kotlin之map委托

fun main(arg: Array<String>) {

    val map = mapOf("name" to "tom",
            "age" to 20
    )
    val user = user(map)
    println(user.name)
    println(user.age)
}

class user(var map:Map<String,Any>){
  val name:String by map
  val age:Int by map
}

使用场景:将map中key-value映射到对象的属性中,这通常在解析json 数据时用到