java导出excel

public void infoToExcel(HttpServletResponse response, UserInfoDao userInfoDao ,MyGroupDao groupDao) {
// 创建HSSFWorkbook对象(excel的文档对象)
HSSFWorkbook wb = new HSSFWorkbook();
// 建立新的sheet对象（excel的表单）
HSSFSheet sheet = wb.createSheet("textMsg");
// 时间戳转换为日期对象
TimeStapToDate tsd = new TimeStapToDate();

HSSFRow row;
row = sheet.createRow(0);
row.createCell(0).setCellValue("昵称");
row.createCell(1).setCellValue("备注名");
row.createCell(2).setCellValue("性别");
row.createCell(3).setCellValue("国家");
row.createCell(4).setCellValue("省份");
row.createCell(5).setCellValue("城市");
row.createCell(6).setCellValue("关注时间");
row.createCell(7).setCellValue("分组名");

List<UserInfo> list = userInfoDao.findAll();//实体对象的集合

UserInfo user;
for (int i = 0; i < list.size(); i++) {
user = list.get(i);
row = sheet.createRow(i + 1);
row.createCell(0).setCellValue(user.getNickName());
row.createCell(1).setCellValue(user.getRemark());
row.createCell(2).setCellValue(user.getSex());
row.createCell(3).setCellValue(user.getCountry());
row.createCell(4).setCellValue(user.getProvince());
row.createCell(5).setCellValue(user.getCity());
String stamp = user.getSubscribeTime()+"";
row.createCell(6).setCellValue(tsd.timeStampToDateYear(stamp));
row.createCell(7).setCellValue(groupDao.findById(user.getGroupId()).getGroupName());
}

// 输出Excel文件
OutputStream output;
try {
output = response.getOutputStream();
response.reset();
response.setHeader("Content-disposition", "attachment; filename=userInfo.xls");
response.setContentType("application/msexcel");
wb.write(output);
output.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}