play-json -找不到参数um的隐值。

Question

我知道这个问题已经问过很多次了，但是他们都用喷雾器.我想用玩偶。这可能就是为什么提出的解决方案不能解决问题。route的特性位于一个名为RestApi.scala的单独文件中。使用它的Http.bindAndHandle位于名为Main.scala的文件中。没有删除不相关元素的两个文件如下所示。如果你想看到整个文件，请点击上面的链接。

RestApi.scala

package restApi

import akka.actor.{ActorSystem, Props}
import akka.http.scaladsl.model.StatusCodes
import akka.http.scaladsl.server.Directives._
import akka.pattern.ask
import akka.stream.ActorMaterializer
import akka.util.Timeout

import scala.concurrent.ExecutionContext
import scala.concurrent.duration._

trait RestApi {
  import models._
  import cassandraDB.{WriterActor, ReaderActor}
  implicit val system: ActorSystem
  implicit val materializer: ActorMaterializer
  implicit val ec: ExecutionContext

  implicit val timeout = Timeout(20 seconds)

  val cassandraWriterWorker = system.actorOf(Props[WriterActor], "cassandra-writer-actor")
  val cassandraReaderWorker = system.actorOf(Props[ReaderActor], "cassandra-reader-actor")

  val route =
    pathPrefix("api") {
      pathSuffix("contact") {
        // the line below has the error
        (post & entity(as[Contact])) { contact =>
          complete {
            cassandraWriterWorker ! contact
            StatusCodes.OK
          }
        }
      } ~
      pathSuffix("gps"/ "log") {
        // an analogous error message is shown in the line below
        (post & entity(as[GpsLog])) { gpsLog =>
          complete {
            cassandraWriterWorker ! gpsLog
            StatusCodes.OK
          }
        }
      }
    }
}

Main.scala

package initialization

import akka.actor.{ActorSystem, Props}
import akka.http.scaladsl.Http
import akka.stream.ActorMaterializer
import cassandraDB.{ConfigCassandraCluster, ReaderActor, WriterActor}
import gcm.GcmServer
import restApi.RestApi

object Main extends App with ConfigCassandraCluster with RestApi {

  override implicit val system = ActorSystem()
  override implicit val materializer = ActorMaterializer()
  override implicit val ec = system.dispatcher

  val write = system.actorOf(Props(new WriterActor(cluster)))
  val read = system.actorOf(Props(new ReaderActor(cluster)))
  val gcmServer = system.actorOf(Props(new GcmServer(11054...,"AIzaSyCOnVK...")), "gcm-server")
  val bindingFuture = Http().bindAndHandle(route, "localhost", 8080)


}

我指出了在RestApi.scala错误消息中错误发生的行：

Error:(31, 26) could not find implicit value for parameter um: akka.http.scaladsl.unmarshalling.FromRequestUnmarshaller[models.Contact]
        (post & entity(as[Contact])) { contact =>
                         ^

Contact是在Contact.scala中定义的数据模型。

我希望这不是复制，但我真的不这么认为。任何帮助都是非常感谢的。

Answer 1

事实证明，有一个简单的解决办法。只需将resolvers += Resolver.bintrayRepo("hseeberger", "maven")添加到构建文件中，然后将"de.heikoseeberger" %% "akka-http-play-json" % "1.5.3"添加到libraryDependencies中并将import de.heikoseeberger.akkahttpplayjson.PlayJsonSupport._导入代码中即可。现在你可以像使用喷雾一样使用play-json了。