JSON列表到Scala列表

Question

我正在用Play Framework和Scala创建一个后端API。我想将传入的请求映射到scala对象。该对象的实例变量之一是通道列表。以下是我目前拥有的：

接受请求并尝试将其映射到用户的Controller方法：

def addUser = Action(parse.json) { request =>
  request.body.validate[User].fold({ errors =>
    BadRequest(Json.obj(
      "status" -> "Error",
      "message" -> "Bad JSON",
      "details" -> JsError.toFlatJson(errors)
    ))
  }, { user =>
    User.create(user.pushToken, user.channels)
    Ok(Json.obj("status" -> "OK", "message" -> "User created"))
  })
}

用户案例类：

case class User(id: Pk[Long], pushToken: String, channels: List[String])

implicit val userFormat = (
  (__ \ "id").formatNullable[Long] and
  (__ \ "pushToken").format[String] and
  (__ \ "channels").format[List[String]]
  )((id, pushToken, channels) => User(id.map(Id(_)).getOrElse(NotAssigned), pushToken, channels),
  (u: User) => (u.id.toOption, u.pushToken, u.channels))

def create(pushToken: String, channels: List[String]) {
  DB.withConnection { implicit c =>
    SQL("insert into user (pushToken, channels) values ({pushToken}, {channels})").on(
      'pushToken -> pushToken,
      'channels -> channels
    ).executeUpdate()
  }
}

Compilation error[could not find implicit value for parameter extractor: anorm.Column[List[String]]]

理想情况下，我希望作为一个用户能够接受这一点：

{
  "pushToken":"4jkf-fdsja93-fjdska34",
  "channels": [
    "channelA", "channelB", "channelC"
  ]
}

并从中创建用户。

Answer 1

在Anorm中不能使用list[String]作为列值，这就是问题所在

您应该使用mkString方法或smth else