DOM操作XML

XML文件信息： 

JAVA代码：

package action;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

import org.w3c.dom.*;
import org.xml.sax.SAXException;

import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.*;
import javax.xml.xpath.*;

public class Test {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
		Element theBook = null, theElem = null, root = null;
		try {
			factory.setIgnoringElementContentWhitespace(true);

			DocumentBuilder db = factory.newDocumentBuilder();
			Document xmldoc = db.parse(new File("D:" + File.separator + "mldnwebdemo"
					+ File.separator + "test1.xml"));
			root = xmldoc.getDocumentElement();

			// --- 新建一本书开始 ----
			theBook = xmldoc.createElement("book");
			theElem = xmldoc.createElement("name");
			theElem.setTextContent("新书");
			theBook.appendChild(theElem);

			theElem = xmldoc.createElement("price");
			theElem.setTextContent("20");
			theBook.appendChild(theElem);

			theElem = xmldoc.createElement("memo");
			theElem.setTextContent("新书的更好看。");
			theBook.appendChild(theElem);
			root.appendChild(theBook);
			System.out.println("--- 新建一本书开始 ----");
			output(xmldoc);
			// --- 新建一本书完成 ----

			// --- 下面对《哈里波特》做一些修改。 ----
			// --- 查询找《哈里波特》----
			theBook = (Element) selectSingleNode("/books/book[name='哈里波特']",
					root);
			System.out.println("--- 查询找《哈里波特》 ----");
			output(theBook);
			// --- 此时修改这本书的价格 -----
			theBook.getElementsByTagName("price").item(0).setTextContent("15");// getElementsByTagName返回的是NodeList，所以要跟上item(0)。另外，getElementsByTagName("price")相当于xpath的".//price"。
			System.out.println("--- 此时修改这本书的价格 ----");
			output(theBook);
			// --- 另外还想加一个属性id，值为B01 ----
			theBook.setAttribute("id", "B01");
			System.out.println("--- 另外还想加一个属性id，值为B01 ----");
			output(theBook);
			// --- 对《哈里波特》修改完成。 ----

			// --- 要用id属性删除《三国演义》这本书 ----
			theBook = (Element) selectSingleNode("/books/book[@id='B02']", root);
			System.out.println("--- 要用id属性删除《三国演义》这本书 ----");
			output(theBook);
			theBook.getParentNode().removeChild(theBook);
			System.out.println("--- 删除后的ＸＭＬ ----");
			output(xmldoc);

			// --- 再将所有价格低于10的书删除 ----
			NodeList someBooks = selectNodes("/books/book[price<10]", root);
			System.out.println("--- 再将所有价格低于10的书删除 ---");
			System.out.println("--- 符合条件的书有　" + someBooks.getLength()
					+ "本。 ---");
			for (int i = 0; i < someBooks.getLength(); i++) {
				someBooks.item(i).getParentNode()
						.removeChild(someBooks.item(i));
			}
			output(xmldoc);

			saveXml("D:" + File.separator + "mldnwebdemo"
					+ File.separator + "Test1_Edited.xml", xmldoc);
		} catch (ParserConfigurationException e) {
			e.printStackTrace();
		} catch (SAXException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	public static void output(Node node) {// 将node的XML字符串输出到控制台
		TransformerFactory transFactory = TransformerFactory.newInstance();
		try {
			Transformer transformer = transFactory.newTransformer();
			transformer.setOutputProperty("encoding", "gb2312");
			transformer.setOutputProperty("indent", "yes");

			DOMSource source = new DOMSource();
			source.setNode(node);
			StreamResult result = new StreamResult();
			result.setOutputStream(System.out);

			transformer.transform(source, result);
		} catch (TransformerConfigurationException e) {
			e.printStackTrace();
		} catch (TransformerException e) {
			e.printStackTrace();
		}
	}

	public static Node selectSingleNode(String express, Object source) {// 查找节点，并返回第一个符合条件节点
		Node result = null;
		XPathFactory xpathFactory = XPathFactory.newInstance();
		XPath xpath = xpathFactory.newXPath();
		try {
			result = (Node) xpath
					.evaluate(express, source, XPathConstants.NODE);
		} catch (XPathExpressionException e) {
			e.printStackTrace();
		}

		return result;
	}

	public static NodeList selectNodes(String express, Object source) {// 查找节点，返回符合条件的节点集。
		NodeList result = null;
		XPathFactory xpathFactory = XPathFactory.newInstance();
		XPath xpath = xpathFactory.newXPath();
		try {
			result = (NodeList) xpath.evaluate(express, source,
					XPathConstants.NODESET);
		} catch (XPathExpressionException e) {
			e.printStackTrace();
		}

		return result;
	}

	public static void saveXml(String fileName, Document doc) {// 将Document输出到文件
		TransformerFactory transFactory = TransformerFactory.newInstance();
		try {
			Transformer transformer = transFactory.newTransformer();
			transformer.setOutputProperty("indent", "yes");

			DOMSource source = new DOMSource();
			source.setNode(doc);
			StreamResult result = new StreamResult();
			result.setOutputStream(new FileOutputStream(fileName));

			transformer.transform(source, result);
		} catch (TransformerConfigurationException e) {
			e.printStackTrace();
		} catch (TransformerException e) {
			e.printStackTrace();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		}
	}

}

控制台输出的运行结果：