Easypoi导出报文件扩展名与文件格式或文件扩展名无效问题

public class ExcelExportUtil

//导出的时候格式很重要 .xls对应 ExcelType.HSSF   .xlsx对应 ExcelType.XSSF  默认ExportParams.type= ExcelType.HSSF
public static Workbook exportExcel(ExportParams entity, Class<?> pojoClass,
                                       Collection<?> dataSet) {
        Workbook workbook = getWorkbook(entity.getType(),dataSet.size());
        new ExcelExportService().createSheet(workbook, entity, pojoClass, dataSet);
        return workbook;
    }

 private static Workbook getWorkbook(ExcelType type, int size) {
        if (ExcelType.HSSF.equals(type)) {
            return new HSSFWorkbook();
        } else if (size < 100000) {
            return new XSSFWorkbook();
        } else {
            return new SXSSFWorkbook();
        }
    }