Question

假设我必须使用它来读取和写入JSON

case class OrganizationData(var kind: Option[String],var id: Option[String],var organizationReference: OrganizationReferenceData,var objectHash: Option[String],var friendlyName: Option[String])



case class OrganizationReferenceData(var organizationId:String)

以下是读写

implicit val organizationWrites = (
(__ \ "kind").writeNullable[String] and
  (__ \ "id").writeNullable[String] and
  (__ \ "organizationReference").write[OrganizationReferenceData] and
  (__ \ "objectHash").writeNullable[String] and
  (__ \ "friendlyName").writeNullable[String]
) ( unlift( OrganizationData.unapply ) )

  implicit val OrganizationReferenceDataWrites:Writes[OrganizationReferenceData] = (
(__ \ "organizationId").write[String]
) ( unlift( OrganizationReferenceData.unapply ) )

当我尝试编译时，我收到以下错误。

Error:(54, 34) overloaded method value write with alternatives:
(t: String)(implicit w:   play.api.libs.json.Writes[String])play.api.libs.json.OWrites[play.api.libs.json.JsValue] <and>
(implicit w: play.api.libs.json.Writes[String])play.api.libs.json.OWrites[String]
cannot be applied to (config.core.OrganizationReferenceData => String)
(__ \ "organizationId").write[String]
                             ^

我在这里错过了一些东西吗？我看到的一个奇怪的事情是，如果我在“OrganizationReferenceDataWrites”类中添加另一个字段并且编译它的write元素。那么，如果我们不能有一个单一元素，那么最佳做法是什么呢？

Answer 1

我不确定你为什么要收到这条消息，但另一种方法可能是：

implicit val OrganizationReferenceDataWrites = new Writes[OrganizationReferenceData] {
  def writes(organizationReferenceData: OrganizationReferenceData) = Json.obj(
    "organizationId" -> organizationReferenceData.organizationId)
}

警告：我不知道我的combinators是否足以知道这是完全等效。

BTW您是否因为某种原因使用了可变（ var ）变量？

JSON隐式读取/写入Playframerowk，其中一个元素不起作用

1 个答案: