Moshi错误:@JSONClass不能应用于[class]。不得密封

Question

想象一下这个数据示例

    "meta_data": [
                {
                    "id": 40097,
                    "key": "_wcf_frm_created",
                    "value": ""
                },
                {
                    "id": 40098,
                    "key": "_wcf_custom_degin_checkbox",
                    "value": ""
                },
                {
                    "id": 40099,
                    "key": "_wcf_frm_data",
                    "value": {
                        "1": {
                            "1": "",
                            "2": "",
                            "3": "chk_box"
                        }
                    }
                },
                {
                    "id": 40119,
                    "key": "_vendor_select",
                    "value": "6484"
                },
                {
                    "id": 40120,
                    "key": "_vendor_percentage",
                    "value": "1"
                },
                {
                    "id": 40121,
                    "key": "_vendor_pro_cat",
                    "value": "Accessories"
                }
            ]

sealed class Value {
        class StringMapMapValue(val value: Map<String, Map<String, String>>) : Value()
        class StringValue(val value: String)                                 : Value()
    }

    @JsonClass(generateAdapter = true)
    data class MetaDatum (
            val id: Long,
            val key: String,
            val value: Value
    )
    @JsonClass(generateAdapter = true)
    sealed class Value {
        class StringMapMapValue(val value: Map<String, Map<String, String>>) : Value()
        class StringValue(val value: String)                                 : Value()
    }

我想要注意的是，完整的json要比这个大得多。然而，这是我唯一的问题。我也有一些枚举问题，但可以用字符串替换

我收到的错误是error:@JSONClass不能应用于NET......activity.Value：必须不是密封的公共静态抽象类值

因此，我的问题是，如何使用多个枚举类型解码json。

enum Value: Codable {
    case string(String)
    case stringMapMap([String: [String: String]])
    
    init(from decoder: Decoder) throws {
        let container = try decoder.singleValueContainer()
        if let x = try? container.decode([String: [String: String]].self) {
            self = .stringMapMap(x)
            return
        }
        if let x = try? container.decode(String.self) {
            self = .string(x)
            return
        }
        throw DecodingError.typeMismatch(Value.self, DecodingError.Context(codingPath: decoder.codingPath, debugDescription: "Wrong type for Value"))
    }
    
    func encode(to encoder: Encoder) throws {
        var container = encoder.singleValueContainer()
        switch self {
        case .string(let x):
            try container.encode(x)
        case .stringMapMap(let x):
            try container.encode(x)
        }
    }
}

调用数据

fun retrieveMenu(sku: Int, SSLAuth: String)
    {

        doAsync {

            val client = OkHttpClient().newBuilder()
                .build()
            val formBody: RequestBody = FormBody.Builder()
                .build()
            val request: Request = Request.Builder()
                .url("https://carteapp.net/..................")
                .method("Get", formBody)
                .build()
            client.newCall(request).execute().use { response ->
                if (!response.isSuccessful) throw IOException("Unexpected code $response")

                val gist =
                        gistJsonAdapter.fromJson(response.body!!.source())
                println(gist)


            }
        }

    }

private val moshi = Moshi.Builder().build()
private val gistJsonAdapter = moshi.adapter(BarcodeScannerActivity.WcProductCall::class.java)
@JsonClass(generateAdapter = true)
    data class WcProductCall (
            val id: Long,
            ...........
            val metaData: List<MetaDatum>,
           ...
    )

Answer 1

这有点棘手，因为Moshi不允许密封/抽象类，我的想法是使用DTO模式（这是一种使用数据传输对象在单个网络请求中传递尽可能多的数据的模式）

创建一个包含两个/所有数据的数据类（您的DTO）

@JsonClass(generateAdapter = true)
data class MetaDatumDTO (
        val id: Long,
        val key: String,
        val value1: Value1DTO?,
        val value2: Value2DTO?
)

@JsonClass(generateAdapter = true)
data class Value1DTO(val value: Map<String, Map<String, String>>)

@JsonClass(generateAdapter = true)
data class Value2DTO(val value: String) 

然后在您的存储库/模型中，当您检索数据时，使用映射器函数将数据映射到您想要使用的数据类

data class MetaDatum(
    val id: Long,
    val key: String,
    val value: Value?
)

sealed class Value {
    data class Value1(val value: Map<String, Map<String, String>>) : Value()
    data class Value2(val value: String) : Value()
}

fun MetaDatumDto.mapFromNetworkRequest(): MetaDatum {
    return MetaDatum(
        id = id,
        key = key,
        value = getValueFromDTO()
    )
}

fun MetaDatumDto.getValueFromDTO(): Value? {
    return (value1 as? Value1) ?: (value2 as? Value2)
}