Winsock 传输文件

文件传输的原理：发送方把文件读到socket发送端缓冲区中，接收方把socket接收端缓端冲区中的数据写到一个新文件中。当然了，大文件需要循环读写！

服务器端为发送端：

#include "stdafx.h"
#include<winsock2.h>
#include<iostream>
#pragma comment(lib,"ws2_32.lib")

using namespace std;
int main(){
    WSADATA wsaData;
    SOCKET s;
    int errStartup,errBind;
    errStartup=WSAStartup(MAKEWORD(2,2),&wsaData);
    if(errStartup!=0){
        cout<<"初始化失败"<<endl;
        return -1;
    }
    s=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
    if(s==INVALID_SOCKET){
        cout<<"创建socket失败"<<endl;
        return -2;
    }
    SOCKADDR_IN addr;
    memset(&addr,0,sizeof(addr));
    addr.sin_family=AF_INET;
    addr.sin_addr.S_un.S_addr=htonl(INADDR_ANY);
    addr.sin_port=htons(30000);

    errBind= bind(s,(SOCKADDR*)&addr,sizeof(addr));
    if(errBind!=0){
        cout<<"bind failed!"<<endl;
        return -3;
    }
    listen(s,3);

    SOCKADDR_IN addrClient;
    int len=sizeof(addrClient);

    char *filename="e:\winSQL.zip";
    while (true)
    {
        SOCKET sockClient=accept(s,(SOCKADDR*)&addrClient,&len);
        //用于发送文件名
         char *sendBuf="winSQL.zip";
        int sendNum= send(sockClient,sendBuf,strlen(sendBuf)+1,0);
       
        char sendFileBuf[1024];
        memset(sendFileBuf,0,sizeof(sendFileBuf));
        DWORD dwRead=NULL;
        HANDLE hFile=CreateFile(filename,GENERIC_READ,0,0,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,0);
        while (true)
        {
            if(!ReadFile(hFile,sendFileBuf,1024,&dwRead,0)){
                cout<<"read buf error!"<<endl;
                break;
            }else if(dwRead==0)
            {
                cout<<"send over"<<endl;
                break;
            }else
            {
                send(sockClient,sendFileBuf,dwRead,0);
            }
        }
        CloseHandle(hFile);
        shutdown(sockClient,SD_BOTH);
        closesocket(sockClient);
    }
    
    closesocket(s);
    WSACleanup();
    system("pause");
    return 0;
}

客户端为接收端：

#include "stdafx.h"
#include <WinSock2.h>
#include <iostream>
using namespace std;

#pragma comment(lib,"ws2_32.lib")

 
int _tmain(int argc, TCHAR *argv[]) 
{ 
   WSADATA wsaData;
   SOCKADDR_IN s;
   int conerr;
    WSAStartup(MAKEWORD(2,2),&wsaData);

    SOCKET clientSock=socket(AF_INET,SOCK_STREAM,0);
    memset(&s,0,sizeof(s));
    s.sin_family=AF_INET;
    s.sin_addr.S_un.S_addr=inet_addr("172.18.4.161");
    s.sin_port=htons(30000);
    conerr= connect(clientSock,(SOCKADDR*)&s,sizeof(s));
    if(conerr!=0){
        cout<<"connect failed:"<<conerr<<endl;

    }
    //接收文件名，并拼接文件存放路径
    char recBuf[128];
    recv(clientSock,recBuf,128,0);
    
    char filename[128]="c:\";
    strcat(filename,recBuf);

    cout<<"文件位置"<<filename<<endl;
        char recFileBuf[1024];
        
        int numRead;
        DWORD dwWrite;
        DWORD tmp=0;
        HANDLE hFile=CreateFile(filename,GENERIC_WRITE,0,0,CREATE_ALWAYS,FILE_ATTRIBUTE_NORMAL,0);
    while (true)
        {
            numRead=recv(clientSock,recFileBuf,1024,0);
            if(numRead==SOCKET_ERROR){
                cout<<"connect error"<<endl;
                break;
            }
            tmp=tmp+numRead;
            if(numRead==0){
                cout<<"receive over"<<endl;        
                break;
            }
            if(!WriteFile(hFile,recFileBuf,numRead,&dwWrite,0)){
                cout<<"write failed!"<<endl;
                break;
            }        
        }
    cout<<"共接收："<<tmp<<" 字节"<<endl;
    CloseHandle(hFile);
    system("pause");
   return 0; 
}