多继承

1.特质：trait 实现多继承，注意观察父子类的构造器的执行顺序 1.先父后子 2.有多个父类，按书写顺序从左向右排序！

object class26 {
  trait A {
    println("A")
  }

  trait B {
    println("B")
  }

  class Class1 extends A with B {
    println("Class1")
  }

  def main(args: Array[String]): Unit = {
    new Class1()
  }

}

object class26 {
  trait A {
    println("A")
  }
  trait BB {
    println("BB")
  }
  trait B extends BB{
    println("B")
  }

  trait CC {
    println("CC")
  }

  trait C extends CC {
    println("C")
  }
  class Class1 extends C with A with B{
    println("Class1")
  }

  def main(args: Array[String]): Unit = {
    new Class1()
  }
}

import java.io.FileWriter
import java.io.BufferedWriter

object class27 {
  trait FileLogger {
    val filename: String
    // 使用 BufferedWriter 并确保资源能正确关闭
    private def withWriter[T](op: BufferedWriter => T): T = {
      val writer = new BufferedWriter(new FileWriter(filename, true))
      try {
        op(writer)
      } finally {
        writer.close()
      }
    }

    def writeLog(msg: String): Unit = {
      withWriter { writer =>
        writer.write(msg + "\n") // 添加换行符，让每条日志单独一行
      }
    }
  }

  class MyFileLogger extends FileLogger {
    override val filename = "11-26.log"
  }

  def main(args: Array[String]): Unit = {
    val fileLogger = new MyFileLogger()
    fileLogger.writeLog("今天上午上Scala课程")
    fileLogger.writeLog("今天下午没课")
  }
}