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scalajson4s

Reverse operation of extract (json4s)

json4s allows user to convert a JsonAST object to a case class using extract.

import org.json4s._
import org.json4s.jackson.JsonMethods._

implicit val formats = DefaultFormats

case class Item(name: String, price: Double)
val json = parse("""{"name": "phone", "price": 1000.0}""") // JObject(List((name,JString(phone)), (price,JDouble(1000.0))))
val item = json.extract[Item] // Item(phone,1000.0)

However, to convert a case class into a JsonAST object, the only way I can think of is:

  1. serialize a case class using write
  2. deserialize a string using extract

Like below:

parse(write(item)) // JObject(List((name,JString(phone)), (price,JDouble(1000.0))))

Is there any better way for the conversion? Thank you!

Solution

  • Extraction.decompose converts a case class object into a JsonAST. 

    Extraction.decompose(item) // JObject(List((name,JString(phone)), (price,JDouble(1000.0))))