MultipartHttpServletRequest multipartRequest = (MultipartHttpServletRequest) request;
MultipartFile multipartFile = multipartRequest.getFile("file");
HSSFWorkbook wb = new HSSFWorkbook(multipartFile.getInputStream());
HSSFSheet sheet = wb.getSheetAt(0);
int num = sheet.getPhysicalNumberOfRows();
num获得的结果 ,如果我清除了内容 它还一直保持着结果记录,怎么解决这个问题 ,谢谢