code: public static EntityColumn getLogicDeleteColumn(Class<?> entityClass) {
          EntityColumn logicDeleteColumn = null;
          Set<EntityColumn> columnSet = EntityHelper.getColumns(entityClass);
          boolean hasLogicDelete = false;
          for (EntityColumn column : columnSet) {
              if (column.getEntityField().isAnnotationPresent(LogicDelete.class)) {
                  if (hasLogicDelete) {
                      throw new LogicDeleteException(entityClass.getCanonicalName() + " 中包含多个带有 @LogicDelete 注解的字段，一个类中只能存在一个带有 @LogicDelete 注解的字段!");
                  }
                  hasLogicDelete = true;
                  logicDeleteColumn = column;
              }
          }
          return logicDeleteColumn;
      }
docs: 获取逻辑删除注解的列，若没有返回null
  
  @param entityClass
  @return