linux 导出文件名乱码

String agent = this.getRequest().getHeader("User-Agent");
  if(null == filename || null == agent){
   return _filename;
  }
  if(agent.toLowerCase().contains("firefox")){
   _filename = filename;
  }else {//非火狐浏览器
   try {
    _filename = new String(filename.getBytes("ISO8859-1"),"UTF-8");
    _filename = java.net.URLEncoder.encode(filename, "UTF-8");
   } catch (UnsupportedEncodingException e) {
    e.printStackTrace();
    return filename;
   }
  }
     return _filename;