jsp实例：一个简单的用户登陆系统
java用户登录界面的代码
java用户登录界面的代码以下是一个简单的Java用户登录界面的代码示例，其中包括了GUI界面设计和用户验证的代码：```javaimport javax.swing.JFrame;import javax.swing.JLabel;import javax.swing.JTextField;import javax.swing.JPasswordField;import javax.swing.JButton;import java.awt.event.ActionListener;import java.awt.event.ActionEvent;public class LoginWindow extends JFrame implements ActionListener {private JLabel usernameLabel, passwordLabel;private JTextField usernameTextField;private JPasswordField passwordField;private JButton loginButton;public LoginWindow() {setTitle("用户登录");setSize(400, 200);setLocationRelativeTo(null);setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);usernameLabel = new JLabel("用户名：");passwordLabel = new JLabel("密码：");usernameTextField = new JTextField();passwordField = new JPasswordField();loginButton = new JButton("登录");loginButton.addActionListener(this);setLayout(null);usernameLabel.setBounds(50, 30, 80, 25);passwordLabel.setBounds(50, 70, 80, 25);usernameTextField.setBounds(130, 30, 200, 25);passwordField.setBounds(130, 70, 200, 25);loginButton.setBounds(150, 120, 100, 25);add(usernameLabel);add(passwordLabel);add(usernameTextField);add(passwordField);add(loginButton);setVisible(true);}public void actionPerformed(ActionEvent e) {String username = usernameTextField.getText();String password = newString(passwordField.getPassword());if (isValidUser(username, password)) {System.out.println("用户登录成功！");// 在这里可以跳转到下一个界面} else {System.out.println("用户名或密码错误！");}}private boolean isValidUser(String username, String password) {// 在这里实现用户验证的代码// 比如查询数据库是否有该用户并且密码是否匹配等等// 如果验证成功则返回true，否则返回falsereturn false;}public static void main(String[] args) {new LoginWindow();}}```该代码创建了一个窗口界面，包括“用户名”和“密码”两个文本框，以及一个“登录”按钮。
JSP Ajax 用户登录
JSP Ajax 用户登录
使用Ajax技术来实现用户登录，将会提交登录区域数据。
练习使用这种方法来实现用户登录校验。
（1）创建客户端程序，通过有参数请求把客户的用户名和密码发送到服务器，然后根据服务器返回的结果来判断是否登录成功。
其中发送有参数请求的JavaScri
（3）实现页面的登录界面，注意一些标签的id属性的设置不能有错，不然将
（4）实现服务器处理——check.java文件，它是一个Servlet，主要功能是起到一个控制器作用，将调用逻辑处理模块（一个JavaBean）SqlCheck来判断用户是否
（5）实现逻辑处理模块——SqlCheck.java，它是一个JavaBean，主要功能是查
（6）编译并部署各文件，运行效果如图9-15所示：
图9-15 登录成功。
简单登录实例Login
简单登录实例Login本⼈菜鸟~~学习过程中~~请求⽼⼤们指导！！谢谢！！！从基础学习，坚持下去，每天进步⼀点点！！1.⾸先要实现登录，通俗点总得有个登陆的样⼦吧，也就是⼈要有个脸⾯嘛！说做就做！⾃⼰属于菜鸟级别的，所以也就直接上简单的！当做⾃⼰的练⼿嘛！新建⼀个WinForm项⽬，取名AdoLogin往Form⾥⾯相对应的label和textbox以及button设置各个控件的属性，其中label1和label2的Text分别为⽤户名和密码，TextBox1和TextBox2分别设置为txtUserName和txtPassWord，button1设置为btnLogin，其中label3的属性Visible设置为false。
设计数据库：点击button进⼊后台写button的click事件在这⾥复习⼀下操纵数据库的⼏个对象。
（1）connection（2）command（3）DataAdapter（4）DataSet（5）DataRead其中注意⼀下DataSet与DataRead的区别：说下⾃⼰的理解（菜鸟级别理解~~呵呵~~~⼤⽜们给予知道！谢谢！）*DataReader是从数据库中⼀条⼀条数据的往下读，占⽤的内存空间⼩，⽽DataSet试讲数据库中的数据⼀次性的加载到缓冲池中，占⽤的内存空间⽐较⼤。
*DataReader保持与数据库的连接，⽽DataSet将数据加载完成后，断开与数据的连接！{这条是⾃⼰出学校进⼊公司时⾯试说掉的⼀条~不过项⽬经理好⼈啊~~呵呵（⼥的）~~给个提⽰我就记得啦！在此分享下说下！感觉⾯试⼼态放好点~⾯试官还是⽐较好的~不懂得还是会给予你提⽰的！}*DataReader读取数据速度较慢，DataSet读取数据速度较快！*在对DataReader中的数据进⾏更新以后，没有办法进⾏数据库更新；⽽DataSet数据集中的数据更新以后，可以把数据更新会原来的数据库。
*DataSet⽀持数据的分页，动态排序等功能；⽽DataReader没有数据的分页、动态排序功能！其中说到ExecuteNonQuery和ExecuteScalar：*ExecuteNonQuery⽤于对数据库de增加，删除，修改操作，执⾏成功，则返回1，失败则返回0.*ExecuteScalar返回表结构的⾸⾏⾸列，忽略其他的⾏和列！1using System;2using System.Collections.Generic;3using ponentModel;4using System.Data;5using System.Drawing;6using System.Linq;7using System.Text;8using System.Windows.Forms;9using System.Data.SqlClient;1011namespace AdoLogin12 {13public partial class Form1 : Form14 {15public Form1()16 {17 InitializeComponent();18 }1920private void btnLogin_Click(object sender, EventArgs e)21 {22string UserName = txtUserName.Text.Trim();23string PassWord = txtPassWord.Text;24if (UserName == "" || PassWord == "")25 {26 MessageBox.Show("⽤户名或密码不能为空！");27 }28else29 {30string conStr = @"Data Source=.;Initial Catalog=MyDataBase01;Integrated Security=True";31string sqlStr = @"select count(*) from Login where UserName=@UserName and PassWord=@PassWord";32 SqlConnection myConnection = new SqlConnection(conStr);33 SqlCommand myCommand = new SqlCommand(sqlStr, myConnection);34 myConnection.Open();35 myCommand.Parameters.AddWithValue("@UserName", UserName);36 myCommand.Parameters.AddWithValue("@PassWord", PassWord);37int res = Convert.ToInt32(myCommand.ExecuteScalar());38 myConnection.Close();39if (res > 0)40 {41 show.Visible = true;42 show.ForeColor = Color.Red;43 show.Text = "登录成功！";44 }45else46 {47 show.Visible = true;48 show.ForeColor = Color.Red;49 show.Text = "登录失败！请检查⽤户名和密码！";50 }515253 }54 }55 }56 }本⼈菜鸟~·希望寻得⼤⽜指导~~万分感谢！。
使用JSP实现简单的用户登录注册页面示例代码解析
使⽤JSP实现简单的⽤户登录注册页⾯⽰例代码解析实验要求：将实验2中的系统⽤户登录和注册页⾯改为JSP页⾯，并部署⾃⼰的Web应⽤于Tomcat服务器中具体要求：完成登录JSP页⾯设计和注册页⾯设计在登录页⾯表单中使⽤request对象获取⽤户信息，建⽴新的JSP页⾯完成登录验证（⽤户名和密码⾃⼰指定即可）。
验证结果显⽰（如登录成功/⽤户名密码错误，可以使⽤JavaScript，也可以使⽤新的JSP页⾯）。
在注册页⾯表单中使⽤request对象获取⽤户注册信息（注册项⽬由⾃⼰指定），在新的JSP页⾯显⽰⽤户注册信息，并提⽰注册成功。
代码登录页⾯index.html<!DOCTYPE html><html lang="zh-CN"><head><meta charset="utf-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1"><title>jsp作业</title><link href="css/bootstrap.min.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="stylesheet"></head><body><nav class="navbar navbar-default"><div class="container-fluid"><div class="navbar-header"><a class="navbar-brand" href="./" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >jsp作业</a></div><div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1"><ul class="nav navbar-nav navbar-right"><li><a href="login.jsp" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >登录</a></li></ul></div></div></nav><div class="container"><div class="jumbotron"><h1>Hello, world!</h1><p>这是⼀个jsp作业</p></div></div></body></html>登录页⾯login.jsp<%@ page contentType="text/html; charset=utf-8" language="java"%><html lang="zh-CN"><head><meta charset="utf-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1"><title>登录</title><link href="css/bootstrap.min.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="stylesheet"></head><body><nav class="navbar navbar-default"><div class="container-fluid"><div class="navbar-header"><a class="navbar-brand" href="./" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >jsp作业</a></div><div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1"><ul class="nav navbar-nav navbar-right"><li><a href="login.jsp" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >登录</a></li></ul></div></div></nav><div class="container"><div class="row"><div class="col-md-4"></div><div class="col-md-4"><form class="form-signin" method="post" action="login-check.jsp"><h2 class="form-signin-heading">登录到jsp作业</h2><label for="">⽤户名</label><input type="text" name="username" id="username" class="form-control" placeholder="请输⼊⽤户名" required autofocus><br><label for="">密码</label><input type="password" name="password" id="password" class="form-control" placeholder="请输⼊密码" required><div class="checkbox"><label><input type="checkbox" value="remember-me" checked="checked"> 记住密码</label></div><button type="submit" class="btn btn-primary" id="btn-login">登录</button><a href="reg.jsp" rel="external nofollow" rel="external nofollow" class="btn btn-default">注册</a></form></div><div class="col-md-4"></div></div></body></html>登录结果页⾯login-check.jsp<%@ page contentType="text/html; charset=utf-8" language="java"%><html lang="zh-CN"><head><meta charset="utf-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1"><title>登录</title><link href="css/bootstrap.min.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="stylesheet"></head><body><nav class="navbar navbar-default"><div class="container-fluid"><div class="navbar-header"><a class="navbar-brand" href="./" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >jsp作业</a><div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1"><ul class="nav navbar-nav navbar-right"><li><a href="login.jsp" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >登录</a></li></ul></div></div></nav><div class="container"><div class="row"><div class="col-md-4"></div><div class="col-md-4"><form class="form-signin" method="post" action="login-check.jsp"><h2 class="form-signin-heading">登录到jsp作业</h2><label for="">⽤户名</label><input type="text" name="username" id="username" class="form-control" placeholder="请输⼊⽤户名" required autofocus><br><label for="">密码</label><input type="password" name="password" id="password" class="form-control" placeholder="请输⼊密码" required><div class="checkbox"><label><input type="checkbox" value="remember-me" checked="checked"> 记住密码</label></div><button type="submit" class="btn btn-primary" id="btn-login">登录</button><a href="reg.jsp" rel="external nofollow" rel="external nofollow" class="btn btn-default">注册</a></form></div><div class="col-md-4"></div></div></body></html>注册页⾯reg.jsp<%@ page contentType="text/html; charset=utf-8" language="java"%><html lang="zh-CN"><head><meta charset="utf-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1"><title>注册</title><link href="css/bootstrap.min.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="stylesheet"></head><body><nav class="navbar navbar-default"><div class="container-fluid"><div class="navbar-header"><a class="navbar-brand" href="./" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >jsp作业</a></div><div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1"><ul class="nav navbar-nav navbar-right"><li><a href="login.jsp" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >登录</a></li></ul></div></div></nav><div class="container"><div class="row"><div class="col-md-4"></div><div class="col-md-4"><form class="form-signin" action="reg-submit.jsp" method="post"><h2 class="form-signin-heading">注册到jsp作业</h2><div id="info"></div><label for="">⽤户名</label><input type="text" name="username" id="username" class="form-control" placeholder="请输⼊⽤户名" required autofocus><br><label for="">密码</label><input type="password" name="password" id="password" class="form-control" placeholder="请输⼊密码" required><br><label for="">重复密码</label><input type="password" name="password2" id="password2" class="form-control" placeholder="请再次输⼊密码" required maxLength="16"><br><button type="submit" class="btn btn-primary" id="btn-reg">注册</button><a href="login.jsp" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" class="btn btn-default" id="btn-reg">返回登录</a> </form></div><div class="col-md-4"></div></div></body></html>注册结果页⾯reg-submit.jsp<%@ page contentType="text/html; charset=utf-8" language="java"%><html lang="zh-CN"><head><meta charset="utf-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1"><title>结果</title><link href="css/bootstrap.min.css" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="stylesheet"></head><body><nav class="navbar navbar-default"><div class="container-fluid"><div class="navbar-header"><a class="navbar-brand" href="./" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >jsp作业</a></div><div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1"><ul class="nav navbar-nav navbar-right"><li><a href="login.jsp" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" rel="external nofollow" >登录</a></li></ul></div></div></nav><div class="container"><% String username = request.getParameter("username");String password = request.getParameter("password");String password2 = request.getParameter("password2");%><%if(password.equals(password2)){out.println("<div class='alert alert-success' role='alert'>注册成功</div>");out.println("<ul class='list-group'>");out.println("<li class='list-group-item'>⽤户名：" + username + "</li>");out.println("<li class='list-group-item'>密码：" + password + "</li>");out.println("</ul>");else{out.println("<div class='alert alert-danger' role='alert'>两次密码输⼊不⼀致，请重新输⼊</div>"); }%><!-- <%=username %><%=password %><%=password2 %> --></div>效果到此这篇关于使⽤JSP实现简单的⽤户登录注册页⾯⽰例代码解析的⽂章就介绍到这了,更多相关JSP实现简单的⽤户登录注册页⾯内容请搜索以前的⽂章或继续浏览下⾯的相关⽂章希望⼤家以后多多⽀持！。
第3章J讲义SP实现用户注册
3.2 JSP处理请求数据
隐含对象
所属的类
说明
session
javax.servlet.http.HttpSession 与请求有关的会话
application pageContext exception
javax.servlet.ServletContext javax.servlet.jsp.PageContext ng.Throwable
提供全局的数据， 一旦创建就保持到 服务器关闭
JSP页面的上下文， 用于访问页面属性
针对错误网页，捕 捉一般网页中未捕 捉的异常
•与属性作用域有关的对象：session、application、 pageContext。
•与错误处理有关的对象：exception
3.2.1 request对象处理用户请求信息
3.2.1 request对象处理用户请求信息
• 例如: String
name=(String)request.getParameter("username"); 表示把“username”（请求页面的值）赋给“name”（本
页面中的值）。 • String[] getParameterValues(String name)，用来
"> </FORM>
3.1.3 实现用户信息填写界面
• 本小节主要是通过一个例子来进一步熟悉HTML， 为后面的学习打下良好的基础。
• 实现用户信息填写最简单也历，通 过下面的实践就可以实现和网站上一样的注册了。
• 这里用到了上面介绍过的表单元素，有单行文本 框、密码框、单选框、复选框、下拉列表、多行 文本域还有提交和重置按钮。
• request对象实现的 是:javax.servlet.http.HttpServletRequest接 口，表示客户端对网页的请求，并使用HTTP协议 处理客户端的请求。
JSP登陆界面
用Jsp做的一个简单的登陆界面，连接Mysql，数据库名字为school，表为user。
主要分为四个Jsp界面：index.jsp登陆界面，check.jsp检验页面，main.jsp登陆成功界面，error.jsp登陆失败界面。
如下所示：<%@page language="java"import="java.util.*" pageEncoding="utf-8"%><html><head><meta http-equiv="Content-Type" content="text/html;charset=UTF-8"><title>登陆界面</title></head><body><br><br><br><br><br><br><br><br><center><form action="check.jsp"method="post"><table width="380"border="2"bgcolor="#95BDFF"><tr><td><br><h1>      欢迎光临，请登陆</h1></td></tr><tr><td><br>        用户名字:  <input name="username"type="text" size="28"><br><br>        用户密码 :  <input name="userpass"type="password" size="29"><br><br>                 <input type="submit"name="submit"value="提交"style="height:30px;width:80px">           <input type="reset"name="reset"value="取消"style="height:30px;width:80px"><br> </td></tr></table></form></center></body></html><%@page language="java"import="java.sql.*" pageEncoding="utf-8"%><html><head><meta http-equiv="Content-Type" content="text/html;UTF-8"><title>登陆界面</title></head><body><%String username = new String(request.getParameter("username").getBytes("ISO-8859-1") ,"utf-8");String password = new String(request.getParameter("userpass").getBytes("ISO-8859-1") ,"utf-8");session.setAttribute("name",username);Connection dbconn = null;Statement stmt = null;ResultSet rs = null;if(username.equals("")){response.sendRedirect("index.jsp");}try{String driver = "com.mysql.jdbc.Driver";String url = "jdbc:mysql://localhost:3306/school";String user = "sa";String Password = "123";Class.forName(driver);dbconn = DriverManager.getConnection(url, user, Password);stmt = dbconn.createStatement();String sql1 = "select * from user where username='"+username+"'";rs = stmt.executeQuery(sql1);if(rs.next()){//String sql2 = "select * from user where password='"+password+"'";//rs = stmt.executeQuery(sql2);//判断用户密码是否正确String userpass = rs.getString("password");if(userpass.equals(password)){response.sendRedirect("main.jsp");}else{response.sendRedirect("error.jsp");}}else{response.sendRedirect("error.jsp");}}catch(Exception e){e.printStackTrace();}finally{rs.close();stmt.close();dbconn.close();}%></body></html><%@page language="java"import="java.util.*" import="java.text.*"pageEncoding="utf-8"%><html><head><meta http-equiv="Content-Type" content="text/html;charset=UTF-8"><title>登陆成功界面</title></head><body><h1>登陆成功，<%=session.getAttribute("name")%>欢迎您！</h1><%Date now = new Date();DateFormat mediumDateFormat = DateFormat.getDateTimeInstance( DateFormat.MEDIUM, DateFormat.MEDIUM);%><h2>       <%out.println(mediumDateFormat.format(now));%></h2> </body></html><%@page language="java"import="java.util.*" pageEncoding="utf-8"%><html><head><meta http-equiv="Content-Type" content="text/html;charset=UTF-8"><title>登陆失败界面</title></head><body><h1>登陆失败，您输入的用户名或者密码不正确！</h1></body></html>。
JSP制作简单登录界面实例
JSP制作简单登录界⾯实例现在很多web项⽬都能⽤到登录界⾯，本⽂介绍⼀下JSP制作简单登录界⾯，分享给⼤家，具体如下：运⾏环境eclipse+tomcat+MySQL 不知道的可以参考项⽬列表这⾥我先把jsp⽂件先放在Web-INF外⾯访问1.需要建⽴的⼏个⽂件在图上.jsp2.还要导⼊MySQL的jar包mysql-5.0.5.jar，导到WEB-INF中的lib⽂件夹就可以不需要Bulid Path3.开始编写代码：代码演⽰：index.jsp就好像⼀般⽹站的⾸页⼀样感觉，将header.jsp和footer.jsp引⼊其中<%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>⾸页</title><style>#nav>ul>li{float:left;margin-left:50px;}#login{clear:both;}</style></head><body><!-- 引⼊header.jsp的头部⽂件 --><%@ include file="header.jsp" %><div id="login"><a href="login.jsp" rel="external nofollow" ><button>登陆</button></a></div><!-- 引⼊footer.jsp的脚部⽂件 --><%@include file="footer.jsp" %></body></html>header.jsp<%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%><div id="nav"><ul><li ><a href="">导航1</a></li><li><a href="">导航2</a></li><li><a href="">导航3</a></li><li><a href="">导航4</a></li><li><a href="">导航5</a></li><li><a href="">导航6</a></li></ul></div>footer.jsp<%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%><div><p>xxxxxxxxxxx可以试试|xxxxxxxxxxxx技术有限公司</p><p>京 ICP 证 1234567 号|Copyright © 1999-2017, All Rights Reserved </p></div>页⾯内容展⽰：login.jsp登陆⽤户名密码填写界⾯<%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "/TR/html4/loose.dtd"> <html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>登陆页⾯</title></head><body><%--表单--%><fieldset><legend>登陆界⾯</legend><form action="test.jsp" method="post"><input type="text" name="username"><br><input type="password" name="password"><br><input type="submit" value="登陆"><!-- EL语句，后⾯验证表单时，验证错误反回信息-->${error}</form></fieldset></body></html>内容显⽰：test.jsp 是对表单login.jsp 的提交的内容与数据库中的数据对⽐验证，再相应的跳转<%@page import="java.sql.*"%><%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%><%//请求获取login.jsp的⽤户名username的值String username=request.getParameter("username");//请求获取login.jsp的密码password的值String password=request.getParameter("password");//数据库MySQL的地址String DBURL="jdbc:mysql://localhost:3306/zhou?useUnicode=true&characterEncoding=utf-8";String DBName="root"; //登⼊⽤户名String DBPwd="123456";//登⼊密码//加载mysql驱动Class.forName("com.mysql.jdbc.Driver");//连接数据库Connection conn=DriverManager.getConnection(DBURL,DBName,DBPwd);//创建Statement对象Statement st=conn.createStatement();//sql语句，搜索这个username和password在数据库是否存在String sql="select * from user where name='"+username+"'and pwd='"+password+"'";//运⾏sql语句，并把得到的结果放⼊结果集ResultSet中ResultSet rs=st.executeQuery(sql);//判断这个结果集是否存在，⼀般username只有⼀个if(rs.next()){//设置⼀个username，将后⾯username其内容赋值给前⾯⼀个username，可以以便下⼀个页⾯使⽤request.setAttribute("username", username);//跳转页⾯到userpage.jsprequest.getRequestDispatcher("userpage.jsp").forward(request, response);}else{//设置⼀个error,将后⾯的字赋给这个error，以便先⼀个跳转页⾯的使⽤，request的作⽤域有限request.setAttribute("error", "⽤户名或密码错误");request.getRequestDispatcher("login.jsp").forward(request, response);}conn.close();rs.close();%>登陆错误显⽰的页⾯内容：userpage.jsp这个页⾯就是登陆成功之后显⽰的页⾯<%@page import="javafx.scene.chart.PieChart.Data"%><%@page import="java.util.Date"%><%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>⽤户界⾯</title></head><body><div><!-- ${username}是获取到test.jsp 中判断中重新设置的username，知道是谁登陆了，这个是谁的页⾯ --> <p>${username},你好，登陆成功！！</p></div><%//session的作⽤域问题，可以记录⼀个⽹站的浏览量。
Jsp学生信息管理系统登录验证全代码
1.jsp登录界面 Login.jspNo.:00000000000000587 <%@page language="java"contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%><html><head><meta http-equiv="Content-Type"content="text/html;charset=UTF-8"><title>用户登录界面</title></head><form action="LoginServlet"method="post"><body bgcolor="blue"><marquee direction="right"onmouseover="stop()"onmouseout="start()"style="font-family: 楷体_GB2312"><p><font size="10px"color="red">学生信息信息管理系统</font></p></marquee><table align=center width="237"><tr><td><table width=100%><tr><td colspan=6><font size=2><div id="b2bContent"style="FILTER: revealTrans(Duration = 1, Transition =</font></td></tr><tr><td align=center STYLE='cursor: hand'><font size=2><div class="b2bbutton"id="bt0"onclick="javascript:showPage(0);clearTimeout(theTimer);theTimer=s etTimeout('turnPage()',speed);checkBt();">1</div></font></td><td align=center STYLE='cursor: hand'><font size=2><div class="b2bbutton"id="bt1"onclick="javascript:showPage(1);clearTimeout(theTimer);theTimer=s etTimeout('turnPage()',speed);checkBt();">2</div></font></td><td align=center STYLE='cursor: hand'><font size=2><div class="b2bbutton"id="bt2"onclick="javascript:showPage(2);clearTimeout(theTimer);theTimer=s etTimeout('turnPage()',speed);checkBt();">3</div></font></td><td align=center STYLE='cursor: hand'><font size=2><div class="b2bbutton"id="bt3"onclick="javascript:showPage(3);clearTimeout(theTimer);theTimer=s etTimeout('turnPage()',speed);checkBt();">4</div></font></td><td align=center STYLE='cursor: hand'><font size=2><div class="b2bbutton"id="bt4"onclick="javascript:showPage(4);clearTimeout(theTimer);theTimer=s etTimeout('turnPage()',speed);checkBt();">5</div></font></td><td align=center STYLE='cursor: hand'><font size=2><div class="b2bbutton"id="bt5"onclick="javascript:showPage(5);clearTimeout(theTimer);theTimer=s etTimeout('turnPage()',speed);checkBt();">6</div></font></td></tr></table><script language="javascript">b2bStr = new Array();b2bStr[0]= "<div style='float:left; width:100%;overflow:hidden;'><a href=1.gif target=_blank><img src=1.gif width=214px height=145px border=0></a><br><a target=_blank title=太阳岛公园一角 href=1.gif>太阳岛公园一角</a></div>";width:100%;overflow:hidden;'><a href=2.gif target=_blank><img src=2.gif width=214px height=145px border=0></a><br><a target=_blank title=太阳岛公园湖光山色 href=2.gif>太阳岛公园湖光山色</a></div>";b2bStr[2] = "<div style='float:left; width:100%;overflow:hidden;'><a href=3.gif target=_blank><img src=3.gif width=214px height=145px border=0></a><br><a target=_blank title=哈尔滨雪雕 href=3.gif>哈尔滨雪雕</a></div>";b2bStr[3] = "<div style='float:left; width:100%;overflow:hidden;'><a href=4.gif target=_blank><img src=4.gif width=214px height=145px border=0></a><br><a target=_blank title=镜泊湖 href=4.gif>镜泊湖</a></div>";b2bStr[4] = "<div style='float:left; width:100%;overflow:hidden;'><a href=5.gif target=_blank><img src=5.gif width=214px height=145px border=0></a><br><a target=_blank title=太阳岛公园瀑布 href=5.gif>太阳岛公园瀑布</a></div>";b2bStr[5] = "<div style='float:left; width:100%;overflow:hidden;'><a href=6.gif target=_blank><img src=6.gif width=214px height=145px border=0></a><br><a target=_blank title=镜泊湖夜色 href=6.gif>镜泊湖夜色</a></div>";var page=0;var speed=3000;function showPage(id){setTransition();b2bContent.innerHTML=b2bStr[id];b2bContent.filters.revealTrans.play();}function turnPage(){showPage(page);theTimer=setTimeout("turnPage()", speed);checkBt();page++;if(page>=6) page=0;}function checkBt(){for(var i=0;i<6;i++){btObj=eval('bt'+i);if(page==i){btObj.style.color='#FFFFFF';btObj.style.backgroundCol or='#FF781C';}else{btObj.style.color='#000000';btObj.style.backgroundColor='#F7 F7F7';}}}function setTransition(){b2bContent.filters.revealTrans.Transition=Math.round(Math.random( )*23);b2bContent.filters.revealTrans.apply();}turnPage();</script></TD></TR></table><hr color="green"width="540"><table align="center"><tr><td>用户名:<input type="text"name="username"size="8" maxlength="6"></td></tr><tr><td>密 码:<input type="password" name="password"size="10"maxlength="6"></td></tr><tr><td><input type="submit"value="登录"> <input type="reset"value="取消"></td></table></form></body></html>2.java代码(1)User.Java 定义的属性和数据库中的字段相对应package com.softeem.dt;public class User {private int id;private String username;private String password;private String xh;private String college;public int getId(){return id;}public void setId(int id){this.id = id;}public String getUsername() {return username;}ername = username;}public String getPassword() {return password;}public void setPassword(String password) { this.password = password;}public String getXh() {return xh;}public void setXh(String xh) {this.xh = xh;}public String getCollege() {return college;}public void setCollege(String college) { this.college = college;}}(2)UserDAO.java 操作数据库tb_user,验证用户登录package com.softeem.dao;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import com.softeem.db.DBManager;import er;public class UserDAO {/***验证用户登录*@return*/public boolean checkDenglu(User user) {boolean flag = false;// 获得数据库连接Connection conn = DBManager.getConnection();// 用select * from查询数据库中的所有字段String sql = "select count(*) from tb_user where username=? and password=?";try {PreparedStatement pst = conn.prepareStatement(sql);pst.setString(1, user.getUsername());pst.setString(2, user.getPassword());ResultSet rs = pst.executeQuery();while (rs.next()) {int count = rs.getInt(1);//用count和0比较,若大于0表示该用户存在,否则不存在if(count > 0){flag = true;}}} catch (SQLException e) {e.printStackTrace();}return flag;}}3.LoginServlet,点击登录跳转到服务器端package com.softeem.servlet;import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import er;/*** Servlet implementation class LoginServlet*/public class LoginServlet extends HttpServlet {private static final long serialVersionUID = 1L;/*** @see HttpServlet#HttpServlet()*/public LoginServlet() {super();}/*** @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)*/protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { super.doGet(request, response);}/*** @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)*/protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //获取表单数据//处理乱码request.setCharacterEncoding("utf-8");String username = request.getParameter("username");String password = request.getParameter("password");//封装到user对象中User user = new User();user.setUsername(username);user.setPassword(password);//调用dao的checkLogin方法UserDAO dao = new UserDAO();boolean flag = dao.checkLogin(user);String message = null;String path = null;if(flag){message = "登录成功";path="success.jsp";request.getSession().setAttribute("user", user);}else{message ="对不起密码错误,请重新输入!";path="fail.jsp";}//response返回messageresponse.setCharacterEncoding("utf-8");response.getWriter().write(message);*///属于服务器跳转,浏览器地址栏没有发生改变request.getRequestDispatcher(path).forward(request,response);}}青年人首先要树雄心，立大志，其次就要决心作一个有用的人才。
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三个文件如下：
//登录界面
/** *//**
* @(#)Login.Java
*
*
* @author shiyi05
* @version 1.00 2008/5/10
*/
package com.rao;
import javax.Servlet.http.*;
import java.io.*;
public class Login extends HttpServlet
{
public Login()
{
}
//处理Get请求
public void doGet(HttpServletRequest req,HttpServletResponse res) {
try
{
//中文乱码
res.setContentType("text/html; charset=gbk");
PrintWriter pw=res.getWriter();
//返回登陆界面
pw.println("<html>");
pw.println("<body>");
pw.println("<h1>登陆界面</h1>");
pw.println("<form action=LoginCl method=post>");
pw.println("用户名: <input type=text nam e=username><br>"); pw.println("密码：<input type=password name=passwd><br>"); pw.println("<input type=submit value=loing><br>");
pw.println("</body>");
pw.println("</html>");
}
catch(Exception ex)
{
ex.printStackTrace();
}
}
public void doPost(HttpServletRequest req,HttpServletResponse res) {
this.doGet(req,res);
}
}
//用户验证
/** *//**
* @(#)LoginCl.java
*
* @author shiyi05
* @version 1.00 2008/5/10
*/
package com.rao;
import javax.servlet.http.*;
import java.io.*;
public class LoginCl extends HttpServlet
{
public LoginCl()
{
}
//处理Get请求
public void doGet(HttpServletRequest req,HttpServletResponse res) {
try
{
//中文乱码
res.setContentType("text/html; charset=gbk");
//接收用户名和密码
String u=req.getParameter("username");
String p=req.getParameter("passwd");
//验证
if(u.equals("sp") && p.equals("123"))
//合法
res.sendRedirect("Welcome");
}
else
{
//不合法
res.sendRedirect("Login");
}
}
catch(Exception ex)
{
ex.printStackTrace();
}
}
public void doPost(HttpServletRequest req,HttpServletResponse res) {
this.doGet(req,res);
}
}
//欢迎界面
/** *//** *//** *//**
* @(#)Welcome.java
*
*
* @author shiyi05
* @version 1.00 2008/5/10
*/
package com.rao;
import javax.servlet.http.*;
import java.io.*;
public class Welcom e extends HttpServlet
{
public Welcome()
{
}
//处理Get请求
public void doGet(HttpServletRequest req,HttpServletResponse res) {
try
{
//中文乱码
res.setContentType("text/html; charset=gbk");
PrintWriter pw=res.getWriter();
//返回登陆界面
pw.println("<html>");
pw.println("<body>");
pw.println("<h1>Welcome</h1>");
pw.println("</body>");
pw.println("</html>");
}
catch(Exception ex)
{
ex.printStackTrace();
}
}
public void doPost(HttpServletRequest req,HttpServletResponse res) {
this.doGet(req,res);
}
}。