How to use @Autowired in subclass for field defined in base class?

Question

Is it possible to autowire an instance in a subclass for a field which is fdefined in the base class?

So, The interface:

public interface Xyz { ...}

The abstract base class:

public abstract class Abc {
    Xyz xyz;
}

The subclass(es) of the absctract class where I want to autowire a concrete implementation of the interface:

public class Def extend Abc {
    @Autowired
    // Here I want to autowire a concrete implementation of Xyz, maybe called XyzImpl. Can I do this maybe in a constructor or ...?
}

public class Ghi extend Abc {
    @Autowired
    // Here I want to autowire a concrete implementation of Xyz, maybe called XyzImpl. Can I do this maybe in a constructor or ...?
}

public class Jkl extend Abc {
    @Autowired
    // Here I want to autowire a concrete implementation of Xyz, maybe called XyzImpl. Can I do this maybe in a constructor or ...?
}

Do you have exactly one bean that implements Xyz or is it ambiguous? You can stick the `@Autowired` on the instance of xyz in `Abc` otherwise and it'll work out fine. I do this all the time. (Alternatively you can do constructor injection.) — Roddy of the Frozen Peas, May 02 '19 at 16:02

score 1 · Accepted Answer · answered May 02 '19 at 15:57

Try this:

In the Abc class, make this change private final Xyz xyz;
In the Abc class, add a constructor that takes an Xyz parameter; set the xyz field in this constructor.
in the Def class, add a constructor that takes an Xyz parameter and which calls super(xyz).
Autowire the xyz parameter in the Def constructor.

How to use @Autowired in subclass for field defined in base class?

1 Answers1