DartVM服务器开发（第二十一天）--Dart中的Gson(jaguar_serializer)
今天我们来学习一下如何使用jaguar_serializer包，这里说明一下，该包在三端平台都是可用的(Flutter，dart web ,dart vm)，学习过安卓的，都知道gson吧，该包类似于gson
1.引入包
#pubspec.yaml
dependencies:
jaguar_serializer: ^2.2.0
dev_dependencies:
build_runner:
jaguar_serializer_cli:执行pub get命令
获取成功.png
导包
import 'package:jaguar_serializer/jaguar_serializer.dart';2.初始化
- 新增一个实体类
class Person {
String name;
int age;
}- 添加生成脚本标记
@GenSerializer()
class PersonSerializer extends Serializer<Person> with _$PersonSerializer {
}- 运行脚本
使用脚本命令
pub run build_runner build
image.png
- 导入生成代码
回到
person这个类的文件中，添加
part 'person.jser.dart';3．使用
main() async {
Jaguar(port: 1000)
..get('/person', (ctx){
PersonSerializer personSerializer=new PersonSerializer();
Person person=new Person()
..name='rhyme'
..age=18;
//personSerializer.toMap(person)获取到map对象
return Response.json( personSerializer.toMap(person));
})
..log.onRecord.listen(print)
..serve(logRequests: true);
}然后我们来请求一下
image.png
成功返回了json数据
4.使用详解
- json与对象相互转换
import 'dart:convert';
main(){
String jsonString='{"name":"rhyme","age":18}';
PersonSerializer personSerializer=new PersonSerializer();
// json to entity
Person person=personSerializer.fromMap(json.decode(jsonString));
print('name:${person.name} ,age: ${person.age}');
//entity to json
String toJson= json.encode( personSerializer.toMap(person));
print(toJson);
}- json 与对象列相互转换
main(){
String jsonString='[{"name":"rhyme","age":18},{"name":"ben","age":21}]';
PersonSerializer personSerializer=new PersonSerializer();
// list: json to entity
//因为目前fromList不支持dynamic的值，所以，我们需要吧json.decode出来的List<dynamic>转化为List<Map>，不然会报异常
List<Map> mapList=(json.decode(jsonString) as List<dynamic>).map((dy)=>dy as Map).toList();
List<Person> persons=personSerializer.fromList(mapList);
for(Person p in persons){
print('name:${p.name} ,age: ${p.age}');
}
//list: entity to json
String fromJson=json.encode(personSerializer.toList(persons));
print(fromJson);
}- 对象内嵌对象与json相互转换
在对象内添加一个对象
class Person {
String name;
int age;
//new
Info info;
//new
}
//new
class Info{
String address;
String phoneNumber;
}
//edit
@GenSerializer( serializers: [ InfoSerializer])
//edit
class PersonSerializer extends Serializer<Person> with _$PersonSerializer {
}
//new
@GenSerializer()
class InfoSerializer extends Serializer<Info> with _$InfoSerializer {
}
//new 运行命令pub run build_runner build
image.png
转换跟上面相同
String jsonString='{"name":"rhyme","age":18,"info":{"address":"广州","phoneNumber":"159xxxxxxxx"}}';
PersonSerializer personSerializer=new PersonSerializer();
// json to entity
Person person=personSerializer.fromMap(json.decode(jsonString));
print('name:${person.name} ,age: ${person.age}');
//entity to json
String toJson= json.encode(personSerializer.toMap(person));
print(toJson);- 对象内嵌对象列
将上面的Info改为List<Info>
重新运行命令pub run build_runner build
转换跟上面一样
String jsonString='[{"name":"rhyme","age":18,"info":[{"address":"广州","phoneNumber":"159xxxxxxxx"},{"address":"北京","phoneNumber":"158xxxxxxxx"}]},{"name":"ben","age":21}]';
PersonSerializer personSerializer=new PersonSerializer();
// list: json to entity
//因为目前fromList不支持dynamic的值，所以，我们需要吧json.decode出来的List<dynamic>转化为List<Map>，不然会报异常
List<Map> mapList=(json.decode(jsonString) as List<dynamic>).map((dy)=>dy as Map).toList();
List<Person> persons=personSerializer.fromList(mapList);
for(Person p in persons){
print('name:${p.name} ,age: ${p.age}');
}
//list: entity to json
String fromJson=json.encode(personSerializer.toList(persons));
print(fromJson);- 对象内嵌多个对象
class Person {
String name;
int age;
List<Info> info;
//new
Avatar avatar;
//new
}
class Info{
String address;
String phoneNumber;
}
//new
class Avatar{
String url;
String path;
}
//new
//edit
@GenSerializer( serializers: [ InfoSerializer,AvatarSerializer])
//edit
class PersonSerializer extends Serializer<Person> with _$PersonSerializer {
}
@GenSerializer()
class InfoSerializer extends Serializer<Info> with _$InfoSerializer {
}
//new
@GenSerializer()
class AvatarSerializer extends Serializer<Avatar> with _$AvatarSerializer {
}
//new然后重新运行命令pub run build_runner build
使用也是跟上面相同
String jsonString='[{"name":"rhyme","age":18,"avatar":{"url":"http://www.baidu.com","path":"baidu"},"info":[{"address":"广州","phoneNumber":"159xxxxxxxx"},{"address":"北京","phoneNumber":"158xxxxxxxx"}]},{"name":"ben","age":21}]';
PersonSerializer personSerializer=new PersonSerializer();
// list: json to entity
//因为目前fromList不支持dynamic的值，所以，我们需要吧json.decode出来的List<dynamic>转化为List<Map>，不然会报异常
List<Map> mapList=(json.decode(jsonString) as List<dynamic>).map((dy)=>dy as Map).toList();
List<Person> persons=personSerializer.fromList(mapList);
for(Person p in persons){
print('name:${p.name} ,age: ${p.age}');
}
//list: entity to json
String fromJson=json.encode(personSerializer.toList(persons));
print(fromJson);- 别名
有时候，我们的实体类成员变量名跟json数据中对应的字段不相同，可以使用@Alias('')对需要的字段进行标记，里面的值为json对应的字段
class Person {
@Alias('Name')
String name;
int age;
List<Info> info;
Avatar avatar;
}要使上面生效，需要重新运行命令pub run build_runner build
- Build命令
我们可以发现，当我每次做一个修改，都需要执行pub run build_runner build命令，这样是非常容易导致疏忽的，jaguar_serializer已经为我们考虑到了，
我们可以使用命令
pub run build_runner watch当该命令运行后，我们的每次点击保存，都会重新激活一次脚本，如下图
image.png
如果你是Flutter开发，可以使用下面的build命令
flutter packages pub run build_runner buildFlutter的监听命令
flutter packages pub run build_runner watchok，今天就到这里了，我们明天见!
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