老生常谈 -- Servlet取jsp页面的中文参数 乱码

首先是Jsp页面，
Java code:

<%@page pageEncoding="GB18030" contentType="text/html; charset=gb18030"%>
<LINK href="../../resources/survey/style.css" rel=stylesheet>
<form action=../../vote?cmd=modify method=post>
<br>
<TABLE width=98% align=center border=0 >
<tr>
<td>选项1：</td>
<td><input type=text size=40% name=item1 maxlength=10></td>
</tr>
</table>
<br>
<INPUT class=buttonface type=submit value=发布 name=Submit>
<INPUT class=buttonface type=button value=返回 name=Submit2 onClick=history.back()>
</form>



填写是出入“中文”二字。

然后是servlet获取参数的语句：
Java code:

String s = req.getCharacterEncoding();
System.out.println(s); //这里输出的是“UTF-8” ①
String a = req.getParameter("item1"); //a=?? ②
a = new String(req.getParameter("item1").getBytes("UTF-8"),"gb18030"); //这里a=?? ③
System.out.println(a);



获取参数时，①处显示是utf-8，那③处的转换怎么不生效呢？该怎么办

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gbk或者gb2312吧

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Spring 也有个Filter
<filter>
<filter-name>encodingFilt