DOM 操作XML(CRUD)

<?xml version="1.0" encoding="UTF-8" standalone="no"?><书架>
	<书>
		<书名 name="dddd">C语言程序设计</书名>
		<作者>张孝祥</作者>
		<售价>40</售价>
	</书>
	<书>
		<书名>C++教程</书名>
		<作者>自己</作者>
		<售价>50</售价>
	</书>
</书架>

　　

package com.gbx.it;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.StreamCorruptedException;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Result;
import javax.xml.transform.Source;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
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.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

public class XMLDemo {
	public String path = "src/book.xml";
	/*
	 * 获得指定的Document
	 */
	public Document getDocument() throws ParserConfigurationException, SAXException, IOException {
		//1: 获得dom解析工厂
		DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
		//2：获得dom解析
		DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
		//获得Document
		Document document = documentBuilder.parse(path);

		return document;
	}
	/*
	 * 将XML文件由内存写入硬盘
	 */
	public void refreshXML(Source xmlSource, Result outputTarget) throws TransformerException {
		TransformerFactory factory = TransformerFactory.newInstance();
		Transformer transformer = factory.newTransformer();
		transformer.transform(xmlSource, outputTarget);
	}
	//   ----------R------------------
	/*
	 * 遍历DOM树
	 */
	@Test
	public void read1() throws ParserConfigurationException, SAXException, IOException {
		Document document = getDocument();
		NodeList nodeList = document.getElementsByTagName("书架");
		for (int i = 0; i < nodeList.getLength(); ++i) {
			listNodes(nodeList.item(i));
		}
	}
	private void listNodes(Node item) {
		if (item instanceof Element) {
			System.out.println(item.getNodeName());
		}
		NodeList nodeList = item.getChildNodes();
		for (int i = 0; i < nodeList.getLength(); ++i) {
			listNodes(nodeList.item(i));
		}
	}
	/*
	 * 读取标签内的内容 <书名 name="dddd">java web就业</书名>
	 */
	@Test
	public void read2() throws ParserConfigurationException, SAXException, IOException {
		Document document = getDocument();
		Element book = (Element) document.getElementsByTagName("书名").item(0);
		String value = book.getTextContent();
		System.out.println("书名: " + value);
	}
	/*
	 * 读取标签的属性
	 */
	@Test
	public void read3() throws ParserConfigurationException, SAXException, IOException {
		Document document = getDocument();
		Element book = (Element) document.getElementsByTagName("书名").item(0);
		if (book.hasAttributes()) {
			NamedNodeMap nodeMap = book.getAttributes();
			for (int i = 0; i < nodeMap.getLength(); ++i) {
				String attrName = nodeMap.item(i).getNodeName();
				String attrValue = nodeMap.item(i).getNodeValue();
				System.out.println("name ： " + attrName + " value :" + attrValue);
			}
		}

		String value = book.getAttribute("name");
		System.out.println(value);
	}
	// ----------------C-------------------

	/*
	 * 添加标签  C
	 */
	//在指定标签的最后边添加标签
	@Test
	public void add1() throws ParserConfigurationException, SAXException, IOException, TransformerException {
		Document document = getDocument();
		Element book = (Element) document.getElementsByTagName("书").item(0);
		Element newChild = document.createElement("你行");
		newChild.setTextContent("嘿嘿");
		book.appendChild(newChild);

		refreshXML(new DOMSource(document), new StreamResult(new FileOutputStream(path)));
	}
	//在指定标签的指定位置添加标签
	@Test
	public void add2() throws ParserConfigurationException, SAXException, IOException, TransformerException {
		Document document = getDocument();
		Element book = (Element) document.getElementsByTagName("书").item(0);

		Element newChild = document.createElement("你行");
		newChild.setTextContent("嘿嘿");

		Element refChild = (Element) document.getElementsByTagName("售价").item(0);

		book.insertBefore(newChild, refChild);

		refreshXML(new DOMSource(document), new StreamResult(new FileOutputStream(path)));
	}
	//添加属性
	@Test
	public void add3() throws ParserConfigurationException, SAXException, IOException, TransformerException {
		Document document = getDocument();

		Element e = (Element) document.getElementsByTagName("售价").item(0);
		e.setAttribute("value", "RMB");
		refreshXML(new DOMSource(document), new StreamResult(new FileOutputStream(path)));
	}
	//----------------D----------------
	//删除标签
	@Test
	public void delElement() throws ParserConfigurationException, SAXException, IOException, TransformerException {
		Document document = getDocument();
		Element element = (Element) document.getElementsByTagName("你行").item(0);
		element.getParentNode().removeChild(element);
		refreshXML(new DOMSource(document), new StreamResult(new FileOutputStream(path)));
	}
	//删除标签的属性

	@Test
	public void delAttr() throws ParserConfigurationException, SAXException, IOException, TransformerException {
		Document document = getDocument();
		Element element = (Element) document.getElementsByTagName("售价").item(0);
		element.removeAttribute("value");
		refreshXML(new DOMSource(document), new StreamResult(new FileOutputStream(path)));
	}
	//-------------U------------
	@Test
	public void update() throws ParserConfigurationException, SAXException, IOException, TransformerException {
		Document document = getDocument();
		Element element = (Element) document.getElementsByTagName("书名").item(0);
		element.setTextContent("C语言程序设计");
		refreshXML(new DOMSource(document), new StreamResult(new FileOutputStream(path)));
	}
}

　　

参考：方立勋老师视频