ch5.jsp基本语法 -- 用户登录页面

最新推荐文章于 2022-05-21 17:47:44 发布

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本文介绍了一个简单的用户登录系统的实现过程，包括数据库表的设计、登录页面的构建、验证逻辑的处理及成功与失败页面的展示。

一个用户登录页面的结构

在数据库中下建立登录表：

/*=============删除数据库=============*/
DROP DATABASE IF EXISTS usr;
/*=============创建数据库=============*/
CREATE DATABASE usr;
/*=============使用数据库=============*/
USE usr;
/*=============删除数据库表===========*/
DROP TABLE IF EXISTS login;
/*=============创建数据库表===========*/
CREATE TABLE login(
	userid			VARCHAR(30)			PRIMARY KEY,
	name			VARCHAR(30)			NOT NULL,
	password		VARCHAR(32)			NOT NULL
);

INSERT INTO login(userid, name, password)VALUES('admin', 'admin', 'admin');

用login.html写出登录页面表单：

<html>
	<head>
		<title>www.thystar.com</title>
	</head>
	<body>
	<center>
		<h1>登陆操作</h1>
		<hr>
		<form action = "login_check.jsp" method = "post">
			<table border = "1">
			<tr>
				<td colspan="2">用户登录</td>
			</tr>
			<tr>
				<td>登陆ID</td>
				<td><input type = "text" name = "id"></td>
			</tr>
			<tr>
				<td>登陆密码</td>
				<td><input type = "password" name = "password"></td>
			</tr>
			<tr>
				<td colspan = "2">
					<input type = "submit" value = "登陆">
					<input type = "reset" value = "重置">
				</td>
			</tr>
			</table>
		</form>
	</center>
	</body>
</html>

登录验证页面 login_check.jsp

<%@ page contentType = "text/html" pageEncoding = "GBK"%>
<%@ page import = "java.sql.*"%>
<html>
	<head>
		<title>www.thystar.com</title>
	</head>
	<body>
	<%!
		public static final String DBDRIVER = "org.gjt.mm.mysql.Driver";
		public static final String DBURL = "jdbc:mysql://localhost:3306/usr";
		public static final String DBUSER = "root";
		public static final String DBPASS = "mysqladmin";
	%>
	<%
		Connection conn = null;
		PreparedStatement pstmt = null;
		ResultSet rs = null;
		boolean flag = false;
		String name = null;         //接受用户姓名
	%>
	<%
		try{
			Class.forName(DBDRIVER);
			conn = DriverManager.getConnection(DBURL, DBUSER, DBPASS);
			String sql = "SELECT name FROM login WHERE userid = ? AND password = ?";
			pstmt = conn.prepareStatement(sql);
			pstmt.setString(1, request.getParameter("id"));
			pstmt.setString(2, request.getParameter("password"));
			rs = pstmt.executeQuery();
			if(rs.next()){
				flag = true;
				name = rs.getString(1);	
			}
		}catch(Exception e){
			System.out.println(e);
		}
		finally{
			try{
				rs.close() ;
				pstmt.close() ;
				conn.close() ;
			} catch(Exception e){}
		}
	%>
	<%
		if(flag){  //登陆成功，则跳转到成功页
	%>
			<jsp:forward page = "login_success.jsp">
				<jsp:param name = "uname" value = "<%=name%>"/>
			</jsp:forward>	
	<%		
		}else{   // 登陆失败，则跳转到失败页
	%>
			<jsp:forward page = "login_failure.html"/>
	<%	
		}
	%>
	
	</body>
</html>

登录成功页：login_success.jsp

<%@ page contentType = "text/html" pageEncoding = "GBK"%>
<html>
	<head>
		<title>www.thystar.com</title>
	</head>
	<body>
		<center>
			<h2>登陆成功</h2>
			<h2>欢迎<font color = "red"><%=request.getParameter("uname")%></font></h2>
		</center>
	</body>
</html>

登陆失败页：login_failure.html

<html>
	<head>
		<title>www.thystar.com</title>
	</head>
	<body>
		<center>
			<h2>登陆失败</h2>
		</center>
	</body>
</html>

结果：

《Java Web开发实战经典--基础篇》