Dart实体类格式

• 方案一：手写实体类
• 方案二：生产力工具：网页自动生成实体类
• 方案三：生产力工具：json_serializable使用技巧
  那个方案适合我？

Dart实体类格式

class CategoryMo {
  String name;
  int count;

  CategoryMo({this.name, this.count});
  //将map转成mo
  CategoryMo.fromJson(Map<String, dynamic> json) {
    name = json['name'];
    count = json['count'];
  }
  //将mo转成map，可缺省
  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['name'] = this.name;
    data['count'] = this.count;
    return data;
  }
}

手写实体类

owner json

{
  "name": "伊零Onezero",
  "face": "http://i2.hdslb.com/bfs/face/1c57a17a7b077ccd19dba58a981a673799b85aef.jpg",
  "fans": 0
}

model转换与使用

var ownerMap = {
  "name": "伊零Onezero",
  "face":
      "http://i2.hdslb.com/bfs/face/1c57a17a7b077ccd19dba58a981a673799b85aef.jpg",
  "fans": 0
};
Owner owner = Owner.fromJson(ownerMap);
print('name:${owner.name}');
print('fans:${owner.fans}');
print('face:${owner.face}');

网页自动生成实体类

• 通过：https://www.devio.org/io/tools/json-to-dart/ 在线生成实体类

  {
    "id": "5633",
    "vid": "BV1q4411Y7zY",
    "title": "精神病人采访实录.突然觉得他们是那么的正常…",
    "tname": "影视剪辑",
    "url": "https://o.devio.org/files/video/BV1yt4y1Q7SS.mp4",
    "cover": "http://i1.hdslb.com/bfs/archive/4d628fdc730243c78ad393fe1ab7d6a43ab7d0c7.jpg",
    "pubdate": 1557474141,
    "desc": "剪自《人间世》很棒的纪录片，没做好准备千万别去看。",
    "view": 1333965,
    "duration": 145,
    "owner": {
      "name": "锦书致南辞",
      "face": "http://i0.hdslb.com/bfs/face/3f79d1df624218ab9a7774682fdb1d50a407ff88.jpg",
      "fans": 0
    },
    "reply": 2202,
    "favorite": 15392,
    "like": 36864,
    "coin": 3344,
    "share": 1841,
    "createTime": "2022-11-15 12:53:27",
    "size": 8161
  }

json_serializable使用技巧

• 官方demo：https://github.com/google/json_serializable.dart/tree/master/example

Step1：插件安装

dependencies:
...
  dio: ^3.0.10
  json_annotation: ^3.1.0


dev_dependencies:
...
  json_serializable: ^3.5.0
  build_runner: ^1.0.0

Step2：配置实体类

对于下面的json使用json_serializable该如何配置呢？

{
    "code": 0,
    "method": "GET",
    "requestPrams": "dd"
}

import 'package:json_annotation/json_annotation.dart';

// result.g.dart 将在我们运行生成命令后自动生成
part 'result.g.dart';

///这个标注是告诉生成器，这个类是需要生成Model类的
@JsonSerializable()
class Result {
  //定义构造方法
  Result(this.code, this.method, this.requestPrams);
  //定义字段
  int code;
  String method;
  String requestPrams;

  //固定格式，不同的类使用不同的mixin即可
  factory Result.fromJson(Map<String, dynamic> json) => _$ResultFromJson(json);
  //固定格式
  Map<String, dynamic> toJson() => _$ResultToJson(this);
}

因为实体类的生成代码还不存在，所以上代码会提示一些错误是正常现象

Step3：执行build生成实体类

flutter packages pub run build_runner build

那个方案适合我？