如何在 Kotlin 中使用 Gson 反序列化嵌套类？

Question

I have json as in below, I'm really new on kotlin and i tried all examples but cannot set my nested class values when i convert to json

Here my json

{"Init":{"MOP":[{"Id":"1","Type":"0","ProtocolVersion":"1.0","MopCode":"*NEXB","TerminalId":"'P400Plus-275008565'","IP":"'192.168.1.15'","Currency":"EUR"},{"Id":"2","Type":"0","ProtocolVersion":"1.0","MopCode":"*NEXF","TerminalId":"'P400Plus-275008565'","IP":"'10.0.0.0:901'","Currency":"EUR"}]}}

Here my POJO

class Root {
@JsonProperty("Init")
var init: Init? = null
}

class MOP {
@JsonProperty("Id")
var id: String? = null

@JsonProperty("Type")
var type: String? = null

@JsonProperty("ProtocolVersion")
var protocolVersion: String? = null

@JsonProperty("MopCode")
var mopCode: String? = null

@JsonProperty("TerminalId")
var terminalId: String? = null

@JsonProperty("IP")
var ip: String? = null

@JsonProperty("Currency")
var currency: String? = null
}

class Init {
@JsonProperty("MOP")
var mop: List<MOP>? = null
 }

Here my trial

val root: TestClass.Root = gson.fromJson(receiveString,TestClass.Root::class.java)
        val initList = HashMap<String?,String?>()
        if (root.init != null){
            val mopList = root.init!!.mop
            if (mopList != null) {
                for (item in mopList){
                    initList.put(item.mopCode,item.id)
                }
            }

        }

Always root.init and root.init.mop are null

What you can suggest me?

Thanks

Answer 1

Your Json construction has different tree.

You should use following structure:

data class Root (
    @SerializedName("Init") val init : Init
)

data class Init (
    @SerializedName("MOP") val mOP : List<MOP>
)

data class MOP (
    @SerializedName("Id") val id : Int,
    @SerializedName("Type") val type : Int,
    @SerializedName("ProtocolVersion") val protocolVersion : Double,
    @SerializedName("MopCode") val mopCode : String,
    @SerializedName("TerminalId") val terminalId : String,
    @SerializedName("IP") val iP : String,
    @SerializedName("Currency") val currency : String
)

And you can parse just with:

Gson().fromJson(data,Root::class.java)

Also if you are using Gson, you should use SerializedName instead JsonProperty .