将映射转换为数据类

为什么不直接使用映射委托呢?

class MyData(val map: Map<String, String>) {
    val foo by map
    val bar by map
}

或者可以使用一个伴生对象包装它,并使用 MyData.from(mymap)

data class MyData(val foo: String, val bar: String) {
    companion object {
        fun from(map: Map<String, String>) = object : {
            val foo by map
            val bar by map

            val data = MyData(foo, bar)
        }.data
    }

也许 吧 delegated properties

class YourData { 
  val backedMap = mutableMapOf<String, String>()
  var someProp by backedMap
}

val obj = YourData().apply {
    someProp = "value"
}

现在如果 backedMap 是可见的,则也可以添加以下内容,即使不存在任何此类属性:

obj.backedMap["unknown prop"] = "some other value"

但另一方面,相同的地图可用于自动填充您的字段:

val sourceMap = mutableMapOf("someProp" to "newValue") // the map you want to use to automatically fill up your data class
sourceMap.forEach { key, newValue -> obj.backedMap[key] = newValue }

另一种方法是“仅仅”使用反射。这样就省略了备份映射,而只扫描属性,例如:

val mutableProps = YourData::class.memberProperties.filterIsInstance<KMutableProperty<*>>()
sourceMap.forEach { key, newValue ->
    mutableProps.forEach {
        if (key == it.name) {
            it.setter.call(obj, newValue)
        }
    }
}