Spring mvc框架 在service中写了一个int型方法返回时报错?报错

 @Override
    public int savebuyingoriginalglass(BuyingVo buyingVo,List<BuyingDetailVo> listB) {
    Buying buying = BeanCopy.object2Object(buyingVo, Buying.class);
    int saveCount = buyingMapper.insertSelective(buying);
    List<BuyingDetailVo> listNew = new ArrayList<BuyingDetailVo>();
    for (BuyingDetailVo buyingDetailVo :listB ){
    buyingDetailVo.setBuyingId(buying.getBuyingId());
    listNew.add(buyingDetailVo);
    }
    saveCount +=buyingDetailMapper.insertBatches(listNew);
    return 2;//saveCount;

    }

前面所有的数据库操作都执行成功，但是在return 2;的时候报错，controller拿不到返回值。

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