使用JAXP对xml文档进行DOM解析基础

 DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();

 DocumentBuilder builder = factory.newDocumentBuilder();

 DocumentBuilder builder = factory.newDocumentBuilder();

<?xml version="1.0" encoding="utf-8" standalone="no"?>
<书架>
    <书 name="xxxx">
        <售价>55元</售价>
        <书名>Java就业培训教程</书名>
        <作者>张孝祥</作者>
    </书>
    <书>
        <书名>JavaScript网页开发</书名>
        <作者>张孝祥</作者>
        <售价>28.00元</售价>
    </书>
</书架>

package wys.jaxp; import java.io.File; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.transform.Transformer; import javax.xml.transform.TransformerFactory; import javax.xml.transform.dom.DOMSource; import javax.xml.transform.stream.StreamResult; import org.junit.Test; import org.w3c.dom.Document; import org.w3c.dom.Element; import org.w3c.dom.Node; import org.w3c.dom.NodeList; public class Demo1 { public static void main(String[] args) throws Exception { // 获取工厂
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); // 产生解析器
        DocumentBuilder builder = factory.newDocumentBuilder(); // 解析xml文档，获取代表文档的document
        Document document = builder.parse(new File("src/xml/book1.xml")); read(document); } // 读取指定节点值
    public static void read(Document document) { NodeList nodelist = document.getElementsByTagName("售价"); Node node = nodelist.item(0); String val = node.getTextContent(); System.out.println(val); } // 更新节点内容
    public static void update() throws Exception { DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); DocumentBuilder builder = factory.newDocumentBuilder(); Document document = builder.parse(new File("src/xml/book1.xml")); // 获取售价节点
        Node price = document.getElementsByTagName("售价").item(0); price.setTextContent("5555元"); TransformerFactory tfactory = TransformerFactory.newInstance(); Transformer tformer = tfactory.newTransformer(); tformer.transform(new DOMSource(document),new StreamResult(new File( "src/xml/book1.xml"))); } // 向指定节点中增加子节点
    public static void add() throws Exception { DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); DocumentBuilder builder = factory.newDocumentBuilder(); Document document = builder.parse(new File("src/xml/book1.xml")); // 创建一个售价节点在内存中
        Node price = document.createElement("售价"); price.setTextContent("1888元"); // 获取要加入位置的父节点
        Node shu = document.getElementsByTagName("书").item(0); // 把需要增加的节点挂到父节点上
 shu.appendChild(price); // 将内存中的document写入xml文件，先用转换工厂得到转换器
        TransformerFactory tf = TransformerFactory.newInstance(); Transformer transformer = tf.newTransformer(); transformer.transform(new DOMSource(document),new StreamResult( new File("src/xml/book1.xml"))); } //向指定位置插入新的节点
 @Test public void add2() throws Exception { DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); DocumentBuilder builder = factory.newDocumentBuilder(); Document document = builder.parse(new File("src/xml/book1.xml")); Node price = document.createElement("售价"); price.setTextContent("指定位置：16元"); // 向指定节点之前插入新节点
        Node shu = document.getElementsByTagName("书").item(0); shu.insertBefore(price,document.getElementsByTagName("书名").item(0)); // 将内存中的document写入xml文件，先用转换工厂得到转换器
        TransformerFactory tf = TransformerFactory.newInstance(); Transformer transformer = tf.newTransformer(); transformer.transform(new DOMSource(document),new StreamResult( new File("src/xml/book1.xml"))); } @Test //删除指定节点
    public void delete() throws Exception { DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); DocumentBuilder builder = factory.newDocumentBuilder(); Document document = builder.parse(new File("src/xml/book1.xml")); // 获取要删除的节点，调用父节点删除（自己不能删除自己）
        Node price = document.getElementsByTagName("售价").item(2); price.getParentNode().removeChild(price); TransformerFactory tf = TransformerFactory.newInstance(); Transformer transformer = tf.newTransformer(); transformer.transform(new DOMSource(document),new StreamResult( new File("src/xml/book1.xml"))); } // 操作xml文档属性
 @Test public void updateAttribute() throws Exception { DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); DocumentBuilder builder = factory.newDocumentBuilder(); Document document = builder.parse(new File("src/xml/book1.xml")); // Element继承自Node,Node没有操作属性的方法，操作节点属性需要强制转换为元素节点
        Element shu = (Element) document.getElementsByTagName("书").item(0); shu.setAttribute("name","yyyyyyy"); shu.setAttribute("password","12345678"); shu.removeAttribute("password"); TransformerFactory tf = TransformerFactory.newInstance(); Transformer transformer = tf.newTransformer(); transformer.transform(new DOMSource(document),new StreamResult( new File("src/xml/book1.xml"))); } }