Dart导入自定义库，系统内置库，第三方库

import 'common.dart'; //导入自定义库
import 'dart:io'; //导入系统内置的库 请求服务器接口的库
import 'dart:convert';

main() async {
  var result = await getData();
  print(result);
}
//发起服务器的请求
getData() async {
  // 创建HTTPClient()对象
  var httpClient = new HttpClient();
  //创建Uri对象
  var uri = new Uri.http('news-at.zhihu.com', '/api/3/stories/latest');
  // 发起请求，等待请求
  var request = await httpClient.getUrl(uri);
  // 关闭请求，等待响应
  var response = await request.close();
  // 解码响应的内容
  return await response.transform(utf8.decoder).join();
}

name: xxx
description: A new flutter module project.
dependencies:
   date_format: ^1.0.8

import 'package:date_format/date_format.dart';

void main() async {
  print(formatDate(DateTime(1989, 2, 21), [yyyy, '-', mm, '-', dd]));
}