val person = Person("Jane", 23)
val copy = person::class.memberFunctions.first { it.name == "copy" }
val instanceParam = copy.instanceParameter!!
val ageParam = copy.parameters.first { it.name == "age" }
val result = copy.callBy(mapOf(instanceParam to person, ageParam to 18))
println(result) // Person(name=Jane, age=18)
val person = Person("Jane", 23)
val copy = person::class.memberFunctions.first { it.name == "copy" }
val result = copy.call(person, person.name, 18)
println(result) // Person(name=Jane, age=18)
val person = Person("Jane", 23)
val copy = person::class.java.methods.first { it.name == "copy" }
val result = copy.invoke(person, person.name, 18)
println(result) // Person(name=Jane, age=18)
fun <T : Any> clone (obj: T): T {
if (!obj::class.isData) {
println(obj)
throw Error("clone is only supported for data classes")
}
val copy = obj::class.memberFunctions.first { it.name == "copy" }
val instanceParam = copy.instanceParameter!!
return copy.callBy(mapOf(
instanceParam to obj
)) as T
}
2条答案
按热度按时间lyfkaqu11#
对于所有
data
类,没有通用的超类型。基本上,
copy
是一个普通的成员函数,您可以使用Kotlin reflection API调用它,如下所示:确保将
kotlin-reflect
添加为依赖项。上面的示例说明了如何省略默认参数的值-不为
name
传递值。如果要传递所有参数,可以用更简单的方法完成:Kotlin反射API对于调用函数来说不是绝对必要的,如果你为所有参数传递实参,你也可以通过Java反射来实现:
ojsjcaue2#
因此,根据https://stackoverflow.com/users/2196460/hotkey的上述回答: