基于MFC下的网络编程基本知识

1,通信
(1)身份:IP
(2)规则:协议
(3)分机:端口号

2,UDP,无需确认,实时性高.例如:视频会议,视频点播.

3,网络字节顺序: 网络高位先存.
intel:低位先存.

4,网间进程通信完全是异步的.

给出两个实例:(注意工程设置,需要加载库文件ws2_32.lib)
(1)基于TCP可靠连接的SOCKET.
服务器端:

#include <stdio.h>
#include <WINSOCK2.H>

int main()
{
	WORD wVersionRequested;//版本号
	WSADATA wsaData; //记录套接字的详细信息
	int err;
	
	wVersionRequested = MAKEWORD( 1, 1 );//宏,返回版本号
	
	err = WSAStartup( wVersionRequested, &wsaData );//加载套接字库
	//initiates use of the Winsock DLL by a process.
	//成功返回0.
	if ( err != 0 ) //表示有错误发生.
	{
		return 1;
	}
	
	if ( LOBYTE( wsaData.wVersion ) != 1 ||HIBYTE( wsaData.wVersion ) != 1 ) 
	{                     
		WSACleanup( );//有加载,就要有对应的释放.
		return 1; 
	}

	SOCKET sockSvrver=socket(AF_INET,SOCK_STREAM,0);//创建套接字
	if(sockSvrver==INVALID_SOCKET)
	{
		printf("套接字创建失败.");
		return 1;
	}
	SOCKADDR_IN addServer; //定义地址结构体变量
	addServer.sin_addr.S_un.S_addr=htonl(INADDR_ANY);//u_long类型转换为网络字节序  htons u_short类型
	addServer.sin_family=AF_INET;
	addServer.sin_port=htons(6000);
	
	int re_bind;
	re_bind=bind(sockSvrver,(SOCKADDR*)&addServer,sizeof(SOCKADDR)); //绑定
	if(re_bind==SOCKET_ERROR)
	{
		closesocket(sockSvrver);
		printf("套接字绑定失败.");
		return 1;		
	}
	listen(sockSvrver,5);//等待队列的最大成员数
	SOCKADDR_IN addrClient; //接受变量
	int len=sizeof(SOCKADDR);//接收变量的长度

	char recvBuf[100];
	char sendBuf[100];
	char tempBuf[100];
	SOCKET sockConnect=accept(sockSvrver,(SOCKADDR*)&addrClient,&len);
	while(1)
	{		
		recv(sockConnect,recvBuf,100,0);
		sprintf(tempBuf,"%s say: %s", inet_ntoa(addrClient.sin_addr),recvBuf);
		printf("%s\n",tempBuf);
		if('q'==recvBuf[0])//表示客户端想要退出
		{
			send(sockConnect,"q",strlen("q")+1,0);
			printf("Chat end!\n");
			break;
		}
	
		printf("Please input data:\n");	
		gets(sendBuf);//可以得到一行数据
		send(sockConnect,sendBuf,strlen(sendBuf)+1,0);		
	}
	closesocket(sockConnect); //关闭套接字
	WSACleanup();
	//如果不是死循环,需要关闭监听套接字
	//并调用WSACleanup()关闭套接字库
	return 0;
}

客户端:

#include <stdio.h>
#include <WINSOCK2.H>

int main()
{
	WORD wVersionRequested;//版本号
	WSADATA wsaData; //记录套接字的详细信息
	int err;
	
	wVersionRequested = MAKEWORD( 1, 1 );//宏,返回版本号
	
	err = WSAStartup( wVersionRequested, &wsaData );//加载套接字库
	//initiates use of the Winsock DLL by a process.
	//成功返回0.
	if ( err != 0 ) //表示有错误发生.
	{
		return 1;
	}
	
	if ( LOBYTE( wsaData.wVersion ) != 1 ||HIBYTE( wsaData.wVersion ) != 1 ) 
	{                     
		WSACleanup( );//有加载,就要有对应的释放.
		return 1; 
	}
	
	SOCKET sockClient=socket(AF_INET,SOCK_STREAM,0);//创建套接字
	SOCKADDR_IN addrServer;
	addrServer.sin_addr.S_un.S_addr=inet_addr("127.0.0.1");//本地环路地址
	addrServer.sin_port=htons(6000);
	addrServer.sin_family=AF_INET;
	connect(sockClient,(SOCKADDR*)&addrServer,sizeof(SOCKADDR));


	char recvBuf[100];
	char sendBuf[100];
	char tempBuf[100];
	while(1)
	{	
		printf("Please input data:\n");	
		gets(sendBuf);//可以得到一行数据
		send(sockClient,sendBuf,strlen(sendBuf)+1,0);

		recv(sockClient,recvBuf,100,0);
		sprintf(tempBuf,"server say: %s",recvBuf);
		printf("%s\n",tempBuf);
		if('q'==recvBuf[0])//表示客户端想要退出
		{
			send(sockClient,"q",strlen("q")+1,0);
			printf("Chat end!\n");
			break;
		}
		
	}
	//5.终止对套接字库的使用
	closesocket(sockClient); //关闭套接字
	WSACleanup();
	return 0;
}

(2)基于UDP连接的SOCKET.
服务器端:

//编写一个基于UDP的聊天工具
//发送端代码
#include <Winsock2.h>
#include <stdio.h>
void main()
{
	WORD wVersionRequested;
	WSADATA wsaData;
	int err;
	wVersionRequested = MAKEWORD( 1, 1 );//版本号1.1
//1.加载套接字库	
	err = WSAStartup( wVersionRequested, &wsaData );
	if ( err != 0 ) 
	{
		return;	
	}
	//判断是否我们请求的winsocket版本，如果不是
	//则调用WSACleanup终止winsocket的使用并返回
	if ( LOBYTE( wsaData.wVersion ) != 1 ||HIBYTE( wsaData.wVersion ) != 1 )
	{
		WSACleanup( );
		return; 	
	}
//2.创建套接字
	SOCKET sockSrv = socket(AF_INET,SOCK_DGRAM,0);
	SOCKADDR_IN addrSrv;
	addrSrv.sin_addr.S_un.S_addr = htonl(INADDR_ANY);
	addrSrv.sin_family = AF_INET;
	addrSrv.sin_port = htons(6000);
	bind (sockSrv,(SOCKADDR*)&addrSrv,sizeof(SOCKADDR));
	char recvBuf[100];
	char sendBuf[100];
	char tempBuf[100];
	SOCKADDR_IN addrClient;
	int len = sizeof(SOCKADDR);
	while(1)
	{
		recvfrom(sockSrv,recvBuf,100,0,(SOCKADDR*)&addrClient,&len);
		if('q'==recvBuf[0])//表示客户端想要退出
		{
			sendto(sockSrv,"q",strlen("q")+1,0,(SOCKADDR*)&addrClient,len);
			printf("Chat end!\n");
			break;
		}
		sprintf(tempBuf,"%s say: %s", inet_ntoa(addrClient.sin_addr),recvBuf);
		printf("%s\n",tempBuf);
		printf("Please input data:\n");
		
		gets(sendBuf);//可以得到一行数据
		sendto (sockSrv,sendBuf,strlen(sendBuf)+1,0,
			(SOCKADDR*)&addrClient,len);//发送数据
	}
	closesocket(sockSrv);
	WSACleanup();
}

客户端:

//发送端代码
#include <Winsock2.h>
#include <stdio.h>
void main()
{
	WORD wVersionRequested;
	WSADATA wsaData;
	int err;
	wVersionRequested = MAKEWORD( 1, 1 );//版本号1.1
//1.加载套接字库	
	err = WSAStartup( wVersionRequested, &wsaData );
	if ( err != 0 ) 
	{
		return;	
	}
	//判断是否我们请求的winsocket版本，如果不是
	//则调用WSACleanup终止winsocket的使用并返回
	if ( LOBYTE( wsaData.wVersion ) != 1 || HIBYTE( wsaData.wVersion ) != 1 )
	{
		WSACleanup( );
		return; 	
	}
//2.创建套接字
	SOCKET sockClient = socket(AF_INET,SOCK_DGRAM,0);
//3.发送消息
	SOCKADDR_IN addrSrv;
	addrSrv.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");
	addrSrv.sin_family = AF_INET;
	addrSrv.sin_port = htons(6000);

	char recvBuf[100];
	char sendBuf[100];
	char tempBuf[200];
	int len = sizeof(SOCKADDR);
	while (1)
	{
		printf("Please input data:\n");
		gets(sendBuf);
		sendto(sockClient,sendBuf,strlen(sendBuf)+1,0,(SOCKADDR*)&addrSrv,len);
		recvfrom(sockClient,recvBuf,100,0,(SOCKADDR*) &addrSrv,&len);
		if('q' ==recvBuf[0])
		{
			sendto(sockClient,"q",strlen("q")+1,0,(SOCKADDR*) &addrSrv,len);
			printf("chat end!\n");
			break;
		}
		sprintf(tempBuf,"%s say: %s",inet_ntoa(addrSrv.sin_addr),recvBuf);
		printf("%s\n",tempBuf);

	}	

	closesocket(sockClient);
	WSACleanup();
}