1. Problems arising
I am executing the mytest program. Yes, I reported an error.
1. Dao layer interface
1 int insertSale(Sale sale);
2. Service layer
1 @Override 2 public void buy(Integer goodsId, Integer nums) { 3 4 // Record sales information and add records to the sale table 5 .... 6 saleDao.insertSale(sale); 7 }
The above error will be reported after running the program
2. Error reason
The reason for this error is that the service layer buy() method does not return a value. And we defined the dao layer method is to return int, there will be the following prompt
3. Solution
This is a problem with the Dao layer. The Dao layer is modified as follows:
1 void insertSale(Sale sale);