How to parse an XML file with the DOM API?

If you want to parse an XML file with the DOM API, you can follow these suggestions:

1. Use the factory class to create DocumentBuilder object:

      DocumentBuilderFactory f = DocumentBuilderFactory.newInstance();
      DocumentBuilder b = f.newDocumentBuilder();

2. Call the parse() method on the DocumentBuilder object to parse the XML file into a Document object:

      Document d = b.parse(new File(args[0]));
      System.out.println("Implementation class:\n   "+d.getClass().getName());

3. Retrieve any information from the XML document:

    Node n = d.getDocumentElement();

Here is a complete example of parsing an XML file with DOM API, DomXmlParser.java:

// Copyright (c) 2017 FYIcenter.com
import java.io.*;
import javax.xml.parsers.*;
import org.w3c.dom.*;

public class DomXmlParser {
   static String dot = "............................................................";
   public static void main(String[] args) throws Exception {
      DocumentBuilderFactory f = DocumentBuilderFactory.newInstance();
      DocumentBuilder b = f.newDocumentBuilder();
      Document d = b.parse(new File(args[0]));
      System.out.println("Implementation class:\n   "+d.getClass().getName());
    
      System.out.println("DOM object elements and text contents:");
    Node n = d.getDocumentElement();
    printText(n, 1);
   }
   public static void printText(Node n, int l) {
      String v = "";
      if (n.getNodeType()==Node.TEXT_NODE) v = n.getTextContent();
      System.out.println(dot.substring(0,l)+n.getNodeName()+":"+v);
    NodeList c = n.getChildNodes();
    for (int i=0; i<c.getLength(); i++) {
       printText(c.item(i),l+1);
    }
   }
}

Compile and run the example program, DomXmlParser.java:

>\fyicenter\jdk-1.8.0\bin\javac DomXmlParser.java

>\fyicenter\jdk-1.8.0\bin\java DomXmlParser user.xml

Implementation class:
   com.sun.org.apache.xerces.internal.dom.DeferredDocumentImpl

DOM object elements and text contents:
.User:
..#text:

..ID:
...#text:101
..#text:

..BirthDate:
...#text:1970-01-01+00:01
..#text:

..Name:
...#text:Frank Y. Ivy
..#text:

..Sex:
...#text:Male
..#text:

Note that whitespaces between elements are also parsed as TextNode objects. See the next tutorial on how to handle whitespaces.

⇒ DomXmlParserWhitespace.java - Parse XML File without Whitespaces

⇐ DomDocumentTree.java - Build DOM Document Tree

⇑ Using XML DOM API with Apache Xerces

⇑⇑ FAQ for Apache Xerces XML Parser