jsp提交数据为null,不知原因,请教?
下面是页面
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%@ page language="java" import="java.util.*" pageEncoding="GB2312"%>
<%
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>电表信息设置</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">
-->
<script type="text/javascript">
function mysubmit(type){
ammeterInfo.action = ammeterInfo.action + type ;
}
</script>
</head>
<body>
<table width="80%" border="1" align="center"
bordercolor="#99CCFF">
<tbody>
<tr>
<td width="5%">
</td>
<td width="24%" height="5%" align="center" valign="middle">
电表类型
</td>
<td width="24%" height="5%" align="center" valign="middle">
电表名称
</td>
<td width="23%" height="5%" align="center" valign="middle">
生产厂家
</td>
<td width="24%" height="5%" align="center" valign="middle">
电表常数
</td>
<td width="24%" height="5%" align="center" valign="middle">
表安培数
</td>
<td width="24%" height="5%" align="center" valign="middle">
表电压数
</td>
<td width="24%" height="5%" align="center" valign="middle">
电表相数
</td>
<td width="24%" height="5%" align="center" valign="middle">
过载倍数
</td>
<td width="24%" height="5%" align="center" valign="middle">
型号版本
</td>
</tr>
<c:forEach var="ammeter" items="${listInfo}">
<tr>
<td>
<input type="checkbox" name="id" value="${ammeter.电表类型}" />
</td>
<td width="24%" height="5%" align="center" valign="middle">
${ammeter.电表类型}
</td>
<td width="24%" height="5%" align="center" valign="middle">
${ammeter.电表名称}
</td>
<td width="23%" height="5%" align=