java生成文件名时汉字变为下划线？

public static void exportToExcel(String uid, String name, String htmlText, 

HttpServletRequest request, HttpServletResponse response) {
      htmlText = htmlText.replaceFirst("<table>", "<tableFirst>");
      htmlText = htmlText.replaceAll("<table>",
            "<table cellpadding=\"3\" cellspacing=\"0\"  border=\"1\" rull=\"all\" 

style=\"border-collapse: collapse\">");
      htmlText = htmlText.replaceFirst("<tableFirst>", "<table>");
      try (OutputStream out = response.getOutputStream()) {
         String fileName = name+ "_" + DateUtils.getNow("yyyyMMddHHmmss");
//       fileName = new String(fileName.getBytes(),"utf-8")+ ".xls";
         if ("large".equals(htmlText)) {
            ReportingPo report = reportingService.getByUid(uid);
            Map<String, Object> formParameters = generationService.getFormParameters(request.getParameterMap(), 

report.getDataRange());
            ReportTable reportTable = generationService.getReportTable(report, formParameters);
            htmlText = reportTable.getHtmlText();
         }
//       response.reset();
         response.addHeader("Content-Disposition", "attachment;filename=" +

 new String(fileName.getBytes("utf-8"),"iso-8859-1")+ ".xls");
//       response.setHeader("Content-Disposition", String.format("attachment; filename=%s", fileName));
         response.setContentType("application/vnd.ms-excel; charset=utf-8");
         response.setCharacterEncoding("utf-8");
         response.addCookie(new Cookie("fileDownload", "true"));
//       out.write(new byte[] { (byte) 0xEF, (byte) 0xBB, (byte) 0xBF }); // 生成带bom的utf8文件
         out.write(htmlText.getBytes("utf-8"));
         out.flush();
      } catch (Exception ex) {
         throw new RuntimeException(ex);
      }
   }

注意这里两个编码：

 new String(fileName.getBytes("utf-8"),"iso-8859-1")+ ".xls"