1,Trait
When a class inherits trait, the first keyword uses extends, followed by with

trait Read{
  def read(name:String) {
    println(s"$name is reading.....")
  }
}
  trait Listen {
    def listen(name: String) {
      println(s"$name is listening.....")
    }
  }
class  Person() extends Read with Listen {
}
object Demo9_Trait1 {
  def main(args: Array[String]): Unit = {
  val p = new Person()
    p.read("zhangsan")
    p.listen("lisi")
  }
}

It can be implemented in method body or unimplemented in method body, and unimplemented in subclass

trait IsEquale{
  def isEqu(o:Any):Boolean
  def isNotEqu(o:Any):Boolean = !isEqu(o)
}
class Point(xx:Int,xy:Int)extends IsEquale {
  val x = xx
  val y = xy
  override def isEqu(o:Any):Boolean={
    o.isInstanceOf[Point]&&o.asInstanceOf[Point].x == this.x
  }
}
object Demo10_Trait2 {
  def main(args: Array[String]): Unit = {
    val p1 = new Point(xx=1,xy=2)
    val p2 = new Point(xx=1,xy=3)
    println(p1.isEqu(p2))
    println(p1.isNotEqu(p2))
  }
}

2. Match pattern matching

object Demo11_Match {
  def main(args: Array[String]): Unit = {
    val tp = (1,1.2,"abc",'a',true)
    val iter = tp.productIterator
    iter.foreach(MatchTest)
  }
  def MatchTest(o:Any): Unit ={
    o match {
      case 1=>println("value is 1")
      case i=>println(s"type is Int, value is $i")
      case d=>println(s"type is Double, value is $d")
      case s=>println(s"type is String, value is $s")
      case 'a'=>println("value is a")
      case _=>{println("no match...")}
    }
  }
}

3. Partial function

object Demo12_PartialFun {
  def MyTest:PartialFunction[String,Int]={
    case "abc"=>2
    case  "a"=>1
    case _=>200

  }
  def main(args: Array[String]): Unit = {
    val result = MyTest("abc")
    println(result)
    println(MyTest("abcd"))
  }
}

4. Example class CaseClass

/**
  * Sample class
  * 1,The class defined by case is the sample class,
  * It implements the getter method of class construction parameters (the default construction is declared as val),
  * When the construction parameter is var, it will help you implement setter and getter methods
  * 2,The sample class implements toString, equals by default. copy and hashCode etc
  * 3,The sample class can be new or not new
  */
case class Person1(name:String,age:Int){

}
object Demo13_CaseClass {
  def main(args: Array[String]): Unit = {
    val p1 = new Person1("zhangsan",19)
    val p2 = new Person1("zhangsan",19)
    println(p1.equals(p2))
    println(p1)
  }
}