Question

我想从Scala中的文件中读取一个序列化对象，恢复类似于Python的pickle的功能。我破碎的物体阅读代码如下所示：

def ReadObjectFromFile[A](filename: String): A = {
  val input = new ObjectInputStream(new FileInputStream(filename))
  val obj = input.readObject()
  obj match {
    case a: A => a
    case _ => sys.error("Type not what was expected when reading from file")
  }
}

但是，此代码会导致警告“类型模式A中的抽象类型A未被选中，因为它已被擦除”。这样做的正确方法是什么？

Answer 1

您可以使用implicits绕过类型擦除，如this blog post：

中所述

def ReadObjectFromFile[A](filename: String)(implicit m:scala.reflect.Manifest[A]): A = {
  val input = new ObjectInputStream(new FileInputStream(filename))
  val obj = input.readObject()
  obj match {
    case x if m.erasure.isInstance(x) => x.asInstanceOf[A]
    case _ => sys.error("Type not what was expected when reading from file")
  }
}

Scala：从文件中读取序列化对象

1 个答案: