How to implement Service Layer with Spring?

The service layer is where you will have all your business rules before persistence and of course where you will control the database transaction.

//declare aqui a anotação service
@Service
public class MyService {

      ...
}

For transaction control use @Transactional (readOnly = true) by default spring already sets the commit to commit only when all goes well with your method.

You can change this with:

 @Transactional(propagation=Propagation.REQUIRED,readOnly=false) 
    public void save(ProductTech product) { 
        currentSession().save(product); 
        System.out.println(“product saved with sucess”); 
    } 

PROPAGATION_MANDATORY : Requires the use of a transaction, if there is no current transaction, an exception is thrown.

PROPAGATION_NESTED : Runs within a nested transaction if a current transaction exists.

PROPAGATION_NEVER : Prevents use of a transaction. If an existing transaction exists, an exception is thrown.

PROPAGATION_NOT_SUPPORTED : Do not use the current transaction. This is always executed without any transaction.

PROPAGATION_REQUIRED : Uses the current transaction if it exists, if it does not exist create a new transaction.

PROPAGATION_REQUIRES_NEW : Create a new transaction, if a current already exists, suspend it.

PROPAGATION_SUPPORTS : Uses the current transaction if it exists, otherwise it runs without transaction.

Ready after that, just inject your Service into your Controller