Flutter XML序列化与反序列化插件xml_serializable的使用
Flutter XML序列化与反序列化插件 xml_serializable 的使用
xml_serializable 是一个用于处理XML的Dart构建器。它通过注解生成代码，使得你可以轻松地将XML文档转换为Dart对象，并且可以从Dart对象生成XML文档。
使用步骤
1. 定义目标XML文档
首先，定义你想要序列化的XML文档：
<?xml version="1.0"?>
<bookshelf>
<book>
<title lang="English">XML Pocket Reference</title>
<author>Simon St. Laurent</author>
<author>Michael James Fitzgerald</author>
<price></price>
</book>
<book>
<title lang="English">HTML and XHTML Pocket Reference</title>
<author>Jennifer Niederst Robbins</author>
<price></price>
</book>
</bookshelf>
2. 创建对应的Dart类模型
根据上面的XML文档创建相应的Dart类模型：
class Book {
Title? title;
List<String>? authors;
String? price;
Book({
this.title,
this.authors,
this.price,
});
}
class Bookshelf {
List<Book>? books;
String? price;
Bookshelf({
this.books,
this.price,
});
}
enum Language {
mandarin,
spanish,
english,
hindi,
bengali,
}
class Title {
Language? language;
String? text;
Title({
this.language,
this.text,
});
}
3. 添加注解
使用 xml_annotation 包中的注解来标记这些类和属性：
import 'package:xml_annotation/xml_annotation.dart' as annotation;
[@annotation](/user/annotation).XmlRootElement(name: 'book')
[@annotation](/user/annotation).XmlSerializable()
class Book {
[@annotation](/user/annotation).XmlElement(name: 'title')
Title? title;
[@annotation](/user/annotation).XmlElement(name: 'author')
List<String>? authors;
[@annotation](/user/annotation).XmlElement(name: 'price', isSelfClosing: false)
String? price;
Book({
this.title,
this.authors,
this.price,
});
factory Book.fromXmlElement(XmlElement element) => _$BookFromXmlElement(element);
// 其他方法...
}
[@annotation](/user/annotation).XmlRootElement(name: 'bookshelf')
[@annotation](/user/annotation).XmlSerializable()
class Bookshelf {
[@annotation](/user/annotation).XmlElement(name: 'book')
List<Book>? books;
[@annotation](/user/annotation).XmlElement(name: 'price', includeIfNull: false)
String? price;
Bookshelf({
this.books,
this.price,
});
factory Bookshelf.fromXmlElement(XmlElement element) => _$BookshelfFromXmlElement(element);
// 其他方法...
}
[@annotation](/user/annotation).XmlEnum(fieldRename: annotation.FieldRename.pascal)
enum Language {
mandarin,
spanish,
english,
hindi,
bengali,
}
[@annotation](/user/annotation).XmlRootElement(name: 'title')
[@annotation](/user/annotation).XmlSerializable()
class Title {
[@annotation](/user/annotation).XmlAttribute(name: 'lang')
Language? language;
[@annotation](/user/annotation).XmlText()
String? text;
Title({
this.language,
this.text,
});
factory Title.fromXmlElement(XmlElement element) => _$TitleFromXmlElement(element);
// 其他方法...
}
4. 添加辅助方法
在每个类中添加必要的序列化辅助方法：
// 在Book类中
factory Book.fromXmlElement(XmlElement element) => _$BookFromXmlElement(element);
void buildXmlChildren(XmlBuilder builder, {Map<String, String> namespaces = const {}}) => _$BookBuildXmlChildren(this, builder, namespaces: namespaces);
// 其他方法...
// 在Bookshelf类中
factory Bookshelf.fromXmlElement(XmlElement element) => _$BookshelfFromXmlElement(element);
void buildXmlChildren(XmlBuilder builder, {Map<String, String> namespaces = const {}}) => _$BookshelfBuildXmlChildren(this, builder, namespaces: namespaces);
// 其他方法...
// 在Title类中
factory Title.fromXmlElement(XmlElement element) => _$TitleFromXmlElement(element);
void buildXmlChildren(XmlBuilder builder, {Map<String, String> namespaces = const {}}) => _$TitleBuildXmlChildren(this, builder, namespaces: namespaces);
// 其他方法...
5. 添加Part指令
在包含上述类的文件顶部添加 part 指令：
part 'example.g.dart';
6. 添加依赖项
在项目的 pubspec.yaml 文件中添加以下依赖项：
dependencies:
xml: ^6.0.0
xml_annotation: ^4.0.0
dev_dependencies:
build_runner: ^2.0.0
xml_serializable: ^5.0.0
然后运行命令安装依赖：
dart pub get
7. 运行构建器生成序列化代码
运行以下命令生成序列化代码：
dart run build_runner build
这将在你的项目中生成 example.g.dart 文件，其中包含了所有必要的序列化逻辑。
示例Demo
下面是一个完整的示例演示如何使用 xml_serializable 进行XML序列化与反序列化：
import 'package:xml/xml.dart';
import 'package:xml_annotation/xml_annotation.dart' as annotation;
part 'xml_serializable_example.g.dart';
void main() {
final document = XmlDocument.parse(
'''<?xml version="1.0"?>
<bookshelf>
<book>
<title lang="English">XML Pocket Reference</title>
<author>Simon St. Laurent</author>
<author>Michael James Fitzgerald</author>
<price></price>
</book>
<book>
<title lang="English">HTML and XHTML Pocket Reference</title>
<author>Jennifer Niederst Robbins</author>
<price></price>
</book>
</bookshelf>''',
);
final bookshelf = Bookshelf.fromXmlElement(document.rootElement);
print(bookshelf);
final element = bookshelf.toXmlElement();
print(element);
}
[@annotation](/user/annotation).XmlRootElement(name: 'book')
[@annotation](/user/annotation).XmlSerializable()
class Book {
[@annotation](/user/annotation).XmlElement(name: 'title')
Title? title;
[@annotation](/user/annotation).XmlElement(name: 'author')
List<String>? authors;
[@annotation](/user/annotation).XmlElement(name: 'price', isSelfClosing: false)
String? price;
Book({
this.title,
this.authors,
this.price,
});
factory Book.fromXmlElement(XmlElement element) => _$BookFromXmlElement(element);
[@override](/user/override)
String toString() {
return 'Book{title: $title, authors: $authors, price: $price}';
}
void buildXmlChildren(XmlBuilder builder, {Map<String, String> namespaces = const {}}) => _$BookBuildXmlChildren(this, builder, namespaces: namespaces);
// 其他方法...
}
[@annotation](/user/annotation).XmlRootElement(name: 'bookshelf')
[@annotation](/user/annotation).XmlSerializable()
class Bookshelf {
[@annotation](/user/annotation).XmlElement(name: 'book')
List<Book>? books;
[@annotation](/user/annotation).XmlElement(name: 'price', includeIfNull: false)
String? price;
Bookshelf({
this.books,
this.price,
});
factory Bookshelf.fromXmlElement(XmlElement element) => _$BookshelfFromXmlElement(element);
[@override](/user/override)
String toString() {
return 'Bookshelf{books: $books, price: $price}';
}
void buildXmlChildren(XmlBuilder builder, {Map<String, String> namespaces = const {}}) => _$BookshelfBuildXmlChildren(this, builder, namespaces: namespaces);
// 其他方法...
}
[@annotation](/user/annotation).XmlEnum(fieldRename: annotation.FieldRename.pascal)
enum Language {
mandarin,
spanish,
english,
hindi,
bengali,
}
[@annotation](/user/annotation).XmlRootElement(name: 'title')
[@annotation](/user/annotation).XmlSerializable()
class Title {
[@annotation](/user/annotation).XmlAttribute(name: 'lang')
Language? language;
[@annotation](/user/annotation).XmlText()
String? text;
Title({
this.language,
this.text,
});
factory Title.fromXmlElement(XmlElement element) => _$TitleFromXmlElement(element);
[@override](/user/override)
String toString() {
return 'Title{language: $language, text: $text}';
}
void buildXmlChildren(XmlBuilder builder, {Map<String, String> namespaces = const {}}) => _$TitleBuildXmlChildren(this, builder, namespaces: namespaces);
// 其他方法...
}
更多关于Flutter XML序列化与反序列化插件xml_serializable的使用的实战系列教程也可以访问 https://www.itying.com/category-92-b0.html
1 回复
更多关于Flutter XML序列化与反序列化插件xml_serializable的使用的实战系列教程也可以访问 https://www.itying.com/category-92-b0.html
当然，以下是如何在Flutter中使用xml_serializable插件进行XML序列化与反序列化的详细代码示例。
第一步：添加依赖
首先，在你的pubspec.yaml文件中添加xml_serializable依赖：
dependencies:
flutter:
sdk: flutter
xml_serializable: ^x.y.z # 请替换为最新版本号
dev_dependencies:
build_runner: ^x.y.z # 请替换为最新版本号
第二步：创建数据模型
接下来，创建一个数据模型类，并使用@XmlRootElement和@XmlElement注解来标记类及其字段。例如，我们创建一个简单的Person类：
import 'package:xml_serializable/xml_serializable.dart';
part 'person.g.dart';
@XmlRootElement(name: 'person')
class Person {
@XmlElement(name: 'name')
String? name;
@XmlElement(name: 'age')
int? age;
// 构造函数
Person({this.name, this.age});
// 为了方便，添加一个工厂方法从XML字符串创建对象
factory Person.fromXml(String xmlString) => Person._$fromXml(xmlString);
// 为了方便，添加一个方法将对象转换为XML字符串
String toXml() => Person._$toXml(this);
}
注意，我们使用了part 'person.g.dart';来生成序列化和反序列化所需的代码。
第三步：生成序列化代码
在项目根目录运行以下命令来生成序列化代码：
flutter pub run build_runner build
这将生成一个person.g.dart文件，包含Person类的序列化和反序列化逻辑。
第四步：使用序列化和反序列化
现在，你可以使用生成的代码来序列化和反序列化Person对象。
序列化示例
void main() {
Person person = Person(name: 'John Doe', age: 30);
String xmlString = person.toXml();
print(xmlString); // 输出：<person><name>John Doe</name><age>30</age></person>
}
反序列化示例
void main() {
String xmlString = '<person><name>Jane Doe</name><age>25</age></person>';
Person person = Person.fromXml(xmlString);
print(person.name); // 输出：Jane Doe
print(person.age); // 输出：25
}
总结
以上是如何在Flutter中使用xml_serializable插件进行XML序列化与反序列化的完整示例。通过使用注解和生成代码的方式，你可以方便地将Dart对象转换为XML字符串，以及从XML字符串创建Dart对象。
