Question

我正在尝试使用Akka-http构建一个简单的Web服务。我遵循了这个指南：http://doc.akka.io/docs/akka/2.4.9/scala/http/low-level-server-side-api.html，当我运行sbt run时，一切正常。

当我执行java -jar PROJECT.jar时，它返回：

Exception in thread "main" java.lang.NoClassDefFoundError: akka/actor/ActorRefFactory
    at WebServer.main(WebServer.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

我的build.sbt：

name := "APPNAME"

version := "0.0.1"

scalaVersion := "2.11.8"

artifactName := { (sv: ScalaVersion, module: ModuleID, artifact: Artifact) =>
    artifact.name + "-" + module.revision + "." + artifact.extension
}

libraryDependencies ++= Seq(
    "com.typesafe.akka" %% "akka-http-core" % "2.4.9"
)

我的主要目标：

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

object WebServer {
    def main(args: Array[String]) {

        implicit val system = ActorSystem("APPNAME")
        implicit val materializer = ActorMaterializer()
        implicit val executionContext = system.dispatcher

        val requestHandler: HttpRequest => HttpResponse = {

            case HttpRequest(GET, Uri.Path("/"), _, _, _) => {

                HttpResponse(entity = HttpEntity(
                    ContentTypes.`text/html(UTF-8)`,
                    "<html><body>Hello world!</body></html>")
                )

            }

            case HttpRequest(GET, Uri.Path("/crash"), _, _, _) => {
                sys.error("BOOM!")
            }

            case r: HttpRequest => {
                r.discardEntityBytes() // important to drain incoming HTTP Entity stream
                HttpResponse(404, entity = "Unknown resource!")
            }

        }

        val bindingFuture = Http().bindAndHandleSync(requestHandler, "localhost", 8080)
        println(s"Server online at http://localhost:8080/\nPress RETURN to stop...")
        StdIn.readLine() // let it run until user presses return
        bindingFuture
            .flatMap(_.unbind()) // trigger unbinding from the port
            .onComplete(_ => system.terminate()) // and shutdown when done

    }
}

我已经找到java.lang.NoSuchMethodError: akka.actor.ActorCell.addFunctionRef和https://github.com/sbt/sbt-assembly/issues/204但是删除我的scala lib文件夹中的Akka-Actor没有帮助。我还尝试在与akka-http相同的版本中添加akka-actor作为依赖项。

Answer 1

Sbt正在使用java本机应用程序打包来打包scala项目。所以你不必使用sbt组装或创建一个胖罐。你可以尝试这些方法：

在项目根目录中：

sbt universal:packageBin

运行：

 ./target/universal/stage/bin/[project name]

Answer 2

添加到project/plugins.sbt：

resolvers += Resolver.url("bintray-sbt-plugins", url("https://dl.bintray.com/eed3si9n/sbt-plugins/"))(Resolver.ivyStylePatterns)

addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "0.14.5")

通过键入sbt compile
然后sbt assembly

最后输入.jar文件，输入scala target/scala-2.12/YOUR_FILE.assembly-0.1.jar，其中scala-2.12是您的scala版本。

Answer 3

我在带有 play 的 2.8.8 版本 play-sbt-plugin 2.8.2 上遇到了这个异常。当我将 play-sbt-plugin 更新为 2.8.8 时，异常消失了。

Akka-Http 2.4.9抛出java.lang.NoClassDefFoundError：akka / actor / ActorRefFactory异常

3 个答案: