TCP socket编程

本文以windows socket 进行讲解， 开发环境VS2010，测试平台 windows 7

众所周知TCP（Transmission Control Protocol ）是一种面向连接的、可靠的、基于字节流的通信协议。而开发TCP socket应用程序是一件比较简单的事情。下面就用一个比较简单的demo 讲解开发的过程。

该程序分为客户端和服务器端，客户端主要是向服务器端发送数据，服务器端主要是对于接收的数据进行显示。

TCP服务器端和客户端的主要流程：

服务器端：1 创建套接字 2 绑定 3 监听  4 接受连接 5 收发数据 6 关闭

客户端：   1 创建套接字 2 连接 3 收发数据 4 关闭

实现中用到的主要函数及

服务器: 1 WSAStartup() 2 socket() 3 bind() 4 listen() 5 accept() 6 recv() 7 closesocket() 8 WSACleanup()

客户端: 1 WSAStartup() 2 socket() 3 connect() 4 send() 5 closesocket() 6 WSACleanup()

下面是server 和 client 的实现代码，运行的时候首先启动server，然后再启动client， 则在server部分打印出“hello world” 。

Server.cpp  源码

#include "stdafx.h"
#define  BUF_SZIE	 64
#include "winsock2.h"
#pragma comment(lib, "ws2_32.lib")

int main(int argc, char* argv[])
{
	WSADATA			wsd;
	/*初始化套结字动态库*/
	if (WSAStartup(MAKEWORD(2,2), &wsd) != 0)
	{
		printf("WSAStartup failed!\n");
		return 1;
	}
	
	/*创建套接字*/
	SOCKET sServer = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);	
	if(INVALID_SOCKET == sServer)
	{
		printf("socket failed!\n");
		WSACleanup();
		return  -1;
	}
	
	/*服务器套接字地址*/ 
	SOCKADDR_IN  addrServ;
	addrServ.sin_family = AF_INET;
	addrServ.sin_port = htons(4999);
	addrServ.sin_addr.s_addr = INADDR_ANY;		
	
	/*绑定套接字*/
	int retVal = bind(sServer, (LPSOCKADDR)&addrServ, sizeof(SOCKADDR_IN));
	if (SOCKET_ERROR == retVal)
	{	
		closesocket(sServer);
		WSACleanup();
		return -1;
	}
	
	/*开始监听*/ 
	retVal = listen(sServer, 1);
	if(SOCKET_ERROR == retVal)
	{		
		closesocket(sServer);
		WSACleanup();
		return -1;
	}
	
	/*接受客户端请求*/
	sockaddr_in addrClient;
	int addrClientlen = sizeof(addrClient);
	SOCKET sClient = accept(sServer,(sockaddr FAR*)&addrClient, &addrClientlen);
	if(INVALID_SOCKET == sClient)
	{
		closesocket(sServer);
		WSACleanup();
		return -1;
	}
	
	
	/*接收客户端数据*/
	char buf[BUF_SZIE];
	ZeroMemory(buf, BUF_SZIE);
	retVal = recv(sClient, buf, BUF_SZIE, 0);
	if (SOCKET_ERROR == retVal)
	{	
		closesocket(sServer);
		closesocket(sClient);	
		WSACleanup();
		return -1;
	}

	printf("%s\n", buf);

	/*退出*/
	closesocket(sServer);
	closesocket(sClient);
	WSACleanup();
	getchar();

	return 0;
}

　Client.cpp 源码

#include "stdafx.h"
#define	BUF_SZIE	64
#include "winsock2.h"
#pragma comment(lib, "ws2_32.lib")

int main(int argc, char* argv[])
{
	WSADATA	wsd;
	if (WSAStartup(MAKEWORD(2,2), &wsd) != 0)
	{
		printf("WSAStartup failed!\n");
		return -1;
	}

	/*创建套接字*/
	SOCKET sHost = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);	
	if(INVALID_SOCKET == sHost)
	{
		WSACleanup();
		return  -1;
	}

	/*设置服务器地址*/
	SOCKADDR_IN		servAddr;
	servAddr.sin_family =AF_INET;
	servAddr.sin_addr.s_addr = inet_addr("127.0.0.1");
	servAddr.sin_port = htons((short)4999);
	int	nServAddlen  = sizeof(servAddr);

	/*连接服务器*/
	int retVal = connect(sHost, (LPSOCKADDR)&servAddr, sizeof(servAddr));	
	if(SOCKET_ERROR == retVal)
	{	
		closesocket(sHost);
		WSACleanup();
		return -1;
	}

	/*向服务器发送数据*/
	char buf[BUF_SZIE];
	ZeroMemory(buf, BUF_SZIE);
	strcpy(buf, "Hello world");
	retVal = send(sHost, buf, strlen(buf), 0);
	if (SOCKET_ERROR == retVal)
	{
		closesocket(sHost);
		WSACleanup();
		return -1;
	}

	/**退出*/
	closesocket(sHost);
	WSACleanup();

	getchar();
	return 0;
}