<students> 
  <student id="1"> 
    <name>张三</name>  
    <gender>男</gender>  
    <grade>计算机一班</grade>  
    <address>广州</address> 
  </student>  
  <student id="2"> 
    <name>王甜甜</name>  
    <gender>男</gender>  
    <grade>计算机一班</grade>  
    <address>广州</address> 
  </student> 
</students>

		Document doc= DocumentHelper.createDocument();
		Element root =doc.addElement("students");
		Element student1=   root.addElement("student").addAttribute("id", "1");
		student1.addElement("name").setText("张三");
		student1.addElement("gender").setText("男");
		student1.addElement("grade").setText("计算机一班");
		student1.addElement("address").setText("广州");
		
		Element studentElem2 = root.addElement("Student");
		//2.2 增加属性
		studentElem2.addAttribute("id", "2");
		//2.3 增加标签，同时设置文本
		studentElem2.addElement("name").setText("李四");
		studentElem2.addElement("gender").setText("女");
		studentElem2.addElement("grade").setText("计算机2班");
		studentElem2.addElement("address").setText("广州越秀");
		
		FileOutputStream  out= new FileOutputStream("e:/student.xml");
		OutputFormat format= OutputFormat.createPrettyPrint();
		format.setEncoding("utf-8");
		XMLWriter  writer= new XMLWriter(out, format);
		writer.write(doc);
		writer.close();

 1         //1.查询到id为2的学生并修改 该名学生！
 2         Document doc = new SAXReader().read(new File("e:/student.xml"));        
 3         Element root = doc.getRootElement();
 4         Iterator<Element> it = root.elementIterator();
 5 
 6            while(it.hasNext()) {
 7                   Element e = it.next();
 8                   if(e.attributeValue("id").equals("2")){
 9             
10                       e.element("name").setText("王甜甜");
11                     break;
12                 }
13            }
14 
15         //3.1 输出位置
16         FileOutputStream out = new FileOutputStream("e:/student.xml");
17         //3.2 指定格式
18         OutputFormat format = OutputFormat.createPrettyPrint();
19         // 设置编码
20         format.setEncoding("utf-8");
21         XMLWriter writer = new XMLWriter(out,format);
22         //3.3 写出内容
23         writer.write(doc);
24         //3.4关闭资源
25         writer.close();
26     }

 1         Document doc = new SAXReader().read(new File("e:/student.xml"));        
 2         Element root = doc.getRootElement();
 3         Iterator<Element> it = root.elementIterator("student");
 4 
 5            while(it.hasNext()) {
 6                   Element e = it.next();
 7                   if(e.attributeValue("id").equals("2")){
 8             
 9                       e.element("name").setText("王ba");
10                     break;
11                 }
12            }