WEB 页面轮播图随机出5张图

package cn.itcast.xml.dom; import java.io.File; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.transform.Result; import javax.xml.transform.Source; 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.NodeList; public class Demo2 { //dom是否将空白字符当作一个有效的元素对待 public static void main(String[] args) throws Exception{ Document document = getDocument(); Element rootElement = document.getDocumentElement(); NodeList nodeList = rootElement.getChildNodes(); System.out.println("共有" + nodeList.getLength()+"个直接元素"); } @Test public void create() throws Exception{ Document document = getDocument(); Element newCarElement = document.createElement("汽车"); newCarElement.setTextContent("我的汽车"); Element rootElement = document.getDocumentElement(); //rootElement.appendChild(newCarElement); rootElement.insertBefore( newCarElement, rootElement.getElementsByTagName("汽车").item(1)); write2xml(document); } @Test public void update() throws Exception{ Document document = getDocument(); Element secondCarElement = (Element) document.getElementsByTagName("汽车").item(1); secondCarElement.getElementsByTagName("产地").item(0).setTextContent("深圳"); secondCarElement.getElementsByTagName("车牌").item(0).getAttributes().getNamedItem("出产时间").setTextContent("2012年"); write2xml(document); } @Test public void delete() throws Exception{ Document document = getDocument(); Element rootElement = document.getDocumentElement(); Element secondCarElement = (Element) rootElement.getElementsByTagName("汽车").item(1); rootElement.removeChild(secondCarElement); write2xml(document); } private void write2xml(Document document)throws Exception { //将内存中的document对象写到外存的xml文件 TransformerFactory tf = TransformerFactory.newInstance(); Transformer transformer = tf.newTransformer(); //源 Source source = new DOMSource(document); //目 Result result = new StreamResult(new File("src/cn/itcast/xml/dom/car.xml")); transformer.transform(source,result); } private static Document getDocument() throws Exception { DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); //设置dom解析器将空白字符过滤 factory.setIgnoringElementContentWhitespace(true); DocumentBuilder domParser = factory.newDocumentBuilder(); Document document = domParser.parse(new File("src/cn/itcast/xml/dom/car.xml")); return document; } }