用include标签包含的文件中的汉字在页面中全是??号，什么原因啊？代码如下
<%@ page contentType= "text/html; charset=GB2312 " language= "java " import= "java.sql.* " errorPage= " " %>
<html >
<head>
<meta http-equiv= "Content-Type " content= "text/html; charset=gb2312 " />
<title> 无标题文档 </title>
</head>
<body>
<table width= "200 " border= "1 ">
<tr>
<td> <%@ include file= "head.txt " %> </td>
</tr>
</table>
<H1>
<CENTER>
<p> 欢迎光临网上书店 </p>
<p> </p>
</CENTER>
</body>
</html>
------解决方案--------------------
http://community.csdn.net/Expert/topic/5532/5532558.xml?temp=.7193109