userdao.java

一个非常简单的mvc留言板MVC框架是STRUTS框架的基础

package com.aptech.dao;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.text.MessageFormat;

import com.aptech.bean.User;
import com.aptech.util.DatabaseTool;

public class UserDAO {
	private DatabaseTool dt = DatabaseTool.getInstance();
	
	/**
	 * 注册用户
	 * @param user User对象
	 * @return
	 */
	public boolean regesterUser(User user){
		MessageFormat mf = new MessageFormat("insert into users(uname, upassword, uregdate) values(''{0}'', ''{1}'', ''{2}'')");
		String sql = mf.format(new Object[]{
				user.getUname(),
				user.getUpassword(),
				new java.util.Date().toLocaleString()
		});
		return dt.insertOrUpdateOrDelete(sql);
	}
	
	/**
	 * 登录
	 * @param uname 用户名
	 * @param upassword 密码
	 * @return 如果返回非null,则表示登陆失败,如果返回的是User对象,则表示登录成功
	 */
	public User login(String uname, String upassword){
		String sql = "select * from users where uname=''{0}'' and upassword=''{1}''";
		MessageFormat mf = new MessageFormat(sql);
		sql = mf.format(new Object[]{
				uname, upassword
		});
		ResultSet rs = dt.select(sql);
		try {
			User user = new User();
			if(rs != null && rs.next()){
				user.setUid(rs.getInt("uid"));
				user.setUname(uname);
				user.setUpassword(upassword);
				user.setUregdate(rs.getString("uregdate"));
				return user;
			}else{
				return null;
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			return null;
		} finally{
			dt.closeConnection();
		}
	}
	
	/**
	 * 修改用户名
	 * @param user User对象
	 * @return 如果修改成功,返回真,否则返回假
	 */
	public boolean update(User user){
		String sql = "update users set uname=''{0}'', upassword=''{1}'' where uid={2}";
		MessageFormat mf = new MessageFormat(sql);
		sql = mf.format(new Object[]{
				user.getUname(), 
				user.getUpassword(), 
				user.getUid()}
		);
		
		return dt.insertOrUpdateOrDelete(sql);
	}
	
	public boolean update(String uname, String oldPassword, 
			String newPassword){
		//先判断旧密码是否正确
		User user = this.login(uname, oldPassword);
		if(user ==  null){
			return false;
		}
		//再更新密码
		user.setUpassword(newPassword);
		return this.update(user);
	}
}