DOM 操作XML(CRUD)

时间：2023-11-19 17:34:56
<?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

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