C#中Socket的简单使用

大家好，又见面了，我是你们的朋友全栈君。

以前学过的Socket,后来没怎么用过,就基本忘了,所以闲来时重新回顾学习一番.

一.Socket的概念
Socket其实并不是一个协议,而是为了方便使用TCP或UDP而抽象出来的一层,是位于应用层和传输控制层之间的一组接口.

当两台主机通信是,必须通过Socket连接,Socket则利用TCP/IP协议建立TCP连接.TCP连接则更依赖于底层的IP协议.Socket是控制层传输协议.

双向的通信连接实现数据的交换,连接的一端成为一个Socket.

二.网络通信三要素
IP地址(网络上主机设备的唯一标识)
端口号(定位程序)
有效端口:0~65535,其中0~1024由系统使用,开发中一般使用1024以上端口.
传输协议(用什么样的方式进行交互)
常见协议:TCP(面向连接,提供可靠的服务),UDP(无连接,传输速度快)
三.Socket的通信流程

四.C#中Socket的简单使用步骤
第一步:服务端监听某个端口

第二步:客户端向服务端地址和端口发起Socket请求

第三步:服务器接收连接请求后创建Socket连接,并维护这个连接队列

第四步:客户端和服务端就建立起了双工同信,客户端与服务端就可以实现彼此发送消息

五.简单代码实例

1.服务端代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;

namespace SocketUtil
{
public class SocketServer
{
private string _ip = string.Empty;
private int _port = 0;
private Socket _socket = null;
private byte[] buffer = new byte[1024 * 1024 * 2];
/// <summary>
/// 构造函数
/// </summary>
/// <param name=”ip”>监听的IP</param>
/// <param name=”port”>监听的端口</param>
public SocketServer(string ip, int port)
{
this._ip = ip;
this._port = port;
}
public SocketServer(int port)
{
this._ip = “0.0.0.0”;
this._port = port;
}

public void StartListen()
{
try
{
//1.0 实例化套接字(IP4寻找协议,流式协议,TCP协议)
_socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
//2.0 创建IP对象
IPAddress address = IPAddress.Parse(_ip);
//3.0 创建网络端口,包括ip和端口
IPEndPoint endPoint = new IPEndPoint(address, _port);
//4.0 绑定套接字
_socket.Bind(endPoint);
//5.0 设置最大连接数
_socket.Listen(int.MaxValue);
Console.WriteLine(“监听{0}消息成功”, _socket.LocalEndPoint.ToString());
//6.0 开始监听
Thread thread = new Thread(ListenClientConnect);
thread.Start();

}
catch (Exception ex)
{
}
}
/// <summary>
/// 监听客户端连接
/// </summary>
private void ListenClientConnect()
{
try
{
while (true)
{
//Socket创建的新连接
Socket clientSocket = _socket.Accept();
clientSocket.Send(Encoding.UTF8.GetBytes(“服务端发送消息:”));
Thread thread = new Thread(ReceiveMessage);
thread.Start(clientSocket);
}
}
catch (Exception)
{
}
}

/// <summary>
/// 接收客户端消息
/// </summary>
/// <param name=”socket”>来自客户端的socket</param>
private void ReceiveMessage(object socket)
{
Socket clientSocket = (Socket)socket;
while (true)
{
try
{
//获取从客户端发来的数据
int length = clientSocket.Receive(buffer);
Console.WriteLine(“接收客户端{0},消息{1}”, clientSocket.RemoteEndPoint.ToString(), Encoding.UTF8.GetString(buffer, 0, length));
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
clientSocket.Shutdown(SocketShutdown.Both);
clientSocket.Close();
break;
}
}
}
}
}

2.客户端代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace SocketUtil
{
public class SocketClient
{
private string _ip = string.Empty;
private int _port = 0;
private Socket _socket = null;
private byte[] buffer = new byte[1024 * 1024 * 2];

/// <summary>
/// 构造函数
/// </summary>
/// <param name=”ip”>连接服务器的IP</param>
/// <param name=”port”>连接服务器的端口</param>
public SocketClient(string ip, int port)
{
this._ip = ip;
this._port = port;
}
public SocketClient(int port)
{
this._ip = “127.0.0.1”;
this._port = port;
}

/// <summary>
/// 开启服务,连接服务端
/// </summary>
public void StartClient()
{
try
{
//1.0 实例化套接字(IP4寻址地址,流式传输,TCP协议)
_socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
//2.0 创建IP对象
IPAddress address = IPAddress.Parse(_ip);
//3.0 创建网络端口包括ip和端口
IPEndPoint endPoint = new IPEndPoint(address, _port);
//4.0 建立连接
_socket.Connect(endPoint);
Console.WriteLine(“连接服务器成功”);
//5.0 接收数据
int length = _socket.Receive(buffer);
Console.WriteLine(“接收服务器{0},消息:{1}”, _socket.RemoteEndPoint.ToString(), Encoding.UTF8.GetString(buffer,0,length));
//6.0 像服务器发送消息
for (int i = 0; i < 10; i++)
{
Thread.Sleep(2000);
string sendMessage = string.Format(“客户端发送的消息,当前时间{0}”, DateTime.Now.ToString());
_socket.Send(Encoding.UTF8.GetBytes(sendMessage));
Console.WriteLine(“像服务发送的消息:{0}”, sendMessage);
}
}
catch (Exception ex)
{
_socket.Shutdown(SocketShutdown.Both);
_socket.Close();
Console.WriteLine(ex.Message);
}
Console.WriteLine(“发送消息结束”);
Console.ReadKey();
}
}
}

3.分别开启客户端和服务端

using SocketUtil;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SocketClientApp
{
class Program
{
static void Main(string[] args)
{
SocketClient client = new SocketClient(8888);
client.StartClient();
Console.ReadKey();
}
}
}

using SocketUtil;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SocketServerApp
{
class Program
{
static void Main(string[] args)
{
SocketServer server = new SocketServer(8888);
server.StartListen();
Console.ReadKey();
}
}
}