[javaEE] 三层架构案例-用户模块（一）

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>