利用MFC的Wininet以http方式下载小文件

直接上函数代码：

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#include <afxwin.h>         // MFC 核心组件和标准组件 #include <Wininet.h> #include <iostream> #include <string> using namespace std; //walker 2013.05 //hostname主机名，例如www.baidu.com //suburl，例如asp/test.asp?num=3 //port，端口号 string GetHttpFile(const char hostname[], const char suburl[], unsigned short port) {     HINTERNET   hInternet = NULL,         hConnect = NULL,         hRequest = NULL;     BOOL bRtn;     string strResponse;     hInternet = InternetOpen("User-Agent",INTERNET_OPEN_TYPE_PRECONFIG,NULL,NULL, 0 );     if (NULL == hInternet)     {         cout << "InternetOpen Failed!" << endl;         goto exception_over;     }     hConnect = InternetConnect(hInternet, hostname, port, NULL, " HTTP/1.1 " ,INTERNET_SERVICE_HTTP, 0 , 0 );     if (NULL == hConnect)     {         cout << "InternetConnect Failed!" << endl;         goto exception_over;     }     hRequest  =  HttpOpenRequest(hConnect, "GET", suburl, " HTTP/1.1 " ,NULL,NULL,INTERNET_FLAG_RELOAD, 0 );     if (NULL == hRequest)     {         cout << "HttpOpenRequest Failed!" << endl;         goto exception_over;     }     //三种超时值     DWORD TimeOuts[] = {5*1000, 5*1000, 10*1000};     InternetSetOption(hRequest,INTERNET_OPTION_CONNECT_TIMEOUT , &(TimeOuts[0]), sizeof(DWORD));     InternetSetOption(hRequest,INTERNET_OPTION_SEND_TIMEOUT , &(TimeOuts[1]), sizeof(DWORD));     InternetSetOption(hRequest,INTERNET_OPTION_RECEIVE_TIMEOUT, &(TimeOuts[2]), sizeof(DWORD));     bRtn  =  HttpSendRequest(hRequest,NULL, 0 , NULL, 0);     if (!bRtn)     {         cout << "HttpSendRequest Failed!" << endl;         goto exception_over;     }     char buf[1000] = {0};     DWORD dwLengthBufQuery = sizeof(buf);     bRtn = HttpQueryInfo(hRequest,  HTTP_QUERY_CONTENT_LENGTH, buf, &dwLengthBufQuery, NULL);     if (!bRtn)     {         cout << "HttpQueryInfo Failed!" << endl;         goto exception_over;     }     int file_len = atoi(buf);     cout << "filelen: " << file_len << "bytes" << endl;     int i = 1;     const int BUF_LEN = 256;     char cReadBuffer[BUF_LEN] = {0};     unsigned long sum_recv = 0;     unsigned long read_len;     while (TRUE)     {         memset(cReadBuffer, 0 , BUF_LEN);         unsigned long  lNumberOfBytesRead;         read_len = (file_len - sum_recv) > (BUF_LEN - 1) ? (BUF_LEN - 1) : (file_len - sum_recv);         bRtn  =  InternetReadFile(hRequest, cReadBuffer, read_len , &lNumberOfBytesRead);         //注意：这里认为文件中不会有'\0'         strResponse  =  strResponse +  cReadBuffer;         cout << "第" << i << "次: " << lNumberOfBytesRead << "bytes" << endl;         if ( !bRtn  || strResponse.size() >= (unsigned int)file_len)         {             break ;         }         ++i;     } exception_over:     if (NULL != hRequest)     {         InternetCloseHandle(hRequest);     }     if (NULL != hConnect)     {         InternetCloseHandle(hConnect);     }     if (NULL != hInternet)     {         InternetCloseHandle(hInternet);     }     return strResponse; }

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本文转自walker snapshot博客51CTO博客，原文链接http://blog.51cto.com/walkerqt/1206538如需转载请自行联系原作者

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