第八周作业
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。
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
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<!DOCTYPE HTML >
<html>
<head>
<title>My JSP 'index.jsp' starting page</title>
</head>
<body>
<script>
function yz() {
if (form.user.value == "") {
alert('用户名不能为空');
return;
}
if (form.password.value =="") {
alert('密码不能为空');
return;
}
form.submit();
}
</script>
<form action="index.jsp" method="post" name="form">
<table>
<tr>
<td>用户名：</td>
<td><input type="text" name="user"></td>
</tr>
<tr>
<td>密码：</td>
<td><input type="password" name="password"></td>
</tr>
<tr>
<td><input type="button" value="登录" onclick="yz()"></td>
</tr>
</table>
</form>
</body>
</html>
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<!DOCTYPE HTML >
<html>
<head>
<title>My JSP 'index.jsp' starting page</title>
</head>
<body>
<%
String user = request.getParameter("user");
String password = request.getParameter("password");
if (user.equals(password)) {
session.setAttribute("user", user);
request.getRequestDispatcher("index1.jsp").forward(request,
response);
} else {
response.sendRedirect("Copy of index.jsp");
}
%>
</body>
</html>
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<!DOCTYPE HTML >
<html>
<head>
<title>My JSP 'index.jsp' starting page</title>
</head>
<body>
<%
String user = (String) session.getAttribute("user");
if (user == null) {
response.sendRedirect("Copy of index.jsp");
}
%>
欢迎你<%=user%>
<a href="index2.jsp">退出登录</a>
<form action="index3.jsp" method="post">
<table border="1" cellpadding="0" cellspacing="0" width="500">
<thead>
<tr>
<th>商品名称</th>
<th>价格</th>
<th>加购</th>
</tr>
</thead>
<tbody>
<tr>
<td>方便面</td>
<td>3</td>
<td align="center"><input type="checkbox" name="sp" value="方便面">
</td>
</tr>
<tr>
<td>元气森林</td>
<td>5</td>
<td align="center"><input type="checkbox" name="sp" value="元气森林">
</td>
</tr>
<tr>
<td>面包</td>
<td>4</td>
<td align="center"><input type="checkbox" name="sp" value="面包">
</td>
</tr>
<tr>
<td colspan="3"><input type="submit" value="加购">
</td>
</tr>
</tbody>
</table>
</form>
</body>
</html>
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<!DOCTYPE HTML >
<html>
<head>
<title>My JSP 'index.jsp' starting page</title>
</head>
<body>
<%
session.invalidate();
response.sendRedirect("Copy of index.jsp");
%>
</body>
</html>
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<!DOCTYPE HTML >
<html>
<head>
<title>显示购物车</title>
</head>
<body>
<%
request.setCharacterEncoding("utf-8");
String[] sp = request.getParameterValues("sp");
for (int i = 0; sp != null && i < sp.length; i++) {
out.print(sp[i] + "<br>");
}
%>
</body>
</html>
