Android flutter Json转Dart Model类

自动生成Model

json_serializable

1. pubspec.yaml

dependencies:
  flutter:
    sdk: flutter

  # The following adds the Cupertino Icons font to your application.
  # Use with the CupertinoIcons class for iOS style icons.
  cupertino_icons: ^0.1.2
  json_serializable: ^3.3.0

dev_dependencies:
  flutter_test:
    sdk: flutter
  build_runner: ^1.10.0
  json_serializable: ^3.3.0

build_runner是dart团队提供的一个生成dart代码文件的外部包

2. lib代码

example.dart

import 'package:json_annotation/json_annotation.dart';

part 'example.g.dart';

@JsonSerializable(nullable: false)
class Person {
  final String firstName;
  final String lastName;
  final DateTime dateOfBirth;
  Person({this.firstName, this.lastName, this.dateOfBirth});
  factory Person.fromJson(Map<String, dynamic> json) => _$PersonFromJson(json);
  Map<String, dynamic> toJson() => _$PersonToJson(this);
}

3. 运行代码生成器自动生成Model类

在当前项目的根目录下运行:

flutter packages pub run build_runner build

运行成功，在lib文件夹下生成example.g.dart
这个example.g.dart就是build_runner根据JsonSerializable生成的json解析文件
与example.dart相对应的example.g.dart内代码如下：

part of 'example.dart';

Person _$PersonFromJson(Map<String, dynamic> json) {
  return Person(
    firstName: json['firstName'] as String,
    lastName: json['lastName'] as String,
    dateOfBirth: DateTime.parse(json['dateOfBirth'] as String),
  );
}

Map<String, dynamic> _$PersonToJson(Person instance) => <String, dynamic>{
      'firstName': instance.firstName,
      'lastName': instance.lastName,
      'dateOfBirth': instance.dateOfBirth.toIso8601String(),
    };

4. 序列化和反序列化

JSON反序列化

将JSON格式的字符串转为Dart对象：
通过dart:convert中内置的JSON解码器json.decode()方法可以根据JSON字符串具体内容将其转为List或Map，通过Map转为Dart对象

Map<String, dynamic> map = json.decode(json);
Person person = Person.fromJson(map);

参考链接：
https://pub.dev/packages/json_serializable
https://book.flutterchina.club/chapter11/json_model.html
https://www.jianshu.com/p/b307a377c5e8