1.rust tokio tcp服务器代码示例，依赖tokio1.0.1

use std::io;
use tokio::net::TcpListener;
use tokio::io::AsyncReadExt;

#[tokio::main]
async fn main()->io::Result<()>{
    let listener=TcpListener::bind("0.0.0.0:8890").await?;
    loop{
        let (mut socket,_)=listener.accept().await?;
        tokio::spawn(async move {
            let (mut reader, mut writer)=socket.split();
            // let mut b1=Vec::new();
            // reader.read_to_end(&mut b1).await?;
            // println!("{:?}",String::from_utf8_lossy(&b1));
            tokio::io::copy(&mut reader,&mut writer).await//上面注释取消的话，writter中将不会写入任何信息，因为reader中的值，已经被读取完。
        });
    }
}

2.flutter示例

import 'dart:convert';
import 'dart:io';

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}
class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,

         // This makes the visual density adapt to the platform that you run
        // the app on. For desktop platforms, the controls will be smaller and
        // closer together (more dense) than on mobile platforms.
        visualDensity: VisualDensity.adaptivePlatformDensity,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  // This widget is the home page of your application. It is stateful, meaning
  // that it has a State object (defined below) that contains fields that affect
  // how it looks.

  // This class is the configuration for the state. It holds the values (in this
  // case the title) provided by the parent (in this case the App widget) and
  // used by the build method of the State. Fields in a Widget subclass are
  // always marked "final".

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  String _response = "";

  @override
  Widget build(BuildContext context) {
    // This method is rerun every time setState is called, for instance as done
    // by the _incrementCounter method above.
    //
    // The Flutter framework has been optimized to make rerunning build methods
    // fast, so that you can just rebuild anything that needs updating rather
    // than having to individually change instances of widgets.
    return Scaffold(
      appBar: AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
     body: Center(
        // Center is a layout widget. It takes a single child and positions it
        // in the middle of the parent.
        child: Column(
          children: <Widget>[
            RichText(
              text: TextSpan(
                text: "$_response",
                style: TextStyle(fontSize: 14, color: Colors.blue),
              ),
            ),

            RaisedButton(
                onPressed: () async {
                  var socket = await Socket.connect("192.168.0.223", 8890);//此处地址为自己的本地tcp socket地址
                  socket.write("hello,world");
                  socket.listen((List<int> event) {
                    print(utf8.decode(event));//输出服务器返回的值
                    setState(() {
                      _response = utf8.decode(event);//将服务器更新的值更新至界面
                      print(_response);
                    });
                  });
                  await socket.flush();
                  await socket.close();
                },
                child: Text("发送"))
          ],
        ),
      ),
    );
  }
}