URLDownloadToFile

簡介

指從指定URL地址讀取內容並將讀取到的內容保存到特定的檔案里，下面列舉了幾種常見程式語言的實現方法。

Delphi

⒈uses UrlMon;

⒉//-------------------------------------------------------------------------------

⒊functionDownloadFile(SourceFile, DestFile: string): Boolean;

⒋// 參數 下載檔案路徑, 保存檔案路徑

⒌// 返回 下載結果

⒍　begin

⒎　try

⒏　Result := UrlDownloadToFile(nil, PChar(SourceFile), PChar(DestFile), 0, nil) = 0;

⒐　except

⒑　Result := False;

⒒　end;

⒓　end;

函式調用：

⒈var

⒉　url,destFile:string;

⒊url := 'http****filename.rar'

⒋destFile := 'E:\filename.rar'

⒌ifDownloadFile(url, DestFile)then

⒍　begin

⒎　ShowMessage('保存成功！');

⒏　end

⒐　else

⒑　begin

⒒　ShowMessage('保存不成功！');

⒓　end;

C++

Syntax:

HRESULT URLDownloadToFile(     LPUNKNOWN pCaller,    LPCTSTR szURL,    LPCTSTR szFileName,    DWORD dwReserved,    LPBINDSTATUSCALLBACK lpfnCB);

Parameters:

pCallerPointer to the controlling IUnknown interface of the calling Microsoft ActiveX component (if the caller is an ActiveX component). //控制項的接口,如果不是控制項則為0.

szURL

Pointer to a string value containing the URL to be downloaded. Cannot be set to NULL

//要下載的url地址,不能為空.

szFileName

Pointer to a string value containing the name of the file to create for bits that come from the download.

//下載後保存的檔案名稱.

dwReserved

Reserved. Must be set to 0.

//保留欄位,必需為0

lpfnCB

Pointer to the caller's IBindStatusCallback interface. URLDownloadToFile calls this interface's IBindStatusCallback::OnProgress method on a connection activity, including the arrival of data. IBindStatusCallback::OnDataAvailable is never called.

//下載進度狀態回調

Return Value

Returns one of the following values.

S_OK : The download started successfully.

E_OUTOFMEMORY: The buffer length is invalid, or there is insufficient memory to complete the operation.

INET_E_DOWNLOAD_FAILURE:The specified resource or callback interface was invalid.

Example:

#include "stdafx.h"#include <iostream>#include <UrlMon.h>#pragma comment(lib, "urlmon.lib")　using namespace std;int _tmain(int argc, _TCHAR* argv[]){    HRESULT hr = URLDownloadToFile(0,_T("***ui.the9.**/wshell/WShell.exe"),    _T ("D:\\WShell.exe"), 0,NULL);    if (hr== S_OK)    {        cout<< "ok"<< endl;    }    return 0;}

vb

該函式是VB的一個用來調用API進行網路下載的函式，過程如下：

後台下載

聲明：

Private Declare Function URLDownloadToFile Lib "urlmon" Alias "URLDownloadToFileA" (ByVal pCaller As Long, ByVal szURL As String, ByVal szFileName As String, ByVal dwReserved As Long, ByVal lpfnCB As Long) As Long

'//調用

然後在代碼里直接調用：

Call URLDownloadToFile(0, "網頁地址", "保存到本地檔案名稱和地址", 0, 0)

如

Call URLDownloadToFile(0, "*****.baidu**/", "c:\1.htm", 0, 0)

相當於另外儲存為

聲明：

Private Declare Function DoFileDownload Lib "shdocvw.dll"(ByVal lpszFile As String) As Long

'//調用

然後在代碼里直接調用：

Dim gourl As String

gourl = StrConv("網頁地址", vbUnicode)

Call DoFileDownload(gourl)