javaweb-登录验证功能

2022-05-02
作者我爱小小蝶
~3.95K 字

学习记录

MySQL数据库表里，我将管理员跟用户都放一张表里，通过表里的status字段进行权限验证，为1是管理员，0为用户（int）。

1 2	String sql = "select password from user where username=? and status=1;"; String sql = "select password from user where username=? and status=0;";

登录处理LoginController.jsp：

<%@ page import="java.sql.Connection" %>
<%@ page import="com.lan.utils.JDBCUtil" %>
<%@ page import="java.sql.PreparedStatement" %>
<%@ page import="java.sql.ResultSet" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>登录处理</title>
</head>
<body>
<%
    request.setCharacterEncoding("utf-8");
    String userName = request.getParameter("username");
    String password = request.getParameter("password");
    String status = request.getParameter("status");
    Connection conn = JDBCUtil.getConnection();
    String pwd = null;
    PreparedStatement pstm = null;

	// 不同登录权限执行不同的sql，变的只是status权限字段
    if ("管理员".equals(status)) {
        String sql = "select password from user where username=? and status=1;";
        pstm = conn.prepareStatement(sql);  //预编译sql语句
        pstm.setString(1, userName);
    } else if ("用户".equals(status)){
        String sql = "select password from user where username=? and status=0;";
        pstm = conn.prepareStatement(sql);
        pstm.setString(1, userName);
    } 

    ResultSet resultSet =  pstm.executeQuery(); 	// 获取查询的结果集
    while (resultSet.next()) {
        pwd = resultSet.getString("password");  // 获取查询到的密码
    }
    JDBCUtil.close(resultSet, pstm, conn);	// 释放资源


    // 判断数据库返回的密码是否跟用户输入的一致
    if (pwd.equals(password)) {
        System.out.println("登录成功！");
        session.setAttribute("username", userName);
        session.setAttribute("isLogin", "1"); // 1为已登录， 0为还未登录

        // 跳转相应页面
        if ("管理员".equals(status)) {
            response.sendRedirect(request.getContextPath()+"/manager.html");
        } else if ("用户".equals(status)) {
            response.sendRedirect(request.getContextPath()+"/zhuye_1.html");
        }

    } else {
        System.out.println("登录失败！");
        response.setCharacterEncoding("utf-8");
        session.setAttribute("isLogin", "0"); // 1为已登录， 0为还未登录
        request.setAttribute("msg", "登录失败！请检查账号密码是否正确！");
        request.getRequestDispatcher("/index.jsp").forward(request, response); //跳转登录页面
//        response.sendRedirect(request.getContextPath()+"/index.html");
    }
%>
</body>
</html>

下拉列表（后台获取name里的参数）：

<p>
   <label for="sel" class="" >权限：</label>
   <select name="status" id="sel">
       <option>用户</option>
       <option>管理员</option>
   </select>
</p>

获取下拉列表的name参数

1	String status = request.getParameter("status");

控制层可以根据下拉列表进行登录验证（选择登录后台或者前台）

if ("管理员".equals(status)) {
       String sql = "select password from user where username=? and status=1;";
       pstm = conn.prepareStatement(sql);
       pstm.setString(1, userName);
   } else if ("用户".equals(status)){
       String sql = "select password from user where username=? and status=0;";
       pstm = conn.prepareStatement(sql);
       pstm.setString(1, userName);
   } else {
       request.setAttribute("msg", "账号或密码出错！请重新输入！");
       request.getRequestDispatcher("/index.jsp").forward(request, response);
   }