从excel文件读取空白单元格到2d数组

我有一个从第二行（它跳过列名）从xls文件读取login名和密码，并将其写入到二维数组中的以下代码。 但是，只有在任何行中没有空单元格的情况下才有效。 我应该怎么做，使其与空细胞工作？

private static Object[][] getUsersFromXls(String sheetName) { final File excelFile = new File("src//resources//TestData.xls"); FileInputStream fileInputStream; try { fileInputStream = new FileInputStream(excelFile); workbook = new HSSFWorkbook(fileInputStream); } catch (IOException e) { e.printStackTrace(); } sheet = workbook.getSheet(sheetName); final int numberOfRows = sheet.getLastRowNum(); final int numberOfColumns = sheet.getRow(0).getLastCellNum(); final String[][] xlsData = new String[numberOfRows][numberOfColumns]; String cellValue; for (int i = 1; i <= numberOfRows; i++) { final HSSFRow row = sheet.getRow(i); for (int j = 0; j < numberOfColumns; j++) { final HSSFCell cell = row.getCell(j); final int cellType = cell.getCellType(); if (cellType == HSSFCell.CELL_TYPE_FORMULA) { throw new RuntimeException("Cannot process a formula. Please change field to result of formula."); } else { cellValue = String.valueOf(cell); xlsData[i - 1][j] = cellValue; } } } return xlsData; }