Parsing JObject for key and values with json4s-jackson

Question

How can I get the keys scenario0 and scenario1 for each JObject in my List?

poop is a:

poop: List[org.json4s.JsonAST.JValue] = List(JObject(List((street,JString(Bulevard)), (city,JString(Helsinki)))), JObject(List((street,JString(Bulevard)), (city,JString(Helsinki)))))

Code:

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

implicit val formats = DefaultFormats

val json = parse("""
         {
            "address0": {
              "scenario0": {
                "street": "Bulevard",
                "city": "Helsinki"
              },
              "scenario1": {
                "street": "Bulevard",
                "city": "Helsinki"
              }
            },
            "address1": {
              "scenario0": {
                 "street": "Bulevard",
                 "city": "Helsinki"
               },
               "scenario1": {
                 "street": "Bulevard",
                 "city": "Helsinki"
               }
            }
         }""")

val poop = (json \ "address0").children
poop.foreach(p => {

})

score 1 · Answer 1 · answered May 20 '17 at 07:10

Do you mean you want it like this, as as JObject for each one.

json.children.flatMap(_.children) 
res13: List[JValue] = List(
  JObject(List((street,JString(Bulevard)), (city,JString(Helsinki)))),
  JObject(List((street,JString(Bulevard)), (city,JString(Helsinki)))),
  JObject(List((street,JString(Bulevard)), (city,JString(Helsinki)))),
  JObject(List((street,JString(Bulevard)), (city,JString(Helsinki))))
)

But you may find it more useful to parse them to a case class with a library like circe, play-json or argonaut. That way you dont have to keep parsing json everywhere.

Sorry but no. I am already iterating the List. Each JObject in the list, I want to get the JObject's key, which is `scenario0` and `scenario1`. So for `JObject(List((street,JString(Bulevard)), (city,JString(Helsinki))))` I want to extract `scenario0`. I'm pretty new to scala so I'm not sure how to do so =/ — Liondancer, May 20 '17 at 07:13

score 1 · Accepted Answer · answered May 20 '17 at 07:22

If you need values and don't have fixed schema: val poop: Map[String, Any] = json.asInstanceOf[JObject].values returns Map(address0 -> Map(scenario0 -> Map(street -> Bulevard, city -> Helsinki), scenario1 -> Map(street -> Bulevard, city -> Helsinki)), address1 -> Map(scenario0 -> Map(street -> Bulevard, city -> Helsinki), scenario1 -> Map(street -> Bulevard, city -> Helsinki)))
If you need values and have fixed schema then extracting of case class could be useful.
If you need AST: val poop = json.asInstanceOf[JObject].obj gives List[org.json4s.JsonAST.JField] = List((address0,JObject(List((scenario0,JObject(List((street,JString(Bulevard)), (city,JString(Helsinki))))), (scenario1,JObject(List((street,JString(Bulevard)), (city,JString(Helsinki)))))))), (address1,JObject(List((scenario0,JObject(List((street,JString(Bulevard)), (city,JString(Helsinki))))), (scenario1,JObject(List((street,JString(Bulevard)), (city,JString(Helsinki)))))))))

p.s. I omitted guardian checks for the sake of simplicity.

Parsing JObject for key and values with json4s-jackson

2 Answers2