParser calls startDocument() when it starts parsing a document
**/
public void startDocument ()
throws SAXException
{
log( "Start SAX parse" );
}

/**
* SAXParser calls endDocument() when it finishes parsing a document
**/
public void endDocument ()
throws SAXException
{
log( "End SAX parse" );
}

/**
* SAXParser calls startElement() when it encounters an opening element tag (eg <item>)
**/
public void startElement (String name, AttributeList attrs)
throws SAXException
{
log( "<" + name + ">" );
}

/**
* SAXParser calls endElement() when it encounters a closing element tag (eg </item>)
**/
public void endElement (String name)
throws SAXException
{
log( "</" + name + ">" );
}

/**
* SAXParser calls characters() when it encounters text outside of any tags
**/
public void characters(char[] p0, int p1, int p2)
throws SAXException
{
String str = new String( p0, p1, p2 ).trim();
if( str.length() > 0 )
log( str );
}


}