jsp登录页面的简单实例 雏形

%@ page language="java" contentType="text/html; charset=UTF-8"
  pageEncoding="UTF-8"%>
!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
html>
head>
meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
title>欢迎页面/title>
/head>
body>
%
session.invalidate();//销毁session

%>

a href="denglu.jsp" >亲，请登录/a>
a href="zhuce.jsp">注册/a>
/body>
/html>

%@ page language="java" contentType="text/html; charset=UTF-8"
  pageEncoding="UTF-8"%>
!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
html>
head>
meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
title>登录/title>
/head>
body>
form action="test_denglu.jsp" method="post"> 
table width="300" height="300" border="0" align="center">
  tr height="80" align="center">
    td colspan="2">font size="24">OO登录/font>/td>/tr>
  tr height="30">
    td width="80" align="right">用户名：/td>             
    td>input type="text" name="username">/td>/tr>
  tr height="30">
    td width="80" align="right"> 密nbsp;nbsp;码：/td>
    td> input type="password" name="password">/td>/tr>
    tr>td height="40" align="center" colspan="2">
    input type="submit" value="登录">
    /td>/tr>
 /table>
/form>
/body>
/html>

%@ page language="java" contentType="text/html; charset=UTF-8"
  pageEncoding="UTF-8"%>
!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
html>
head>
meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
title>注册/title>
/head>
body>
form action="test_zhuce.jsp" method="post"> 
table width="300" height="300" border="0" align="center">
  tr height="80" align="center">
    td colspan="2">font size="24">OO注册/font>/td>/tr>
  tr height="30">
    td width="80" align="right">用户名：/td>             
    td>input type="text" name="username">/td>/tr>
  tr height="30">
    td width="80" align="right"> 密nbsp;nbsp;码：/td>
    td> input type="password" name="password">/td>/tr>
    tr>td height="40" align="center" colspan="2">
    input type="submit" value="提交">
    /td>/tr>
 /table>
/form>
/body>
/html>

%@ page language="java" contentType="text/html; charset=UTF-8"
  pageEncoding="UTF-8" import="java.sql.*"%>
!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
html>
head>
meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
title>检测跳转中/title>
/head>
body>
%
String name = new String(request.getParameter("username").getBytes("ISO-8859-1"),"UTF-8");
String pw = request.getParameter("password"); 

String str = "select * from USERS WHERE username = '" + name + "'";
String str1 = "insert into users values(xuhao.nextval,'" + name + "','" + pw +"')";

try{
  
   //连接数据库
   Connection conn = null;
   Class.forName("oracle.jdbc.driver.OracleDriver");
   String strURL = "jdbc:oracle:thin:@localhost:1521:SP";
   conn = DriverManager.getConnection(strURL, "test", "123");
   System.out.println("数据库连接成功");
   Statement st = conn.createStatement();
   ResultSet rs = st.executeQuery(str);
   if(rs.next()){
     if(name.equals(rs.getString(2))){
       out.println("对不起，用户名已使用。");
       out.println("br>建议使用用户名：" + name +"99"); 
       response.setHeader("refresh", "5;URL=zhuce.jsp");
     }
   }else{
     int a = st.executeUpdate(str1);
     if(a == 1){
       out.println("恭喜你，注册成功");
       session.setAttribute("username", name);
       response.setHeader("refresh", "3;URL=denglu.jsp");
     }
   }
   
   rs.close();
   st.close();
   conn.close();
}catch(Exception e){
  e.printStackTrace();
}
%>
br>br>

/body>
/html>

%@ page language="java" contentType="text/html; charset=UTF-8"
  pageEncoding="UTF-8"%>
!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
html>
head>
meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
title>主页面/title>
/head>
body>
主页面
%
Object obj = session.getAttribute("username");
if(obj != null){
  String str = obj.toString();
  out.println(str + "登陆成功");
}else{
  out.println("登录超时，请重新登录"); 
  response.setHeader("refresh", "5;URL=denglu.jsp");
}
%>
br>

a href="yemian.jsp">退出账号/a>

/body>
/html>