Retain white space in JSON keys - scala

Question

White Space in scala keys are not retained
case class c1(
state :String,
`Card No`:String
)
Request payload
{
"state": "HH",
"Card No": "c1234",
"xxxx": "xxxx"
}
When used that case class in code after converting from gson to Json
it becomes
{"state":"HH","Card$u0020No":"c1234","xxx":"xxx"}

Answer 1

I haven't tried out gson for JSON processing. I use Play JSON play.api.libs.json framework.
The below works in play JSON:
import play.api.libs.json._
case class MyClass(State: String, `Card No`: String)
// Play can convert any case class into a JsValue, using macros.
// you will need an implicit `Writes` for `MyClass`
implicit private val MyClassWrites = Json.writes[MyClass]
val myobj = MyClass(State = "Bangalore", `Card No` = "Bl##1234")
val json = Json.toJson(myobj)
println(json)
Gives the below JSON:
{"State":"Bangalore","Card No":"Bl##1234"}
Will update this once I checkout gson lib.
Update: With Gson
I would like you not having backquotes to define case class values, rather have it in the standard format - maybe as camel cases. This would help keep the code cleaner.
Like below:
case class MyClassA (state: String, cardNo: String)
and use the gson FieldNamingPolicy to get the right formatting while building the JSON.
You can create a gson builder and do something like this
val status = MyClassA(State = "Bangalore", cardNo = "Bl##1234")
val gson = new GsonBuilder()
.setFieldNamingPolicy(FieldNamingPolicy.UPPER_CAMEL_CASE_WITH_SPACES)
.setPrettyPrinting().create()
println(gson.toJson(status))
FieldNamingPolicy.UPPER_CAMEL_CASE_WITH_SPACES will ensure that the first letter of the field name is capitalized when serialized to its JSON form and the words will be separated by a space.
above will produce the below JSON.
{
"State": "Bangalore",
"Card No": "Bl##1234"
}
Also, you can use #SerializedName annotation on any field name to specify the serialized name.
Using annotation
Using the SerializedName as below:
import com.google.gson.annotations.SerializedName
import com.google.gson.GsonBuilder
import com.google.gson.FieldNamingPolicy
import com.google.gson.GsonBuilder._
case class MyClassA (
State: String,
#(SerializedName #scala.annotation.meta.field)("card no")
cardNo: String
)
object Test {
def main(args: Array[String]): Unit = {
val status = MyClassA(State = "Bangalore", CARD = "Bl##1234")
val gson = new GsonBuilder()
.setPrettyPrinting().create()
println(gson.toJson(status))
}
}
UPD: below is the library dependency I am using:
libraryDependencies += "com.google.code.gson" % "gson" % "2.8.6"
You need to use the meta-annotations in scala.annotation.meta. Refer this git issue