快学Scala 第十五课 （二进制读取文件，写文件，访问目录，序列化）

二进制读取文件：

   val file = new File("F:\scalaWorkspace\ScalaLearning\files\test.txt")
   val in = new FileInputStream(file)
   val bytes = new Array[Byte](file.length().toInt)
   in.read(bytes)
   in.close()

写文件：

   val out = new PrintWriter("F:\scalaWorkspace\ScalaLearning\files\test2.txt")
   for (i <- 1 to 100) out.println(i)
   out.close()

访问目录：

  def subdirs(dir: File): Iterator[File] = {
    val children = dir.listFiles.filter(_.isDirectory())
    children.toIterator ++ children.toIterator.flatMap(subdirs _)
  }

   val dir = new File("F:\scalaWorkspace\ScalaLearning")
   for(el <- subdirs(dir)){
     println(el.getAbsolutePath)
   }

运行结果：

F:scalaWorkspaceScalaLearning.settings
F:scalaWorkspaceScalaLearningin
F:scalaWorkspaceScalaLearningfiles
F:scalaWorkspaceScalaLearningsrc

序列化：

@SerialVersionUID(18L) class Animal extends Serializable {
  val id: Int = 1
  val name1: String = "Animal"
}