[英]Could not find implicit value for parameter um
I had an Main app with the following structure:我有一个具有以下结构的主应用程序:
implicit val orgs: RootJsonFormat[GHOrg] = jsonFormat3(GHOrg)
implicit val users: RootJsonFormat[GHUser] = jsonFormat2(GHUser)
implicit val repos: RootJsonFormat[GHRepo] = jsonFormat3(GHRepo)
case class GHUser(login: String, contributions: Option[Int] = None)
case class GHRepo(name: String, owner: GHUser, contributors_url: String)
case class GHOrg(name: String, repos_url: String, members_url: String)
At some point I do在某些时候我会
Unmarshal(e).to[List[GHRepo]]
And everything works, however, I have been doing a little bit of code cleaning and I have moved the three case classes above to a different package, and now I am getting title's error.一切正常,但是,我一直在进行一些代码清理,并将上面的三个案例类移动到不同的 package,现在我得到了标题的错误。 I have tried this suggestion ( spray-json error: could not find implicit value for parameter um ) but does not work.我已经尝试过这个建议( spray-json 错误:找不到参数 um 的隐含值)但不起作用。
Here is how the current code (Not compiling):这是当前代码的方式(未编译):
import akka.actor.ActorSystem
import akka.http.javadsl.model.StatusCodes
import akka.http.scaladsl.marshallers.sprayjson.SprayJsonSupport._
import akka.http.scaladsl.model._
import akka.http.scaladsl.unmarshalling.Unmarshal
import akka.stream.ActorMaterializer
import com.elbauldelprogramador.domain.{GHOrg, GHRepo, GHUser}
import org.slf4j.LoggerFactory
import spray.json.DefaultJsonProtocol._
import spray.json.RootJsonFormat
object Main extends App {
implicit val system: ActorSystem = ActorSystem()
implicit val materializer: ActorMaterializer = ActorMaterializer()
implicit val executionContext: ExecutionContextExecutor = system.dispatcher
implicit val orgs: RootJsonFormat[GHOrg] = jsonFormat3(GHOrg)
implicit val users: RootJsonFormat[GHUser] = jsonFormat2(GHUser)
implicit val repos: RootJsonFormat[GHRepo] = jsonFormat3(GHRepo)
// ....
Unmarshal(e).to[List[GHRepo]] // Error
// ....
}
Here is the full error:这是完整的错误:
could not find implicit value for parameter um: akka.http.scaladsl.unmarshalling.Unmarshaller[akka.http.scaladsl.model.ResponseEntity,List[com.elbauldelprogramador.domain.GHUser]] [error] val users = Unmarshal(e).to[List[GHUser]] [error] ^ could not find implicit value for parameter um: akka.http.scaladsl.unmarshalling.Unmarshaller[akka.http.scaladsl.model.ResponseEntity,List[com.elbauldelprogramador.domain.GHUser]] [error] val users = Unmarshal(e) .to[List[GHUser]] [错误] ^
I finally was able to solve it reading spray's docs :我终于能够阅读喷雾的文档来解决它:
Basically, I created a separated file for each case class and one object called MyJsonProtocol
with the following code:基本上,我为每个案例 class 和一个名为MyJsonProtocol
的 object 创建了一个单独的文件,代码如下:
object MyJsonProtocol extends DefaultJsonProtocol {
implicit val users = jsonFormat2(GHUser)
// ...
}
Then in my main app I just import both things:然后在我的主应用程序中,我只导入这两个东西:
import com.elbauldelprogramador.api.MyJsonProtocol._
import com.elbauldelprogramador.domain.{GHOrg, GHRepo, GHUser}
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