Can't parse json in Kotlin

Question

I have a json like this:

{"ok":true,"result":[{"update_id":853803195,
"message":{"message_id":313,"from":{"id":104906563,"is_bot":false,"first_name":"AL","username":"alzvaracc","language_code":"en"},"chat":{"id":104906563,"first_name":"AL","username":"alzvaracc","type":"private"},"date":1594723984,"text":"/start","entities":[{"offset":0,"length":6,"type":"bot_command"}]}},{"update_id":853803196,
"message":{"message_id":314,"from":{"id":104906563,"is_bot":false,"first_name":"AL","username":"alzvaracc","language_code":"en"},"chat":{"id":104906563,"first_name":"AL","username":"alzvaracc","type":"private"},"date":1594723986,"text":"e"}},{"update_id":853803197,
"message":{"message_id":325,"from":{"id":104906563,"is_bot":false,"first_name":"AL","username":"alzvaracc","language_code":"en"},"chat":{"id":104906563,"first_name":"AL","username":"alzvaracc","type":"private"},"date":1594734252,"text":"\ud83d\ude06"}},{"update_id":853803198,
"message":{"message_id":328,"from":{"id":104906563,"is_bot":false,"first_name":"AL","username":"alzvaracc","language_code":"en"},"chat":{"id":104906563,"first_name":"AL","username":"alzvaracc","type":"private"},"date":1594736358,"text":"5"}}]}

I'm using klaxon library. Like in the first example I created a class:

class Response(val ok: Boolean, val result: String)

I was trying to save the second parameter to a string, so I could parse it, too, later. But I get a exception like this:

Unable to instantiate Response with parameters [ok: true, result: [, , , ]]

I tried making result a JsonObject (or a JsonArray of JsonObjects) and got this

Unable to instantiate JsonObject with parameters []

The only thing that more or less worked was a List<Any>. Result becomes a list of java objects like this:

[java.lang.Object@680362a, java.lang.Object@3569edd5, java.lang.Object@1f651cd8, java.lang.Object@7d0332e1]

But I don't know how to deal with them.
So my question is what do I do? How do I get the result I will be able to work with?

Answer 1

Try this class

import com.beust.klaxon.*

private val klaxon = Klaxon()

data class User (
    val ok: Boolean,
    val result: List<Result>
) {
    public fun toJson() = klaxon.toJsonString(this)

    companion object {
        public fun fromJson(json: String) = klaxon.parse<User>(json)
    }
}

data class Result (
    @Json(name = "update_id")
    val updateID: Long,

    val message: Message
)

data class Message (
    @Json(name = "message_id")
    val messageID: Long,

    val from: From,
    val chat: Chat,
    val date: Long,
    val text: String,
    val entities: List<Entity>? = null
)

data class Chat (
    val id: Long,

    @Json(name = "first_name")
    val firstName: String,

    val username: String,
    val type: String
)

data class Entity (
    val offset: Long,
    val length: Long,
    val type: String
)

data class From (
    val id: Long,

    @Json(name = "is_bot")
    val isBot: Boolean,

    @Json(name = "first_name")
    val firstName: String,

    val username: String,

    @Json(name = "language_code")
    val languageCode: String
)