C# · 12月 30, 2021

使用C#实现基于TCP和UDP协议的网络通信程序的基本示例

C#中使用TCP通信

TCP通信需要通信双方都在线,所以需要先启动服务端进行监听,客户端才能获得连接,服务端代码:

static void Main(string[] args) { TcpClient client = null; NetworkStream stream = null; byte[] buffer = null; string receiveString = null; IPAddress localIP = IPAddress.Parse(“127.0.0.1”); int localPort = 11000; TcpListener listener = new TcpListener(localIP,localPort);//用本地IP和端口实例化Listener listener.Start();//开始监听 while (true) { client = listener.AcceptTcpClient();//接受一个Client buffer = new byte[client.ReceiveBufferSize]; stream = client.GetStream();//获取网络流 stream.Read(buffer,buffer.Length);//读取网络流中的数据 stream.Close();//关闭流 client.Close();//关闭Client receiveString = Encoding.Default.GetString(buffer).Trim(‘\0’);//转换成字符串 Console.WriteLine(receiveString); } }

只有服务端开启监听后,客户端才能正确连接,所以服务端要一直开启监听,客户端每次发送数据,都要首先与服务端建立连接,连接建立完成后才进行数据发送。客户端代码:

static void Main(string[] args) { string sendString = null;//要发送的字符串 byte[] sendData = null;//要发送的字节数组 TcpClient client = null;//TcpClient实例 NetworkStream stream = null;//网络流 IPAddress remoteIP = IPAddress.Parse(“127.0.0.1”);//远程主机IP int remotePort = 11000;//远程主机端口 while (true)//死循环 { sendString = Console.ReadLine();//获取要发送的字符串 sendData = Encoding.Default.GetBytes(sendString);//获取要发送的字节数组 client = new TcpClient();//实例化TcpClient try { client.Connect(remoteIP,remotePort);//连接远程主机 } catch (System.Exception ex) { Console.WriteLine(“连接超时,服务器没有响应!”);//连接失败 Console.ReadKey(); return; } stream = client.GetStream();//获取网络流 stream.Write(sendData,sendData.Length);//将数据写入网络流 stream.Close();//关闭网络流 client.Close();//关闭客户端 } }

C#中使用UDP通信
UDP通信是无连接通信,客户端在发送数据前无需与服务器端建立连接,即使服务器端不在线也可以发送,但是不能保证服务器端可以收到数据。
服务器端代码:

static void Main(string[] args) { UdpClient client = null; string receiveString = null; byte[] receiveData = null; //实例化一个远程端点,IP和端口可以随意指定,等调用client.Receive(ref remotePoint)时会将该端点改成真正发送端端点 IPEndPoint remotePoint = new IPEndPoint(IPAddress.Any,0); while (true) { client = new UdpClient(11000); receiveData = client.Receive(ref remotePoint);//接收数据 receiveString = Encoding.Default.GetString(receiveData); Console.WriteLine(receiveString); client.Close();//关闭连接 } }

客户端代码:

static void Main(string[] args) { string sendString = null;//要发送的字符串 byte[] sendData = null;//要发送的字节数组 UdpClient client = null; IPAddress remoteIP = IPAddress.Parse(“127.0.0.1”); int remotePort = 11000; IPEndPoint remotePoint = new IPEndPoint(remoteIP,remotePort);//实例化一个远程端点 while (true) { sendString = Console.ReadLine(); sendData = Encoding.Default.GetBytes(sendString); client = new UdpClient(); client.Send(sendData,sendData.Length,remotePoint);//将数据发送到远程端点 client.Close();//关闭连接 } }