//使用 jaxp 对xml文档进行dom解析

 public class Demo2 {

     //必要步骤

     @Test

     public void test() throws Exception {

     //1.创建工厂

         DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

     //2.得到dom解析器

         DocumentBuilder db = dbf.newDocumentBuilder();

     //3.解析XML文档，得到代表文档的Document

         Document d = db.parse("src/com/xml/javaweb/book.xml");

     }

 }

 public class Demo3 {

     //读取XML文件中：<书名>javaWEB</书名>  节点中的值

     @Test

     public void read() throws Exception {

         DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

         DocumentBuilder db = dbf.newDocumentBuilder();

         Document d = db.parse("src/com/xml/javaweb/book.xml");    

         NodeList list = d.getElementsByTagName("书名");

         Node node = list.item(1);

         String text = node.getTextContent();

         System.out.println(text);

     }    

     //遍历整个XML文档中的节点

     @Test

     public void read1() throws Exception {

         DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

         DocumentBuilder db = dbf.newDocumentBuilder();

         Document d = db.parse("src/com/xml/javaweb/book.xml");    

         //得到根节点

         NodeList list = d.getElementsByTagName("书架");

         Node root = list.item(0);

         list(root);

     }

     private void list(Node root) {

         if(root instanceof Element)

         System.out.println(root.getNodeName());

         NodeList nodelist = root.getChildNodes();

         for(int i = 0;i<nodelist.getLength();i++) {

             Node node = nodelist.item(i);

             list(node);

         }

     }

     //拿到 name 属性的值

     @Test

     public void read2() throws Exception {

         DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

         DocumentBuilder db = dbf.newDocumentBuilder();

         Document d = db.parse("src/com/xml/javaweb/book.xml");    

         Element node = (Element) d.getElementsByTagName("书名").item(0);   //node 里面的方法不够用了  没有指定名字得到属性，在知道得到的是Element的情况下  ，把node强转一下

         String att = node.getAttribute("name");

         System.out.println(att);

     }

     //向XML文档中添加节点          <售价>39.00元</售价>

     @Test

     public void add() throws Exception {

         DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

         DocumentBuilder db = dbf.newDocumentBuilder();

         Document d = db.parse("src/com/xml/javaweb/book.xml");    

         //创建节点

         Element element = d.createElement("售价");

         element.setTextContent("39.00元");

         //添加节点

         Node node = d.getElementsByTagName("书").item(0);

         node.appendChild(element);

         //更新XML文档

         TransformerFactory tff = TransformerFactory.newInstance();

         Transformer tf = tff.newTransformer();

         tf.transform(new DOMSource(d), new StreamResult(new FileOutputStream("src/com/xml/javaweb/book.xml")));

     }

     //向XML文档中指定位置添加节点          <售价>39.00元</售价>

     @Test

     public void add2() throws Exception {

         DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

         DocumentBuilder db = dbf.newDocumentBuilder();

         Document d = db.parse("src/com/xml/javaweb/book.xml");    

         //创建节点

         Element element = d.createElement("售价");

         element.setTextContent("29.00元");

         //得到参考节点

         Element ref = (Element) d.getElementsByTagName("售价").item(0);

         //添加节点

         Node node = d.getElementsByTagName("书").item(0);

         //往“书”节点的指定位置插入节点

         node.insertBefore(element, ref);    //在参考节点之前插入新建的节点

         //更新XML文档

         TransformerFactory tff = TransformerFactory.newInstance();

         Transformer tf = tff.newTransformer();

         tf.transform(new DOMSource(d), new StreamResult(new FileOutputStream("src/com/xml/javaweb/book.xml")));

     }

     //向XML文档节点上添加属性         <书名> java就业培训课程</书名> 上添加属性  name = "xxxx"

     @Test

     public void add3() throws Exception {

         DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

         DocumentBuilder db = dbf.newDocumentBuilder();

         Document d = db.parse("src/com/xml/javaweb/book.xml");    

         //得到要添加属性的节点

         Element element= (Element) d.getElementsByTagName("书名").item(0);

         //往指定节点添加属性

         element.setAttribute("name", "xxxx");

         //更新XML文档

         TransformerFactory tff = TransformerFactory.newInstance();

         Transformer tf = tff.newTransformer();

         tf.transform(new DOMSource(d), new StreamResult(new FileOutputStream("src/com/xml/javaweb/book.xml")));

     }

     //删除XML文档节点          <售价>39.00元</售价>

     @Test

     public void delete() throws Exception {

         DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

         DocumentBuilder db = dbf.newDocumentBuilder();

         Document d = db.parse("src/com/xml/javaweb/book.xml");    

         //得到要删除的节点

         Element element= (Element) d.getElementsByTagName("售价").item(1);

         //得到要删除的节点的父节点  再调用父节点中删除子节点的方法

         element.getParentNode().removeChild(element);

         //更新XML文档

         TransformerFactory tff = TransformerFactory.newInstance();

         Transformer tf = tff.newTransformer();

         tf.transform(new DOMSource(d), new StreamResult(new FileOutputStream("src/com/xml/javaweb/book.xml")));

     }

     //更新XML文档节点      <作者>张孝祥</作者> -> <作者>xzk</作者>

     @Test

     public void update() throws Exception {

         DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

         DocumentBuilder db = dbf.newDocumentBuilder();

         Document d = db.parse("src/com/xml/javaweb/book.xml");    

         //得到要更新的节点

         Element element= (Element) d.getElementsByTagName("作者").item(1);

         //更新该节点的文本

         element.setTextContent("xzk");

         //更新XML文档

         TransformerFactory tff = TransformerFactory.newInstance();

         Transformer tf = tff.newTransformer();

         tf.transform(new DOMSource(d), new StreamResult(new FileOutputStream("src/com/xml/javaweb/book.xml")));

     }

 }