项目结构
login.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>用户登录</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<form method="post" action="loginCheck.jsp">
<center>
<h4>xxx学生管理系统</h4>
<table>
<tr>
<td>用户名:</td>
<td><input type="text" name="username"></td>
</tr>
<tr>
<td>密 码:</td>
<td><input type="password" name="password"></td>
</tr>
<tr>
<td></td>
<td><input type="submit" value="登录" onclick="check()"> <input type="reset" value="重置"></td>
</tr>
</table>
</center>
</form>
</body>
</html>
界面效果
loginCheck.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>用户登录</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<form method="post" action="loginCheck.jsp">
<center>
<h4>xxx学生管理系统</h4>
<table>
<tr>
<td>用户名:</td>
<td><input type="text" name="username"></td>
</tr>
<tr>
<td>密 码:</td>
<td><input type="password" name="password"></td>
</tr>
<tr>
<td></td>
<td><input type="submit" value="登录" onclick="check()"> <input type="reset" value="重置"></td>
</tr>
</table>
</center>
</form>
</body>
</html>
index.jsp
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>学生管理系统</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
<style type="text/css">
ul{
list-style-type: none;
background-color:#333;
margin:0;
padding:0;
}
li a{
text-decoration: none;
color:white;
}
li{
display: inline;
padding: 10px 16px;
}
</style>
</head>
<body>
<%
String username=session.getAttribute("user").toString();
%>
<ul>
<li><a href="">学生管理</a></li>
<li><a href="">课程管理</a></li>
<li><a href="">成绩管理</a></li>
</ul>
<p><font color="red"><%=username%></font>欢迎您,使用学生管理系统！</p>
</body>
</html>
界面效果
loginError.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>登录错误页面</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
登录失败，用户名或密码输入有误。 <br>
<a href="login.jsp">返回登录</a>
</body>
</html>
DbHelper类
package com;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;
public class DbHelper {
private Connection conn=null;
private Statement stmt=null;
private ResultSet rest=null;
private PreparedStatement prst=null;
public Connection getConn(){
try{
String url="jdbc:mysql://localhost:3306/student";
String username="root";
String password="root";
Class.forName("com.mysql.jdbc.Driver");
conn=DriverManager.getConnection(url,username,password);
if(conn!=null){
System.out.println("数据库连接成功。");
}else{
System.out.println("数据库连接失败。");
}
}catch(Exception e){
e.printStackTrace();
}
return conn;
}
public ResultSet selectUser(String name,String pwd){
try{
conn=getConn();
String sql="select * from user where username=? and password=?";
prst=conn.prepareStatement(sql);
prst.setString(1, name);
prst.setString(2, pwd);
rest=prst.executeQuery();
}catch(Exception e){
e.printStackTrace();
}
return rest;
}
}