Questions about JsonDeserialize.keyUsing,

[Erik Ramfelt]

Hi

If I check the documentation for the keyUsing annotation, it states that it is for methods, fields and constructors. [1] But the documentation at github states that it is for (method, field). [2]

Is it possible to set @JsonDeserialize(keyUsing = classOf[SomeKeyDeserializer]) on a constructor, if so what params would constructor take. Is there any documentation on how to use the keyUsing annotation on a method or constructor?

Is there a way from a reflect.Method obj (method is annotated with JsonDeserialize) to get the deserializers from that method object using jackson, without creating the deserializers manually? I would like to be able to get the deserializer for a reflected method in order to solve a Map[] deserialization problem, where I have annotated a method with the JsonDeserialize.keyUsing. Reasons behind are some what difficult to explain.

Best regards

//Erik

1 - https://fasterxml.github.io/jackson-databind/javadoc/2.3.0/com/fasterxml/jackson/databind/annotation/JsonDeserialize.html#keyUsing()

2 - https://github.com/FasterXML/jackson-databind/wiki/Databind-annotations#user-content-deserialization-reading-json

[Tatu Saloranta]

On Tue, Aug 20, 2019 at 1:03 PM Erik Ramfelt <erik.r...@gmail.com> wrote:
>
> Hi
>
> If I check the documentation for the keyUsing annotation, it states that it is for methods, fields and constructors. [1] But the documentation at github states that it is for (method, field). [2]

Perhaps confusion here is between Constructor methods vs Constructor parameters?
`@JsonDeserialize` is NOT allowed on Constructor methods themselves
but only on Constructor parameters. But it definitely is allowed on
latter, and further, property `keyUsing` should apply similar to if it
was used on setter-method or field.

> Is it possible to set @JsonDeserialize(keyUsing = classOf[SomeKeyDeserializer]) on a constructor, if so what params would constructor take. Is there any documentation on how to use the keyUsing annotation on a method or constructor?

It would be used on parameter, like:

public MyType(@JsonDeserialize(keyUsing = MyKeyDeserializer.class
@JsonProperty("data") Map<MyType, String> data) { .... }

>
> Is there a way from a reflect.Method obj (method is annotated with JsonDeserialize) to get the deserializers from that method object using jackson, without creating the deserializers manually? I would like to be able to get the deserializer for a reflected method in order to solve a Map[] deserialization problem, where I have annotated a method with the JsonDeserialize.keyUsing. Reasons behind are some what difficult to explain.

I am not sure I understand this question.

-+ Tatu +-

>
> Best regards
> //Erik
> 1 - https://fasterxml.github.io/jackson-databind/javadoc/2.3.0/com/fasterxml/jackson/databind/annotation/JsonDeserialize.html#keyUsing()
> 2 - https://github.com/FasterXML/jackson-databind/wiki/Databind-annotations#user-content-deserialization-reading-json
>

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