DOMParser.java - Parsing XML Files with DOM

<< DOM (Document Object Model) - API for XML Files

<< JDK (Java Development Kit) Tutorials

This section provides a tutorial example on how to write an XML file parser, DOMParser.java, with the org.w3c.dom.Document class included in JDK.

What is DOM (Document Object Model)? DOM is an Application Programming Interface (API) that represents an XML file as a document object, which allows application programs to manage the information contained in the document object.

DOM has been implemented in Java in J2SDK 1.4.1_01, which is already installed on my system. So I am ready to play with XML files through DOM in Java.

Here is a program to show how different packages are used together to parse an XML file into a DOM document object:

/**
 * DOMParser.java
 * Copyright (c) 2002 by Dr. Herong Yang
 */
import java.io.*;
import javax.xml.parsers.*;
import org.w3c.dom.*;
import org.xml.sax.*;
class DOMParser {
   public static void main(String[] args) {
      try {
      	 File x = new File(args[0]);
         DocumentBuilderFactory f 
            = DocumentBuilderFactory.newInstance();
         System.out.println(f.toString()); 	
         DocumentBuilder b = f.newDocumentBuilder();
         System.out.println(b.toString()); 	
         Document d = b.parse(x);
         System.out.println(d.toString()); 	
         DOMImplementation i = d.getImplementation();
         System.out.println(i.toString());
      } catch (ParserConfigurationException e) {
         System.out.println(e.toString()); 	
      } catch (SAXException e) {
         System.out.println(e.toString()); 	
      } catch (IOException e) {
         System.out.println(e.toString()); 	
      }
   }
}

Output:

org.apache.crimson.jaxp.DocumentBuilderFactoryImpl@1c78e57
org.apache.crimson.jaxp.DocumentBuilderImpl@13e8d89
org.apache.crimson.tree.XmlDocument@1cfb549
org.apache.crimson.tree.DOMImplementationImpl@1820dda

Note that:

• javax.xml.parsers.DocumentBuilderFactory.newInstance() method is used to create a new fatory instance using a factory implementation from the org.apache.crimson.jaxp.* package.
• javax.xml.parsers.DocumentBuilder.newDocumentBuilder() method is used to create a new builder instance using a builder implementation from org.apache.crimson.jaxp.* package.
• javax.xml.parsers.DocumentBuilder.parse() method is used to parse the XML file into an org.w3c.dom.Document object implemented with org.apache.crimson.tree.XmlDocument class.

Last update: 2006.

Sections in This Chapter

DOMParser.java - Parsing XML Files with DOM

DOMBrowser.java - Browsing DOM Tree Structure

DOMNewDoc.java - Building a New DOM Document

DOMToXML.java - Converting DOM Documents to XML Files