public class TimestampNumberConverter implements Converter<Timestamp> {
    @Override
    public Class<Timestamp> supportJavaTypeKey() {
        return Timestamp.class;
    }

    @Override
    public CellDataTypeEnum supportExcelTypeKey() {
        return CellDataTypeEnum.NUMBER;
    }

    @Override
    public WriteCellData<?> convertToExcelData(Timestamp value, ExcelContentProperty contentProperty,
                                               GlobalConfiguration globalConfiguration) {
        if (contentProperty == null || contentProperty.getDateTimeFormatProperty() == null) {
            return new WriteCellData<>(
                    BigDecimal.valueOf(DateUtil.getExcelDate(value, globalConfiguration.getUse1904windowing())));
        } else {
            return new WriteCellData<>(
                    BigDecimal.valueOf(DateUtil.getExcelDate(value, contentProperty.getDateTimeFormatProperty().getUse1904windowing())));
        }
    }
}

public class TimestampStringConverter implements Converter<Timestamp> {
    @Override
    public Class<Timestamp> supportJavaTypeKey() {
        return Timestamp.class;
    }

    @Override
    public CellDataTypeEnum supportExcelTypeKey() {
        return CellDataTypeEnum.STRING;
    }

    @Override
    public WriteCellData<?> convertToExcelData(Timestamp value, ExcelContentProperty contentProperty,
                                               GlobalConfiguration globalConfiguration) {
        WriteCellData<String> cellData = new WriteCellData<>();
        String cellValue;
        if (contentProperty == null || contentProperty.getDateTimeFormatProperty() == null) {
            cellValue = DateUtils.format(value.toLocalDateTime(), null, globalConfiguration.getLocale());
        } else {
            cellValue = DateUtils.format(value.toLocalDateTime(), contentProperty.getDateTimeFormatProperty().getFormat(),
                    globalConfiguration.getLocale());
        }
        cellData.setType(CellDataTypeEnum.STRING);
        cellData.setStringValue(cellValue);
        cellData.setData(cellValue);
        return cellData;
    }
}

EasyExcel.write(path).registerWriteHandler(horizontalCellStyleStrategy())
                .excelType(ExcelTypeEnum.CSV)
                .registerConverter(new TimestampNumberConverter())
                .registerConverter(new TimestampStringConverter())
                .autoCloseStream(Boolean.TRUE)
                .sheet(sheetName)
                .doWrite(dataList);