Scala 找不到隐式…：akka.http.server.RoutingSetup

在使用akka http 1.0-M2时，我试图创建一个简单的Hello world示例

import akka.actor.ActorSystem
import akka.http.Http
import akka.http.model.HttpResponse
import akka.http.server.Route
import akka.stream.FlowMaterializer
import akka.http.server.Directives._

object Server extends App {

  val host = "127.0.0.1"
  val port = "8080"

  implicit val system = ActorSystem("my-testing-system")
  implicit val fm = FlowMaterializer()

  val serverBinding = Http(system).bind(interface = host, port = port)
  serverBinding.connections.foreach { connection ⇒
    println("Accepted new connection from: " + connection.remoteAddress)
    connection handleWith Route.handlerFlow {
      path("") {
        get {
          complete(HttpResponse(entity = "Hello world?"))
        }
      }
    }
  }
}

编译失败，

无法找到参数设置的隐式值：akka.http.server.RoutingSetup

还有，如果我改变

complete(HttpResponse(entity = "Hello world?"))

与

---

我得到另一个错误：

类型不匹配；找到：String（“Hello world？”）required:akka.http.marshalling.ToResponseMarshallable

通过研究，我能够理解缺少执行上下文的问题。为了解决这两个问题，我需要包括以下内容：

implicit val executionContext = system.dispatcher

查看

akka/http/marshalling/ToResponseMarshallable.scala

我看到

ToResponseMarshallable.apply

需要它，它返回一个

未来的[HttpResponse]

另外，在

akka/http/server/RoutingSetup.scala中，
RoutingSetup.apply
需要它

可能akka团队只需要添加更多的
@implicitNotFound
s。我在：和
上找到了不确切但相关的答案，发现得很好-这个问题在Akka HTTP 1.0-RC2中仍然存在，因此现在的代码必须如下所示（考虑到他们的API更改）：

implicit val executionContext = system.dispatcher

import akka.actor.ActorSystem
import akka.http.scaladsl.server._
import akka.http.scaladsl._
import akka.stream.ActorFlowMaterializer
import akka.stream.scaladsl.{Sink, Source}
import akka.http.scaladsl.model.HttpResponse
import Directives._
import scala.concurrent.Future

object BootWithRouting extends App {

  val host = "127.0.0.1"
  val port = 8080

  implicit val system = ActorSystem("my-testing-system")
  implicit val fm = ActorFlowMaterializer()
  implicit val executionContext = system.dispatcher

  val serverSource: Source[Http.IncomingConnection, Future[Http.ServerBinding]] =
    Http(system).bind(interface = host, port = port)

  serverSource.to(Sink.foreach {
    connection =>
      println("Accepted new connection from: " + connection.remoteAddress)
      connection handleWith Route.handlerFlow {
        path("") {
          get {
            complete(HttpResponse(entity = "Hello world?"))
          }
        }
      }
  }).run()
}