DOM解析方式也可用於修改XML資料，我們可以使用它完成新增元素、刪除元素、修改元素值、修改元素屬性等操作。
我們的XML檔案，內容如下：
employee.xml

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

我們將修改XML檔案的內容：
1.根據員工的性別（gender）修改”id”屬性值，性別為男（Male)的id屬性值中追加”M”，為女（Female)的id屬性值追加”F”。
2.修改name元素的值，全部變成大寫。
3.”gender”元素已經沒有存在的意義了，我們刪除它。
4.在employee節點下新增一個”salary”節點。
當我們完成上述操作後，將內容儲存在一個新的xml檔案中。
下面是使用DOM方式解析的Java程式程式碼：
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<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"));
            }
        }
    }

}

輸出xml檔案內容：
employee_updated.xml

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<Employees>
    <Employee id="M1">
        <name>PANKAJ</name>
        <age>29</age>
        <role>Java Developer</role>

    <salary>10000</salary>
</Employee>
    <Employee id="F2">
        <name>LISA</name>
        <age>35</age>
        <role>CSS Developer</role>

    <salary>10000</salary>
</Employee>
</Employees>