Play Json

example.scala

class DSO(val prop:String) {}

object DSO {
  implicit object DSOFormat extends Format[DSO] {
    def reads(json: JsValue): DSO = new DSO(
      (json \ "prop").asOpt[String].getOrElse("Not Defined")
    )

    def writes(d: DSO): JsValue =
      JsObject(List(
        "prop" -> JsString(d.prop)
      ))
  }

}

Format.scala

trait Format[T] extends Writes[T] with Reads[T]

/**
 * Default Json formatters.
 */
object Format extends DefaultFormat

Json.scala

def parse(input: String): JsValue = JerksonJson.parse[JsValue](input)

def stringify(json: JsValue): String = JerksonJson.generate(json)

// and 

def toJson[T](o: T)(implicit tjs: Writes[T]): JsValue = tjs.writes(o)

def fromJson[T](json: JsValue)(implicit fjs: Reads[T]): T = fjs.reads(json)

Reads.scala

trait Reads[T] {

  /**
   * Convert the JsValue into a T
   */
  def reads(json: JsValue): T

}

usage.scala

scala> val d = new DSO("a prop")
d: DSO = DSO@184a5d6

scala> d.prop
res1: String = a prop

scala> toJson(d)
res2: play.api.libs.json.JsValue = {"prop":"a prop"}

scala> fromJson[DSO](res2).prop
res3: String = a prop</pre>

Writes.scala

trait Writes[T] {

  /**
   * Convert the object into a JsValue
   */
  def writes(o: T): JsValue

}