objectToMap.kt

import kotlin.reflect.KClass
import kotlin.reflect.full.memberProperties

open class A {
    val a = "xxxx"
    var b = 12
}

class B : A() {
    val c: String? = null
}

fun <T : Any> T.toMap(): Map<String, String?> {
    @Suppress("unchecked_cast")
    val klass: KClass<T> = this::class as KClass<T>
    val map = mutableMapOf<String, String?>()
    klass.memberProperties.forEach { p ->
        map[p.name] = p(this)?.toString()
    }
    return map
}

fun main(args: Array<String>) {
    val b = B()
    println(b.toMap())  // {c=null, a=xxxx, b=12}
}