json - 如何使用 Play 框架读取在 JSON 中传递的字符串

Question

我在为从客户端传递到服务器的 JSON 编写读取时遇到问题。客户端总是将 id 作为字符串发送，而它们应该是数字。当我尝试将它们读入 Scala 对象时，这会导致问题。我的案例类希望它们是 Long 以与 DB 匹配，但我不确定如何将 String 读取为 Long。我尝试简单地在 employer_id 上使用 .readNullable[Long] 但随后它只返回它期望 jsnumber 的验证错误。

Play-Scala 2.4.1

斯卡拉 2.11.7

implicit val person_reads: Reads[Person] = (
    Reads.pure(-1L) and
    Reads.pure(None) and
    (JsPath \ "person" \ "given_name").readNullable[String](minLength[String](1)) and
    (JsPath \ "person" \ "surname").readNullable[String](minLength[String](1)) and
    (JsPath \ "person" \ "city").readNullable[String] and
    (JsPath \ "person" \ "state").readNullable[String] and
    (JsPath \ "person" \ "county").readNullable[String] and
    (JsPath \ "person" \ "zip").readNullable[String] and
    (JsPath \ "person" \ "country").readNullable[String] and
    (JsPath \ "person" \ "email").readNullable[String](email) and
    (JsPath \ "person" \ "phone").readNullable[String] and
    (JsPath \ "person" \ "employer_id").readNullable[String] and
    Reads.pure(Set[Long]()) and
    Reads.pure("") and
    Reads.pure("")
)(Person.apply _)

case class Person(
    id:Long, 
    facebook_id:Option[Long], 
    given_name:Option[String], 
    surname:Option[String], 
    city:Option[String], 
    state:Option[String], 
    county:Option[String], 
    zip:Option[String], 
    country:Option[String], 
    email:Option[String], 
    phone:Option[String], 
    employer_id:Option[Long], 
    people_connection_ids:Set[Long], 
    added:String, 
    modified:String
)

示例 JSON POST/PUT

{
  "person": {
    "id": 78447,
    "facebook_id": 12345678987654321,
    "given_name": "Jon",
    "surname": "Smith",
    "city": "",
    "state": "",
    "county": "",
    "zip": "",
    "country": "",
    "email": "",
    "phone": "",
    "added": "",
    "modified": "",
    "employer_id": "1289592", <- This one gets passed as a string instead of number
    "people_connection_ids": [
      73
    ]
  }
}

感谢帮助

Answer 1

扩展@cchantep 的回答，在你的情况下，

  (JsPath \ "person" \ "employer_id").readNullable[String].map(_.map{_.toLong}) and