private static void setDefaultStyle(ExcelCell cell){
setDefaultStyle(cell, null);
}
private static void setDefaultStyle(ExcelCell cell, String cellStyle){
ExcelCellConditionStyle cstyle = new ExcelCellConditionStyle();
cstyle.setCellIndex(cellStyle == null? COLUMN_CELL_INDEX : cellStyle);
cstyle.setCondition("true");
cell.addStyle(cstyle);
}