第八周
1.登陆
输入用户名密码，判断用户名和密码相同，登陆成功，session中保存用户的用户名，进入主页main.jsp，主页有一个退出按钮，点击，回到登陆页login.jsp。要求：退出登录后，如果在浏览器直接输入主页main.jsp，访问不了，直接跳到登陆页。
<%@ 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></title>
</head>
<body>
<form action="MyJsp.jsp" method="post" name="login">
用户名：<input type="text" name="uname" size="20"><br>
密 码：<input type="password" name="upwd" size="20"><br>
<input type="button" value="登录" onClick="validate()">
</form>
<script type="text/javascript">
function validate() {
if (login.uname.value == "") {
alert("用户名不能为空!");
return;
}
if (login.upwd.value == "") {
alert("密码不能为空!");
return;
}
login.submit();
}
</script>
</body>
</html>
<%@ 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></title>
</head>
<body>
<%
//设置编码
request.setCharacterEncoding("UTF-8");
response.setCharacterEncoding("UTF-8");
//获取请求数据
String uname = request.getParameter("uname");
String upwd = request.getParameter("upwd");
//判断密码和用户名是否相同
if (uname.equals(upwd)) {
session.setAttribute("uname",uname);
request.getRequestDispatcher("b.jsp")
.forward(request, response);
} else {
response.sendRedirect("c.jsp");
}
%>
</body>
</html>
<%@ 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></title>
</head>
<body>
<%
String uname = (String) session.getAttribute("uname");
//如果他是空，说明没登陆，直接访问该页面了
if (uname == null) {
response.sendRedirect("text.jsp");
}
%>
欢迎你<%=uname%><br>
<a href="a.jsp">退出登录</a>
<br>
</body>
</html>
<%@ 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></title>
</head>
<body>
<%
session.invalidate();//结束会话
response.setHeader("refresh", "5;url=text.jsp");
%>
</body>
</html>
<%@ 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></title>
</head>
<body>
<h1>登陆失败！！</h1>
<%response.setHeader("refresh", "5;url=text.jsp");%>
</body>
</html>
2.购物车
和上一题一起，在main.jsp中做一个购物车，里面显示3个商品名和价格 每一个后面有一个加入购物车按钮，main.jsp中有一个按钮（或者超链接）可以显示购物车。（选作：在购物车中加删除按钮删除商品）
<body>
<script type="text/javascript">
function val() {
if (loginForm.account.value == "") {
alert("账号不能为空");
return;
} else if (loginForm.pas.value == "") {
alert("密码不能为空");
return;
}
loginForm.submit();
}
</script>
<form action="log.jsp">
账号<input type="text" name="account">
密码<input type="password" name="pas">
<input type="submit" value="登录" />
</form>
</body>
<body>
<%
request.setCharacterEncoding("utf-8");
String uname = request.getParameter("account");
String upwd = request.getParameter("pas");
if(uname.equals(upwd)){
session.getAttribute("uname");
response.sendRedirect("main.jsp");
}else{
response.sendRedirect("no.jsp");
}
%>
</body>
<body>
<input type="button"
onclick="window.location.href='index.jsp';" value="退出登录">
<form action="buy.jsp" method="post">
<table border="0" cellspacing="30">
<tr>
<td>笔记本</td>
<td><input type="checkbox" name="item" value="computer"></td>
<td>￥5000</td>
</tr>
<tr>
<td>香水</td>
<td><input type="checkbox" name="item" value="perfume"></td>
<td>￥200</td>
</tr>
<tr>
<td>鲜花</td>
<td><input type="checkbox" name="item" value="flower"></td>
<td>￥50</td>
</tr>
<tr>
<td>苹果</td>
<td><input type="checkbox" name="item" value="apple"></td>
<td>￥20</td>
</tr>
</table>
<input type="submit" value="添加购物车">
</form>
</body>
<body>
登陆失败<br>用户名或密码错误
</body>
<body>
<h2>购物车的商品有：</h2>
<%
request.setCharacterEncoding("utf-8");
String itemName[] = request.getParameterValues("item");
if (itemName == null) {
out.print("购物车为空！");
} else {
for (int i = 0; i < itemName.length; i++) {
out.print("(" + (i + 1) + ")" + itemName[i] + "<br>");
}
}
%>
</body>
