code: public static <T extends BaseObject<Long>> List<Long> convert2IdList(
              List<T> enTs) {
          List<Long> result = new ArrayList<Long>();
  
          if (enTs == null) {
              return result;
          }
  
          for (T t : enTs) {
              result.add(t.getId());
          }
  
          return result;
      }
docs: 获得List<T> 的ID列表
  
  @param enTs
  
  @return