Modify XML File in Java using DOM parser

In this tutorial we show how can you read and modify the contents of an XML File using a DOM parser.

• We are going to use Document.getElementsByTagName() to get the elements of the document with specific tag name.
• Use Node.getAttributes() to get a NamedNodeMap of the element’s attributes.
• Use NamedNodeMap.getNamedItem to get a specific attributes by name.
• Use Node.setTextContent() to set the value of that specific attributes.
• Use Node.removeChild or Node.addChild in order to remove or add a new property for the specific element.

You download the jar file named as jdom-2.0.4.jar

/*

 * Author : Rajkumar Sahoo

 * */

package Pack;

import java.io.File;

import java.io.IOException;

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.parsers.ParserConfigurationException;

import javax.xml.transform.Transformer;

import javax.xml.transform.TransformerException;

import javax.xml.transform.TransformerFactory;

import javax.xml.transform.dom.DOMSource;

import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Document;

import org.w3c.dom.Element;

import org.w3c.dom.NamedNodeMap;

import org.w3c.dom.Node;

import org.w3c.dom.NodeList;

import org.xml.sax.SAXException;

public class ReadAndModifyXMLFile {

public static final String xmlFilePath = "D:\\employees.xml";

public static void main(String argv[]) {

try {

DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();

DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();

Document document = documentBuilder.parse(xmlFilePath);

// Get employee by tag name

//use item(0) to get the first node with tage name "employee"

Node employee = document.getElementsByTagName("employee").item(0);

System.out.println("employee :"+employee);

// update employee , set the id to 10

NamedNodeMap attribute = employee.getAttributes();

Node nodeAttr = attribute.getNamedItem("id");

nodeAttr.setTextContent("2");

// append a new node to the first employee

Element address = document.createElement("address");

address.appendChild(document.createTextNode("Noida sec-62"));

employee.appendChild(address);

// loop the employee node and update salary value, and delete a node

NodeList nodes = employee.getChildNodes();

for (int i = 0; i < nodes.getLength(); i++) {

Node element = nodes.item(i);

if ("salary".equals(element.getNodeName())) {

element.setTextContent("20000");

}

// remove firstname

if ("firstname".equals(element.getNodeName())) {

employee.removeChild(element);

}

}

// write the DOM object to the file

TransformerFactory transformerFactory = TransformerFactory.newInstance();

Transformer transformer = transformerFactory.newTransformer();

DOMSource domSource = new DOMSource(document);

StreamResult streamResult = new StreamResult(new File(xmlFilePath));

transformer.transform(domSource, streamResult);

System.out.println("The XML File was ");

} catch (ParserConfigurationException pce) {

pce.printStackTrace();

} catch (TransformerException tfe) {

tfe.printStackTrace();

} catch (IOException ioe) {

ioe.printStackTrace();

} catch (SAXException sae) {

sae.printStackTrace();

}

}

}