代码中使用WinSock2函数库，设计并实现了简单的聊天室功能。该程序为命令行程序。对于服务器和客户端，需要：
- 服务器：创建监听套接字，并按本地主机绑定；主线程监听并接受来自客户端的请求，并为该客户端创建单独线程；接收与发送消息的事务放在同各客户端的单独线程中处理。
- 客户端：创建套接字，并对服务器发起连接；主线程始终处于发送消息的状态；副线程用于不断从服务器接收来自其他客户端的消息。
实验代码及部分说明如下：
- 服务器（Server.cpp）
#include <WinSock2.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include<vector>
using namespace std;
#define DEFAULT_PORT 7321
#define BUF_SIZE 1024
typedef struct{
SOCKET info_socket_rev;
sockaddr_in info_addr_rev;
} info2thread;
char szMessage[BUF_SIZE];
std::vector<SOCKET> vClientSockets; //用于保存连接中的Client套接字
DWORD WINAPI ThreadProc(PVOID pParam) ;
int main(int argc,char* argv[]){
WSADATA wsd;
SOCKET sListen,sClient;
sockaddr_in local,client;
int iAddrSize;
HANDLE hThread;
DWORD dwThreadId;
info2thread infoParam;
//加载Winsock
if(WSAStartup(MAKEWORD(2,2),&wsd) != 0){
printf("Failed to load Winsock! ");
exit(1);
}
//创建监听套接字及其地址信息结构体
sListen = socket(AF_INET,SOCK_STREAM,IPPROTO_IP);
local.sin_addr.s_addr = htonl(INADDR_ANY);
local.sin_port = htons(DEFAULT_PORT);
local.sin_family = AF_INET;
//j将套接字和地址信息绑定
if(bind(sListen,(const sockaddr*) &local,sizeof(local)) == SOCKET_ERROR){
printf("bind() failed:%d ",WSAGetLastError());
return 1;
}
//监听
listen(sListen,7);
printf("Server is Ready, listening on Port:%d. > ",ntohs(local.sin_port));
while(1){
//处理连接请求
iAddrSize = sizeof(client);
sClient = accept(sListen,(sockaddr*)&client,&iAddrSize);
if(sClient == INVALID_SOCKET){
printf("accept() failed:%d ",WSAGetLastError());
return 1;
}
printf("Accepted Client: %s:%d ",
inet_ntoa(client.sin_addr), ntohs(client.sin_port));
infoParam.info_addr_rev = client; //infoParam用于构建传给线程的结构体,主要用于IP地址和Port端口的输出
infoParam.info_socket_rev = sClient;
//在vector中保存连接中的客户端Socket
vClientSockets.push_back(sClient);
//创建进程接收数据
hThread = CreateThread(NULL,0,ThreadProc,(LPVOID)&infoParam,0,&dwThreadId);
if (hThread == NULL){
printf("CreateThread() failed: %d ", GetLastError());
break;
}
CloseHandle(hThread); //不再需要这个句柄，关掉它，但并非是关掉对应线程
}
//关闭
closesocket(sListen);
WSACleanup();
return 0;
}
DWORD WINAPI ThreadProc (PVOID pParam) {
int ret,errCode;
info2thread *pInfo = (info2thread*) pParam;
SOCKET sClient = pInfo->info_socket_rev,
sOther;
sockaddr_in client = pInfo->info_addr_rev;
char szIPPort[BUF_SIZE],
szPort[7];
//构造客户端 "IP:Port" 标识
_itoa(ntohs(client.sin_port),szPort,10); //itoa函数用于将整型数转化成对应的字符串，10表示十进制，末尾自动添' '
strcpy(szIPPort,inet_ntoa(client.sin_addr)); //拷贝IP
strcpy(szIPPort+strlen(inet_ntoa(client.sin_addr)),":");
strcpy(szIPPort+strlen(inet_ntoa(client.sin_addr))+1,szPort); //拷贝Port
while(1){
//接收来自客户端的数据
ret = recv(sClient,szMessage,BUF_SIZE,0);
if (ret == SOCKET_ERROR){
errCode = WSAGetLastError();
switch(errCode){
case 10054: //10054：客户端主动退出时的错误代码
printf("%s:%d has exited. ",inet_ntoa(client.sin_addr),ntohs(client.sin_port));
break;
default:
printf("recv() failed:%d from %s ", errCode,szIPPort);
}
break; //跳出while(1)循环
}
szMessage[ret] = ' ';
printf("Server%d REV %s: %s ", GetCurrentProcessId(),
szIPPort,
szMessage);
//向正在连接的所有其他客户端发送消息（聊天室）
for(vector<SOCKET>::iterator it = vClientSockets.begin();it != vClientSockets.end(); ++it){
if(*it == sClient) continue;
sOther = *it;
//广播客户标识信息
ret = send(sOther,szIPPort,strlen(szIPPort),0);
if (ret == SOCKET_ERROR); //do nothing
//广播客户消息
ret = send(sOther,szMessage,strlen(szMessage),0);
if (ret == SOCKET_ERROR); //do nothing
}
}
//关闭套接字，从vector中删除对应的元素
for(vector<SOCKET>::iterator it = vClientSockets.begin(); it != vClientSockets.end(); ){
if(*it == sClient){
it = vClientSockets.erase(it);
break;
}
else{
++it;
}
}
closesocket(sClient);
return 0;
}
- 客户端（Client.cpp）
#include <WinSock2.h>
#include <stdio.h>
#define DEFAULT_PORT 7321
#define BUF_SIZE 128
char szMessage[BUF_SIZE],
szRecieved[BUF_SIZE];
DWORD WINAPI ThreadProc (PVOID);
int main(int argc, char *argv[]){
WSADATA wsd;
SOCKET sClient;
struct sockaddr_in server;
HANDLE hThread;
DWORD dwThreadId;
int ret;
// 加载Winsock
if(WSAStartup(MAKEWORD(2,2), &wsd) != 0){
printf("Failed to load Winsock library! ");
return 1;
}
//创建套接字
sClient = socket(AF_INET,SOCK_STREAM,IPPROTO_IP);
if(sClient == INVALID_SOCKET){
printf("socket() failed on %d ",WSAGetLastError());
return 1;
}
//填写服务器地址信息结构体
server.sin_addr.s_addr = inet_addr("127.0.0.1");
server.sin_port = htons(DEFAULT_PORT);
server.sin_family = AF_INET;
//查询服务器
//连接
if(connect( sClient,(const sockaddr*)&server,
sizeof(server)) == SOCKET_ERROR){
printf("connect() failed: %d ", WSAGetLastError());
return 1;
}
else
{
printf("This Client is Connected. > ");
}
//创建一个用于不停接收服务器数据的进程
hThread = CreateThread(NULL,0,ThreadProc,(LPVOID)&sClient,0,&dwThreadId);
if (hThread == NULL){
printf("CreateThread() failed: %d, can't receive message from SERVER! ", GetLastError());
}
CloseHandle(hThread); //不再需要这个句柄，关掉它，但并非是关掉对应线程
//发送数据
do{
gets_s(szMessage,BUF_SIZE-1);
ret = send(sClient,szMessage,strlen(szMessage),0);
if (ret == SOCKET_ERROR){
printf("send() failed: %d ", WSAGetLastError());
break;
}
}while(ret);
//关闭套接字
closesocket(sClient);
WSACleanup();
return 0;
}
DWORD WINAPI ThreadProc (PVOID pParam){
SOCKET sRecv = *(SOCKET*)pParam;
int ret;
while(1){
//接收标识
ret = recv(sRecv,szRecieved,BUF_SIZE,0);
if(ret == SOCKET_ERROR){
printf("[Unknown]"); //标识接收失败，则统一认其为Unknown用户
}
else{
szRecieved[ret] = ' ';
printf("[%s]",szRecieved);
}
//分割符
printf(":");
//接收消息
ret = recv(sRecv,szRecieved,BUF_SIZE,0);
if(ret == SOCKET_ERROR){
printf("recv() from server failed: %d ",WSAGetLastError());
continue;
}
szRecieved[ret] = ' ';
printf("%s ",szRecieved);
}
return 0;
}
运行结果截图：