Dart笔记：build_runner-用于 Dart 代码生成和模块化编译的构建系统

dev_dependencies:
  build_runner:

dart run build_runner build

const buildExtensions = {
 '.txt': ['.md', '.html'],
};

dependencies:
  json_annotation: ^4.8.1
dev_dependencies:
  build_runner: ^2.4.6
  json_serializable: ^6.1.4

import 'package:json_annotation/json_annotation.dart';
// 这行是必须的,示user_model.dart文件是一个库的一部分
// 而 user_model.g.dart 文件是这个库的另一部分
part 'user_model.g.dart';
@JsonSerializable()
class UserModel {
  final String name;
  final String email;
  UserModel(this.name, this.email);
  factory UserModel.fromJson(Map<String, dynamic> json) =>
      _$UserModelFromJson(json);
  Map<String, dynamic> toJson() => _$UserModelToJson(this);
}

dart run build_runner build

// GENERATED CODE - DO NOT MODIFY BY HAND
part of 'user_model.dart';
// **************************************************************************
// JsonSerializableGenerator
// **************************************************************************
UserModel _$UserModelFromJson(Map<String, dynamic> json) => UserModel(
      json['name'] as String,
      json['email'] as String,
    );
Map<String, dynamic> _$UserModelToJson(UserModel instance) => <String, dynamic>{
      'name': instance.name,
      'email': instance.email,
    };

dependencies:
  flutter:
    sdk: flutter
  floor: ^1.4.2
  sqflite: ^2.3.0
dev_dependencies:
  floor_generator: ^1.4.2
  build_runner: ^2.1.2

// person_entity.dart
import 'package:floor/floor.dart';
@entity
class PersonEntity {
  @primaryKey
  final int id;
  final String name;
  PersonEntity(this.id, this.name);
}

// person_dao.dart
import 'package:floor/floor.dart';
import 'person_entity.dart';
@dao
abstract class PersonDao {
  @Query('SELECT * FROM Person')
  Future<List<PersonEntity>> findAllPeople();
  @insert
  Future<void> insertPerson(PersonEntity person);
}

import 'package:floor/floor.dart';
import 'person_dao.dart';
import 'person_entity.dart';
part 'app_database.g.dart'; // 生成的代码会在那里
@Database(version: 1, entities: [PersonEntity])
abstract class AppDatabase extends FloorDatabase {
  PersonDao get personDao;
}

dart run build_runner build

// GENERATED CODE - DO NOT MODIFY BY HAND
part of 'app_database.dart';
// **************************************************************************
// FloorGenerator
// **************************************************************************
// ignore: avoid_classes_with_only_static_members
class $FloorAppDatabase {
  /// Creates a database builder for a persistent database.
  /// Once a database is built, you should keep a reference to it and re-use it.
  static _$AppDatabaseBuilder databaseBuilder(String name) =>
      _$AppDatabaseBuilder(name);
  /// Creates a database builder for an in memory database.
  /// Information stored in an in memory database disappears when the process is killed.
  /// Once a database is built, you should keep a reference to it and re-use it.
  static _$AppDatabaseBuilder inMemoryDatabaseBuilder() =>
      _$AppDatabaseBuilder(null);
}
class _$AppDatabaseBuilder {
  _$AppDatabaseBuilder(this.name);
  final String? name;
  final List<Migration> _migrations = [];
  Callback? _callback;
  /// Adds migrations to the builder.
  _$AppDatabaseBuilder addMigrations(List<Migration> migrations) {
    _migrations.addAll(migrations);
    return this;
  }
  /// Adds a database [Callback] to the builder.
  _$AppDatabaseBuilder addCallback(Callback callback) {
    _callback = callback;
    return this;
  }
  /// Creates the database and initializes it.
  Future<AppDatabase> build() async {
    final path = name != null
        ? await sqfliteDatabaseFactory.getDatabasePath(name!)
        : ':memory:';
    final database = _$AppDatabase();
    database.database = await database.open(
      path,
      _migrations,
      _callback,
    );
    return database;
  }
}
class _$AppDatabase extends AppDatabase {
  _$AppDatabase([StreamController<String>? listener]) {
    changeListener = listener ?? StreamController<String>.broadcast();
  }
  PersonDao? _personDaoInstance;
  Future<sqflite.Database> open(
    String path,
    List<Migration> migrations, [
    Callback? callback,
  ]) async {
    final databaseOptions = sqflite.OpenDatabaseOptions(
      version: 1,
      onConfigure: (database) async {
        await database.execute('PRAGMA foreign_keys = ON');
        await callback?.onConfigure?.call(database);
      },
      onOpen: (database) async {
        await callback?.onOpen?.call(database);
      },
      onUpgrade: (database, startVersion, endVersion) async {
        await MigrationAdapter.runMigrations(
            database, startVersion, endVersion, migrations);
        await callback?.onUpgrade?.call(database, startVersion, endVersion);
      },
      onCreate: (database, version) async {
        await database.execute(
            'CREATE TABLE IF NOT EXISTS `PersonEntity` (`id` INTEGER NOT NULL, `name` TEXT NOT NULL, PRIMARY KEY (`id`))');
        await callback?.onCreate?.call(database, version);
      },
    );
    return sqfliteDatabaseFactory.openDatabase(path, options: databaseOptions);
  }
  @override
  PersonDao get personDao {
    return _personDaoInstance ??= _$PersonDao(database, changeListener);
  }
}
class _$PersonDao extends PersonDao {
  _$PersonDao(
    this.database,
    this.changeListener,
  )   : _queryAdapter = QueryAdapter(database),
        _personEntityInsertionAdapter = InsertionAdapter(
            database,
            'PersonEntity',
            (PersonEntity item) =>
                <String, Object?>{'id': item.id, 'name': item.name});
  final sqflite.DatabaseExecutor database;
  final StreamController<String> changeListener;
  final QueryAdapter _queryAdapter;
  final InsertionAdapter<PersonEntity> _personEntityInsertionAdapter;
  @override
  Future<List<PersonEntity>> findAllPeople() async {
    return _queryAdapter.queryList('SELECT * FROM Person',
        mapper: (Map<String, Object?> row) =>
            PersonEntity(row['id'] as int, row['name'] as String));
  }
  @override
  Future<void> insertPerson(PersonEntity person) async {
    await _personEntityInsertionAdapter.insert(
        person, OnConflictStrategy.abort);
  }
}

import 'dart:async';
import 'package:sqflite/sqflite.dart' as sqflite;

final database = await $FloorAppDatabase.databaseBuilder('app_database.db').build();
final personDao = database.personDao;
final person = PersonEntity(1, 'Frank');
await personDao.insertPerson(person);
final result = await personDao.findAllPeople();