观看慕课老师milanlover视频JSP状态管理+cookie
创建cookie对象调用它的构造方法，构造方法接收两个参数，是一种键值对描述：键：cookie对象的字符串描述；值：要保存的cookie对象。
Value：字符串
The superclass "javax.servlet.http.HttpServlet" was not found on the Java Build Path
login.jsp：用户登录界面；
dologin.jsp：处理用户登录请求的页面，要保存cookie，页面下方有一个超链接，链接到查看用户信息的页面；
users.jsp：查看用户信息的页面
【python】python新手必碰到的问题---encode与decode，中文乱码[转]
login.jsp：
<%@ page language="java" import="java.util.*,java.net.*" contentType="text/html; charset=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 'index.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>
<body>
<h1>用户登录</h1>
<hr>
<%
request.setCharacterEncoding("utf-8");
String username="";
String password = "";
Cookie[] cookies = request.getCookies();
if(cookies!=null&&cookies.length>0)
{
for(Cookie c:cookies)
{
if(c.getName().equals("username"))
{
username = URLDecoder.decode(c.getValue(),"utf-8");
}
if(c.getName().equals("password"))
{
password = URLDecoder.decode(c.getValue(),"utf-8");
}
}
}
%>
<form name="loginForm" action="dologin.jsp" method="post">
<table>
<tr>
<td>用户名：</td>
<td><input type="text" name="username" value="<%=username %>"/></td>
</tr>
<tr>
<td>密码：</td>
<td><input type="password" name="password" value="<%=password %>" /></td>
</tr>
<tr>
<td colspan="2"><input type="checkbox" name="isUseCookie" checked="checked"/>十天内记住我的登录状态</td>
</tr>
<tr>
<td colspan="2" align="center"><input type="submit" value="登录"/><input type="reset" value="取消"/></td>
</tr>
</table>
</form>
</body>
</html>
dologin.jsp：
<%@ page language="java" import="java.util.*,java.net.*" contentType="text/html; charset=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 'dologin.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>
<body>
<h1>登录成功</h1>
<hr>
<br>
<br>
<br>
<%
request.setCharacterEncoding("utf-8");
//首先判断用户是否选择了记住登录状态
String[] isUseCookies = request.getParameterValues("isUseCookie");
if(isUseCookies!=null&&isUseCookies.length>0)
{
//把用户名和密码保存在Cookie对象里面
String username = URLEncoder.encode(request.getParameter("username"),"utf-8");
//使用URLEncoder解决无法在Cookie当中保存中文字符串问题
String password = URLEncoder.encode(request.getParameter("password"),"utf-8");
Cookie usernameCookie = new Cookie("username",username);
Cookie passwordCookie = new Cookie("password",password);
usernameCookie.setMaxAge(864000);//保存的单位是s
passwordCookie.setMaxAge(864000);//设置最大生存期限为10天
response.addCookie(usernameCookie);
response.addCookie(passwordCookie);
}
else
{
Cookie[] cookies = request.getCookies();
if(cookies!=null&&cookies.length>0)
{
for(Cookie c:cookies)
{
if(c.getName().equals("username")||c.getName().equals("password"))
{
c.setMaxAge(0); //设置Cookie失效
response.addCookie(c); //重新保存。
}
}
}
}
%>
<a href="users.jsp" target="_blank">查看用户信息</a>
</body>
</html>
users.jsp：
<%@ page language="java" import="java.util.*,java.net.*" contentType="text/html; charset=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 'users.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>
<body>
<h1>用户信息</h1>
<hr>
<%
request.setCharacterEncoding("utf-8");
String username="";
String password = "";
Cookie[] cookies = request.getCookies();
if(cookies!=null&&cookies.length>0)
{
for(Cookie c:cookies)
{
if(c.getName().equals("username"))
{
username = URLDecoder.decode(c.getValue(),"utf-8");
}
if(c.getName().equals("password"))
{
password = URLDecoder.decode(c.getValue(),"utf-8");
}
}
}
%>
<BR>
<BR>
<BR>
用户名：<%=username %><br>
密码：<%=password %><br>
</body>
</html>
cookie保存比方说浏览记录、访问习惯、关注的爱好和兴趣等。
session安全性比cookie高。