Jackson - How to specify a single implementation for interface-referenced deserialization?

Question

I want to deserialize a JSON-Object with Jackson. Because the target is an interface I need to specify which implementation should be used.

This information could be

Answer 1

There is another approach that will work if you have just single interface implementation.

public class ClassYouWantToDeserialize {
    @JsonDeserialize(as = ImplementationClass.class)
    private InterfaceClass property;
...
}

This question was answered a while ago but I want to give you another option that doesn't require to tune ObjectMapper and also much simpler then @JsonTypeInfo annotation.

Answer 2

You can use @JsonDeserialize(as = ImplementationClass.class) on the interface as well and all references will be deserialized the same way.

Note, if one of your Implementation classes is an enum, you might need @JsonFormat(shape = JsonFormat.Shape.OBJECT) on the enum as well.

Answer 3

Use a SimpleAbstractTypeResolver:

ObjectMapper mapper = new ObjectMapper();

SimpleModule module = new SimpleModule("CustomModel", Version.unknownVersion());

SimpleAbstractTypeResolver resolver = new SimpleAbstractTypeResolver();
resolver.addMapping(Interface.class, Implementation.class);

module.setAbstractTypes(resolver);

mapper.registerModule(module);