04-Scala高级特性

1.Trait

object CH_0213_Trait {
  def main(args: Array[String]): Unit = {
    val intelligentCar = new IntelligentCar()
    intelligentCar.fly()
    intelligentCar.say()
    intelligentCar.drive()
  }
}

trait Person {

  def say(): Unit ={
    println("Say something....")
  }

}

trait Car {

  def drive()={
    println("driving....")
  }

  def fly()

}

class IntelligentCar extends Car with Person {
  override def fly(): Unit = {
    println("Fly...")
  }
}

2.样例类

object CH_0214_CaseClass {
  def main(args: Array[String]): Unit = {
    val book1 = Book("Python", "人民日报出版", 30)
    val book2 = Book("Python", "人民日报出版", 30)
    println(book1.equals(book2))
    println(book1==book2)

  }
}

//凡是被cass class封装的对象，如果内容一致，则都相等
case class Book(bookName:String,publisher:String,price:Int){}

3.Match

object CH_0215_Match {

  def main(args: Array[String]): Unit = {

    val tup: (Double, Int, String, Boolean, Int) = (1.0,88,"abc",false,44)

    val iter: Iterator[Any] = tup.productIterator

    val res: Iterator[Unit] = iter.map(
      (x) => {
        x match {
          case 1 => println(s"$x...is 1")
          case 88 => println(s"$x ...is 88")
          case false => println(s"$x...is false")
          case w: Int if w > 50 => println(s"$w...is  > 50")
          case _ => println("wo ye bu zhi dao sha lei xing ")
        }
      }
    )
    while(res.hasNext)  res.next()
  }
}

4.偏函数

object CH_0216_PartialFunction {
  def main(args: Array[String]): Unit = {
    def xxx:PartialFunction[  Any,String] ={
      case "hello"  => "val is hello"
      case x:Int => s"$x...is int"
      case _ => "none"
    }
    println(xxx(44))
    println(xxx("hello"))
    println(xxx("hi"))
  }
}

5.隐式转换之隐式方法

object CH_0217_Implicit_Function {

  def main(args: Array[String]): Unit = {
    val value = new java.util.ArrayList[Int]()
    value.add(10)
    value.add(11)
    value.add(22)

    implicit def func01[T](arr:java.util.ArrayList[T])={
      val arrIter = arr.iterator()
      new Test01[T](arrIter)
    }

    value.foreach(println)
  }

}

class Test01[T](itr:java.util.Iterator[T]){
  def foreach(f:(T) => Unit)={
    while(itr.hasNext)f(itr.next())
  }
}

6.隐式转换之隐式转换类

object CH_0217_Implicit_Class {

  def main(args: Array[String]): Unit = {
    val value = new java.util.ArrayList[Int]()
    value.add(10)
    value.add(11)
    value.add(22)


    implicit class Test01[T](itr:java.util.Iterator[T]){
      def foreach(f:(T) => Unit)={
        while(itr.hasNext)f(itr.next())
      }
    }

    implicit def func01[T](arr:java.util.ArrayList[T])={
      val arrIter = arr.iterator()
      new Test01[T](arrIter)
    }

    value.foreach(println)
  }

}

7.隐式转换之隐式转换参数

object CH_0217_Implicit_Par {

  def main(args: Array[String]): Unit = {
    implicit val name = "zhangsan"
    implicit val age:Int = 20
    def func01(name:String)(implicit age:Int)={
      println(s"$name $age")
    }
    func01("lisi")
  }
}