package com.tsh.dao;

import java.util.List;

import org.dom4j.Document;

import org.dom4j.DocumentHelper;

import org.dom4j.Element;

import com.tsh.domain.User;

import 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

     * @param user

     */

    public void addUser(User user){

        Document dom=XmlDaoUtil.getDom();

        Element root=dom.getRootElement();

        //创建<user>元素

        Element userElement=DocumentHelper.createElement("user");

        userElement.setAttributeValue("username", user.getUsername());

        userElement.setAttributeValue("password", user.getPassword());

        //挂载到<users>

        root.add(userElement);

        //回写到xml文件

    }

}

package com.tsh.util;

import java.net.URL;

import org.dom4j.Document;

import org.dom4j.io.SAXReader;

public class 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

     */

    private static Document dom;

    static{

        SAXReader reader=new SAXReader();

        try {

            //类加载器找到物理路径

            dom=reader.read(path);

        } catch (Exception e) {

            e.printStackTrace();

        }

    }

    /**

     * 获取xml

     * @return

     */

    public static Document getDom(){

        return dom;

    }

    /**

     * 写入xml

     */

    public static void writeXml(){

    }

}

package com.tsh.domain;

import java.io.Serializable;

public class User implements Serializable{

    private String username;

    private String password;

    private String password_confirm;

    public String getUsername() {

        return username;

    }

    public void setUsername(String username) {

        this.username = username;

    }

    public String getPassword() {

        return password;

    }

    public void setPassword(String password) {

        this.password = password;

    }

    public String getPassword_confirm() {

        return password_confirm;

    }

    public void setPassword_confirm(String password_confirm) {

        this.password_confirm = password_confirm;

    }

}

<?xml version="1.0" encoding="UTF-8"?>

<users>

<user username="admin" password="admin"></user>

</users>