now I'm trying to parse json to case class, and I have a problem. This is my json string:
{"book_id":"1", "book_name":"Skype", "author_name":"bla bla", "author_country":"Poland"}
And I have 2 case classes:
case class Book(bookId: String, bookName: String){}
case class Author(authorNam: String, authorCountry: String){}
So how can I parse the Json into 2 classes? The output will be:
Book(1, Skype)
Author(bla bla, Poland)
Thank you so much for your help.
There are a few solutions for you, the most obvious of them:
Json4s (it supports jackson)
Spray-Json is a lightweight, clean and efficient JSON implementation in Scala.
UPD Let's consider usage of Json4s:
object JsonExample extends App {
import org.json4s._
import org.json4s.JsonDSL._
import org.json4s.jackson.JsonMethods._
case class Winner(id: Long, numbers: List[Int])
case class Lotto(id: Long, winningNumbers: List[Int], winners: List[Winner], drawDate: Option[java.util.Date])
val winners = List(Winner(23, List(2, 45, 34, 23, 3, 5)), Winner(54, List(52, 3, 12, 11, 18, 22)))
val lotto = Lotto(5, List(2, 45, 34, 23, 7, 5, 3), winners, None)
val json =
("lotto" ->
("lotto-id" -> lotto.id) ~
("winning-numbers" -> lotto.winningNumbers) ~
("draw-date" -> lotto.drawDate.map(_.toString)) ~
("winners" ->
lotto.winners.map { w =>
(("winner-id" -> w.id) ~
("numbers" -> w.numbers))}))
println(compact(render(json)))
}
And this is the answer:
object JsonExample extends App {
import org.json4s._
import org.json4s.JsonDSL._
import org.json4s.jackson.JsonMethods._
implicit val formats = DefaultFormats // Brings in default date formats etc.
case class Book(bookId: String, bookName: String) {}
case class Author(authorName: String, authorCountry: String) {}
val jsonString = """{"book_id":"1", "book_name":"Skype", "author_name":"bla bla", "author_country":"Poland"}"""
val json = parse(jsonString)
println(json.camelizeKeys.extract[Book])
println(json.camelizeKeys.extract[Author])
}
Thank @rukavitsya for this.
Well, you could create another class to get the full Json, as a response class:
case class Response(bookId: String, bookName: String, authorNam: String, authorCountry: String){}
You map your response, that i am assuming comes from a server or other service, and then from this you separate into your two other classes, mapping them.
The better you can do in these cases is getting the whole response that you'll use in your use case, or in your code in general, and then treating the data in your code, before displaying or using the received data.
EDIT: to map the response, using your example, you'll have
Response(1, Skype, bla bla, Poland)
then you would do something like
Book(Response.bookID, Response.bookName)
Author(Response.authorName, Response.authorCountry)
Other approach is having your Response being a case class of the other classes, nesting the case classes, so you'll have both classes inside your Response.
Hope it helps. Cheers!
