0015.scala的多重继承、多重继承构造器执行顺序、基于trait的AOP实现

1.scala的多重继承

packagecom.jn.scala

/**
* Created by admin on 2015/11/12.
*/
classHuman{
  println("Human")
}

traitTTeacherextendsHuman{
  println("TTeacher")
  defteach
}
traitPianoPlayextendsHuman{
  println("PianoPlay")
  defplayPiano = {println("I'm playing piano")}
}
classPianoTeacherextendsHumanwithTTeacherwithPianoPlay{//构造器初始化顺序，从左边到右边，已经加载的，不会重复加载
  override defteach = {println("I'm training students")}
}

objectUseTrait2 {
  defmain(args: Array[String]) {
    val t1 = new PianoTeacher
    t1.playPiano
    t1.teach

  }

}

//运行结果

Human
TTeacher
PianoPlay
I'm playing piano

I'm training students

例2：

packagecom.jn.scala

/**
* Created by admin on 2015/11/12.
*/
classHuman{
  println("Human")
}

traitTTeacherextendsHuman{
  println("TTeacher")
  defteach
}
traitPianoPlayextendsHuman{
  println("PianoPlay")
  defplayPiano = {println("I'm playing piano")}
}
classPianoTeacherextendsHumanwithTTeacherwithPianoPlay{
  override defteach = {println("I'm training students")}
}

objectUseTrait2 {
  defmain(args: Array[String]) {
//    val t1 = new PianoTeacher
//    t1.playPiano
//    t1.teach
    val t2 = new Human with TTeacher with PianoPlay{ //匿名类进行实现需要重写没有实现的接口teach
      override def teach = {println("I'm teaching students")}
}
    t2.playPiano
    t2.teach


  }

}

//运行结果

Human
TTeacher
PianoPlay
I'm playing piano

I'm teaching students