scala类与对象

左手的ㄟ右手 2022-03-01 05:28 325阅读 0赞

# 1, 定义类 #

//接口
    trait A{
      val year=2019//接口中：可以定义变量,常量
      var month=4
    
      def say(mesg:String)
      def say2(): Unit ={//接口中：可以定义普通方法
        println("trait A :hello - world...")
      }
    }
    trait B{
      def walk()
    }
    //父类
    class Person(var id:String,var name:String){
      //一般属性
      val arr=Array(0)
    
      //一般方法
      def getId()=id
      def getName=name
    }
    
    //子类继承：　父类, 接口1, 接口2
    class TestExtends(val id2:String,val name2:String,val age:Int) extends Person(id2,name2) with A with B  {
      override def say(mesg: String): Unit = println(mesg)
      override def walk(): Unit = println("walk...")
    }
    
    //=====================入口: app测试子类继承
    object TestExtends{
      def main(args: Array[String]): Unit = {
        val ext1 = new TestExtends("1","lisi",23)
        //打印父类的数据
        println("ext "+ext1.id +"," +ext1.name+ ","+ext1.getName +",age="+ext1.age)//ext 1,lisi,lisi,age=23
        ext1.walk()//walk...
        ext1.say("hello")//hello
        ext1.say2()//trait A :hello - world...
    
        ext1.month=5
        println(ext1.year+","+ext1.month)//2019,5
      }
    }

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# 2, 类的继承 #

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