当实例化父类或特质时,父类构造器的代码在子类的构造器实例化之前,类定义之后执行。
trait A {
val audience: String
println("Hello " + audience)
}
class BMember(a: String = "World") extends A {
val audience = a
println("I repeat: Hello " + audience)
}
class BConstructor(val audience: String = "World") extends A{
println("I repeat: Hello " + audience)
}
new BMember("Readers")
new BConstructor("Readers")
输出结果:
Hello null
I repeat: Hello Readers
Hello Readers
I repeat: Hello Readers
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