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Demo Example

Here is the input text file that 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

import java.io.File;
import java.io.IOException;
import java.util.List;

import org.jdom2.Attribute;
import org.jdom2.Document;
import org.jdom2.Element;
import org.jdom2.JDOMException;
import org.jdom2.input.SAXBuilder;
import org.jdom2.output.Format;
import org.jdom2.output.XMLOutputter;


public class ModifyXMLFileDemo {

   public static void main(String[] args) {

      try {
         File inputFile = new File("input.txt");
         SAXBuilder saxBuilder = new SAXBuilder();
         Document document = saxBuilder.build(inputFile);
         Element rootElement = document.getRootElement();

         //get first supercar
         Element supercarElement = rootElement.getChild("supercars");

         // update supercar attribute
         Attribute attribute = supercarElement.getAttribute("company");
         attribute.setValue("Lamborigini");

         // loop the supercar child node
         List<Element> list = supercarElement.getChildren();
         
         for (int temp = 0; temp < list.size(); temp++) {
            Element carElement = list.get(temp);
            
            if("Ferrari 101".equals(carElement.getText())) {
               carElement.setText("Lamborigini 001");
            }
            if("Ferrari 202".equals(carElement.getText())) {
               carElement.setText("Lamborigini 002");
            }
         }

         //get all supercars element
         List<Element> supercarslist = rootElement.getChildren();
         
         for (int temp = 0; temp < supercarslist.size(); temp++) {
            Element tempElement = supercarslist.get(temp);
            
            if("luxurycars".equals(tempElement.getName())) {
               rootElement.removeContent(tempElement);
            }        	 
         }

         XMLOutputter xmlOutput = new XMLOutputter();
   
         // display xml
         xmlOutput.setFormat(Format.getPrettyFormat());
         xmlOutput.output(document, System.out); 
      } catch (JDOMException e) {
         e.printStackTrace();
      } catch (IOException e) {
         e.printStackTrace();
      }
   }
}

This would produce the following result −

<?xml version = "1.0" encoding = "UTF-8"?>
<cars>
   <supercars company = "Lamborigini">
      <carname type = "formula one">Lamborigini 001</carname>
      <carname type = "sports">Lamborigini 002</carname>
   </supercars>
</cars>