核心：
在服务器端和客户端的两个Socket实例，共同维持一个连接，而我们还需要一个服务端绑定了特定端口号的固定的serverSocket，用来监听远方clientSocket的申请，并为这个申请建立服务端对应的proxSocket
服务器维护：
serverSocket
| 服务端实例 | 客户端实例 | 关系 |
|---|---|---|
| proxSocket | clientSocket | 一一对应 |
一、要有服务端
--配置--
1、new Socket
Socket serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
2、Bind
ServerSocket.Bind(new IPEndPoint(IPAddress.Parse(txtIP), int.Parse(txtPost))); //服务器绑定本机IP和端口
3、Listen
ServerSocket.Listen(10); //最大连接数是10
4、Accept
Socket proxSocket = ServerSocket.Accept(); //监听Socket连接行为，并为监听到的链接创建Socket实例，会阻塞线程直到端口链接
--信息发送与传输--
5、Receive
proxSocket.Receive(data, 0, data.Length, SocketFlags.None); //data是要写入的byte数组，会阻塞线程直到侦听到slientSocket的Send并持续到IO结束
6、Send
proxSocket.Send(result, 0, result.Length, SocketFlags.None); //result是要上传的byte数组
二、还有客户端
--配置--
1、new Socet
ClientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
2、Connect
ClientSocket.Connect(new IPEndPoint(IPAddress.Parse(txtIP), int.Parse(txtPort))); //尝试链接服务器的相应IP和端口，连接成功后，服务器端创建一个特定的proxSocket用来进行信息交换
--信息发送与传输--
3
ClientSocket.Receive(data, 0, data.Length, SocketFlags.None);
4
ClientSocket.Send(result, 0, result.Length, SocketFlags.None);
三、简单实现
csharp
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
namespace SockerDamo
{
class SocketServer
{
List<Socket> ClientProxSocketList = new List<Socket>();//用于存放客户端链接
Socket ServerSocket { get; set; }
public void Start()//创建服务器Socket，开始侦听客户端，并开始循环接收消息
{
//1.创建socket对象
Socket serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
ServerSocket = serverSocket;
//first is 寻址方式(此处是Ipv4)
//second is the socket's type
//And the thrid is the 传输协议
System.Console.WriteLine("请输入IP地址：");
String txtIP = Console.ReadLine();
System.Console.WriteLine("请输入端口号：");
String txtPost = Console.ReadLine();
//2.绑定端口IP
ServerSocket.Bind(new IPEndPoint(IPAddress.Parse(txtIP), int.Parse(txtPost)));
//socket's Bind action need a IPEndPoint to bind the socket and the computer's ip and post
//so in the IPEndPoint we need a IPAddress and a int number(Post)
//3.开始侦听
ServerSocket.Listen(20);//the number 表示 同时排队的最大限制数量
//同时来了100个链接请求，只能处理一个链接，队列里面放20个等待链接的客户端，其他的返回错误消息。
//4.开始接受客户端的链接
//为了不阻塞主线程,我们应该把以下代码放在一个新的线程(池)中
try
{
System.Console.WriteLine("开始监听链接...");
Socket proxSocket = ServerSocket.Accept();//这个方法会阻塞当前线程，直到监听到链接
AppendTextToTxtLog(string.Format("客户端{0}已链接", proxSocket.RemoteEndPoint.ToString()));
byte[] data = new byte[1024 * 1024 * 256];//用来放数据的数组
int len;
while (true)
{
System.Console.WriteLine("请选择模式：");
System.Console.WriteLine("0.等待接收消息");
System.Console.WriteLine("1.发送消息");
string mo = Console.ReadLine();
//获取客户端数据并返回读取的字节数,会阻塞当前线程,
//当客户端突然掉线,往往会引发异常
if (mo == "0")
{
try
{
len = proxSocket.Receive(data, 0, data.Length, SocketFlags.None);//往data数组里，从index=0开始，最长写入数据长度为data.Length
if (data[0] == 0)
{
StopConnect(proxSocket);
}//正常退出逻辑
else if (data[0] == 1)
{
string str = Encoding.UTF8.GetString(data, 1, len - 1);//在data数组中从0开始，len个数据，转成str
AppendTextToTxtLog(string.Format("接收到客户端:{0} 的信息是:{1}", proxSocket.RemoteEndPoint.ToString(), str));
}
}
catch (Exception)
{
Console.WriteLine("接收数据出错");
StopConnect(proxSocket);
}
}
else if (mo == "1")
{
SendMsg();
}
}
}
catch
{
AppendTextToTxtLog("出问题啦:您在接收客户端的请求的时候,发生了异常,夭寿啦```");
}
}
private void StopConnect(Socket proxSocket)//停止链接
{
try
{
if (proxSocket.Connected)
{
proxSocket.Shutdown(SocketShutdown.Both);
proxSocket.Close(100);
}
}
catch (Exception ex)
{
System.Console.WriteLine("或许没有成功的停止连接" + ex.ToString());
}
}
//发送消息
private void SendMsg()
{
String txtMsg = Console.ReadLine();
foreach (var proxSocket in ClientProxSocketList)
{
if (proxSocket.Connected)
{
byte[] data = Encoding.UTF8.GetBytes(txtMsg);//信息转二进制
byte[] result = new byte[data.Length + 1];//信息的二进制放在1~data.Length
result[0] = 1;//第0个位置是标志位，将来我们可以用这个标志位，分辨文件类型，将来用来传文件
Buffer.BlockCopy(data, 0, result, 1, data.Length);//把 data从0 转 result从1 长度data.Length
proxSocket.Send(result, 0, result.Length, SocketFlags.None);//发送消息
}
}
AppendTextToTxtLog(string.Format("{0}(本机) 的信息是:{1}", ServerSocket.LocalEndPoint.ToString(), txtMsg));
}
private void AppendTextToTxtLog(string txt)
{
Console.WriteLine(txt);
}
}
class SocketClient
{
Socket ClientSocket { get; set; }
public void Start()//创建客户端Socket，并开始循环接收消息
{
#region 获取服务器端口内容
System.Console.WriteLine("请输入服务器IP：");
String txtIP = Console.ReadLine();
System.Console.WriteLine("请输入端口号：");
String txtPort = Console.ReadLine();
#endregion
//客户端链接服务器端
//1.创建Socket对象
ClientSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
//2.连接服务器端Socket
try//如果服务器的Listen队列已满,那么就会返回一个异常
{
ClientSocket.Connect(new IPEndPoint(IPAddress.Parse(txtIP), int.Parse(txtPort)));
}
catch
{
System.Console.WriteLine("当前服务器无法连接");
//Thread.Sleep(1000);
return;
}
//3.接收服务器端消息
byte[] data = new byte[1024 * 1024 * 256];//传输数据放在这里，这里是256MB = 256 * 1024 KB = 256 * 1024 * 1024Byte
int len;
string str;
string wenJianMing = "";
while (true)
{
System.Console.WriteLine("请选择模式：");
System.Console.WriteLine("0.等待接收消息");
System.Console.WriteLine("1.发送消息");
string mo = Console.ReadLine();
len = 0;
str = null;
if (mo == "0")
try
{
len = ClientSocket.Receive(data, 0, data.Length, SocketFlags.None);//获取服务器端数据并返回读取的字节数,会阻塞当前线程,
//当客户端突然掉线,往往会引发异常
if (data[0] == 0)//模式0退出
{
AppendTextToTxtLog(string.Format("服务端:{0} 正常退出", ClientSocket.RemoteEndPoint.ToString()));
StopConnect();
}
else if (data[0] == 1)
{//模式1收到了字符串
str = Encoding.UTF8.GetString(data, 1, len - 1);
AppendTextToTxtLog(string.Format("Socket信息:{0}", str));
}
//一次类推，总共有256种消息的传输模式
}
catch (Exception)
{
AppendTextToTxtLog(string.Format("服务端:{0} 非正常退出",
ClientSocket.RemoteEndPoint.ToString()));
StopConnect();
return;
}
else if(mo == "1"){
SendMsg();
}
}
// 也可以将第3步写入方法ReceiveData
// Thread thread = new Thread(new ParameterizedThreadStart(ReceiveData));
// thread.IsBackground = true;
// thread.Start(); // 然后开启线程
}
private void AppendTextToTxtLog(string txt)
{
Console.WriteLine(txt);
}
private void StopConnect()
{
try
{
if (ClientSocket.Connected)
{
ClientSocket.Shutdown(SocketShutdown.Both);
ClientSocket.Close(100);
}
}
catch (Exception ex)
{
System.Console.WriteLine("或许没有成功的停止连接" + ex.ToString());
}
}
public void SendMsg()
{
if (ClientSocket.Connected)
{
System.Console.WriteLine("请输入要发送信息的模式：");
System.Console.WriteLine("0：结束");
System.Console.WriteLine("1：字符串");
String ms = Console.ReadLine();
if (ms == "0") { }
if (ms == "1")
{
System.Console.WriteLine("请输入要发送的消息：");
String s = Console.ReadLine();
byte[] data = Encoding.UTF8.GetBytes(s);
byte[] result = new byte[data.Length + 1];//信息的二进制放在1~data.Length
result[0] = 1;//第0个位置是标志位，将来我们可以用这个标志位，分辨文件类型，将来用来传文件
Buffer.BlockCopy(data, 0, result, 1, data.Length);//把 data从0 转 result从1 长度data.Length
ClientSocket.Send(result, 0, result.Length, SocketFlags.None);//发送消息
AppendTextToTxtLog(string.Format("本机的信息是:{0}", s));
}
}
}
}
internal class Program
{
static void Main(string[] args)
{
System.Console.WriteLine("0：服务器端");
System.Console.WriteLine("1：客户端");
string ms = Console.ReadLine();
if (ms == "0")
{
SocketServer server = new SocketServer();
server.Start();
}
else if (ms == "1")
{
SocketClient client = new SocketClient();
client.Start();
}
}
}
}