NoClassDefFoundError:Scala中的akka/actor/actorRefactory

我试图用scala中的akka api创建一个Http服务器，但是我得到了

NoClassDefFoundError

我检查了一下

但我不能把它们和我的案子联系起来

/usr/lib/jvm/default-runtime/bin/java ...
Exception in thread "main" java.lang.NoClassDefFoundError: akka/actor/ActorRefFactory
    at main.scala.Main.main(main.scala)
Caused by: java.lang.ClassNotFoundException: akka.actor.ActorRefFactory
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 1 more

这是我的scala代码

package main.scala

import akka.actor.ActorSystem
import akka.http.scaladsl.Http
import akka.http.scaladsl.model._
import akka.http.scaladsl.server.Directives._
import akka.stream.ActorMaterializer
import scala.io.StdIn

object  Main{

  def main(args: Array[String]): Unit = {

    implicit val system = ActorSystem("my-system")
    implicit val materializer = ActorMaterializer()

    implicit val executionContext = system.dispatcher

    val route =
      path("hello") {
        get {
          complete(HttpEntity(ContentTypes.`text/html(UTF-8)`, "<h1>Say hello to akka-http</h1>"))
        }
      }

    val bindingFuture = Http().bindAndHandle(route, "localhost", 8080)

    println(s"Server online at http://localhost:8080/\nPress RETURN to stop...")
    StdIn.readLine()
    bindingFuture
        .flatMap(_.unbind())
        .onComplete(_ => system.terminate())
  }
}

---

您可以将build.sbt更新到下面，因为您引用的akka版本似乎很旧

lazy val akkaHttpVersion = "10.0.10"
lazy val akkaVersion    = "2.5.4"

lazy val root = (project in file(".")).
  settings(
    inThisBuild(List(
      organization    := "com.company-name.application",
      scalaVersion    := "2.12.3"
    )),
    name := "aiengine",
    libraryDependencies ++= Seq(
      "com.typesafe.akka" %% "akka-http"            % akkaHttpVersion,
      "com.typesafe.akka" %% "akka-http-spray-json" % akkaHttpVersion,
      "com.typesafe.akka" %% "akka-stream"          % akkaVersion,
      "com.typesafe.akka" %% "akka-slf4j" % akkaVersion,
      "com.typesafe.akka" %% "akka-http-testkit"    % akkaHttpVersion % Test,
      "com.typesafe.akka" %% "akka-testkit"         % akkaVersion     % Test,
      "com.typesafe.akka" %% "akka-stream-testkit"  % akkaVersion     % Test,
      "org.scalatest"     %% "scalatest"            % "3.0.1"         % Test
    )
  )

---

为什么要将依赖项标记为“已提供”？如果这样做，则假定这些依赖项是由承载应用程序的某个“容器”在运行时提供的，例如web服务器。我不确定你真的这么做了。因此，我建议删除所有“提供的”标记。这应该可以解决问题。谢谢@igorpcholkin解决了我的问题，我是scala的新手，我遵循了sbt文件以这种方式配置的地方。我不认为是从sbt中删除提供的“with sources（）解决了我的问题”的版本问题

lazy val akkaHttpVersion = "10.0.10"
lazy val akkaVersion    = "2.5.4"

lazy val root = (project in file(".")).
  settings(
    inThisBuild(List(
      organization    := "com.company-name.application",
      scalaVersion    := "2.12.3"
    )),
    name := "aiengine",
    libraryDependencies ++= Seq(
      "com.typesafe.akka" %% "akka-http"            % akkaHttpVersion,
      "com.typesafe.akka" %% "akka-http-spray-json" % akkaHttpVersion,
      "com.typesafe.akka" %% "akka-stream"          % akkaVersion,
      "com.typesafe.akka" %% "akka-slf4j" % akkaVersion,
      "com.typesafe.akka" %% "akka-http-testkit"    % akkaHttpVersion % Test,
      "com.typesafe.akka" %% "akka-testkit"         % akkaVersion     % Test,
      "com.typesafe.akka" %% "akka-stream-testkit"  % akkaVersion     % Test,
      "org.scalatest"     %% "scalatest"            % "3.0.1"         % Test
    )
  )