jsp从servlet接收了一个数组，想利用select让用户选择后将选择后的结果提交回servlet，结果在向servlet提交过程中参数一直传不过去，求大神帮忙解决一下
<! --classselect.jsp-->
<%@ 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>My JSP 'banjishumu.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<%String[] a = (String[])request.getSession().getAttribute("a");%>
<%int i=0; %>
<form action="Main" method="post" name="form2">
请选择班级名称：<select name="ok1">
<% while(a[i]!=null)
{%>
<option value='<%=a[i] %>'><% out.println(a[i]);i++;%></option>
<% } %>
</select>
<input type="submit" name="submit1" value="确认"/></form>
</body>
</html>
//Main.java
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=utf-8");
String adname=request.getParameter("adname");
String ok1=request.getParameter("ok1");
String []a=new String[100];
request.getSession().setAttribute("a",a);
request.getRequestDispatcher("classselect.jsp").forward(request, response);
}
