JSP重定向小例子（不讲原理）

编写一个JSP页面lucknum.jsp，产生0-9之间的随机数作为用户幸运数字，将其保存到会话中，并重定向到另一个页面showLuckNum.jsp中，在该页面中将用户的幸运数字显示出来

lucknum.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
<!-- <script type="text/javascript">
    /*产生随机数  */
    function fun(){
        int num = Math.round(Math.random()*9);
    }

</script> -->
</head>
<body >
<%
    //获取幸运数字
    double num = Math.random()*10;
    long lucknum=Math.round(num);
    session.setAttribute("lucknum", lucknum);
    response.sendRedirect("two.jsp");

 %>
</body>
</html>

showLuckNum.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<%
    Object lucknum = session.getAttribute("lucknum");
    if(lucknum.toString().equals("5")){
        out.print("恭喜中奖了，数字是："+lucknum.toString());
    }else{
            out.print("没中奖，数字是："+lucknum.toString());
    
    }
    

 %>
</body>
</html>