使用akka-http、circe时出现的问题

import io.circe._
import io.circe.generic.semiauto._
import io.circe.syntax._

case class User(id: Int, name: String)

object User {
  implicit val decoder: Decoder[User] = deriveDecoder[User]
  implicit val encoder: Encoder[User] = deriveEncoder[User]
}

val user = User(1, "John Doe")
val json = user.asJson.noSpaces
println(json) // 输出: {"id":1,"name":"John Doe"}

val decodedUser = io.circe.parser.decode[User](json)
println(decodedUser) // 输出: Right(User(1,John Doe))

import akka.actor.ActorSystem
import akka.http.scaladsl.Http
import akka.http.scaladsl.server.Directives._
import akka.stream.ActorMaterializer

object Main extends App {
  implicit val system = ActorSystem()
  implicit val materializer = ActorMaterializer()

  val route =
    path("user" / IntNumber) { id =>
      get {
        complete(User(id, "John Doe").asJson.noSpaces)
      }
    }

  Http().bindAndHandle(route, "localhost", 8080)
}

import akka.actor.ActorSystem
import akka.http.scaladsl.Http
import akka.http.scaladsl.server.Directives._
import akka.stream.ActorMaterializer
import scala.concurrent.Future

object Main extends App {
  implicit val system = ActorSystem()
  implicit val materializer = ActorMaterializer()
  import system.dispatcher

  val route =
    path("async") {
      get {
        onComplete(asyncOperation()) {
          case Success(result) => complete(result.asJson.noSpaces)
          case Failure(ex) => complete(StatusCodes.InternalServerError, ex.getMessage)
        }
      }
    }

  def asyncOperation(): Future[String] = Future {
    // 模拟异步操作
    Thread.sleep(1000)
    "Async result"
  }

  Http().bindAndHandle(route, "localhost", 8080)
}