Parse a nested json structure - json

Question

I have a nested json file like below
{
"Message No": 1.0,
"abc": {
"action": {
"ab1": false,
"ab2": false
},
"val": "Global"
},
"tyu": {
"lmp": [{
"Currency": "USD",
"Amount": "32401.32"
}]
},
"Payments": {
"Array": ["Hi", "There"],
"Details": [{
"Date": "2019-04-11"
}]
}
}
I have found a piece of code from google which will convert it into a simple key value pair
The code is like below
def Simply(m: Map[String, Any], tree: List[String] = List()) : Iterable[(String, Any)] = m.flatten
{
case (k: String, v: Map[String, Any] #unchecked) => Simply(v, tree :+ k)
case (k: String, v: List[Map[String, Any]] #unchecked) => v.flatten(Simply(_, tree :+ k))
case (k: String, v: Any) => List((tree :+ k.toString).mkString("_") ->v)
case (k,null) => List((tree :+ k.toString).mkString("_") ->"null")
}
The code works fine but it can not process the Array element in the json
"Array": ["Hi", "There"],
I tried to put an extra condition like
case (k: String, v: List[String]) => List((tree :+ k.toString).mkString("_") ->v.mkString(","))
but then this condition is blocking the below case in the simply function
case (k: String, v: List[Map[String, Any]] #unchecked) => v.flatten(Simply(_, tree :+ k))
Please help me understand If I am putting the condition in wrong place or any code change i need to do
Expected output
(tyu_lmp_Amount,32401.32)
(abc_action_ab1,false)
(Message No,1.0)
(abc_action_ab2,false)
(tyu_lmp_Currency,USD)
(Payments_Details_Date,2019-04-11)
(Payments_Array,{Hi, There})
(abc_val,Global)

Answer 1

I hope this is what you want:
package advanced
import org.json4s._
import org.json4s.jackson.JsonMethods._
object JsonTest extends App {
val s =
"""
|{
| "Message No": 1.0,
| "abc": {
| "action": {
| "ab1": false,
| "ab2": false
| },
| "val": "Global"
| },
|
| "tyu": {
| "lmp": [{
| "Currency": "USD",
| "Amount": "32401.32"
| }]
| },
|
| "Payments": {
| "Array": ["Hi", "There"],
| "Details": [{
| "Date": "2019-04-11"
| }]
| }
|}
|""".stripMargin
def jsonStrToMap(jsonStr: String): Map[String, Any] = {
implicit val formats = org.json4s.DefaultFormats
parse(jsonStr).extract[Map[String, Any]]
}
def Simply(m: Map[String, Any], tree: List[String] = List()) : Iterable[(String, Any)] = m.flatMap {
case (k: String, v: Map[String, Any]) => Simply(v, tree :+ k)
case (k: String, v: List[Any]) if v.headOption.exists(_.isInstanceOf[Map[String, Any]]) => v.flatMap{ subNode =>
Simply(subNode.asInstanceOf[Map[String, Any]], tree :+ k)
}
case (k: String, v: List[String]) => List((tree :+ k.toString).mkString("_") -> v.mkString(","))
case (k: String, v: Any) => List((tree :+ k.toString).mkString("_") ->v)
case (k,null) => List((tree :+ k.toString).mkString("_") ->"null")
}
val map = jsonStrToMap(s)
println(Simply(jsonStrToMap(s)))
//
// Map(tyu_lmp_Amount -> 32401.32, abc_action_ab1 -> false, Message No -> 1.0, abc_action_ab2 -> false, tyu_lmp_Currency -> USD, Payments_Details_Date -> 2019-04-11, Payments_Array -> Hi,There, abc_val -> Global)
//
}
pattern match on [Any] will try to cast it to any type in pattern match cases so that v: List[String] is swallowing any subnode that is a list of objects.