Kotlin Jackson - How to process (deserialize) nested JSON?

Question

I am trying to deserialize nested JSON into a single DTO in a Spring Boot application. The JSON:

{
   "values":[
      {
         "name":"test",
         "map":{
            "d1":"d1Value",
            "d2":"d2Value",
            "d3":"d3Value"
         }
      },
      {
         "name":"test1",
         "map":{
            "d1":"d1Value",
            "d4":"d4Value"
         }
      }
   ]
}

My kotlin classes:

    data class A(
        val values: List<B>,
    )

    data class B(
        val name: C,
        val map: Map<D, String>,
    )

    data class C(@JsonValue val value: String)
    data class D(@JsonValue val value: String)

When I try deserialize json using jacksonObjectMappermapper.readValue<A>(jsonObject) I receive error:

Cannot construct instance of `...C` (although at least one Creator exists): no String-argument constructor/factory method to deserialize from String value ('test')

Answer 1

I figured out what was the problem, the solution:

data class C(@get:JsonValue val value: String)
data class D(@get:JsonValue val value: String)

based on: Is there a generic way to deserialize single-valued value objects (without custom Deserializer) in Jackson