Make JsonDeserializer global effect - json

Question

When deserialize json to Map<out Any, Any>, gson will use Double to fill the Map, even the field is int number, so I use a MapDeserializerDoubleAsIntFix to covert number to int if it is possible.
{
"person":{
"name":"jack",
"age":24,
"height":174.5
}
}
class MapDeserializerDoubleAsIntFix: JsonDeserializer<Map<out Any, Any>> {
override fun deserialize(
json: JsonElement,
typeOfT: Type,
context: JsonDeserializationContext
): Map<out Any, Any>? {
return deserialize(json) as Map<out Any, Any>
}
private fun deserialize(jsonElement: JsonElement): Any? {
when {
jsonElement.isJsonArray -> {
val list: MutableList<Any?> = ArrayList()
val arr = jsonElement.asJsonArray
for (anArr in arr) {
list.add(deserialize(anArr))
}
return list
}
jsonElement.isJsonObject -> {
val map: MutableMap<String, Any?> = LinkedTreeMap()
val obj = jsonElement.asJsonObject
val entitySet = obj.entrySet()
for ((key, value) in entitySet) {
map[key] = deserialize(value)
}
return map
}
jsonElement.isJsonPrimitive -> {
val prim = jsonElement.asJsonPrimitive
when {
prim.isBoolean -> {
return prim.asBoolean
}
prim.isString -> {
return prim.asString
}
prim.isNumber -> {
// Here is what i do
// use int or long if it is possible
val numStr = prim.asString
return if (numStr.contains(".")) {
prim.asDouble
} else {
val num = prim.asNumber
val numLong = num.toLong()
return if (numLong < Int.MAX_VALUE && numLong > Int.MIN_VALUE) {
numLong.toInt()
} else {
numLong
}
}
}
}
}
}
return null
}
}
object MapTypeToken: TypeToken<Map<out Any, Any>>()
private val GSON = GsonBuilder()
.registerTypeAdapter(MapTypeToken.type, MapDeserializerDoubleAsIntFix())
.create()
And when I use GSON deserialize json as map, it works.
val map: Map<out Any, Any> = GSON.fromJson(json, MapTypeToken.type)
But when the map is in a data class as a field, the MapDeserializerDoubleAsIntFix not work.
data class Test(
val person: Map<out Any, Any>
)
val test = GSON.fromJson(json, Test::class.java)
So is there any way to deserialize map or filed map ?

Answer 1

Now I use this to solve.
class TestJsonDeserializer: JsonDeserializer<Test> {
override fun deserialize(
json: JsonElement,
typeOfT: Type,
context: JsonDeserializationContext,
): Test {
val jsonObject = json.asJsonObject
val personElement = jsonObject.get("person")
val person = context.deserialize<Map<out Any, Any>>(personElement, MapTypeToken.type)
return Test(person)
}
}
private val GSON = GsonBuilder()
.registerTypeAdapter(MapTypeToken.type, MapDeserializerDoubleAsIntFix())
.registerTypeAdapter(Test::class.java, TestJsonDeserializer())
.create()
But if another data class has map, I have to write another JsonDeserializer and register it.
Hope there is a better way to make the MapDeserializerDoubleAsIntFix work as global.