[C#基础]网络编程(二):TcpListener & TcpClient

TcpListener & TcpClient，可以看作为对socket的进一步封装(基于tcp协议)，TcpListener为服务器端，TcpClient为客户端。

TcpListener ：https://msdn.microsoft.com/zh-cn/library/system.net.sockets.tcplistener(v=vs.110).aspx

TcpClient：https://msdn.microsoft.com/zh-cn/library/system.net.sockets.tcpclient(v=vs.110).aspx

NetworkStream：https://msdn.microsoft.com/zh-cn/library/system.net.sockets.networkstream(v=vs.110).aspx

0.NetworkStream(提供网络访问的基础数据流)

a.将 Write 和 Read 方法用于简单的单线程同步阻止 I/O。若要使用不同的线程来处理 I/O，则请考虑使用 BeginWrite 和 EndWrite 方法，或 BeginRead 和 EndRead 方法进行通信。

b.可以对 NetworkStream 类的实例同时执行读和写操作而无需同步。只要写操作有一个唯一线程，读操作有一个唯一线程，则读和写线程之间不会存在交叉引用，因而无需同步。

1.TcpListener(侦听来自 TCP 网络客户端的连接)

Start()：开始侦听传入的连接请求。类似socket中的listen。

Accept：可使用 Socket 或 TcpClient 来连接 TcpListener。

Stop()：关闭侦听器。

至于Send和Receive，则由NetworkStream进行处理

using System;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Text;

class MyTcpListener
{
public static void Main()
{
TcpListener server=null;
try
{
// Set the TcpListener on port 13000.
Int32 port = 13000;
IPAddress localAddr = IPAddress.Parse("127.0.0.1");

// TcpListener server = new TcpListener(port);
server = new TcpListener(localAddr, port);

// Start listening for client requests.
server.Start();

// Buffer for reading data
Byte[] bytes = new Byte[256];
String data = null;

// Enter the listening loop.
while(true)
{
Console.Write("Waiting for a connection... ");

// Perform a blocking call to accept requests.
// You could also user server.AcceptSocket() here.
TcpClient client = server.AcceptTcpClient();
Console.WriteLine("Connected!");

data = null;

// Get a stream object for reading and writing
NetworkStream stream = client.GetStream();

int i;

// Loop to receive all the data sent by the client.
while((i = stream.Read(bytes, 0, bytes.Length))!=0)
{
// Translate data bytes to a ASCII string.
data = System.Text.Encoding.ASCII.GetString(bytes, 0, i);
Console.WriteLine("Received: {0}", data);

// Process the data sent by the client.
data = data.ToUpper();

byte[] msg = System.Text.Encoding.ASCII.GetBytes(data);

// Send back a response.
stream.Write(msg, 0, msg.Length);
Console.WriteLine("Sent: {0}", data);
}

// Shutdown and end connection
client.Close();
}
}
catch(SocketException e)
{
Console.WriteLine("SocketException: {0}", e);
}
finally
{
// Stop listening for new clients.
server.Stop();
}

Console.WriteLine("\nHit enter to continue...");
Console.Read();
}
}

2.TcpClient(为 TCP 网络服务提供客户端连接)
Connect：有两种方法，一种是使用无参构造方法创建TcpClient，然后调用Connect方法；另一种是使用带host与port的构造方法。

static void Connect(String server, String message)
{
try
{
// Create a TcpClient.
// Note, for this client to work you need to have a TcpServer
// connected to the same address as specified by the server, port
// combination.
Int32 port = 13000;
TcpClient client = new TcpClient(server, port);

// Translate the passed message into ASCII and store it as a Byte array.
Byte[] data = System.Text.Encoding.ASCII.GetBytes(message);

// Get a client stream for reading and writing.
// Stream stream = client.GetStream();

NetworkStream stream = client.GetStream();

// Send the message to the connected TcpServer.
stream.Write(data, 0, data.Length);

Console.WriteLine("Sent: {0}", message);

// Receive the TcpServer.response.

// Buffer to store the response bytes.
data = new Byte[256];

// String to store the response ASCII representation.
String responseData = String.Empty;

// Read the first batch of the TcpServer response bytes.
Int32 bytes = stream.Read(data, 0, data.Length);
responseData = System.Text.Encoding.ASCII.GetString(data, 0, bytes);
Console.WriteLine("Received: {0}", responseData);

// Close everything.
stream.Close();
client.Close();
}
catch (ArgumentNullException e)
{
Console.WriteLine("ArgumentNullException: {0}", e);
}
catch (SocketException e)
{
Console.WriteLine("SocketException: {0}", e);
}

Console.WriteLine("\n Press Enter to continue...");
Console.Read();
}