Is JsonElement integer or float?

Question

Is it possible to determine whether a GSON JsonElement instance is an integer or is it a float?

I'm able to determine whether it's a number:

JsonElement value = ...
boolean isNumber = value.getAsJsonPrimitive().isNumber();

But how to determine if it's an integer or a float, so I can subsequently use the correct conversion method? Either

float f = value.getAsJsonPrimitive().getAsFloat();

or

int i = value.getAsJsonPrimitive().getAsInt();

Edit: The other question may answer why this may be not implemented in GSON, but this question definitely isn't its duplicate.

Possible duplicate of [How to prevent Gson from expressing integers as floats](https://stackoverflow.com/questions/15507997/how-to-prevent-gson-from-expressing-integers-as-floats) — lucidbrot, Nov 13 '18 at 15:03
quoting: "Since JSON doesn't distinguish between integer and floating point fields Gson has to default to Float/Double for numeric fields.". Sounds to me like exactly what you're asking about — lucidbrot, Nov 13 '18 at 15:15
@lucidbrot I see this answer as being orthogonal to my question. Whatever the way Gson defaults numbers, there could be a way of it answering whether the number essentially "contains a dot" or not. — Rok Povsic, Nov 13 '18 at 16:29

score 0 · Answer 1 · answered Nov 13 '18 at 17:07

0

The only way I've found so far is using regex on a string:

if (value.getAsJsonPrimitive().isNumber()) {
    String num = value.getAsString();
    boolean isFloat = num.matches("[-+]?[0-9]*\\.[0-9]+");
    if (isFloat)
        System.out.println("FLOAT");
    else
        System.out.println("INTEGER");
}

This correctly determines 123 as integer, and both 123.45 and 123.0 as floats.

answered Nov 13 '18 at 17:07

Rok Povsic

4,626
5
37
53

It does work, but it excludes the fact that it can still be `Long`/`Double`. – Polv Jul 27 '19 at 07:53
did u find a way? – Ahmed Nawaz Khan Nov 12 '20 at 09:06

score -1 · Answer 2 · answered Nov 13 '18 at 15:09

-1

use something like, and so if return json object is an instance of float or integer you can then apply the required get:

JSONObject jObj = new JSONObject(jString);
Object aObj = jObj.get("a");
if(aObj instanceof Integer){
    System.out.println(aObj);
}

answered Nov 13 '18 at 15:09

Ptyler649

69
1

This does not work since `jObj.get("a")` returns `JsonElement` which is never `Integer` or `Float` (i.e. `Integer` is not a child of `JsonElement`). – Rok Povsic Nov 13 '18 at 16:41
This is a direct copy from [here](https://stackoverflow.com/a/15920281/3271729). At least link give credit to the original answer – Eamon Scullion Nov 13 '18 at 17:02
Additionally, this answer uses `org.json.simple.*` and not Gson. – Rok Povsic Nov 13 '18 at 17:14

Is JsonElement integer or float?

2 Answers2