JavaWeb导出Excel文件并弹出下载框

/**
       * 以下为生成Excel操作
       */
      // 1.创建一个workbook，对应一个Excel文件
      HSSFWorkbook wb = new HSSFWorkbook();
      // 2.在workbook中添加一个sheet，对应Excel中的一个sheet
      HSSFSheet sheet = wb.createSheet("XXX表");
      // 3.在sheet中添加表头第0行，老版本poi对excel行数列数有限制short
      HSSFRow row = sheet.createRow((int) 0);
      // 4.创建单元格，设置值表头，设置表头居中
      HSSFCellStyle style = wb.createCellStyle();
      // 居中格式
      style.setAlignment(HSSFCellStyle.ALIGN_CENTER);

      // 设置表头
      HSSFCell cell = row.createCell(0);
      cell.setCellValue("表头1");
      cell.setCellStyle(style);

      cell = row.createCell(1);
      cell.setCellValue("表头2");
      cell.setCellStyle(style);

      cell = row.createCell(2);
      cell.setCellValue("表头3");
      cell.setCellStyle(style);

      cell = row.createCell(3);
      cell.setCellValue("表头4");
      cell.setCellStyle(style);

      cell = row.createCell(4);
      cell.setCellValue("表头5");
      cell.setCellStyle(style);

// 循环将数据写入Excel
      for (int i = 0; i < lists.size(); i++) {
        row = sheet.createRow((int) i + 1);
        List list= lists.get(i);
        // 创建单元格，设置值
        row.createCell(0).setCellValue(list.getXXX());
        row.createCell(1).setCellValue(list.getXXX());
        row.createCell(2).setCellValue(list.getXXX());
        row.createCell(3).setCellValue(list.getXXX());
        row.createCell(4).setCellValue(list.getXXX());
      }

FileOutputStream out =new FileOutputStream("E:/XXX.xls");
wb.write(out); 
out.close();

String fileName = "XXX表";
      ByteArrayOutputStream os = new ByteArrayOutputStream();
      wb.write(os);
      byte[] content = os.toByteArray();
      InputStream is = new ByteArrayInputStream(content);
      // 设置response参数，可以打开下载页面
      res.reset();
      res.setContentType("application/vnd.ms-excel;charset=utf-8");
      res.setHeader("Content-Disposition", "attachment;filename="
          + new String((fileName + ".xls").getBytes(), "iso-8859-1"));
      ServletOutputStream out = res.getOutputStream();
      BufferedInputStream bis = null;
      BufferedOutputStream bos = null;

      try {
        bis = new BufferedInputStream(is);
        bos = new BufferedOutputStream(out);
        byte[] buff = new byte[2048];
        int bytesRead;
        // Simple read/write loop.
        while (-1 != (bytesRead = bis.read(buff, 0, buff.length))) {
          bos.write(buff, 0, bytesRead);
        }
      } catch (Exception e) {
        // TODO: handle exception
        e.printStackTrace();
      } finally {
        if (bis != null)
          bis.close();
        if (bos != null)
          bos.close();
      }