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Demo Example

Here is the input xml file we need to modify −

<?xml version = "1.0" encoding = "UTF-8" standalone = "no"?>
<cars>
   <supercars company = "Ferrari">
      <carname type = "formula one">Ferrari 101</carname>
      <carname type = "sports">Ferrari 202</carname>
   </supercars>
   
   <luxurycars company = "Benteley">
      <carname>Benteley 1</carname>
      <carname>Benteley 2</carname>
      <carname>Benteley 3</carname>
   </luxurycars>
</cars>

ModifyXmlFileDemo.java

package com.adglob.xml;

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

public class ModifyXmlFileDemo {

   public static void main(String argv[]) {

      try {
         File inputFile = new File("input.xml");
         DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
         DocumentBuilder docBuilder = docFactory.newDocumentBuilder();
         Document doc = docBuilder.parse(inputFile);
         Node cars = doc.getFirstChild();
         Node supercar = doc.getElementsByTagName("supercars").item(0);
         
         // update supercar attribute
         NamedNodeMap attr = supercar.getAttributes();
         Node nodeAttr = attr.getNamedItem("company");
         nodeAttr.setTextContent("Lamborigini");

         // loop the supercar child node
         NodeList list = supercar.getChildNodes();
         
         for (int temp = 0; temp < list.getLength(); temp++) {
            Node node = list.item(temp);
            if (node.getNodeType() == Node.ELEMENT_NODE) {
               Element eElement = (Element) node;
               if ("carname".equals(eElement.getNodeName())) {
                  if("Ferrari 101".equals(eElement.getTextContent())) {
                     eElement.setTextContent("Lamborigini 001");
                  }
                  if("Ferrari 202".equals(eElement.getTextContent()))
                     eElement.setTextContent("Lamborigini 002");
               }
            }
         }
         NodeList childNodes = cars.getChildNodes();
         
         for(int count = 0; count < childNodes.getLength(); count++) {
            Node node = childNodes.item(count);
            
            if("luxurycars".equals(node.getNodeName()))
               cars.removeChild(node);
         }

         // write the content on console
         TransformerFactory transformerFactory = TransformerFactory.newInstance();
         Transformer transformer = transformerFactory.newTransformer();
         DOMSource source = new DOMSource(doc);
         System.out.println("-----------Modified File-----------");
         StreamResult consoleResult = new StreamResult(System.out);
         transformer.transform(source, consoleResult);
      } catch (Exception e) {
         e.printStackTrace();
      }
   }
}

This would produce the following result −

-----------Modified File-----------
<?xml version = "1.0" encoding = "UTF-8" standalone = "no"?>

<cars>
   <supercars company = "Lamborigini">
      <carname type = "formula one">Lamborigini 001</carname>
      <carname type = "sports">Lamborigini 002</carname>
   </supercars>
</cars>