Dart 中三种网络请求实现方式

贺公子之数据科学与艺术

发布于 2025-12-18 08:50:29

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HttpClient 网络请求实现

创建 HttpClient 实例并设置超时时间为 5 秒。构造目标 URI 并添加自定义请求头后发起 GET 请求，接收响应后需手动处理数据解码：

Future<void> fetchData() async {
  final client = HttpClient();
  client.idleTimeout = Duration(seconds: 5);
  
  final uri = Uri.parse("https://api.example.com/data");
  final request = await client.getUrl(uri);
  request.headers.add('user-agent', 'Custom-UA');
  
  final response = await request.close();
  if (response.statusCode == HttpStatus.ok) {
    final data = await response.transform(utf8.decoder).join();
    print(data);
  }
}

http 库简化请求流程

通过 http 包可更简洁地完成网络请求，自动处理连接关闭和编码转换：

dependencies:
  http: ^0.13.4

Future<void> fetchData() async {
  final uri = Uri.parse("https://api.example.com/data");
  final response = await http.get(uri, headers: {'user-agent': 'Custom-UA'});
  
  if (response.statusCode == 200) {
    print(response.body);
  }
}

dio 高级功能实现

dio 支持拦截器、文件传输等高级特性，需先添加依赖：

dependencies:
  dio: ^4.0.0

基础请求示例

final dio = Dio();
final response = await dio.get(
  'https://api.example.com/data',
  options: Options(headers: {'user-agent': 'Custom-UA'})
);

文件上传实现

final formData = FormData.fromMap({
  'file': await MultipartFile.fromFile('path/to/file.txt')
});
await dio.post('https://upload.example.com', data: formData);

并发请求处理

final responses = await Future.wait([
  dio.get('https://api1.example.com'),
  dio.post('https://api2.example.com')
]);

拦截器配置

dio.interceptors.add(InterceptorsWrapper(
  onRequest: (options, handler) {
    options.headers['token'] = 'auth_token';
    return handler.next(options);
  }
));

响应数据处理建议

对于 JSON 格式响应，推荐使用 jsonDecode 进行解析：

final Map<String, dynamic> data = jsonDecode(response.body);
print(data['key']);

对于大型文件下载，建议使用分块处理：

await dio.download(
  'https://example.com/largefile.zip',
  'local/path.zip',
  onReceiveProgress: (received, total) {
    print('${(received/total*100).toStringAsFixed(0)}%');
  }
);