public static CellStyle buildCellStyle(Workbook workbook, CellStyle originCellStyle,
        WriteCellStyle writeCellStyle) {
        CellStyle cellStyle = workbook.createCellStyle();
        if (originCellStyle != null) {
            cellStyle.cloneStyleFrom(originCellStyle);
        }
        if (writeCellStyle == null) {
            return cellStyle;
        }
        buildCellStyle(cellStyle, writeCellStyle);
        return cellStyle;
    }
Build  cell style

@param workbook
@param originCellStyle
@param writeCellStyle
@return
fastexcel-core/src/main/java/cn/idev/excel/util/StyleUtil.java