我是AkkaHTTP的新手，我想去掉JSON响应中不必要的字段，只取必要的字段。我使用this端点来获取响应，它包含了一堆字段。目前我只需要“name”和“versions”。我想知道如何将其反序列化为只包含“name”和“versions”的case类。我编写了下面几行代码以获得字符串形式的响应。

import akka.http.scaladsl.Http
import akka.http.scaladsl.model.{HttpRequest, HttpResponse}
import akka.stream.scaladsl.{Flow, Sink, Source}
import akka.stream.{ActorMaterializer, OverflowStrategy}

import scala.concurrent.Future
import scala.concurrent.duration.DurationInt
import scala.language.postfixOps
import scala.util.{Failure, Success}

object SoftwareRegistry extends App {

  implicit val system = ActorSystem("NPMRegistry")
  implicit val materializer = ActorMaterializer()

  import system.dispatcher

  case class NPMPackage(name: String)

  // reading the packages
  val filename = "B:\\Scala\\NPMRegistry\\src\\main\\resources\\packages.txt"
  val bufferedSource = scala.io.Source.fromFile(filename)
  val listOfPackages: List[NPMPackage] = (for (line <- bufferedSource.getLines) yield {
    NPMPackage(line.trim)
  }).toList
  bufferedSource.close()

  // source
  val sourceList = Source(listOfPackages)

  // sink
  val sink = Sink.foreach[NPMPackage] { p =>
    // https request
    val responseFuture: Future[HttpResponse] =
      Http().singleRequest(HttpRequest(uri = s"https://registry.npmjs.org/${p.name}"))
    val x = responseFuture
      .flatMap(_.entity.toStrict(2 seconds))
      .map(_.data.utf8String)
    x.onComplete {
      case Success(res) => println(res)
      case Failure(_) => sys.error("Something went wrong")
    }
  }

  // flow to slow things down and streaming sink to time-delayed operations
  val bufferedFlow = Flow[NPMPackage]
    .buffer(10, overflowStrategy = OverflowStrategy.backpressure)
    .throttle(1, 3 seconds)

  sourceList.async
    .via(bufferedFlow).async
    .to(sink)
    .run()
}

它会输出以下输出