一、套接字（socket）概念
套接字（socket）是通信的基石，是支持TCP/IP协议的网络通信的基本操作单元。它是网络通信过程中端点的抽象表示，包含进行网络通信必须的五种信息：连接使用的协议，本地主机的IP地址，本地进程的协议端口，远地主机的IP地址，远地进程的协议端口。
应用层通过传输层进行数据通信时，TCP会遇到同时为多个应用程序进程提供并发服务的问题。多个TCP连接或多个应用程序进程可能需要通过同一个 TCP协议端口传输数据。为了区别不同的应用程序进程和连接，许多计算机操作系统为应用程序与TCP／IP协议交互提供了套接字(Socket)接口。应 用层可以和传输层通过Socket接口，区分来自不同应用程序进程或网络连接的通信，实现数据传输的并发服务。
二、建立socket连接
建立Socket连接至少需要一对套接字，其中一个运行于客户端，称为ClientSocket ，另一个运行于服务器端，称为ServerSocket 。
套接字之间的连接过程分为三个步骤：服务器监听，客户端请求，连接确认。
- 服务器监听：服务器端套接字并不定位具体的客户端套接字，而是处于等待连接的状态，实时监控网络状态，等待客户端的连接请求
- 客户端请求：指客户端的套接字提出连接请求，要连接的目标是服务器端的套接字。为此，客户端的套接字必须首先描述它要连接的服务器的套接字，指出服务器端套接字的地址和端口号，然后就向服务器端套接字提出连接请求。
- 连接确认：当服务器端套接字监听到或者说接收到客户端套接字的连接请求时，就响应客户端套接字的请求，建立一个新的线程，把服务器端套接字的描述发给客户 端，一旦客户端确认了此描述，双方就正式建立连接。而服务器端套接字继续处于监听状态，继续接收其他客户端套接字的连接请求。
三、服务端与客户端代码
服务端前台XMAL
1 <Window x:Class="Socket通信.MainWindow" 2 xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 3 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 4 xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 5 xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 6 xmlns:local="clr-namespace:Socket通信" 7 mc:Ignorable="d" 8 Title="服务端" Height="350" Width="525" Loaded="Window_Loaded" > 9 <Grid> 10 <Grid.RowDefinitions> 11 <RowDefinition Height="50*"/> 12 <RowDefinition Height="190*"/> 13 <RowDefinition Height="81*"/> 14 </Grid.RowDefinitions> 15 <Grid Grid.Row="0"> 16 <WrapPanel VerticalAlignment="Center"> 17 <Label Padding="5">IP:</Label> 18 <TextBox Padding="3" Width="150" Name="IP"></TextBox> 19 <Label Padding="5">Port:</Label> 20 <TextBox Padding="3" Width="100" Name="Port"></TextBox> 21 <Button Padding="3" Margin="3" Click="Start_View_Click">开始监听</Button> 22 <Button Padding="3" Margin="3" Click="Stop_Click">停止监听</Button> 23 </WrapPanel> 24 </Grid> 25 <Grid Grid.Row="1"> 26 <ListBox Name="ListConnet"></ListBox> 27 </Grid> 28 <Grid Grid.Row="2"> 29 <Grid.ColumnDefinitions> 30 <ColumnDefinition Width="405*"/> 31 <ColumnDefinition Width="113*"/> 32 </Grid.ColumnDefinitions> 33 34 <TextBox Name="SentConnet"></TextBox> 35 <Button Grid.Column="1" Click="Send_Click">发送</Button> 36 37 </Grid> 38 </Grid> 39 </Window>
服务端后台代码
1 using System; 2 using System.Net; 3 using System.Net.Sockets; 4 using System.Text; 5 using System.Threading; 6 using System.Windows; 7 8 9 10 namespace Socket通信 11 { 12 /// <summary> 13 /// MainWindow.xaml 的交互逻辑 14 /// </summary> 15 public partial class MainWindow : Window 16 { 17 public MainWindow() 18 { 19 InitializeComponent(); 20 } 21 Socket socketSend; 22 private void Start_View_Click(object sender, RoutedEventArgs e) 23 { 24 try 25 { 26 //点击开始监听时 在服务端创建一个负责监听IP和端口号的Socket 27 Socket socketWatch = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); 28 IPAddress ip = IPAddress.Any; //创建对象端口 29 IPEndPoint point = new IPEndPoint(ip, Convert.ToInt32(Port.Text)); 30 socketWatch.Bind(point);//绑定端口号 31 ShowMsg("监听成功!"); 32 socketWatch.Listen(10);//设置监听 33 //创建监听线程 34 Thread thread = new Thread(Listen); 35 thread.IsBackground = true; 36 thread.Start(socketWatch); 37 } 38 catch { } 39 40 41 42 } 43 44 void Listen(object o) 45 { 46 try 47 { 48 Socket socketWatch = o as Socket; 49 while (true) 50 { 51 socketSend = socketWatch.Accept();//等待接收客户端连接 52 ShowMsg(socketSend.RemoteEndPoint.ToString() + ":" + "连接成功!"); 53 //开启一个新线程，执行接收消息方法 54 Thread r_thread = new Thread(Received); 55 r_thread.IsBackground = true; 56 r_thread.Start(socketSend); 57 } 58 } 59 catch { } 60 } 61 62 63 64 /// <summary> 65 /// 服务器端不停的接收客户端发来的消息 66 /// </summary> 67 /// <param name="o"></param> 68 void Received(object o) 69 { 70 try 71 { 72 Socket socketSend = o as Socket; 73 while (true) 74 { 75 //客户端连接服务器成功后，服务器接收客户端发送的消息 76 byte[] buffer = new byte[1024 * 1024 * 3]; 77 //实际接收到的有效字节数 78 int len = socketSend.Receive(buffer); 79 if (len == 0) 80 { 81 break; 82 } 83 string str = Encoding.UTF8.GetString(buffer, 0, len); 84 ShowMsg("接收到的客户端数据：" + socketSend.RemoteEndPoint + ":" + str); 85 } 86 } 87 catch { } 88 } 89 /// <summary> 90 /// 服务器向客户端发送消息 91 /// </summary> 92 /// <param name="str"></param> 93 void Send(string str) 94 { 95 byte[] buffer = Encoding.UTF8.GetBytes(str); 96 socketSend.Send(buffer); 97 } 98 99 void ShowMsg(string msg) 100 { 101 Dispatcher.Invoke(() => { ListConnet.Items.Add(msg + " "); }); 102 } 103 104 105 106 private void Send_Click(object sender, RoutedEventArgs e) 107 { 108 Send(SentConnet.Text.Trim()); 109 } 110 111 private void Window_Loaded(object sender, RoutedEventArgs e) 112 { 113 } 114 private void Stop_Click(object sender, RoutedEventArgs e) 115 { 116 socketSend.Close(); 117 ShowMsg("已经停止监听!"); 118 } 119 } 120 }
客户端前台XMAL
1 <Window x:Class="Socket_Client.MainWindow" 2 xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 3 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 4 xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 5 xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 6 xmlns:local="clr-namespace:Socket_Client" 7 mc:Ignorable="d" 8 Title="客户端" Height="350" Width="525"> 9 <Grid> 10 <Grid.RowDefinitions> 11 <RowDefinition Height="50*"/> 12 <RowDefinition Height="190*"/> 13 <RowDefinition Height="81*"/> 14 </Grid.RowDefinitions> 15 <Grid Grid.Row="0"> 16 <WrapPanel VerticalAlignment="Center"> 17 <Label Padding="5">IP:</Label> 18 <TextBox Padding="3" Width="150" Name="IP"></TextBox> 19 <Label Padding="5">Port:</Label> 20 <TextBox Padding="3" Width="100" Name="Port"></TextBox> 21 <Button Padding="3" Margin="3" Click="Start_View_Click">连接</Button> 22 <Button Padding="3" Margin="3" Click="Stop_Click">断开连接</Button> 23 </WrapPanel> 24 </Grid> 25 <Grid Grid.Row="1"> 26 <TextBox Name="ListConnet"></TextBox> 27 </Grid> 28 <Grid Grid.Row="2"> 29 <Grid.ColumnDefinitions> 30 <ColumnDefinition Width="405*"/> 31 <ColumnDefinition Width="113*"/> 32 </Grid.ColumnDefinitions> 33 34 35 36 <TextBox Name="SentConnet"></TextBox> 37 <Button Grid.Column="1" Click="Send_Click">发送</Button> 38 39 </Grid> 40 </Grid> 41 </Window>
客户端后台代码
1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4 using System.Net; 5 using System.Net.Sockets; 6 using System.Text; 7 using System.Threading; 8 using System.Threading.Tasks; 9 using System.Windows; 10 using System.Windows.Controls; 11 using System.Windows.Data; 12 using System.Windows.Documents; 13 using System.Windows.Input; 14 using System.Windows.Media; 15 using System.Windows.Media.Imaging; 16 using System.Windows.Navigation; 17 using System.Windows.Shapes; 18 19 20 21 namespace Socket_Client 22 { 23 /// <summary> 24 /// MainWindow.xaml 的交互逻辑 25 /// </summary> 26 public partial class MainWindow : Window 27 { 28 public MainWindow() 29 { 30 InitializeComponent(); 31 } 32 Socket socketSend; 33 34 35 36 private void Start_View_Click(object sender, RoutedEventArgs e) 37 { 38 try 39 { 40 //创建客户端Socket，获得远程ip和端口号 41 socketSend = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); 42 IPAddress ip = IPAddress.Parse(IP.Text); 43 IPEndPoint point = new IPEndPoint(ip, Convert.ToInt32(Port.Text)); 44 45 socketSend.Connect(point); 46 ShowMsg("连接成功!"); 47 //开启新的线程，不停的接收服务器发来的消息 48 Thread c_thread = new Thread(Received); 49 c_thread.IsBackground = true; 50 c_thread.Start(); 51 } 52 catch (Exception) 53 { 54 ShowMsg("IP或者端口号错误..."); 55 } 56 57 58 59 60 } 61 void ShowMsg(string str) 62 { 63 64 65 66 Dispatcher.Invoke(() => { ListConnet.AppendText(str + " "); }); 67 } 68 /// <summary> 69 /// 接收服务端返回的消息 70 /// </summary> 71 void Received() 72 { 73 while (true) 74 { 75 try 76 { 77 byte[] buffer = new byte[1024 * 1024 * 3]; 78 //实际接收到的有效字节数 79 int len = socketSend.Receive(buffer); 80 if (len == 0) 81 { 82 continue; 83 } 84 string str = Encoding.UTF8.GetString(buffer, 0, len); 85 ShowMsg("接收到的服务端数据：" + socketSend.RemoteEndPoint + ":" + str); 86 } 87 catch 88 { 89 90 91 92 } 93 } 94 } 95 96 97 98 private void Send_Click(object sender, RoutedEventArgs e) 99 { 100 try 101 { 102 string msg = SentConnet.Text.Trim(); 103 byte[] buffer = new byte[1024 * 1024 * 3]; 104 buffer = Encoding.UTF8.GetBytes(msg); 105 socketSend.Send(buffer); 106 } 107 catch { } 108 109 110 111 } 112 113 private void Stop_Click(object sender, RoutedEventArgs e) 114 { 115 socketSend.Close(); 116 ShowMsg("连接已经断开!"); 117 } 118 } 119 }
运行结果
