public Format createFormat(Cell cell) {

        int formatIndex = cell.getCellStyle().getDataFormat();
        String formatStr = cell.getCellStyle().getDataFormatString();
        return createFormat(cell.getNumericCellValue(), formatIndex, formatStr);
    }
Create and return a Format based on the format string from a cell's style. If the pattern cannot be parsed,
return a default pattern.

@param cell The Excel cell
@return A Format representing the excel format. May return null.
fastexcel-test/src/test/java/cn/idev/excel/test/temp/dataformat/DataFormatter1.java