jsp Model1设计模式实现用户登录验证

设计，用户实体类，用户登录页面jsp登录验证，登录成功页面，登录失败页面与前面的注释相同jsp登录验证，如果感兴趣，可以参考

更新部分: UserDao业务逻辑类，DBUtil工具类，登录验证页面

代码部分

1. UserDao业务逻辑类

package dao;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import db.DBUtil;
import entity.User;
public class UserDao {
    private static Connection conn;
    private static PreparedStatement pstt;
    private static ResultSet rs;
    private static String sql;
    /**
     * 给定User对象 通过用户名查询密码是否匹配
     * @param user
     * @return
     */
    public boolean queryUserByName(User user) {
        boolean query = false;
        conn = DBUtil.getConn();
        sql = "SELECT password FROM tb_user WHERE userName = ?";
        try {
            pstt = conn.prepareStatement(sql);
            pstt.setString(1, user.getUserName());
            rs = pstt.executeQuery();
            if (rs.next()) {
                String password = rs.getString("password");
                if (password.equals(user.getPassword())) {
                    query = true;
                }else {
                    query = false;
                }
            }           
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.queryClose(rs, pstt, conn);
        }
        return query;
    }
}

2. DBUtil工具类

package db;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
/**
 * 连接准备工作
 * @author SsssZzzz
 *
 */
public class DBUtil {
    private static final String DBDriver = "com.mysql.jdbc.Driver";
    private static final String URL = "jdbc:mysql://localhost:3306/db_users"
            + "?useUnicode=true&characterEncoding=utf8&useSSL=false";
    private static final String USER = "root";
    private static final String PASSWORD = "fyz123456";
    private static Connection conn = null;
    static{
        try {
            Class.forName(DBDriver);
            conn = DriverManager.getConnection(URL, USER, PASSWORD);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
    /**
     * 获取链接
     * @return
     */
    public static Connection getConn() {
        return conn;
    }
    /**
     * 向插入数据后关闭资源
     * @param pstt
     * @param conn
     */
    public static void addClose(PreparedStatement pstt, Connection conn) {
        try {
            if (!pstt.isClosed()) {
                pstt.close();
            }
            if (!conn.isClosed()) {
                conn.close();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
    /**
     * 查询数据后关闭资源
     * @param rs
     * @param pstt
     * @param conn
     */
    public static void queryClose(ResultSet rs, PreparedStatement pstt, Connection conn) {
        try {
            if (!rs.isClosed()) {
                rs.close();
            }
            if (!pstt.isClosed()) {
                pstt.close();
            }
            if (!conn.isClosed()) {
                conn.close();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

3. 登录验证页面

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<jsp:useBean id="user" class="entity.User" scope="page"></jsp:useBean>
<jsp:useBean id="userDao" class="dao.UserDao" scope="page"></jsp:useBean>
<jsp:setProperty property="*" name="user"/>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
    if(userDao.queryUserByName(user)){
        session.setAttribute("userName", user.getUserName());
        request.getRequestDispatcher("success.jsp").forward(request, response);
    }else{
        response.sendRedirect("failure.jsp");
    }
%>

摘要

通过Model1设计模式，将经过验证的业务逻辑封装到UserDao中，并将连接代码封装到DBUtil工具类中. 登录验证页面的代码已简化. 实现控制层和业务逻辑的分离，提高代码的可重用性和可伸缩性.

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