使用akka stream消费文件的步骤如下:
下面是一个示例代码:
import java.io.File
import akka.{ Done, NotUsed }
import akka.actor.ActorSystem
import akka.stream.scaladsl._
import akka.util.ByteString
import scala.concurrent._
import scala.concurrent.duration._
object FileConsumer extends App {
implicit val system = ActorSystem("FileConsumer")
implicit val ec = system.dispatcher
val inputFile = new File("input.txt")
val outputFile = new File("output.txt")
// 定义一个Source,从文件中逐行读取数据
val source: Source[String, Future[IOResult]] = FileIO
.fromPath(inputFile.toPath)
.via(Framing.delimiter(ByteString("\n"), maximumFrameLength = 1024, allowTruncation = true))
.map(_.utf8String.trim)
// 定义一个sink,将数据写入到控制台或者写入另外一个文件中
val sink: Sink[String, Future[IOResult]] = FileIO.toPath(outputFile.toPath)
// 连接Source和sink,定义流操作
val runnable: RunnableGraph[Future[IOResult]] = source.toMat(sink)(Keep.right)
// 执行流操作并等待完成
val result: Future[IOResult] = runnable.run()
result.onComplete {
case scala.util.Success(IOResult(_, Success(Done))) =>
println("Stream processing finished.")
system.terminate()
case scala.util.Failure(e) =>
println(s"Stream processing failed with ${e.getMessage}.")
system.terminate()
}
Await.ready(system.whenTerminated, Duration.Inf)
}
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