怎么样通过VC++实现TCP服务器?
怎么样通过VC++实现TCP服务器?
(一)介绍:
本文主要采用Winsock API实现了一个Tcp服务器。对初学者而言,相当实用。
(二)准备工作:
1、使用VC6向导建立控制台工程(console application),并选择支持MFC。
2、在stdafx.h中加入头文件conio.h和winsock2.h。
3、在头文件中加入:#pragma comment(lib, "ws2_32.lib")。
(三)主程序:主要是启动服务器线程并等待用户退出的命令。
int _tmain(int argc, TCHAR* argv[], TCHAR* envp[]) { int nRetCode = 0; cout << "Press ESCAPE to terminate program/r/n"; AfxBeginThread(ServerThread,0); //启动一条线程 while(_getch()!=27); //用户按ESC键则退出 return nRetCode; } |
(四)线程代码:一个简单的tcp服务器,返回客户的ip地址。
UINT ServerThread(LPVOID pParam) { cout << "Starting up TCP server/r/n"; //A SOCKET is simply a typedef for an unsigned int. //In Unix, socket handles were just about same as file //handles which were again unsigned ints. //Since this cannot be entirely true under Windows //a new data type called SOCKET was defined. //定义一个socket句柄作为服务器 SOCKET server; //WSADATA is a struct that is filled up by the call //to WSAStartup //这是一个结构体,用于调用函数WSAStartup时作为参数 WSADATA wsaData; //The sockaddr_in specifies the address of the socket //for TCP/IP sockets. Other protocols use similar structures. //存放ip地址的结构体 sockaddr_in local; //WSAStartup initializes the program for calling WinSock. //The first parameter specifies the highest version of the //WinSock specification, the program is allowed to use. //初始化winsock,每次必须最先调用 int wsaret=WSAStartup(0x101,&wsaData); //WSAStartup returns zero on success. //If it fails we exit. //测试初始化是否成功 if(wsaret!=0) { return 0; } //Now we populate the sockaddr_in structure //填充服务器的ip地址和端口号 local.sin_family=AF_INET; //Address family local.sin_addr.s_addr=INADDR_ANY; //Wild card IP address local.sin_port=htons((u_short)8888); //port to use //the socket function creates our SOCKET //建立一个tcp socket server=socket(AF_INET,SOCK_STREAM,0); //If the socket() function fails we exit if(server==INVALID_SOCKET) { return 0; } //bind links the socket we just created with the sockaddr_in //structure. Basically it connects the socket with //the local address and a specified port. //If it returns non-zero quit, as this indicates error //绑定服务器的ip地址和端口号 if(bind(server,(sockaddr*)&local,sizeof(local))!=0) { return 0; } //listen instructs the socket to listen for incoming //connections from clients. The second arg is the backlog //监听客户端请求,最大同时连接数10 if(listen(server,10)!=0) { return 0; } //we will need variables to hold the client socket. //thus we declare them here. //接受请求后,实际同客户端socket进行交互的SOCKET client SOCKET client; sockaddr_in from; int fromlen=sizeof(from); while(true)//we are looping endlessly { char temp[512]; //accept() will accept an incoming //client connection //接受一个连接请求,并返回一个同客户端交互的socket给变量client client=accept(server, (struct sockaddr*)&from,&fromlen); //得到客户端的ip地址,并写入缓冲区 sprintf(temp,"Your IP is %s/r/n",inet_ntoa(from.sin_addr)); //we simply send this string to the client // 发送回缓冲中的内容(即:客户端的ip地址) send(client,temp,strlen(temp),0); cout << "Connection from " << inet_ntoa(from.sin_addr) <<"/r/n"; //close the client socket //关闭连接 closesocket(client); } //closesocket() closes the socket and releases the socket descriptor //释放socket资源 closesocket(server); //originally this function probably had some use //currently this is just for backward compatibility //but it is safer to call it as I still believe some //implementations use this to terminate use of WS2_32.DLL //必须作的最后的事 WSACleanup(); return 0; } |
(五)运行:
服务器端:
E:/work/Server/Debug>server Press ESCAPE to terminate program Starting up TCP server Connection from 203.200.100.122 Connection from 127.0.0.1 E:/work/Server/Debug> |
客户端:
E:/work/Server/Debug>telnet 202.89.211.88 8888 Trying 202.89.211.88... Connected to 202.89.211.88. Escape character is ’^]’. Your IP is 203.200.100.122 Connection closed by foreign host. |
(六)说明:
这只是一个极为简单的tcp server程序,目的是帮助初学者学习winsock编程。因此,程序本着简单的原则,对于很多方面考虑都较少。比如,退出时候可能有socket句柄未释放的危险;只有一条线程,客户端很多时不够实用等等。这些都需要进一步的考虑。<script type="text/javascript"><!-- google_ad_client = "pub-0208493183109887"; google_ad_width = 728; google_ad_height = 90; google_ad_format = "728x90_as"; google_ad_type = "text_image"; google_ad_channel ="3214794117"; google_color_border = "FFFFFF"; google_color_bg = "FFFFFF"; google_color_link = "000000"; google_color_text = "000000"; google_color_url = "000000"; //--></script> <script src="WinSock初学入门:实现TCP服务器.files/show_ads.js" type="text/javascript"> </script>