jsp登陆校验演示servlet、login、success的方法技巧
jsp的登录校验Demo
part_1:login.jsp:登录页面:
<%@ 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>My JSP 'Login.jsp' starting page</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>
<%
String fdbkMsg = (String) request.getAttribute("fdbkMsg");
if (null == fdbkMsg) {
fdbkMsg = "";
}
%>
<%
Boolean logedIn = (Boolean) session.getAttribute("logedIn");
if (null == logedIn) {
logedIn = false;
} else if (logedIn) {
//如果在本次会话已经登陆，直接重定向到success-page-1
response
.sendRedirect("/ServletDemoProject/LOGIN-DEMO/success-page-1.jsp");
}
%>
<%
String username = "";
Cookie[] cookies = request.getCookies();
if ((null != cookies) && (cookies.length > 0)) {
for (Cookie c : cookies) {
if ("admin".equals(c.getValue())) {
username = "admin";
break;
}
}
}//end if-condition
%>
<body>
<br>
<div align="center">
请登录:
<br>
<form action="/ServletDemoProject/servlet/LoginVerificationServlet"
method="post">
用户名：
<input type="text" name="username" value="<%=username%>" />
<br>
密 码：
<input type="password" name="password" value="" />
<br>
<font color='red'><%=fdbkMsg%></font>
<br>
<input type="submit" value="提交" />
<br>
</form>
</div>
</body>
</html>
part_2:LoginVerificationServlet.java:校验登录信息，此处没有连接数据库，默认只有username：admin，password：888888才算登录成功；登陆失败时：重新转发到Login.jsp并提示用户登陆失败，重新登陆；
package cn.mike.servlet.test_1209_Login;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class LoginVerificationServlet extends HttpServlet {
private static final long serialVersionUID = -6886327892796230543L;
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String username = request.getParameter("username");
String password = request.getParameter("password");
if (("admin".equals(username)) && ("888888".equals(password))) {// 登录成功
// 保存cookie到客户端
Cookie userCookie = new Cookie("username", username);
userCookie.setMaxAge(60 * 2);// expiry : 2 minutes
response.addCookie(userCookie);
// 重定向到一个新的页面，并提示XXX用户登录成功（使用session存取用户名）;
request.getSession().setAttribute("username", username);
request.getSession().setAttribute("logedIn", true);
response
.sendRedirect("/ServletDemoProject/LOGIN-DEMO/success-page-1.jsp");
} else {// 登陆失败
// 转发到登录界面，并提示错误信息：
request.setAttribute("fdbkMsg", "用户名或密码错误！");
request.getRequestDispatcher("/LOGIN-DEMO/Login.jsp").forward(
request, response);
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// do same as GET-method :
doGet(request, response);
}
}
part_3:success-page-1.jsp:校验登录成功后重定向到该页面，提示用户已经成功登陆；如果用户试图通过不正当途径，e.g:从地址栏访问，将会转发到登录界面，并作提示；
<%@ 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>My JSP 'success-page-1.jsp' starting page</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>
<%
String username = (String) session.getAttribute("username");
if (null == username) {
//如果username为空值，说明不是通过正常渠道来的，转发到Login页面；
request.setAttribute("fdbkMsg", "别想走后门进来，赶紧登录！");
request.getRequestDispatcher("/LOGIN-DEMO/Login.jsp").forward(
request, response);
}
%>
<body>
<br>
<%=username%>已经成功登陆。
<br>
<font>您可以选择浏览：</font>
<br>
<a href="/ServletDemoProject/LOGIN-DEMO/success-page-2.jsp">点这儿有精彩.</a>
<br>
<a href="/ServletDemoProject/LOGIN-DEMO/success-page-2.jsp">点这儿更精彩.</a>
<br />
<a href="/ServletDemoProject/LOGIN-DEMO/success-page-2.jsp">你敢点这儿吗.</a>
<br />
</body>
</html>
part_4:success-page-2.jsp:登陆成功页面2，如果已经登陆成功将用户名保存到session，在访问该页面时将会校验一下，防止从地址栏暴力访问；
<%@ page language="java" import="java.util.Date" pageEncoding="UTF-8"%>
<%@ page language="java" import="java.text.SimpleDateFormat"%>
<%
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>My JSP 'success-page-2.jsp' starting page</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>
<%
String username = (String) session.getAttribute("username");
if (null == username) {
request.setAttribute("fdbkMsg", "呵呵嗒，这里是你来的地方吗？快登陆！");
//转发到登录界面:
request.getRequestDispatcher("/LOGIN-DEMO/Login.jsp").forward(
request, response);
}
SimpleDateFormat sDateFormat = new SimpleDateFormat("a");
Date today = new Date();
String am_pm_str = sDateFormat.format(today);
String am_pm_str_in_chinese = "";
if ("am".equalsIgnoreCase(am_pm_str)) {
am_pm_str_in_chinese = "上午";
} else
am_pm_str_in_chinese = "下午";
// set null;
sDateFormat = null;
today = null;
am_pm_str = null;
%>
<body>
<br />
<font><b><%=username%><%=am_pm_str_in_chinese%>好，能来到页面2真不简单.</b>
</font>
</body>
</html>
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