Question

给定一个同类型对象流，如何将它们序列化为二进制，将它们写入磁盘，从磁盘读取它们，然后使用Scala Pickling对它们进行反序列化？

例如：

gem 'foo'
gem 'bar'
gem 'nokogiri'

Answer 1

我找到了标准文件的方法：

object PickleIOExample extends App {
    import scala.pickling.Defaults._
    import scala.pickling.binary._
    import scala.pickling.static._

    val tempPath = File.createTempFile("pickling", ".gz").getAbsolutePath
    val outputStream = new FileOutputStream(tempPath) 
    val inputStream = new FileInputStream(tempPath) 

    val persons = for{
        i <- 1 to 100
    } yield Person(i.toString, i)

    val output = new StreamOutput(outputStream)
    persons.foreach(_.pickleTo(output))
    outputStream.close()

    val personsIt = new Iterator[Person]{
        val streamPickle = BinaryPickle(inputStream)

        override def hasNext: Boolean = inputStream.available > 0

        override def next(): Person = streamPickle.unpickle[Person]
    }

    println(personsIt.mkString(", "))
    inputStream.close()
}

但我仍然无法找到适用于gzip压缩文件的解决方案。既然我不知道如何检测EOF？以下抛出EOFexception，因为GZIPInputStream可用方法不指示EOF：

object PickleIOExample extends App {
    import scala.pickling.Defaults._
    import scala.pickling.binary._
    import scala.pickling.static._

    val tempPath = File.createTempFile("pickling", ".gz").getAbsolutePath
    val outputStream = new GZIPOutputStream(new FileOutputStream(tempPath))
    val inputStream = new GZIPInputStream(new FileInputStream(tempPath))

    val persons = for{
        i <- 1 to 100
    } yield Person(i.toString, i)

    val output = new StreamOutput(outputStream)
    persons.foreach(_.pickleTo(output))
    outputStream.close()

    val personsIt = new Iterator[Person]{
        val streamPickle = BinaryPickle(inputStream)

        override def hasNext: Boolean = inputStream.available > 0

        override def next(): Person = streamPickle.unpickle[Person]
    }

    println(personsIt.mkString(", "))
    inputStream.close()
}

使用Pickling序列化到磁盘并反序列化Scala对象

1 个答案: