MFC用http类下载文件

CString url=_T("http://192.168.0.88:8089/a.jpg");
 CString dol=_T("C:/a.jpg");
 commun->Down(url,dol);

/

bool CCOMMUN::Down(const CString& strFileURLInServer, //待下载文件的URL
 const CString & strFileLocalFullPath)//存放到本地的路径
{
    #define ArraySize(A)  RTL_NUMBER_OF_V2(A)

 ASSERT(strFileURLInServer != "");
 ASSERT(strFileLocalFullPath != "");
 CInternetSession session;
 CHttpConnection* pHttpConnection = NULL;
 CHttpFile* pHttpFile = NULL;
 CString strServer, strObject;
 INTERNET_PORT wPort;
 bool bReturn = false;

 DWORD dwType;
 const int nTimeOut = 2000;
 session.SetOption(INTERNET_OPTION_CONNECT_TIMEOUT, nTimeOut); //重试之间的等待延时
 session.SetOption(INTERNET_OPTION_CONNECT_RETRIES, 1); //重试次数
 char* pszBuffer = NULL;

 try
 {
  AfxParseURL(strFileURLInServer, dwType, strServer, strObject, wPort);
  pHttpConnection = session.GetHttpConnection(strServer, wPort);
  pHttpFile = pHttpConnection->OpenRequest(CHttpConnection::HTTP_VERB_GET, strObject);
  if(pHttpFile->SendRequest() == FALSE)
   return false;
  DWORD dwStateCode;

  pHttpFile->QueryInfoStatusCode(dwStateCode);
  if(dwStateCode == HTTP_STATUS_OK)
  {
   HANDLE hFile = CreateFile(strFileLocalFullPath, GENERIC_WRITE,
    FILE_SHARE_WRITE, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL,
    NULL); //创建本地文件
   if(hFile == INVALID_HANDLE_VALUE)
   {
    pHttpFile->Close();
    pHttpConnection->Close();
    session.Close();
    return false;
   }

   char szInfoBuffer[1000]; //返回消息
   DWORD dwFileSize = 0; //文件长度
   DWORD dwInfoBufferSize = sizeof(szInfoBuffer);
   BOOL bResult = FALSE;
   bResult = pHttpFile->QueryInfo(HTTP_QUERY_CONTENT_LENGTH,
    (void*)szInfoBuffer,&dwInfoBufferSize,NULL);

   dwFileSize = atoi(szInfoBuffer);
   const int BUFFER_LENGTH = 1024 * 10;
   pszBuffer = new char[BUFFER_LENGTH]; //读取文件的缓冲
   DWORD dwWrite, dwTotalWrite;
   dwWrite = dwTotalWrite = 0;
   UINT nRead = pHttpFile->Read(pszBuffer, BUFFER_LENGTH); //读取服务器上数据

   while(nRead > 0)
   {
    WriteFile(hFile, pszBuffer, nRead, &dwWrite, NULL); //写到本地文件
    dwTotalWrite += dwWrite;
    nRead = pHttpFile->Read(pszBuffer, BUFFER_LENGTH);
   }

   delete[]pszBuffer;
   pszBuffer = NULL;
   CloseHandle(hFile);
   bReturn = true;
  }
 }
 catch(CInternetException* e)
 {
  TCHAR tszErrString[256];
  e->GetErrorMessage(tszErrString, ArraySize(tszErrString));
  TRACE(_T("Download XSL error! URL: %s,Error: %s"), strFileURLInServer, tszErrString);
  e->Delete();
 }
 catch(...)
 {
 }

 if(pszBuffer != NULL)
 {
  delete[]pszBuffer;
 }
 if(pHttpFile != NULL)
 {
  pHttpFile->Close();
  delete pHttpFile;
 }
 if(pHttpConnection != NULL)
 {
  pHttpConnection->Close();
  delete pHttpConnection;
 }
 session.Close();
 return bReturn;
}