Question

我一直在使用一些遗留代码而且我遇到了一些麻烦。我有其他人写的枚举，现在我应该写入数据库中的一些数据并从中读取。这里有一些例子：

这是枚举

object MarketType extends scala.Enumeration {
  type MarketType = Value
  val Continent, Country, State, City = Value
  implicit val marketTypeReads = EnumUtility.enumFormat(MarketType)
}

case class Market(
  id: ObjectId = new ObjectId,
  name: String,
  marketType: Option[MarketType] = None,
)

object Market {
  val writes = new Writes[Market] {
    def writes(o: Market) = Json.obj(
      "id" -> o.id,
      "name" -> o.name,
      "type" -> o.marketType
)
}

 val reads: Reads[Market] = (
    (JsPath \ "id").readNullable[ObjectId].map(validateAndFetchObjectId) and
      (JsPath \ "name").read[String] and
      (JsPath \ "type").read[MarketType]
)(Market.apply _)


implicit val format: Format[Market] = Format(reads, writes)

这是我从前端获取的JSON以及我应该写入数据库的内容：

{"name":"Name","type":"state","description":"Desc"}

Answer 1

更改此：

val reads: Reads[Market] = (
  (JsPath \ "id").readNullable[ObjectId].map(validateAndFetchObjectId) and
  (JsPath \ "name").read[String] and
  (JsPath \ "type").read[MarketType]
)(Market.apply _)

进入：

val reads: Reads[Market] = (
  (JsPath \ "id").readNullable[ObjectId].map(validateAndFetchObjectId) and
  (JsPath \ "name").read[String] and
  (JsPath \ "type").read[MarketType]
)((id, name, type) => Market(id, name, Some(MarketType.withName(type))))

需要注意的事项：

您发布的JSON的小写type字段的值为;这将在传递到MarketType.withName()方法时在生产中抛出NoSuchElement异常。确保API的客户端以Camel case

发送此字段

示例：{ .., type: "State", .. }

将scala枚举写入数据库并从中读取

1 个答案: