NPOI中单元格如何设为“会计专用”格式？

            cell.setCellValue(20000);
            HSSFCellStyle cellStyle = demoWorkBook.createCellStyle();
            HSSFDataFormat format= demoWorkBook.createDataFormat();
            cellStyle.setDataFormat(format.getFormat("_ ¥* #,##0.00_ ;_ ¥* -#,##0.00_ ;_ ¥* "-"??_ ;_ @_ "));
            cell.setCellStyle(cellStyle);