JDOM解析xml

 <?xml version="1.0" encoding="utf-8" standalone="no"?><书架>
 <书 name="xxxx">
  <售价>109</售价>
  <书名>Java</书名>
  <作者>老张</作者>
 </书>

</书架>

@Test
 public void read() throws Exception{
  
  //1.获取工厂
  DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
  DocumentBuilder builder = factory.newDocumentBuilder();
  Document document = builder.parse(new File("src/book.xml"));
  
  NodeList list = document.getElementsByTagName("售价");
  Node price = list.item(0);
  String value = price.getTextContent();
  System.out.println(value);
 }
 
 //修改结点的值:<售价>39.00元</售价>改为109
 @Test
 public  void update() throws Exception{
  
  DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
  DocumentBuilder  builder = factory.newDocumentBuilder();
  Document document = builder.parse(new File("src/book1.xml"));
  
  Node price = document.getElementsByTagName("售价").item(0);
  price.setTextContent("109");
  
  
  //把内存中的document写到xml文档
  TransformerFactory tf = TransformerFactory.newInstance();
  //得到转换器
  Transformer ts = tf.newTransformer();
  ts.transform(new DOMSource(document), new StreamResult(new File("src/book1.xml")));
 }
 
 
 //向指定节点中增加孩子节点（售价节点）
 @Test
 public void add() throws Exception{
  DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
  DocumentBuilder  builder = factory.newDocumentBuilder();
  Document document = builder.parse(new File("src/book1.xml"));
  
  //创建需要增加的节点
  Node price = document.createElement("售价");
  price.setTextContent("59元");
  
  //得到需要增加的节点的父亲
  Node parent = document.getElementsByTagName("书").item(0);
  
  //把需要增加的节点挂到父结点上
  parent.appendChild(price);
  
  
  TransformerFactory tf = TransformerFactory.newInstance();
  Transformer ts = tf.newTransformer();
  ts.transform(new DOMSource(document), new StreamResult(new File("src/book1.xml")));

 }
 
 //向指定位置上插入售价节点
 @Test
 public void add2() throws Exception{
  DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
  DocumentBuilder  builder = factory.newDocumentBuilder();
  Document document = builder.parse(new File("src/book1.xml"));
  
  Node node = document.createElement("售价");
  node.setTextContent("39元");
  
  Node parent = document.getElementsByTagName("书").item(0);
  parent.insertBefore(node, document.getElementsByTagName("书名").item(0));
  
  TransformerFactory tf = TransformerFactory.newInstance();
  Transformer ts = tf.newTransformer();
  ts.transform(new DOMSource(document), new StreamResult(new File("src/book1.xml")));
 }
 
 //删除xml文档的售价结点
 @Test
 public void delete() throws Exception{
  DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
  DocumentBuilder  builder = factory.newDocumentBuilder();
  Document document = builder.parse(new File("src/book1.xml"));
  
  Node node = document.getElementsByTagName("售价").item(2);
  node.getParentNode().removeChild(node);
  
  TransformerFactory tf = TransformerFactory.newInstance();
  Transformer ts = tf.newTransformer();
  ts.transform(new DOMSource(document), new StreamResult(new File("src/book1.xml")));
 }
 
 //操作xml文档属性
 @Test
 public void updateAttribute() throws Exception{
  DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
  DocumentBuilder  builder = factory.newDocumentBuilder();
  Document document = builder.parse(new File("src/book1.xml"));
  
  
  //操作xml文档的元素时，一般都把元素当作node对象，但是程序员如果发现node不好使时，就应把node强转成相应类型
  Node node  = document.getElementsByTagName("书").item(0);
  Element book = null;
  if(node.getNodeType()==Node.ELEMENT_NODE){  //在作结点转换之前，最好先判断结点类型
   book  = (Element)node;
  }
  
  book.setAttribute("name", "yyyyyyy");
  book.setAttribute("password", "123");
  book.removeAttribute("password");
  
  TransformerFactory tf = TransformerFactory.newInstance();
  Transformer ts = tf.newTransformer();
  ts.transform(new DOMSource(document), new StreamResult(new File("src/book1.xml")));
 }
 
 //遍历
 public static void list(Node node){
  
  if(node.getNodeType()==Node.ELEMENT_NODE){
   System.out.println(node.getNodeName());
  }
  
  NodeList list = node.getChildNodes();
  for(int i=0;i<list.getLength();i++){
   Node child = list.item(i);
   list(child);
  }
 }