Scala与Java Streaming：Scala不打印,Java可以工作

我正在分别使用 akka-stream和 RxJava对Scala与Java Reactive Spec实现进行比较.我的用例是一个简单的grep：给定一个目录,一个文件过滤器和一个搜索文本,我在该目录中查找具有该文本的所有匹配文件.然后我流式传输(filename – >匹配行)对.
这适用于Java,但对于Scala,没有打印任何内容.没有例外但也没有输出.
测试数据是从互联网上下载的,但正如您所看到的,代码也可以轻松地使用任何本地目录进行测试.

斯卡拉：

object Transformer {
  implicit val system = ActorSystem("transformer")
  implicit val materializer = ActorMaterializer()
  implicit val executionContext: ExecutionContext = {
    implicitly
  }

  import collection.JavaConverters._

  def run(path: String,text: String,fileFilter: String) = {
    Source.fromIterator { () =>
      Files.newDirectoryStream(Paths.get(path),fileFilter).iterator().asScala
    }.map(p => {
      val lines = io.Source.fromFile(p.toFile).getLines().filter(_.contains(text)).map(_.trim).to[ImmutableList]
      (p,lines)
    })
      .runWith(Sink.foreach(e => println(s"${e._1} -> ${e._2}")))
  }
}

Java的：

public class Transformer {
    public static void run(String path,String text,String fileFilter) {
        Observable.from(files(path,fileFilter)).flatMap(p -> {
            try {
                return Observable.from((Iterable<Map.Entry<String,List<String>>>) Files.lines(p)
                        .filter(line -> line.contains(text))
                        .map(String::trim)
                        .collect(collectingAndThen(groupingBy(pp -> p.toAbsolutePath().toString()),Map::entrySet)));
            } catch (IOException e) {
                throw new UncheckedIOException(e);
            }
        }).toBlocking().forEach(e -> System.out.printf("%s -> %s.%n",e.getKey(),e.getValue()));
    }

    private static Iterable<Path> files(String path,String fileFilter) {
        try {
            return Files.newDirectoryStream(Paths.get(path),fileFilter);
        } catch (IOException e) {
            throw new UncheckedIOException(e);
        }
    }
}

使用Scala测试进行单元测试：

class TransformerSpec extends FlatSpec with Matchers {
  "Transformer" should "extract temperature" in {
    Transformer.run(NoaaClient.currentConditionsPath(),"temp_f","*.xml")
  }

  "Java Transformer" should "extract temperature" in {
    JavaTransformer.run(JavaNoaaClient.currentConditionsPath(false),"*.xml")
  }
}

def run(path: String,fileFilter: String) = {
  val files = Files.newDirectoryStream(Paths.get(path),fileFilter)

  val future = Source(files.asScala.toList).map(p => {
    val lines = io.Source.fromFile(p.toFile).getLines().filter(_.contains(text)).map(_.trim).to[ImmutableList]
    (p,lines)
    })
    .filter(!_._2.isEmpty)
    .runWith(Sink.foreach(e => println(s"${e._1} -> ${e._2}")))

  Await.result(future,10.seconds)

  files.close

  true // for testing
}