How to ignoring empty string during deserialization by GSON

Question

I would like to remove empty string by using toJson from GSON. Example object:

public class ExampleObject {
    String defaultEmpty = "";
    String example;

    public ExampleObject() {
        this.example = "foo";
    }

and after

using

new Gson().toJson(new ExampleObject());

I am receiving

  "defaultEmpty " : "",
   "position" : "foo"

Is there any way to not including empty string during deserialization? I know GSON is ignoring null, but sometimes I have an empty string in my object and I have to ignore it.

If you don't want the behavior of the default `toJson`, then write your own `toJson`. I'm not sure exactly what the question is meant to be here. — Silvio Mayolo, Jun 08 '21 at 19:20
@SilvioMayolo I would like to skip empty json in the result of the string — kamil wilk, Jun 08 '21 at 19:23
https://stackoverflow.com/questions/48800319/how-do-i-treat-empty-strings-as-null-objects-with-gson — Sergey Afinogenov, Jun 08 '21 at 20:29
I've read that one, but this is not what I've expected. I can't manipulate model - anyway, thanks! — kamil wilk, Jun 08 '21 at 20:33

score 0 · Answer 1 · answered Jun 09 '21 at 00:50

Here is a simplified example.

static class ExampleObjectSerializer implements JsonSerializer<ExampleObject> {

    @Override
    public JsonElement serialize(ExampleObject src, Type typeOfSrc, JsonSerializationContext context) {
        JsonObject object = new JsonObject();
        object.addProperty("example", src.example);
        if(src.defaultEmpty != null && !src.defaultEmpty.equals("")) {
            object.addProperty("defaultEmpty", src.defaultEmpty);
        }
        return object;
    }
}

public static void main(String[] args) {
    Gson gson = new GsonBuilder().registerTypeAdapter(ExampleObject.class, new ExampleObjectSerializer()).create();
    ExampleObject exampleObject = new ExampleObject();
    String result = gson.toJson(exampleObject);
    System.out.println(result);
}

How to ignoring empty string during deserialization by GSON

1 Answers1