Im new to Akka framework and i get the below error message when im trying to run my code.

The method which is called through the api code returns a Future[List[HashMap[String,Object]]]

The api code(akka-http route) which calls this method:

@GET
  @Path("getList/{name}")
  @Authorization("basicAuth")
  @Operation(summary = "Get list", description = "Returns a list",
    parameters = Array(new Parameter(name = "name", in = ParameterIn.PATH, description = "name", required=true)),
    security = Array(new SecurityRequirement(name="basicAuth")),
  )
    def getList: Route = {
      path("getList" / Segment) { name =>
        get {
          complete(getListService(name))
        }
      }
    }

I get the below error message

type mismatch;
 found   : scala.concurrent.Future[List[scala.collection.immutable.HashMap[String,Object]]]
 required: akka.http.scaladsl.marshalling.ToResponseMarshallable
          complete(getList(param))

returning a future should not be giving this error, i'm a bit confused as im not able to pinpoint where the mistake is. Any suggestions would greatly help.Kindly let me know if any more info is required.

CodePudding user response：

It requires an entity that it can serialize to JSON. HashMap[String, Object] isn't something that Akka is able to serialize out of the box. You have to either change the return type to something other than Object or define a custom marshaller. I doubt that you need an Object serializer, you probably want to have some class here instead. Here you have examples of serialization using spray: https://doc.akka.io/docs/akka-http/current/common/json-support.html