Question

根据activator-akka-cassandra示例，我创建了自己的应用程序，将数据保存到cassandra。

我将数据模型定义如下

import play.api.libs.json.Json

case class Location(lat: Double, long: Double)
object Location {
  implicit def toLocation(lat: Double, long: Double) = Location(lat, long)
}

case class LocationWithTime(location: Location, time: Long)
object LocationWithTime {
  implicit def toLocationWithTime(location: Location, time: Long) = LocationWithTime(location, time)
}

case class Ping(pingUuid: String, senPhoneNumber: String, recPhoneNumber: Set[String], locationWithTime: LocationWithTime)
object Ping {
  implicit val LocationFormat = Json.format[Location]
  implicit val LocationWithTimeFormat = Json.format[LocationWithTime]
  implicit val PingFormat = Json.format[Ping]
}

不幸的是应该保存数据的代码：

def insertPing(ping: Ping): Unit =
    session.executeAsync(insertPing.bind(ping.pingUuid, ping.senPhoneNumber, ping.recPhoneNumber,
      ping.locationWithTime.location.lat, ping.locationWithTime.location.long, ping.locationWithTime.time))

不编译并返回错误

Error:(24, 38) the result type of an implicit conversion must be more specific than AnyRef
      ping.locationWithTime.location.lat, ping.locationWithTime.location.long, ping.locationWithTime.time))
                                 ^

example data model中的案例类扩展了AnyVal。基于this我会猜测在我的情况下类似的东西也可以做到，但是我不能这样做，因为ValueClasses只能有一个参数。我该如何解决这个问题？

Answer 1

虽然我不熟悉Cassandra，但我认为你的问题是bind需要Java Object s（即AnyRef s）和lat，是{ {1}}（即Java scala.Double），不是double。

您可以将AnyRef包裹在scala.Double中来实现。

java.lang.Double

自动映射和隐式转换必须比Any Ref＆＃34;更具体。错误

1 个答案: