package com.tsh.dao;

import java.util.List;

 org.dom4j.Document;
 org.dom4j.DocumentHelper;
 org.dom4j.Element;

 com.tsh.domain.User;
 com.tsh.util.XmlDaoUtil;

public class XmlUserDao {
    /**
     * 根据用户名查找user
     * @param username
     * @return
     */
    public User findUserByUsername(String username){
        Document dom=XmlDaoUtil.getDom();
        Element root=dom.getRootElement();
        //使用XPATH语法
        List<Element> list=root.selectNodes("//user[@username='"+username+"']");
        if(list.size()>0){
            Element userElement=list.get(0);
            String uname=userElement.attributeValue("username");
            String password=userElement.attributeValue("password");
            将用户信息封装到bean
            User user=new User();
            user.setUsername(uname);
            user.setPassword(password);
            user.setPassword_confirm(password);
            return user;
        }
        return null;
    }
    
     * 添加用户
     *  user
     void addUser(User user){
        Document dom=创建<user>元素
        Element userElement=DocumentHelper.createElement("user");
        userElement.setAttributeValue("username",user.getUsername());
        userElement.setAttributeValue("password"挂载到<users>
        root.add(userElement);
        回写到xml文件
        
    }
}

 com.tsh.util;

 java.net.URL;

 org.dom4j.io.SAXReader;

 XmlDaoUtil {
    private static URL path=XmlDaoUtil.class.getClassLoader().getResource("user.xml");
    
     * 使用静态代码块，对象只实例化一次
     static Document dom;
    {
        SAXReader reader= SAXReader();
        try {
            类加载器找到物理路径
            dom=reader.read(path);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
     * 获取xml
     *  Document getDom(){
         dom;
    }
    
     * 写入xml
     static  writeXml(){
        
    }
}

 com.tsh.domain;

 java.io.Serializable;

class User implements Serializable{
    private String username;
     String password;
     String password_confirm;
     String getUsername() {
         username;
    }
     setUsername(String username) {
        this.username = String getPassword() {
         password;
    }
     setPassword(String password) {
        this.password = String getPassword_confirm() {
         password_confirm;
    }
     setPassword_confirm(String password_confirm) {
        this.password_confirm = password_confirm;
    }
    
}

<?xml version="1.0" encoding="UTF-8"?>
<users>
user username="admin" password="admin"></user</>