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class Person1(val name : String, var age : Int){
println("The primary constructor of Person")
val school = "BJU"
def sleep = "8 hours"
override def toString = "I am a Person1!"
}

跟在java中一樣，任何class都是預設繼承自object，這裡override了toString方法

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class Worker(name : String, age : Int, val salary : Long) extends Person1(name, age){ //建立Worker例項時，也會使用name、age填充父類例項。子類也必須將父類的主構造器的引數填滿
println("This is the subClass of Person, Primary constructor of Worker")
override val school = "Spark" //覆蓋父類的屬性
override def toString = "I am a Worker!" + super.sleep //super呼叫父類的方法
}

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object OverrideOperations{
def main(args: Array[String]) {
val w = new Worker("Spark", 5, 100000)
println("School :" + w.school)
println("Salary :" + w.salary)
println(w.toString())
}
}

結果：
The primary constructor of Person //先構造父類（跟java一樣）
This is the subClass of Person, Primary constructor of Worker //構建子類
School :Spark // 屬性被覆蓋
Salary :100000 //子類屬性
I am a Worker!8 hours //子類覆蓋

Scala的繼承

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