Flutter 如何使用在线转码工具将 JSON 转为 Model

目标 json:

{
    "posts": [
      {
        "id": "0",
        "created": 1590453935992,
        "content": "提供基于GraphQL API的数据查询及访问,「Hasura」获990万美元A轮..."
      },
      {
        "id": "1",
        "created": 1590453935992,
        "content": "为什么GraphQL是API的未来"
      },
      {
        "id": "2",
        "created": 1590453935992,
        "content": "Netflix:我们为什么要将 GraphQL 引入前端架构?"
      }
    ]
}

打开 quicktype 网站（可能需要科学访问网络）：Instantly parse JSON in any language | quicktype

点击右上角 Options 按钮，并作如下配置：

粘贴 JSON 到输入框中，并在左上角输入模型名称 PostsData：

右侧会自动生成模型：

复制右侧代码，创建相关类型：

/lib/PostsData.dart:

// To parse this JSON data, do
//
//     final postsData = postsDataFromJson(jsonString);

import 'dart:convert';

class PostsData {
    final List<Post> posts;

    PostsData({
        this.posts,
    });

    factory PostsData.fromJson(String str) => PostsData.fromMap(json.decode(str));

    String toJson() => json.encode(toMap());

    factory PostsData.fromMap(Map<String, dynamic> json) => PostsData(
        posts: json["posts"] == null ? null : List<Post>.from(json["posts"].map((x) => Post.fromMap(x))),
    );

    Map<String, dynamic> toMap() => {
        "posts": posts == null ? null : List<dynamic>.from(posts.map((x) => x.toMap())),
    };
}

class Post {
    final String id;
    final int created;
    final String content;

    Post({
        this.id,
        this.created,
        this.content,
    });

    factory Post.fromJson(String str) => Post.fromMap(json.decode(str));

    String toJson() => json.encode(toMap());

    factory Post.fromMap(Map<String, dynamic> json) => Post(
        id: json["id"] == null ? null : json["id"],
        created: json["created"] == null ? null : json["created"],
        content: json["content"] == null ? null : json["content"],
    );

    Map<String, dynamic> toMap() => {
        "id": id == null ? null : id,
        "created": created == null ? null : created,
        "content": content == null ? null : content,
    };
}

完成，Good Job!

其他在线转换工具

一. 在线生成网站：

https://javiercbk.github.io/json_to_dart/

二. JsonToDart 插件【推荐】

在 Android Studio 中安装 JsonToDart 插件，

a.打开 Preferences(Mac)或者 Setting(Window)，

b.选择 Plugins，搜索 JsonToDart

点击 Install(上图已经安装)，安装完成后重启即可

选定目录，点击右键，选择 New->Json to Dart

将json字符串复制进去，填写类明后，点击Generate按钮即可

附快捷键:

Windows：ALT + Shift + D

Mac：Option + Shift + D

三. 高效率JSON转Model

在pubspec.yaml中添加依赖

json_annotation: ^3.1.0
json_serializable: ^3.5.0
build_runner: ^1.0.0

在Android Stuido中执行Pub get

新建模型类(mode/demo_model.dart)

class DemoModel{
    
}

在网页上把后端请求到的JSON数据转换成Model：
https://czero1995.github.io/json-to-model/:网站转换支持无限层次嵌套复杂对象的转换

比如将以下JSON数据复制到网页上(左边):

{
  "code": 0,
  "data": {
    "avatar": "xxx.png",
    "id": 7,
    "float":0.1,
    "is_deleted": false,
    "nickname": "nickName",
    "openId": null,
    "phone": "13641418383",
    "store_ids": [1,2],
    "updated": "2020-11-05 11:53:10",
    "more":[{"a":1,"b":"b","c":{"c1":0.2,"c2":2}}]
  }
}

然后转换成Model数据(右边)

import 'package:json_annotation/json_annotation.dart';
part 'demo_model_data.g.dart'; 
@JsonSerializable(explicitToJson: true)
class DemoModelModel {
    DemoModelData data;
    DemoModelModel({
      this.data,
      this.code,
      this.message
    });
    factory DemoModelModel.fromJson(Map<String, dynamic> json) => _$DemoModelModelFromJson(json);
    Map<String, dynamic> toJson() => _$DemoModelModelToJson(this);
}

@JsonSerializable(explicitToJson: true)
class DemoModelData {
    String avatar;
    int id;
    double float;
    bool is_deleted;
    String nickname;
    var openId;
    String phone;
    List<int> store_ids; 
    String updated;
    List<MoreData> more; 
    DemoModelData({
        this.avatar, 
        this.id, 
        this.float, 
        this.is_deleted, 
        this.nickname, 
        this.openId, 
        this.phone, 
        this.store_ids, 
        this.updated, 
        this.more, 
    });
  factory DemoModelData.fromJson(Map<String, dynamic> json) => _$DemoModelDataFromJson(json);
  Map<String, dynamic> toJson() => _$DemoModelDataToJson(this);
}

@JsonSerializable(explicitToJson: true) 
class MoreData{ 
    int a;
    String b;
    CData c;
    MoreData({
        this.a, 
        this.b, 
        this.c, 
    });
    factory MoreData.fromJson(Map<String, dynamic> json) => _$MoreDataFromJson(json);
    Map<String, dynamic> toJson() => _$MoreDataToJson(this);
}

@JsonSerializable(explicitToJson: true) 
class CData{ 
    double c1;
    int c2;
    CData({
        this.c1, 
        this.c2, 
    });
    factory CData.fromJson(Map<String, dynamic> json) => _$CDataFromJson(json);
    Map<String, dynamic> toJson() => _$CDataToJson(this);
}

再将转换之后的数据复制出来覆盖到demo_model.dart文件上

执行build_runner

在项目终端下执行命令:

flutter pub run build_runner build

执行完成后，会生成demo_model.g.dart文件

整个执行流程如下(打开下面链接查看)

https://image-static.segmentfault.com/305/532/3055326920-21e28cc64f409c11

四. JSON to Dart Converter

JSON to Dart Converter - Convert JSON Code Online

Flutter 如何使用在线转码工具将 JSON 转为 Model

整个执行流程如下(打开下面链接查看)

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