public void modifyXmlByDom() {

DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

    dbf.setIgnoringElementContentWhitespace(true);

    String xmlName = System.getProperty("user.dir") + "\\data\\Students.xml";

    try {

        DocumentBuilder db = dbf.newDocumentBuilder();

        Document doc = db.parse(xmlName);

        // 获取根节点

        Element root = doc.getDocumentElement();

        // 利用xpath定位sequence为2的节点

        XPathFactory xpathFactory = XPathFactory.newInstance();

        XPath xpath = xpathFactory.newXPath();

        Element node = (Element)xpath.evaluate(

"/class/student[@sequence='2']", root, XPathConstants.NODE);

        // 将degree节点的内容更改为研究生

        node.getElementsByTagName("degree").item(0).setTextContent("研究生");

        // 保存

        TransformerFactory factory = TransformerFactory.newInstance();

        Transformer former = factory.newTransformer();

        former.transform(new DOMSource(doc), new StreamResult(

new File(xmlName)));

    } catch (Exception e) {

        System.out.println(e.getMessage());

    }

}

// 与修改节点内容类似，只需要对查找到的节点进行删除即可

root.removeChild(node);

package com.woniuxy.java.io;

import java.io.*;

import java.util.Iterator;

import java.util.List;

import org.dom4j.Document;

import org.dom4j.DocumentHelper;

import org.dom4j.Element;

import org.dom4j.io.OutputFormat;

import org.dom4j.io.SAXReader;

import org.dom4j.io.XMLWriter;

public class Dom4JReadWrite {

String xmlFile = System.getProperty("user.dir") + "\\data\\Students.xml";

String xmlFile2 = System.getProperty("user.dir") + "\\data\\Person.xml";

public static void main(String[] args) {

Dom4JReadWrite d4j = new Dom4JReadWrite();

// d4j.readXml();

// d4j.createXml();

// d4j.modifyXml();

// d4j.deleteXml();

}

// 打开XML文档

public Document getDocument(String fileName) {

SAXReader sr = new SAXReader();

org.dom4j.Document doc = null;

try {

doc = sr.read(new File(fileName));

} catch (Exception e) {

e.printStackTrace();

}

return doc;

}

// 保存XML文档的修改

public void writeToFile(Document doc, String fileName) {

try {

Writer writer = new FileWriter(fileName);

OutputFormat format = OutputFormat.createPrettyPrint();

format.setEncoding("UTF-8");

XMLWriter xmlWriter = new XMLWriter(writer, format);

xmlWriter.write(doc);

xmlWriter.close();

System.out.println("文件写入成功.");

} catch (Exception e) {

e.printStackTrace();

}

}

// 读取XML文档内容

public void readXml() {

Document doc = getDocument(xmlFile);

List nameList = doc.selectNodes("/class/student/name");

List ageList = doc.selectNodes("/class/student/age");

List sexList = doc.selectNodes("/class/student/sex");

for (int i = 0; i < nameList.size(); i++) {

String name = ((Element) nameList.get(i)).getTextTrim();

System.out.println("name = " + name);

String age = ((Element) ageList.get(i)).getTextTrim();

System.out.println("age = " + age);

String sex = ((Element) sexList.get(i)).getTextTrim();

System.out.println("sex = " + sex);

System.out.println("=======================");

}

}

// 新建XML文档

public void createXml() {

Element root = DocumentHelper.createElement("Person");

Document document = DocumentHelper.createDocument(root);

// 给根节点添加属性

root.addAttribute("学校", "南大").addAttribute("位置", "江西");

// 给根节点添加孩子节点

Element element1 = root.addElement("学生");

element1.addElement("姓名").addAttribute("婚姻", "单身")

.addText("小章");

element1.addElement("年龄").addText("21");

Element element2 = root.addElement("学生");

element2.addElement("姓名").addAttribute("婚姻", "单身")

.addText("小红").addElement("爱好").addText("唱歌");

element2.addElement("年龄").addText("22");

// 把生成的xml文档存放在硬盘上, true代表是否换行, "  "代表缩进

OutputFormat format = new OutputFormat("    ", true);

format.setEncoding("UTF-8");// 设置编码格式

try {

XMLWriter xmlWriter = new XMLWriter(

new FileOutputStream(xmlFile2), format);

xmlWriter.write(document);

xmlWriter.close();

} catch (Exception e) {

e.printStackTrace();

}

}

// 修改XML文档 - 通过name查找

public void modifyXml() {

String name = "何国学"; // 通过姓名查找是否存在此节点

String key = "degree"; // 修改何国学的学历 字段

String value = "研究生"; // 修改后的新值

Document doc = getDocument(xmlFile);

List nameList = doc.selectNodes("/class/student/name");

Iterator iterator = nameList.iterator();

while (iterator.hasNext()) {

Element element = (Element) iterator.next();

if (name != null && name.equals(element.getText())) {

Element pe = element.getParent();

List childList = pe.elements();

for (int i = 0; i < childList.size(); i++) {

String nodeName = ((Element) childList.get(i)).getName();

if (key != null && key.equals(nodeName)) {

((Element) childList.get(i)).setText(value);

}

}

}

}

// 将修改写入文件中

this.writeToFile(doc, xmlFile);

}

// 删除或修改指定节点

public void deleteXml() {

try {

SAXReader reader = new SAXReader();

Document doc = reader.read(new File(xmlFile2));

// 获取节点的两种方式

Element node = doc.getRootElement().element("学生").element("姓名");

//  Element node = (Element)doc.selectSingleNode("/Person/学生/姓名/爱好");

//删除节点

node.getParent().remove(node);

// 也可以通过此方式对节点进行更新

// Element node = document.getRootElement().element("学生").element("姓名");

//  node.setText("张三");

// 另外一种

this.writeToFile(doc, xmlFile2);

}

catch (Exception e) {

}

}

}