网络编程基础（一）——使用TCP

  网络编程中最基本的是TCP/UDP协议，而目前比较流行的是使用已经非常成熟socket库来处理。

 

  下面举例说明：

首先必须在使用socket的地方包含库，这里使用微软封装好的winsocket库：

#include <winsock2.h>#pragma comment(lib, "WS2_32.lib") 

客户端代码：

int TCPSocket::TCPSocketClient(){#pragma region 初始化套接字WSADATA wsaData;int iResult = WSAStartup(MAKEWORD(1, 1), &wsaData); //版本1.1if (NO_ERROR != iResult){AfxMessageBox(_T("Error at WSAStartup()/n"));return -1;}if ( LOBYTE( wsaData.wVersion ) != 1 ||HIBYTE( wsaData.wVersion ) != 1 ) {WSACleanup( );return -1;}//如果不是1.1的则退出#pragma endregion 初始化套接字#pragma region 创建套接字//----------------------// Create a SOCKET for listening for incoming connection requestsSOCKET socketClient = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);if (INVALID_SOCKET == socketClient) {//cout<<"Error at socket():/n"<< WSAGetLastError();AfxMessageBox(_T("Error at socket():/n"));WSACleanup();return -1;}#pragma endregion 创建套接字#pragma region 请求服务器SOCKADDR_IN addrSrv;addrSrv.sin_family = AF_INET;addrSrv.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");addrSrv.sin_port = htons(8086);int err;/************************************************************************//* 连接服务器 *//************************************************************************/err = connect(socketClient, (SOCKADDR*)&addrSrv, sizeof(SOCKADDR));//向服务器发出连接请求（connect）。if (SOCKET_ERROR == err){//cout<<"Error at Connect():/n"<< WSAGetLastError();AfxMessageBox(_T("Error at Connect():/n"));closesocket(socketClient);WSACleanup();return -1;}#pragma endregion 请求服务器#pragma region 接受数据/************************************************************************//* 接受数据 *//************************************************************************/char recvBuf[100];//和服务器端进行通信（send/recv）。err = recv(socketClient, recvBuf, 100,0);if (SOCKET_ERROR == err){//cout<<"Error at Recv from Service:/n"<< WSAGetLastError();AfxMessageBox(_T("Error at Recv from Service:/n"));closesocket(socketClient);WSACleanup();return -1;}//printf("%s/n",recvBuf);#pragma endregion 接受数据#pragma region 发送数据/************************************************************************//* 发送数据 *//************************************************************************/err = send(socketClient,"This is Client", strlen("This is Client")+1, 0);if (SOCKET_ERROR == err){//cout<<"Error at Send to Service:/n"<< WSAGetLastError();AfxMessageBox(_T("Error at Send to Service:/n"));closesocket(socketClient);WSACleanup();return -1;}#pragma endregion 发送数据closesocket(socketClient);WSACleanup();return 1;} 

服务器端代码：

int TCPSocket::TCPSocketServer(){#pragma region 初始化套接字库WSADATA wsaData;int iResult = WSAStartup(MAKEWORD(1, 1), &wsaData); //版本1.1if (NO_ERROR != iResult){//cout<<"Error at WSAStartup()/n";AfxMessageBox(_T("Error at WSAStartup()/n"));return -1;}if ( LOBYTE( wsaData.wVersion ) != 1 ||HIBYTE( wsaData.wVersion ) != 1 ) {WSACleanup( );return -1;}//如果不是1.1的则退出#pragma endregion 初始化套接字库#pragma region 创建套接字//----------------------// Create a SOCKET for listening for incoming connection requestsSOCKET socketSrv = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);if (INVALID_SOCKET == socketSrv) {//cout<<"Error at socket():/n"<< WSAGetLastError();AfxMessageBox(_T("Error at socket():/n"));WSACleanup();return -1;}#pragma endregion 创建套接字#pragma region 绑定套接字// The sockaddr_in structure specifies the address family,// IP address, and port for the socket that is being bound.sockaddr_in addrSrv;addrSrv.sin_family = AF_INET;addrSrv.sin_addr.S_un.S_addr = htonl(INADDR_ANY);addrSrv.sin_port = htons(8086);int err;/************************************************************************//* 绑定套接字 *//************************************************************************/err = bind(socketSrv, (sockaddr*)&addrSrv, sizeof(addrSrv));if (SOCKET_ERROR == err){//cout<<"Error at Bind!/n"<< WSAGetLastError();AfxMessageBox(_T("Error at Bind!/n"));closesocket(socketSrv);WSACleanup();return -1;}#pragma endregion 绑定套接字#pragma region 监听套接字/************************************************************************//*监听套接字 *//************************************************************************/err = listen(socketSrv, SOMAXCONN);if (SOCKET_ERROR == err){//cout<<"Error at Listen!/n"<< WSAGetLastError();AfxMessageBox(_T("Error at Listen!/n"));closesocket(socketSrv);WSACleanup();return -1;}#pragma endregion 监听套接字#pragma region 持续接受从客户端来的消息/************************************************************************//* 接受数据 *//************************************************************************/sockaddr_in addrClient;//定义地址族int len = sizeof(sockaddr);//初始化这个参数，这个参数必须被初始化while (1){SOCKET sockAccept = accept(socketSrv, (sockaddr*) &addrClient, &len);if (INVALID_SOCKET == sockAccept){//cout<<"Error at accept!/n"<< WSAGetLastError();AfxMessageBox(_T("Error at accept!/n"));}char sendBuf[100];sprintf_s(sendBuf, 100, "Welcome %s to This Service!", inet_ntoa(addrClient.sin_addr));/************************************************************************//* 发送数据 *//************************************************************************/err = send(sockAccept, sendBuf, strlen(sendBuf)+1, 0);if (SOCKET_ERROR == err){//cout<<"Error at Send to Client!/n"<< WSAGetLastError();AfxMessageBox(_T("Error at Send to Client!/n"));}/************************************************************************//* 接受数据 *//************************************************************************/char recvBuf[100];err = recv(sockAccept, recvBuf, 100, 0);if (SOCKET_ERROR == err){//cout<<"Error at Recv from Client!/n"<< WSAGetLastError();AfxMessageBox(_T("Error at Recv from Client!/n"));}//printf("%s/n",recvBuf);CString str;str.Format(_T("s%"), recvBuf);AfxMessageBox(str);closesocket(sockAccept);//关闭套接字。等待另一个用户请求}#pragma endregion 持续接受从客户端来的消息closesocket(socketSrv);WSACleanup();return 1;} 

 

代码比较基本，也比较简单，没有复杂功能。测试环境SP3+VS2008