Java&Xml教程（三）使用DOM方式修改XML文件内容

你的名字 2022-08-18 05:48 185阅读 0赞

DOM解析方式也可用于修改XML数据，我们可以使用它完成新增元素、删除元素、修改元素值、修改元素属性等操作。  
我们的XML文件，内容如下：  
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>

我们将修改XML文件的内容：  
1.根据员工的性别（gender）修改”id”属性值，性别为男（Male)的id属性值中追加”M”，为女（Female)的id属性值追加”F”。  
2.修改name元素的值，全部变成大写。  
3.”gender”元素已经没有存在的意义了，我们删除它。  
4.在employee节点下新增一个”salary”节点。  
当我们完成上述操作后，将内容保存在一个新的xml文件中。  
下面是使用DOM方式解析的Java程序代码：  
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"));
                }
            }
        }
    
    }

输出xml文件内容：  
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>

原文地址：[http://www.journaldev.com/901/how-to-edit-xml-file-in-java-dom-parser][http_www.journaldev.com_901_how-to-edit-xml-file-in-java-dom-parser]

[http_www.journaldev.com_901_how-to-edit-xml-file-in-java-dom-parser]: http://www.journaldev.com/901/how-to-edit-xml-file-in-java-dom-parser