@RequestMapping(value = "/export_data")
public void downloadDataInCsv(
        @RequestParam("type") String type,
        @RequestParam("tID") String tableId,
        HttpServletRequest request,
        HttpServletResponse response) throws IOException {
    if (type.equals("csv")) {
        List<UserInfo> list = userInfoDao.findById(tableId);
        ExportCsvUtil.downloadCsv(request, response, list);
    }
}
private void downloadCsv(HttpServletRequest request, HttpServletResponse response, List<UserInfo> list) throws IOException {
    String headerKey = "Content-Disposition";
    String headerValue = String.format("attachment; filename=Table_Data.csv");
    response.setContentType("text/csv");
    response.setHeader(headerKey, headerValue);

    try (final CSVWriter writer = new CSVWriter(response.getWriter(), ",")) {

        writer.writeNext(new String[]{"User Id", "First Name", "Last Name", "Roll No", "Email ID", "Gender"});

        for (UserInfo entry: list) {
            // cast/convert to String where needed
            writer.writeNext(new String[]{entry.getUserId()+"", entry.getFirstName(), entry.getLastName(),entry.getRollNo(),entry.getEmail(),entry.getGender()});
        }
        writer.close();
    }
}