Mongo DB custom conversions in Spring data

Context

We stored our data as JSON as below

{
  data: {
    name: "hello",
    project: {
       value: "demo project"
    }
  }
}

@Document(collection = "tasks")
class Task {
    var data: HashMap<String, TaskFieldValue> = HashMap()
}

class TaskFieldValue() {
    var value: String = ""
}

Problems

org.springframework.core.convert.ConverterNotFoundException: No converter found capable of converting from type [java.lang.String] to type [io.nettable.entity.TaskFieldValue]

Solution

@Configuration
class MongoConfiguration {
    @Bean
    fun customConversions(): MongoCustomConversions {
        val converters = ArrayList<Any>()
        converters.add(String2NetValue())
        return MongoCustomConversions(converters)
    }

    @ReadingConverter
    class String2NetValue : Converter<String, NetTaskFieldValue> {
        override fun convert(source: String): NetTaskFieldValue {
            val value = NetTaskFieldValue()
            value.value = source
            return value
        }

    }
}