@Override
 public Integer updateProductImg(ProductImg productImg) {
   this.productImgMapper.updateByPrimaryKeySelective(productImg);
   return productImg.getProdImgId();
 }
 @Override
 public Integer addProductImg(ProductImg productImg) {
   this.productImgMapper.insertSelective(productImg);
   return productImg.getProdImgId();
 }