求大神解救，一上午也没有挑出来

impl中的代码

 @Override
    @Transactional
    public ItemModel createItem(ItemModel itemModel) throws BusinessException {
//        进行入参校验
        ValidationResult result=validator.validate(itemModel);
        if (result.isHasErrors()){
            throw new BusinessException(EmBusinessError.PARAMETER_VALIDATION_ERROR,result.getErrorMsg());
        }
//        将ItemModel转为Item(方法)
        Item item = convertItem(itemModel);
//将Item写入数据库 因为配置文件中设置了keyProperty="id" useGeneratedKeys="true"，所以这里获得到了自增id
       itemMapper.insertSelective(item);
//        将id给itemmodel
        itemModel.setId(item.getId());
        System.out.println(itemModel+"service...");
//        将ItemModel转为Stock(方法)
        Stock stock = convertStock(itemModel);
//        将Stock写入数据库
       stockMapper.insertSelective(stock);
//        返回创建完成的对象
        return itemDetailById(itemModel.getId());
    }

感觉xml文件没啥问题，加了keyProperty和useGeneratedKeys