Question

Is it possible in myBatis 3 to map a single result to multiple objects, ensuring that the objects all reference the same instance? Is there an example of this I could reference?

Updated to add more detail:

For instance, let’s say I store information regarding Contacts for my application in my DB. I want to know if it’s possible to use myBatis to map the same instance of a contact to, say, a Listing class, which holds a Contact:

public class Listing {
    private Contact myContact;
    //getters & setters...
}

as well as to a ContactsHolder class, which also holds a Contact:

public class ContactsHolder {
    private Contact aContact
    //getters & setters...
}

I need the object that is mapped by myBatis to both the Listing and ContactsHolder classes to be the same instance. Is this possible?

Answer 1

No, MyBatis isn’t able to do that with standard result mapping. (at least to my knowledge). You could select the “Contact” object, then build a Listing and ContactsHolder manually with both of them referencing the Contact.

Or implement a custom ResultSetHandler.

It’s kind of a peculiar request, I’m not sure why you want the same instances shared across two objects like that. That’s probably why no feature like this exists in MyBatis 3.