//首先要下载dom4j.jar
//示例1
package dom4jdemo;
import java.io.File;
import java.io.FileInputStream;
import java.io.StringBufferInputStream;
import java.util.List;

import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.Node;
import org.dom4j.io.SAXReader;
public class Dom4jParseDemo {

 public static void main(String[] args) {
     String xml="";
  xml+="<?xml version=\"1.0\" encoding=\"UTF-8\"?>";
  xml+="<root>";
  xml+="<users userId=\"1\">";
  xml+="<username>admin</username>";
  xml+="<password>111</password>";
  xml+="<quanxian>0</quanxian>";
  xml+="<underling><name>under1</name></underling>";
  xml+="</users>";
  
  xml+="<users userId=\"2\">";
  xml+="<username>hehe</username>";
  xml+="<password>张三</password>";
  xml+="<quanxian>1</quanxian>";
  xml+="<underling><name>under1</name></underling>";
  xml+="</users>";
  
  xml+="<users userId=\"3\">";
  xml+="<username>李鹏</username>";
  xml+="<password>111</password>";
  xml+="<quanxian>2</quanxian>";
  xml+="<underling><name>under1</name></underling>";
  xml+="</users>";
  
  xml+="<users userId=\"4\">";
  xml+="<username>java</username>";
  xml+="<password>111</password>";
  xml+="<quanxian>1</quanxian>";
  xml+="<underling><name>under1</name></underling>";
  xml+="</users>";
  xml+="</root>";
  SAXReader saxReader = new SAXReader();
  try {
   //File file=new File("C:\\test.xml");
   //FileInputStream in=new FileInputStream(file);
   //Document document = saxReader.read(in);//从文件流读入xml数据
   StringBufferInputStream strInStream=new StringBufferInputStream(xml);
   Document document = saxReader.read(strInStream);//从STRING对象读入XML数据
   Element root = document.getRootElement();
   List listUsers=root.selectNodes("users");
   for(int i=0;i<listUsers.size();i++){
    Element eleUser=(Element)listUsers.get(i);
    Node nodeUsername=eleUser.selectSingleNode("username");
    Node nodePassword=eleUser.selectSingleNode("password");
    
    System.err.println("username:"+nodeUsername.getText());
    System.err.println("password:"+nodeUsername.getText());
    
    //System.err.println("username:"+nodeUsername.getStringValue());
    //System.err.println("password:"+nodePassword.getStringValue());
   }
  } catch (Exception e) {
   e.printStackTrace();
  }
 }
}
 //示例2
package dom4jdemo;

import java.io.File;
import java.io.FileWriter;
import java.util.Iterator;
import java.util.List;

import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;

import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;

public class Dom4jUpdateDemo {

    public int createXMLFile(String filename){

       /** 返回操作结果, 0表失败, 1表成功 */