多个特质加载顺序

zxfgdjfjfjflfllf

已于 2024-10-28 16:50:38 修改

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文章标签：前端开发语言 scala

于 2024-10-28 16:23:05 首次发布

本文链接：https://blog.youkuaiyun.com/zxfgdjfjfjflfllf/article/details/143302294

版权

//继承多个特质时，加载的顺序
//1.先父后子
//2.从左到右
trait A051{
  println("1")

}
trait B051{
  println("2")
}
class  AB extends A051 with B051{
  println("AB")
}
object Test20_2 {
  def main(args: Array[String]): Unit = {
    new AB()
  }
}

trait A051{println("A051")}
trait AA051 extends A051{println("AA051")}
trait AB051 extends A051{println("AA051")}
trait B051{println("B051")}
trait BA051 extends B051{println("BA051")}
trait BB051 extends B051{println("BB051")}
class AB extends AA051 with BA051 with AB051 with BB051{
  println("AB")
}
object Test21{
  def main(args: Array[String]): Unit = {
    new AB()
  }
}

运行结果（A051
AA051
B051
BA051
AA051
BB051
AB）

import java.io.PrintWriter

trait FileLogger{
  val filename: String
 println("父类",filename)

  //lazy表示不立刻求值而是等到这个变量被使用时去求值
  lazy val fileout=new PrintWriter(filename)
  //用来把msg写入到对应文件
  def log(msg: String): Unit = {
    fileout.println(msg)
    fileout.flush()
  }

}

class Test211 extends FileLogger{
  val filename="2024-10-28.txt"
println("子类",filename)
}
object Test21_1 {
  def main(args: Array[String]): Unit = {
    val t1=new Test211()
    t1.log("text!")
  }
}

import java.io.PrintWriter

trait FileLogger{
  val filename: String
 println("父类",filename)

  //lazy表示不立刻求值而是等到这个变量被使用时去求值
//  lazy val fileout=new PrintWriter(filename)
val fileout=new PrintWriter(filename)
  //用来把msg写入到对应文件
  def log(msg: String): Unit = {
    fileout.println(msg)
    fileout.flush()
  }

}

class Test211 extends FileLogger{
  val filename="2024-10-28.txt"
println("子类",filename)
}
object Test21_1 {
  def main(args: Array[String]): Unit = {
//    val t1=new Test211()
    val t1=new{val filename="2024-10-29.txt"} with FileLogger//匿名类提前定义

    t1.log("text!")
  }
}

方法二val p =new{override val filename="p052.log"} with Person051