I am new in Scala and I want to extract some values from json
I have a big json data as a string and I want to extract only review_score value, I am using import scala.util.parsing.json.JSON
library.
var values = JSON.parseFull(bigJson)
My problem is, after parsing to json, How I get the reviewDetails Map?
parseFull will return an Option[Any] which contains either a List[Any] if the JSON string specifies an array, or a Map[String,Any] if the JSON string specifies an object, as the documentation states.
In your case, the value you want to retrieve is a key-value pair in a map which is itself a key-value pair of the global map.
It is a bit ugly, but since you know the structure of your JSON, a combination of get with asInstanceOf, will permit you to get the typed value you want.
val jsonObject = JSON.parseFull("...")
val globalMap = x.get.asInstanceOf[Map[String, Any]]
val reviewMap = globalMap.get("reviewDetails").get.asInstanceOf[Map[String, Any]]
val reviewScore = reviewMap.get("review_score").get.asInstanceOf[Double]
Note that here I use get "safely" because the value is known to exist in your context, but you can also use isEmpty and getOrElse.
If you want a scalable code, you can effectively look at How to parse JSON in Scala using standard Scala classes?
java.util.NoSuchElementException: None.get error at line 3 where reviewMap
globalMap.get("reviewDetails") instead of "review_details".
x (the invoking object to get)? Is it supposed to be jsonObject?