1.
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<html>
<head>
<title>My JSP 'index.jsp' starting page</title>
</head>
<body>
<script type="text/javascript">
function validate(){
if(loginForm.uname.value==""){
alert("账号不能为空!");
return;
}
if(loginForm.upwd.value==""){
alert("密码不能为空!");
return;
}
loginForm.submit();
}
</script>
<form name="loginForm" action="dologin.jsp" method="post">
用户名:<input type="text" name="uname" ><br>
密码: <input type="password" name="upwd" >
<input type="button" value="登录" onClick="validate()">
</form>
</body>
</html>
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
request.setCharacterEncoding("utf-8");
String uname = request.getParameter("uname");
String upwd = request.getParameter("upwd");
if (uname.equals(upwd)){
//转发到ok页面,但是url没变
session.setAttribute("uname", uname);
request.getRequestDispatcher("main.jsp").forward(request,response);
}
else{
//重定向回login.jsp,浏览器url也变
response.sendRedirect("no.jsp");
}
%>
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<html>
<head>
<title>My JSP 'index.jsp' starting page</title>
</head>
<body>
<%
session.invalidate();
response.setHeader("refresh", "5;url=login.jsp");
%>
退出成功
</body>
</html>
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<html>
<head>
<title>My JSP 'index.jsp' starting page</title>
</head>
<body>
<h1>登陆失败!!</h1>
<%response.setHeader("refresh", "5;url=login.jsp");%>
</body>
</html>

2.
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP 'main.jsp' starting page</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("login.jsp");
}
%>
欢迎你<%=uname%><br>
<a href="loginout.jsp">退出登录</a>
<br>
<form action="buy.jsp">
<hr>
是否加入购物车?<br> <input name="item" type="checkbox" value="weilong">
辣条 $1<br> <input name="item" type="checkbox" value="xizhilang">
果冻 $2<br> <input name="item" type="checkbox" value="menglong">
雪糕 $3<br>
<hr>
<input type="submit" value="加入购物车">
</form>
</body>
</html>
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP 'buy.jsp' starting page</title>
</head>
<body>
<h2>购物车</h2>
<%
request.setCharacterEncoding("utf-8");
String itemName[] = request.getParameterValues("item");
if (itemName == null) {
out.print("购物车为空");
} else {
for (int k = 0; k < itemName.length; k++) {
out.print("(" + (k + 1) + ")" + itemName[k] + "<br>");
}
}
%>
</body>
</html>

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