Modify XML file in Java (DOM Parser) With Examples

Modify XML File in Java

Let’s say we have below source XML file. We will learn how to modify or edit this XML file in java program using DOM parser.

employee.xml


&lt;?xml version="1.0" encoding="UTF-8" standalone="no"?&gt;
&lt;Employees&gt;
	&lt;Employee id="1"&gt;
		&lt;name&gt;Pankaj&lt;/name&gt;
		&lt;age&gt;29&lt;/age&gt;
		&lt;role&gt;Java Developer&lt;/role&gt;
		&lt;gender&gt;Male&lt;/gender&gt;
	&lt;/Employee&gt;
	&lt;Employee id="2"&gt;
		&lt;name&gt;Lisa&lt;/name&gt;
		&lt;age&gt;35&lt;/age&gt;
		&lt;role&gt;CSS Developer&lt;/role&gt;
		&lt;gender&gt;Female&lt;/gender&gt;
	&lt;/Employee&gt;
&lt;/Employees&gt;

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

<name>Pankaj</name>

<role>Java Developer</role>

</Employee>

<role>CSS Developer</role>

<gender>Female</gender>

</Employee>

</Employees>

We will edit the XML file with below changes.

Update the “id” attribute value for all the Employee based on Gender. For Male, id will be prefixed with “M” else prefix with “F”.
Update the value of “name” element by making it to upper case.
Delete “gender” element as it’s not used now.
Add a new element “salary” to all the employee node in the xml.

Once we make above modification to the XML, we will save it to a different file.

Here is the java program that does all the above updates using DOM Parser.

ModifyXMLDOM.java


package com.journaldev.xml;
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.OutputKeys;
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.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
public class ModifyXMLDOM {
    public static void main(String[] args) {
        String filePath = "employee.xml";
        File xmlFile = new File(filePath);
        DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder dBuilder;
        try {
            dBuilder = dbFactory.newDocumentBuilder();
            Document doc = dBuilder.parse(xmlFile);
            doc.getDocumentElement().normalize();
            //update attribute value
            updateAttributeValue(doc);
            //update Element value
            updateElementValue(doc);
            //delete element
            deleteElement(doc);
            //add new element
            addElement(doc);
            //write the updated document to file or console
            doc.getDocumentElement().normalize();
            TransformerFactory transformerFactory = TransformerFactory.newInstance();
            Transformer transformer = transformerFactory.newTransformer();
            DOMSource source = new DOMSource(doc);
            StreamResult result = new StreamResult(new File("employee_updated.xml"));
            transformer.setOutputProperty(OutputKeys.INDENT, "yes");
            transformer.transform(source, result);
            System.out.println("XML file updated successfully");
        } catch (SAXException | ParserConfigurationException | IOException | TransformerException e1) {
            e1.printStackTrace();
        }
    }
    private static void addElement(Document doc) {
        NodeList employees = doc.getElementsByTagName("Employee");
        Element emp = null;
        //loop for each employee
        for(int i=0; i&lt;employees.getLength();i++){
            emp = (Element) employees.item(i);
            Element salaryElement = doc.createElement("salary");
            salaryElement.appendChild(doc.createTextNode("10000"));
            emp.appendChild(salaryElement);
        }
    }
    private static void deleteElement(Document doc) {
        NodeList employees = doc.getElementsByTagName("Employee");
        Element emp = null;
        //loop for each employee
        for(int i=0; i&lt;employees.getLength();i++){
            emp = (Element) employees.item(i);
            Node genderNode = emp.getElementsByTagName("gender").item(0);
            emp.removeChild(genderNode);
        }
    }
    private static void updateElementValue(Document doc) {
        NodeList employees = doc.getElementsByTagName("Employee");
        Element emp = null;
        //loop for each employee
        for(int i=0; i&lt;employees.getLength();i++){
            emp = (Element) employees.item(i);
            Node name = emp.getElementsByTagName("name").item(0).getFirstChild();
            name.setNodeValue(name.getNodeValue().toUpperCase());
        }
    }
    private static void updateAttributeValue(Document doc) {
        NodeList employees = doc.getElementsByTagName("Employee");
        Element emp = null;
        //loop for each employee
        for(int i=0; i&lt;employees.getLength();i++){
            emp = (Element) employees.item(i);
            String gender = emp.getElementsByTagName("gender").item(0).getFirstChild().getNodeValue();
            if(gender.equalsIgnoreCase("male")){
                //prefix id attribute with M
                emp.setAttribute("id", "M"+emp.getAttribute("id"));
            }else{
                //prefix id attribute with F
                emp.setAttribute("id", "F"+emp.getAttribute("id"));
            }
        }
    }
}

package com.journaldev.xml;

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.OutputKeys;

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.Node;

import org.w3c.dom.NodeList;

import org.xml.sax.SAXException;

public class ModifyXMLDOM {

public static void main(String[] args) {

String filePath = "employee.xml";

File xmlFile = new File(filePath);

DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();

DocumentBuilder dBuilder;

try {

dBuilder = dbFactory.newDocumentBuilder();

Document doc = dBuilder.parse(xmlFile);

doc.getDocumentElement().normalize();

//update attribute value

updateAttributeValue(doc);

//update Element value

updateElementValue(doc);

//delete element

deleteElement(doc);

//add new element

addElement(doc);

//write the updated document to file or console

doc.getDocumentElement().normalize();

TransformerFactory transformerFactory = TransformerFactory.newInstance();

Transformer transformer = transformerFactory.newTransformer();

DOMSource source = new DOMSource(doc);

StreamResult result = new StreamResult(new File("employee_updated.xml"));

transformer.setOutputProperty(OutputKeys.INDENT, "yes");

transformer.transform(source, result);

System.out.println("XML file updated successfully");

} catch (SAXException | ParserConfigurationException | IOException | TransformerException e1) {

e1.printStackTrace();

}

private static void addElement(Document doc) {

NodeList employees = doc.getElementsByTagName("Employee");

Element emp = null;

//loop for each employee

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

emp = (Element) employees.item(i);

Element salaryElement = doc.createElement("salary");

salaryElement.appendChild(doc.createTextNode("10000"));

emp.appendChild(salaryElement);

}

private static void deleteElement(Document doc) {

NodeList employees = doc.getElementsByTagName("Employee");

Element emp = null;

//loop for each employee

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

emp = (Element) employees.item(i);

Node genderNode = emp.getElementsByTagName("gender").item(0);

emp.removeChild(genderNode);

}

private static void updateElementValue(Document doc) {

NodeList employees = doc.getElementsByTagName("Employee");

Element emp = null;

//loop for each employee

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

emp = (Element) employees.item(i);

Node name = emp.getElementsByTagName("name").item(0).getFirstChild();

name.setNodeValue(name.getNodeValue().toUpperCase());

}

private static void updateAttributeValue(Document doc) {

NodeList employees = doc.getElementsByTagName("Employee");

Element emp = null;

//loop for each employee

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

emp = (Element) employees.item(i);

String gender = emp.getElementsByTagName("gender").item(0).getFirstChild().getNodeValue();

if(gender.equalsIgnoreCase("male")){

//prefix id attribute with M

emp.setAttribute("id", "M"+emp.getAttribute("id"));

}else{

//prefix id attribute with F

emp.setAttribute("id", "F"+emp.getAttribute("id"));

}

Output modified version of the XML file from above program is given below.

employee_updated.xml

<span style="color: #008000;"><strong><code>
&lt;?xml version="1.0" encoding="UTF-8" standalone="no"?&gt;
&lt;Employees&gt;
	&lt;Employee id="M1"&gt;
		&lt;name&gt;PANKAJ&lt;/name&gt;
		&lt;age&gt;29&lt;/age&gt;
		&lt;role&gt;Java Developer&lt;/role&gt;
	&lt;salary&gt;10000&lt;/salary&gt;
&lt;/Employee&gt;
	&lt;Employee id="F2"&gt;
		&lt;name&gt;LISA&lt;/name&gt;
		&lt;age&gt;35&lt;/age&gt;
		&lt;role&gt;CSS Developer&lt;/role&gt;
	&lt;salary&gt;10000&lt;/salary&gt;
&lt;/Employee&gt;
&lt;/Employees&gt;
</code></strong></span>

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

<name>PANKAJ</name>

<role>Java Developer</role>

</Employee>

<role>CSS Developer</role>

</Employee>

</Employees>

</code></strong></span>

That’s all for a quick example of java edit XML file using DOM parser.

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Modify XML file in Java (DOM Parser) With Examples

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