使用Akka Streams读取CSV文件 [英] Reading a CSV files using Akka Streams

问题描述

我正在读取一个csv文件。我正在使用Akka Streams来执行此操作，以便可以创建要在每一行上执行的操作的图表。我已经启动并运行了以下玩具示例。

I'm reading a csv file. I am using Akka Streams to do this so that I can create a graph of actions to perform on each line. I've got the following toy example up and running.

  def main(args: Array[String]): Unit = {
    implicit val system = ActorSystem("MyAkkaSystem")
    implicit val materializer = ActorMaterializer()

        val source = akka.stream.scaladsl.Source.fromIterator(Source.fromFile("a.csv").getLines)
        val sink = Sink.foreach(println)
        source.runWith(sink)
      }

这两种 Source 类型对我来说并不容易。

The two Source types don't sit easy with me. Is this idiomatic or is there is a better way to write this?

推荐答案

实际上， akka-streams是这样吗？ 提供直接读取文件的功能。

Actually, akka-streams provides a function to directly read from a file.

FileIO.fromPath(Paths.get("a.csv"))
      .via(Framing.delimiter(ByteString("\n"), 256, true).map(_.utf8String))
      .runForeach(println)

这里， runForeach 方法是打印行。如果您有适当的 Sink 来处理这些行，请使用它代替此功能。例如，如果要用'分割行并打印其中的单词总数：

Here, runForeach method is to print the lines. If you have a proper Sink to process these lines, use it instead of this function. For example, if you want to split the lines by ' and print the total number of words in it:

val sink: Sink[String] = Sink.foreach(x => println(x.split(",").size))

FileIO.fromPath(Paths.get("a.csv"))
      .via(Framing.delimiter(ByteString("\n"), 256, true).map(_.utf8String))
      .to(sink)
      .run()

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