Parsing / Reading XML file in Java.

While working on a small requirement, I had to write a small piece of code that can parse an XML file in Java. Although there are number of libraries available in Java which does this task efficiently, I ended up in using normal Java XML parsing using org.w3c.dom parser.

You may want to copy this code and customize it to your to fit it for your need.

Following is the sample XML file that I used.

XML File

<?xml version="1.0"?>
<students>
	<student>
		<name>John</name>
		<grade>B</grade>
		<age>12</age>
	</student>
	<student>
		<name>Mary</name>
		<grade>A</grade>
		<age>11</age>
	</student>
	<student>
		<name>Simon</name>
		<grade>A</grade>
		<age>18</age>
	</student>
</students>

Source Code of XML Parser

Following is the source code of sample XML parser in Java that I used to parse sample XML file.

package net.viralpatel.java.xmlparser;

import java.io.File;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

public class XMLParser {

	public void getAllUserNames(String fileName) {
		try {
			DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
			DocumentBuilder db = dbf.newDocumentBuilder();
			File file = new File(fileName);
			if (file.exists()) {
				Document doc = db.parse(file);
				Element docEle = doc.getDocumentElement();

				// Print root element of the document
				System.out.println("Root element of the document: "
						+ docEle.getNodeName());

				NodeList studentList = docEle.getElementsByTagName("student");

				// Print total student elements in document
				System.out
						.println("Total students: " + studentList.getLength());

				if (studentList != null && studentList.getLength() > 0) {
					for (int i = 0; i < studentList.getLength(); i++) {

						Node node = studentList.item(i);

						if (node.getNodeType() == Node.ELEMENT_NODE) {

							System.out
									.println("=====================");

							Element e = (Element) node;
							NodeList nodeList = e.getElementsByTagName("name");
							System.out.println("Name: "
									+ nodeList.item(0).getChildNodes().item(0)
											.getNodeValue());

							nodeList = e.getElementsByTagName("grade");
							System.out.println("Grade: "
									+ nodeList.item(0).getChildNodes().item(0)
											.getNodeValue());

							nodeList = e.getElementsByTagName("age");
							System.out.println("Age: "
									+ nodeList.item(0).getChildNodes().item(0)
											.getNodeValue());
						}
					}
				} else {
					System.exit(1);
				}
			}
		} catch (Exception e) {
			System.out.println(e);
		}
	}
	public static void main(String[] args) {

		XMLParser parser = new XMLParser();
		parser.getAllUserNames("c:\\test.xml");
	}
}

Following is the output of our XML parser.

Program Output

Root element of the document: students
Total students: 3
==============================
Name: John
Grade: B
Age: 12
==============================
Name: Mary
Grade: A
Age: 11
==============================
Name: Simon
Grade: A
Age: 18

You can customize this code for your input XML file.