jsp第六周作业

1.安装MySQL数据库，建立用户表 uid uname upwd 并插入3条数据

2.制作jsp登录页面 login.jsp 提交到dologin.jsp，使用jdbc连数据库，判断输入的用户名密码是否存在

3.如果存在，把用户名保存在SESSION中，跳转到welcome.jsp，welcome.jsp中读取session中的用户名，显示欢迎你xxx

4.若不存在，跳到登录页面。

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>

<!DOCTYPE HTML >
<html>
<head>


    <title>登录界面</title>
    
    <style type="text/css">
    .contentArea{450px;position:absolute;top:80px;left:250px;height:500px;}
    </style>
</head>

<body style="background:url(images/1.jpg)">
<div class="contentArea">
<p style="font-family:黑体；font-size:56；color：yellow"></p>
登录<br/><br/><br/>
   <form action="db.jsp" method="post" >
   ID：<input type="text" name="uid"><br/><br/>
   密码：<input type="password" name="upwd"><br/> <br/>
   <input type="submit" value="登录"><br/><br/><br/><br/>
   </form>

   </div>
</body >
</html>

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>

</head>
<body>

<%
String name = (String) request.getSession().getAttribute("uname");
%>

<body style="background:url(images/1.jpg)">
<div class="contentArea">
<h1 style="color: red">欢迎<%=name%>登陆！</h1>

</html>

<%@page import="java.nio.channels.SeekableByteChannel"%>
<%@ page language="java" contentType="text/html" pageEncoding="UTF-8"%>
<%@ page import="java.sql.*"%>
<html>
<head>
<title>www.school.com</title>
</head>
<body>
    <%!public static final String DBDRIVER = "com.mysql.jdbc.Driver";
    public static final String DBURL = "jdbc:mysql://localhost:3306/jspwork";
    public static final String DBUSER = "root";
    public static final String DBPASS = "root";%>
    <%
        Connection conn = null;
        PreparedStatement pstmt = null;
        ResultSet rs = null;
        boolean flag = false;
        String name = null;
    %>
    <%
        try {
            Class.forName(DBDRIVER);
            conn = DriverManager.getConnection(DBURL, DBUSER, DBPASS);
            String sql = "SELECT uname FROM num_one WHERE uid=? AND upwd=?";
            pstmt = conn.prepareStatement(sql);
            pstmt.setString(1, request.getParameter("uid"));
            pstmt.setString(2, request.getParameter("upwd"));

            rs = pstmt.executeQuery();
            if (rs.next()) {
                name = rs.getString(1);
                flag = true;
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (rs != null)
                    rs.close();
                if (pstmt != null)
                    pstmt.close();
                if (conn != null)
                    conn.close();
                if (flag) {
                 request.getSession().setAttribute("uname",name);
                 request.getRequestDispatcher("welcome.jsp").forward(request,response);


                } else {
                    response.sendRedirect("no.jsp");
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    %>

</body>
</html>