Can't fetch local JSON, flutter - flutter

Question

I've followed the steps to fetch local JSON, I think the problem is because in the pubspec, when I change the name local JSON different name the console nothing error, so what issues do I have? it's my wrong or flutter update something? it's my code :
import 'dart:convert';
import 'package:fetch_local_data/model.dart';
import 'package:flutter/material.dart';
class HomePage extends StatelessWidget {
const HomePage({Key? key}) : super(key: key);
List<Books> parseJson(String? json) {
if (json == null) {
return [];
}
List result = jsonDecode(json);
return result.map((e) => Books.fromJson(e)).toList();
}
#override
Widget build(BuildContext context) {
return Scaffold(
body: FutureBuilder<String>(
future: DefaultAssetBundle.of(context).loadString('assets/books.json'),
builder: (context, snapshot) {
List<Books> books = parseJson(snapshot.data);
print(books.length);
return ListView.builder(
itemCount: books.length,
itemBuilder: (context, index) {
return Text(books[index].title);
});
},
),
);
}
}
pubspec
name: fetch_local_data
description: A new Flutter project.
version: 1.0.0+1
environment:
sdk: ">=2.17.6 <3.0.0"
cupertino_icons: ^1.0.2
dev_dependencies:
flutter_test:
sdk: flutter
flutter_lints: ^2.0.0
flutter:
uses-material-design: true
assets:
- assets/books.json
folder structure