// 按照行优先进行数据表格的初始化
 public static void createRows() throws IOException {

        Workbook wb = new HSSFWorkbook();
        // 创建表格
        Sheet sheet = wb.createSheet("测试Sheet_01");
        List<String> list = new ArrayList<String>();
        list.add("a");
        list.add("b");
        int rowCount = list.size(); // 根据数据集设置行数
        for (int i = 0; i < rowCount; i++) {
            Row row = sheet.createRow(i);// 创建行，表头是第0行
            for (int j = 0; j < list.size(); j++) {
                // 为第一个单元格赋值
                Cell cell = row.createCell(0);
                cell.setCellValue("测试数据");
                // 为第二个单元格赋值
                Cell cell_1 = row.createCell(1);
                cell_1.setCellValue("test");

            }

        }

        FileOutputStream fos = new FileOutputStream("/Users/file/测试的Excel.xls");
        wb.write(fos);
        if (null != fos) {
            fos.close();
        }
        System.out.println("测试数据完成输出。。");
    }

// 将文件内容转换为二维数组
    @SuppressWarnings("resource")
    private static String[][] getData(FileItem fileItem, int ignoreRows)

    throws FileNotFoundException, IOException {

        List<String[]> result = new ArrayList<String[]>();
        int rowSize = 0;
        BufferedInputStream in = new BufferedInputStream(fileItem.getInputStream());

        Workbook wb;
        if (fileItem.getName().indexOf(".xlsx") > -1) {
            wb = new XSSFWorkbook(in);
        } else {
            wb = new HSSFWorkbook(in);
        }
        Cell cell = null;
        for (int sheetIndex = 0; sheetIndex < wb.getNumberOfSheets(); sheetIndex++) {

            Sheet st = wb.getSheetAt(sheetIndex);
            // 第一行为标题，不取
            for (int rowIndex = ignoreRows; rowIndex <= st.getLastRowNum(); rowIndex++) {
                Row row = st.getRow(rowIndex);
                if (row == null) {
                    continue;
                }

                int tempRowSize = row.getLastCellNum() + 1;
                if (tempRowSize > rowSize) {
                    rowSize = tempRowSize;
                }

                String[] values = new String[rowSize];
                Arrays.fill(values, "");
                boolean hasValue = false;
                for (int columnIndex = 0; columnIndex <= row.getLastCellNum(); columnIndex++) {

                    String value = "";
                    cell = row.getCell(columnIndex);
                    if (cell != null) {
                       //按照单元格数据类型进行数据处理
                        switch (cell.getCellType()) {
                            case HSSFCell.CELL_TYPE_STRING:
                                value = cell.getStringCellValue();
                                break;
                            case HSSFCell.CELL_TYPE_NUMERIC:
                                if (HSSFDateUtil.isCellDateFormatted(cell)) {
                                    Date date = cell.getDateCellValue();
                                    if (date != null) {
                                        value = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(date);
                                    } else {
                                        value = "";
                                    }

                                } else {
                                    value = new DecimalFormat("0").format(cell.getNumericCellValue());

                                }
                                break;
                            case HSSFCell.CELL_TYPE_FORMULA:
                                // 导入时如果为公式生成的数据则无值
                                if (!cell.getStringCellValue().equals("")) {
                                    value = cell.getStringCellValue();
                                } else {
                                    value = cell.getNumericCellValue() + "";
                                }
                                break;
                            case HSSFCell.CELL_TYPE_BLANK:
                                break;
                            case HSSFCell.CELL_TYPE_ERROR:
                                value = "";
                                break;
                            case HSSFCell.CELL_TYPE_BOOLEAN:
                                value = (cell.getBooleanCellValue() == true ? "Y" : "N");
                                break;
                            default:
                                value = "";
                        }

                    }

                    if (columnIndex == 0 && value.trim().equals("")) {
                        break;
                    }

                    values[columnIndex] = rightTrim(value);
                    hasValue = true;
                }

                if (hasValue) {
                    result.add(values);
                }

            }

        }

        in.close();
        String[][] returnArray = new String[result.size()][rowSize];
        for (int i = 0; i < returnArray.length; i++) {
            returnArray[i] = (String[]) result.get(i);
        }
        return returnArray;
    }
            

org.apache.poi.poifs.filesystem.OfficeXmlFileException: The supplied data appears to be in the Office 2007+ XML. You are calling the part of POI that deals with OLE2 Office Documents. You need to call a different part of POI to process this data (eg XSSF instead of HSSF)