code: public <T> HSSFWorkbook object2Excel(Collection<T> list, String propertyKeys, String propertyShowKeys,
        PropertyExtractor exporter) throws Exception {
      HSSFWorkbook wb = new HSSFWorkbook(); // 建立新HSSFWorkbook对象
      object2Excel(wb, "export result", list, propertyKeys, propertyShowKeys, exporter);
      return wb;
    }
docs: List数据集导出生成Excel文件
  
  @param list 对象数据列表
  @param propertyKeys 对象属字符串，中间以","间隔
  @param propertyShowKeys 显示字段的名字字符串，中间以","间隔
  @return 返回单个HSSFWorkbook（excel）
  @throws java.lang.Exception if any.
  @param exporter a {@link org.beangle.commons.transfer.exporter.PropertyExtractor} object.
  @param <T> a T object.