<?xml version="1.0" encoding="UTF-8"?><books> <book> <name>哈里波特</name> <price>10</price> <memo>这是一本很好看的书。</memo> </book> <book id="B02"> <name>三国演义</name> <price>10</price> <memo>四大名著之一。</memo> </book> <book id="B03"> <name>水浒</name> <price>6</price> <memo>四大名著之一。</memo> </book> <book id="B04"> <name>红楼</name> <price>5</price> <memo>四大名著之一。</memo> </book></books>
import java.io.File;import java.io.FileOutputStream;import org.w3c.dom.*;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 { public static void main(String[] args) { DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); Element theBook = null, theElem = null, root = null; try { factory.setIgnoringElementContentWhitespace(true); DocumentBuilder db = factory.newDocumentBuilder(); Document xmldoc = (Document) db.parse(new File("Test.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("Test1_Edited.xml", xmldoc); } catch (Exception e) { e.printStackTrace(); } } /** * 将node的XML字符串输出到控制台 * * @param node */ public static void output(Node node) { 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 (Exception e) { e.printStackTrace(); } } /** * 查找节点，并返回第一个符合条件节点 * * @param express * @param source * @return */ public static Node selectSingleNode(String express, Object source) { 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; } /** * 查找节点，返回符合条件的节点集。 * @param express * @param source * @return */ public static NodeList selectNodes(String express, Object source) { 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; } /** * 将Document输出到文件 * @param fileName * @param doc */ public static void saveXml(String fileName, Document doc) { 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 (Exception e) { e.printStackTrace(); } }} 
