第八周作业
<body>
<form name="form" action="dologin.jsp" method="post">
账号：<input type="text" name="usernaem"><br>
密码：<input type="password" name="psw"><br>
<input type="submit" value="登录" >
</form>
</body>
<body>
<%
request.setCharacterEncoding("utf-8");
String usernaem=request.getParameter("usernaem");
String psw=request.getParameter("psw");
if(usernaem.equals(psw)){
session.setAttribute("usernaem", usernaem);
request.getRequestDispatcher("main.jsp").forward(request,response);
}else{
request.getRequestDispatcher("no.jsp").forward(request,response);
}
%>
</body>
<body>
<h1>登陆成功！</h1>
<%
String usernaem = (String) session.getAttribute("usernaem");
if (usernaem == null)
response.sendRedirect("login.jsp");
%>
<form name="form1" action="logout.jsp" method="post">
<input type="submit" value="退出登录">
</form>
</body>
<body>
<%
session.invalidate();
response.setHeader("refresh", "5;url=login.jsp");
%>
</body>
<body>
<h1>登陆失败！！</h1>
<%response.setHeader("refresh", "5;url=login.jsp");%>
</body>
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>
<%
String usernaem = (String) session.getAttribute("usernaem");
if (usernaem == null)
response.sendRedirect("login.jsp");
%>
欢迎光临
<hr>
商品展示:
<br>
<form action="gouwuche.jsp" method="post">
请选择要加入购物车的商品：<br>
牛肉饭 ￥30 <input type="checkbox" name="list" value="牛肉饭"> <br>
黄焖鸡 ￥25 <input type="checkbox" name="list" value="黄焖鸡"> <br>
汤面 ￥16 <input type="checkbox" name="list" value="汤面"> <br>
<hr>
<input type="submit" value="加入购物车">
<a href="logout.jsp">退出登录</a>
</form>
</body>
<body>
<h2>购物车中的商品有：</h2>
<%
request.setCharacterEncoding("utf-8");
String listName[] = request.getParameterValues("list");
if (listName == null) {
out.print("你没有选购物品");
} else {
for (int i = 0; i < listName.length; i++) {
out.print("(" + (i + 1) + ")" + listName[i] + "<br>");
}
}
%>
</body>
