我有一个简单的层次结构,包含以下内容:
- 抽象类BaseItem
- 打开类项目:BaseItem
- class背包:物品
它们都应该使用Kotlinx序列化。直到我添加了Backpack
类,一切都很顺利。我使用Kotlinx序列化的1.4.32
版本。
这是我的类层次结构的详细
// Items.kt
@Serializable
sealed class BaseItem {
abstract val id: String
abstract val type: ItemType
abstract var brand: String
abstract var model: String
abstract var imageLink: String
abstract var traits: MutableList<Trait>
abstract var implicitTraits: MutableList<Trait>
abstract var details: MutableMap<String, String>
}
@Serializable
open class Item(
override val id: String = UUID.randomUUID().toString(),
override val type: ItemType = ItemType.UNDEFINED,
override var brand: String,
override var model: String,
override var imageLink: String,
override var traits: MutableList<Trait>,
override var implicitTraits: MutableList<Trait>,
override var details: MutableMap<String, String>,
) : BaseItem()
@Serializable // is marked as incorrect
class Backpack(
brand: String,
model: String,
imageLink: String,
traits: MutableList<Trait>,
implicitTraits: MutableList<Trait>,
details: MutableMap<String, String>,
var volume: Int
) : Item(
type = ItemType.BACKPACK,
brand = brand,
model = model,
imageLink = imageLink,
traits = traits,
implicitTraits = implicitTraits,
details = details
)
IDE为Backpack
类附加的@Serialization
注释显示了以下消息。
This class is not serializable automatically because it has primary constructor parameters that are not properties
我无法找到正确的工作方法
val
或var
添加到参数中。这将解决您当前的错误消息:
@Serializable
class Backpack(
override var brand: String,
override var model: String,
override var imageLink: String,
override var traits: MutableList<Trait>,
override var implicitTraits: MutableList<Trait>,
override var details: MutableMap<String, String>,
var volume: Int
) : Item(
type = ItemType.BACKPACK,
brand = brand,
model = model,
imageLink = imageLink,
traits = traits,
implicitTraits = implicitTraits,
details = details
)
但这仍然不会编译,因为您最终会为两个类中使用的所有属性使用Serializable class has duplicate serial name of property 'brand', either in the class itself or its supertypes
。但无论如何,我对这个设计有点惊讶,因为从非抽象类继承通常不是一个好的实践。在不知道意图的情况下,我想知道这样的sth是否对你也不起作用:
sealed class BaseItem {
abstract val id: String
abstract val type: ItemType
abstract var brand: String
abstract var model: String
abstract var imageLink: String
abstract var traits: MutableList<Trait>
abstract var implicitTraits: MutableList<Trait>
abstract var details: MutableMap<String, String>
}
@Serializable
data class Item(
override val id: String = UUID.randomUUID().toString(),
override val type: ItemType = ItemType.UNDEFINED,
override var brand: String,
override var model: String,
override var imageLink: String,
override var traits: MutableList<Trait>,
override var implicitTraits: MutableList<Trait>,
override var details: MutableMap<String, String>,
) : BaseItem()
@Serializable
data class Backpack(
override val id: String = UUID.randomUUID().toString(),
override val type: ItemType = ItemType.BACKPACK,
override var brand: String,
override var model: String,
override var imageLink: String,
override var traits: MutableList<Trait>,
override var implicitTraits: MutableList<Trait>,
override var details: MutableMap<String, String>,
override var var volume: Int
) : BaseItem()
顺便说一句,我从BaseItem
中删除了@Serializable
,因为它是不必要的,因为该类无论如何都是抽象的,因此根本不会序列化。我还制作了data class
类,因为我的印象是,这些类基本上是用来保存数据的,并且通常是用data class
实现的。我留下了我看到的许多var
,因为我不知道它们的原因,但我这边的一个小提示是,你应该更喜欢val
而不是var
,尤其是在data class
中。在这种情况下,var
对我来说就像是一种代码气味,您可能需要考虑使用val
。Kotlin页面本身就是一个很好的文本:https://kotlinlang.org/docs/coding-conventions.html#idiomatic-语言功能的使用
从设计可序列化层次结构:
要使类的层次结构可序列化,父类中的属性必须标记为抽象,使〔parent〕类也是抽象的。