服务器端主体程序

编写Serv类，包含一个Conn类型的对象池，用于维护客户端连接

using System;
using System.Net;
using System.Net.Sockets;

public class Serv
{
//监听嵌套字
public Socket listenfd;
//客户端链接
public Conn[] conns;
//最大链接数
public int maxConn = 50;

//获取链接池索引，返回负数表示获取失败
public int NewIndex()
{
if (conns == null)
return -1;
for (int i = 0; i < conns.Length; i++)
{
if (conns[i] == null)
{
conns[i] = new Conn();
return i;
}
else if (conns[i].isUse == false)
{
return i;
}
}
return -1;
}

//开启服务器
public void Start(string host, int port)
{
//链接池
conns = new Conn[maxConn];
for (int i = 0; i < maxConn; i++)
{
conns[i] = new Conn();
}
//Socket
listenfd = new Socket(AddressFamily.InterNetwork,
SocketType.Stream, ProtocolType.Tcp);
//Bind
//将 IP 地址字符串转换为 IPAddress 实例。
IPAddress ipAdr = IPAddress.Parse(host);
//用指定的地址和端口号初始化 IPEndPoint 类的新实例
IPEndPoint ipEp = new IPEndPoint(ipAdr, port);
listenfd.Bind(ipEp);
//Listen
listenfd.Listen(maxConn);
//Accept
listenfd.BeginAccept(AcceptCb, null);
Console.WriteLine("[服务器]启动成功");
}

//Accept回调
private void AcceptCb(IAsyncResult ar)
{
try
{
Socket socket = listenfd.EndAccept(ar);
int index = NewIndex();

if(index < 0)
{
socket.Close();
Console.Write("[警告]链接已满");
}
else
{
Conn conn = conns[index];
conn.Init(socket);
string adr = conn.GetAdress();
Console.WriteLine("客户端连接 [" + adr　+"] conn池ID：" + index);
conn.socket.BeginReceive(conn.readBuff,
conn.buffCount, conn.BuffRemain(),
SocketFlags.None, ReceiveCb, conn);
}
listenfd.BeginAccept(AcceptCb,null);
}
catch(Exception e)
{
Console.WriteLine("AcceptCb失败:" + e.Message);
}
}

private void ReceiveCb(IAsyncResult ar)
{
Conn conn = (Conn)ar.AsyncState;
try
{
int count = conn.socket.EndReceive(ar);
//关闭信号
if(count <= 0)
{
Console.WriteLine("收到 [" + conn.GetAdress()　+"] 断开链接");
conn.Close();
return;
}
//数据处理
string str = System.Text.Encoding.UTF8.GetString(conn.readBuff, 0, count);
Console.WriteLine("收到 [" + conn.GetAdress()　+"] 数据：" + str);
str = conn.GetAdress() + ":" + str;
byte[] bytes = System.Text.Encoding.Default.GetBytes(str);
//广播
for(int i=0;i < conns.Length; i++)
{
if(conns[i] == null)
continue;
if(!conns[i].isUse)
continue;
Console.WriteLine("将消息转播给 " + conns[i].GetAdress());
conns[i].socket.Send(bytes);
}
//继续接收
conn.socket.BeginReceive(conn.readBuff,
conn.buffCount, conn.BuffRemain(),
SocketFlags.None, ReceiveCb, conn);
}
catch(Exception e)
{
Console.WriteLine("收到 [" + conn.GetAdress()　+"] 断开链接");
conn.Close();
}
}
}