shop--6.店铺注册--service层实现（事务）

事物的回滚

1.插入店铺信息-》2.返回店铺Id-》3.根据店铺Id创建存储图片的文件夹-》4.把文件夹的地址更新回店铺信息中

在实现service接口中添加@Transational事务标签

只有当程序抛出RuntimeException的异常或继承RuntimeException类 时，事务才会回滚，如果只是抛出Exception，事物不会回滚

@Service
public class ShopServiceImpl implements ShopService {

    @Autowired
    private ShopDao shopDao;

    @Override
    @Transactional
    //1.插入店铺信息-》2.返回店铺Id-》3.根据店铺Id创建存储图片的文件夹-》4.把文件夹的地址更新回店铺信息中
    public ShopExecution addShop(Shop shop, CommonsMultipartFile shopImg) {
        //空值判定
        if(shop == null){
            return new ShopExecution( ShopStateEnum.NULL_SHOP);
        }
        try{
            //给店铺信息赋初始值
            //初识店铺都是 0 审核中
            shop.setStatus(0);
            shop.setCreateTime( new Date() );
            shop.setLastEditTime( new Date() );

            int effectedNum = shopDao.insertShop( shop );
            //判断插入店铺是否成功，若不成功，则回滚事务
            if(effectedNum <= 0){
                throw new ShopOperationException("插入店铺信息失败");
            } else{
                //存储图片
                if(shopImg != null){
                    try{
                        addShopImg(shop, shopImg);
                    }catch(Exception e){
                        throw new ShopOperationException( "addShopImg error" + e.getMessage());
                    }
                    effectedNum = shopDao.updateShop( shop );
                    if(effectedNum <= 0){
                        throw new ShopOperationException("更新图片地址失败");
                    }
                }
            }
        }catch (Exception e){
            throw new ShopOperationException("addShop error： " + e.getMessage());
        }
        return new ShopExecution(ShopStateEnum.CHECK, shop);
    }
    /**
     * 将店铺图片添加到用户相对的文件夹下，并且将店铺信息中店铺图片的地址更新
     * @param shop
     * @param shopImg
     */
    private void addShopImg(Shop shop, CommonsMultipartFile shopImg) {
        String relativeImgPath = PathUtil.getShopImgPath(shop.getShopId());
        String realRelativeImgPath = ImageUtil.generateThumbnail( shopImg, relativeImgPath );
        shop.setShopImg(realRelativeImgPath);
    }
}

　　

抛出的RuntimeException可以自己定义一个异常类ShopOperationException，继承RuntimeException，这样看上去更加直观的知道是什么异常

public class ShopOperationException extends RuntimeException {
    public ShopOperationException(String msg){
        super(msg);
    }
}