使用build_runner,对官方json_serializable功能的增加,提供了统一的json解析方法。 支持List解析。
构建器会找到 package:json_annotation注释的 类,生成统一的解析方法。
查看json_serializable的使用方法
- 当前最新版本 json_serializable_plus: ^0.0.3
在已经添加json_serializable 的基础上,只需要在dev_dependencies
中添加json_serializable_plus:^x.x.x
。
最终的pubspec.yaml
文件类似下面这样:
dependencies:
flutter:
sdk: flutter
json_annotation: '>=3.1.0 <3.2.0'
dev_dependencies:
flutter_test:
sdk: flutter
build_runner: ^1.0.0
json_serializable: ^3.5.1
json_serializable_plus: ^0.0.3
- 给
Teacher
和Student
设置@JsonSerializable()
注解
import 'package:json_annotation/json_annotation.dart';
part 'user.g.dart';
@JsonSerializable()
class Teacher {
String teacherName;
int id;
List<Student> students;
Teacher(this.teacherName,this.id,this.students);
factory Teacher.fromJson(Map<String,dynamic> json)=>_$TeacherFromJson(json);
}
@JsonSerializable()
class Student {
String studentName;
int id;
Student(this.studentName,this.id);
factory Student.fromJson(Map<String,dynamic> json)=>_$StudentFromJson(json);
}
-
运行
flutter pub run build_runner build
会在根目录会生成一个json_serializable.dart 文件 -
调用方法解析json
Teacher teacher = JsonSerializablePlus.fromJson(
json.decode("{\"teacherName\":\"hjq\",\"id\":32,\"students\":[{\"studentName\":\"s1\",\"id\":12},{\"studentName\":\"s2\",\"id\":12}]}"));
List<Student> student = JsonSerializablePlus.fromJson(json.decode(
"[{\"studentName\":\"s1\",\"id\":12},{\"studentName\":\"s2\",\"id\":12}]"));
- 增加对json_annotation 字段的解析
- 运行
flutter pub run build_runner build
时出现
Failed to precompile build_runner:build_runner:
../../../../../.pub-cache/hosted/pub.flutter-io.cn/build_resolvers-x.x.x/lib/src/resolver.dart:343:10: Error: Method not found: 'SummaryBuilder'.
return SummaryBuilder(sdkSources, sdk.context)
dev_dependencies
指定build_resolvers
版本 >= ^1.5.1
- 运行
flutter pub run build_runner build
时出现[SEVERE] Conflicting outputs were detected and the build is unable to prompt for permission to remove them.
代码提交时会把生成的*.g.dart提交上去,但是dart_tool/build 不会提交,所以在缺少dart_tool/build的文件情况下,flutter 无法自己删除重建。 运行以下代码
flutter packages pub run build_runner clean
flutter packages pub run build_runner build --delete-conflicting-outputs