如何在Android API < 26 /Java7中使用Gson反序列化YearMonth？

implementation 'com.google.code.gson:gson:2.8.8'

import com.google.gson.TypeAdapter;
import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonToken;
import com.google.gson.stream.JsonWriter;

import java.io.IOException;
import java.time.YearMonth;

public class YearMonthTypeAdapter extends TypeAdapter<YearMonth> {

    @Override
    public void write(JsonWriter out, YearMonth value) throws IOException {
        if (value == null) {
            out.nullValue();
            return;
        }
        out.value(value.toString());
    }

    @Override
    public YearMonth read(JsonReader in) throws IOException {
        if (in.peek() == JsonToken.NULL) {
            in.nextNull();
            return null;
        }
        String yearMonthStr = in.nextString();
        return YearMonth.parse(yearMonthStr);
    }
}

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;

import java.time.YearMonth;

public class Main {

    public static void main(String[] args) {
        Gson gson = new GsonBuilder()
                .registerTypeAdapter(YearMonth.class, new YearMonthTypeAdapter())
                .create();

        String json = "{\"year\":2022,\"month\":12}";
        YearMonth yearMonth = gson.fromJson(json, YearMonth.class);
        System.out.println(yearMonth);
    }
}