下载文件时,文件名乱码

String docname="中文文件名";

String nameStr="form.doc";

String userAgent=request.getHeader("User-Agent");
if(userAgent.contains("MSIE")||userAgent.contains("Trident")){
nameStr=URLEncoder.encode(docname,"UTF-8");
}else{
nameStr=new String(docname.getBytes("UTF-8"),"iso8859-1");
}
response.setHeader("Content-Disposition", "attachment;fileName="
+nameStr);