文件下载 ( 积分: 100 )

提供一个网址如：http：//www.xxx.com/xxx.jsp?id=xxxxxx。我根据这个网址可以下载文件。请问我用什么控件或方法可以根据网址把文件下载到指定的目录中去？有相应的例子吗？提供呀。

提供一个网址如：http：//www.xxx.com/xxx.jsp?id=xxxxxx。我根据这个网址可以下载文件。请问我用什么控件或方法可以根据网址把文件下载到指定的目录中去？有相应的例子吗？提供呀。

API

delphi自带的web组件有

以前写过两个类，不过没有用到实际的工作中

感觉里面有很多需要修改的地方
希望对你有帮助
Unit UAutoUpdate_base;

interface

uses
windows,SysUtils,dialogs,Classes,Forms,
IdBaseComponent,IdComponent, IdTCPConnection, IdTCPClient, IdHTTP,IdURI,
Db
;




type

TOnFileWriteEvent = procedure(FileSize:integer;Bufointer;BufferSize:integer;BufferCount:integer;CurrentBuffer:integer) of object;
//在文件更新过程中触发的事件
TBeforeFileWriteEvent = procedure(FileSize:integer;BufferSize:integer;BufferCount:integer) of object;
//在文件更新之前触发的事件
TAfterFileWriteEvent = procedure(FileSize:integer;BufferSize:integer;BufferCount:integer) of object;
//在文件更新之后触发的事件
FileBuffer = array [0..4095] of byte;
//文件更新时的缓存



TUpDateFile = class (Tobject)
//文件更新类型
private
FTargetFileName:string;
FSourceFileName:string;
FStop:boolean;
FBeforeUpdateFile:TBeforeFileWriteEvent;
FOnUpDateFile:TOnFileWriteEvent;
FAfterUpdateFile:TAfterFileWriteEvent;
procedure FSetTargetFileName(const Value:string);
procedure FSetSourceFileName(const Value:string);
public
function Execute:Boolean;
//执行文件更新操作。返回值执行结果

function UpdateFile(TargetFile:string;SourceFile:string):Boolean;
//根据文件名实现文件的更新

procedure StopUpdate;
//停止文件更新

published
//目标文件名
property TargetFileName:string Read FTargetFileName write FSetTargetFileName;
//源文件名
Property SourceFileName:string Read FSourceFileName write FSetSourceFileName;
Property OnUpDateFile:TOnFileWriteEvent Read FOnUpDateFile write FOnUpDateFile;
//文件更新时触发的事件
Property BeforeUpDateFile:TBeforeFileWriteEvent Read FBeforeUpDateFile Write FBeforeUpDateFile;
//文件更新前触发的事件
Property AfterUpDateFile:TAfterFileWriteEvent Read FAfterUpdateFile Write FAfterUpDateFile;
//文件更新后触发的事件

end;





THttpDownFile = class(Tobject)
//通过HTTP协议下载文件的类型
private
FUrl:WideString;
//文件的网络地址

FTargetFileName:String;
//目标文件的位置

FBeforeDownLoadFile:TBeforeFileWriteEvent;
//文件下载前执行的事件

FOnDownLoadFile:TOnFileWriteEvent;
//文件下载过程中执行的事件

FAfterDownLoadFile:TAfterFileWriteEvent;
//文件下载后执行的事件

FStop:bool;
public
function Execute:Boolean;
//执行文件更新操作

function DownLoadFile(Url:Widestring;TargetFile:String):Boolean;
//根据文件网络位置和目标文件的名称来更新文件
procedure StopDownload;
//停止文件更新操作
published
Property Url:WideString Read FUrl Write FUrl;
//文件地址
property TargetFileName:String Read FTargetFileName Write FTargetFileName;
//目标文件名称
property BeforeDownLoadFile:TBeforeFileWriteEvent Read FBeforeDownLoadFile Write FBeforeDownLoadFile;
property OnDownLoadFile:TOnFileWriteEvent Read FOnDownLoadFile write FOnDownLoadFile;
property AfterDownLoadFile:TAfterFileWriteEvent Read FAfterDownLoadFile Write FAfterDownLoadFile;


end;



TDBDownFile = class(Tobject)
//从数据库取得文件的模块
private
FDataSet:TDataSet;
FFileFieldName:String;
//数据库中保存文件的字段

FTargetFileName:String;
FStop:Boolean;
FBeforeDownLoadFile:TBeforeFileWriteEvent;
//文件下载前执行的事件

FOnDownLoadFile:TOnFileWriteEvent;
//文件下载过程中执行的事件

FAfterDownLoadFile:TAfterFileWriteEvent;
//文件下载后执行的事件

public
function Execute:boolean;
//执行文件下载的操作

function DownLoadFile(FileFieldName:String;TargetFile:string):boolean;

procedure StopDownload;
published
property DataSet:TDataSet Read FDataSet Write FDataset;

Property FileFieldName:String Read FFileFieldName Write FFileFieldName;
//保存文件的数据库字段

Property TargetFile:string Read FTargetFileName Write FTargetFileName;
//要保存文件的位置

Property BeforeDownloadFile:TBeforeFileWriteEvent Read FBeforeDownloadFile Write FBeforeDownloadFile;
//下载前的事件

Property OnDownloadFile:TOnFileWriteEvent Read FOnDownloadFile Write FOnDownloadFile;
//下载中的事件

Property AfterDownloadFile:TAfterFileWriteEvent Read FAfterDownloadFile Write FAfterDownloadFile;
//下载后的事件

end;


implementation

{ TUpDateFile }

function TUpDateFile.Execute: Boolean;
begin
result:=UpdateFile(FTargetFileName,FSourceFileName);
end;

procedure TUpDateFile.FSetSourceFileName(const Value:string);
begin
FSourceFileName:=Value;
end;

procedure TUpDateFile.FSetTargetFileName(const Value: string);
begin
FTargetFileName:=Value;
end;


procedure TUpDateFile.StopUpdate;
begin
FStop:=True;
end;


//文件更新函数
function TUpDateFile.UpdateFile(TargetFile, SourceFile: string): Boolean;
var
SS:TFileStream;
TS:TFileStream;
Buf:FileBuffer;
BufCnt:integer;
BufSize:integer;
FileSize:integer;
i:integer;
begin
Result:=False;
If FileEXists(FSourceFileName) then
begin
SS:=TFileStream.Create(FSourceFileName,fmOpenRead);
TS:=TFileStream.Create(FTargetFileName,fmCreate);
//创建源文件流和目标文件流

SS.Position:=0;
TS.Position:=0;
FileSize:=SS.Size;
BufSize:=Sizeof(buf);
Bufcnt:=Filesize div BufSize;
If (Filesize mod BufSize)<>0 then
BufCnt:=BufCnt+1;
if Assigned(FBeforeUpdateFile) then
FBeforeUpdateFile(FIleSize,BufSize,BufCnt);
zeromemory(@Buf,sizeof(Buf));
FStop:=False;

//写文件
for i:=1 to FileSize div BufSize do
begin
SS.Read(Buf,BufSize);
If Assigned(FOnUpDateFile) then
FOnUpDateFile(FileSize,@buf,Bufsize,Bufcnt,i);
TS.Write(Buf,BufSize);
If Fstop then break;
Application.ProcessMessages;
end;
if ((SS.Size mod BufSize)<>0) and (not Fstop) then
begin
SS.Read(Buf,(SS.Size mod BufSize));
If Assigned(FOnUpDateFile) then
FOnUpDateFile(FileSize,@buf,bufsize,Bufcnt,Bufcnt);
TS.Write(Buf,(SS.Size mod BufSize));
end;
if assigned(FAfterUpDateFile) then
FAfterUpdateFile(FileSize,BufSize,Bufcnt);
Result:=True;
SS.Destroy;
TS.Destroy;
end;
end;

{ THttpDownFile }

function THttpDownFile.DownLoadFile(Url: Widestring;
TargetFile: String): Boolean;
var
HttpC:TIdHttp; //HTTP连接
Http_Header:TStrings; //请求文件的HTTP头
Filesize:Integer; //文件大小
TS:TFileStream; //目标文件流
Buf:FileBuffer;
BufSize:Integer;
BufCnt:integer;
i:integer;
begin
Result:=False;
FStop:=false;
HttpC:=TIdHttp.Create(nil);
Http_Header:=TStringList.Create;
TS:=TFileStream.Create(TargetFile,fmCreate);
//初始化
Try
HttpC.Head(Url); //请求网络文件的头信息
FileSize:=Httpc.Response.ContentLength;
BufSize:=SizeOf(Buf);
BufCnt:=FileSize div BufSize;

if (FileSize mod BufSize) <>0 then
BufCnt:=BufCnt+1;
//计算缓存的个数

if Assigned(FBeforeDownLoadFile) then
FBeforeDownLoadFile(FileSize,BufSize,BufCnt);
//执行文件更新前的事件

Http_Header.Add('GET '+HttpC.URL.Path+HttpC.URL.Document+' HTTP/1.1');
Http_Header.Add('Accept: */*');
Http_Header.Add('RANGE: bytes=1-');
//Http_Header.Add('User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; .NET CLR 1.0.3705)');
Http_Header.Add('Host: '+HttpC.URL.Host);
//生成请求文件的头信息

if not HttpC.Connected then HttpC.Connect;
HttpC.WriteHeader(Http_Header);
//发送请求文件的头信息

while HttpC.ReadLn<>'' do;
Zeromemory(@Buf,sizeof(buf));
for i:=1 to (FileSize div BufSize) do
begin
HttpC.ReadBuffer(Buf,Sizeof(Buf));
if Assigned(FOnDownLoadFile) then
FOnDownLoadFile(Filesize,@Buf,Bufsize,Bufcnt,i);
if Fstop then Break;
TS.WriteBuffer(Buf,Sizeof(Buf));
Application.ProcessMessages;
end;
if ((FileSize mod BufSize) <>0) and (not Fstop) then
begin
HttpC.ReadBuffer(Buf,(FileSize mod BufSize));
if Assigned(FOnDownLoadFile) then
FOnDownLoadFile(Filesize,@Buf,(FileSize mod BufSize),Bufcnt,Bufcnt);
TS.WriteBuffer(Buf,(FileSize mod BufSize));
end;
//读取文件到本地

if Assigned(FAfterDownLoadFile) then
FAfterDownLoadFile(Filesize,BufSize,BufCnt);
HttpC.Disconnect;
Result:=True;
except
//raise Exception.Create('Not Found');
end;
// uri.Destroy;
TS.Destroy;
Http_Header.Destroy;
HttpC.Destroy;
end;

function THttpDownFile.Execute: Boolean;
begin
Result:=DownLoadFile(FUrl,FTargetFileName);
end;





procedure THttpDownFile.StopDownload;
begin
FStop:=true;
end;

{ TDBDownFile }

function TDBDownFile.DownLoadFile(FileFieldName: String;
TargetFile:string): boolean;
var
Filesize:Integer; //文件大小
TS:TFileStream; //目标文件流
Buf:FileBuffer;
BufSize:Integer;
BufCnt:integer;
i:integer;
BlobStream: TStream;
// FileField:TBlobField;
begin
result:=False;
FStop:=False;
If Assigned(FDataset) then
begin
{




TS.Destroy;
BlobStream.Destroy;
if Assigned(FAfterDownLoadFile) then
FAfterDownLoadFile(FileSize,BufSize,BufCnt);
Result:=true;}
if FDataSet.Active then
begin
FDataSet.First;
TS:=TFileStream.Create(TargetFile,fmCreate);
While not FDataSet.Eof do
begin
BlobStream := FDataSet.CreateBlobStream(FDataset.FieldByName(FFileFieldName), bmRead);
Filesize:=BlobStream.Size;
BufSize:=sizeof(Buf);
BufCnt:=(FileSize div BufSize);
if (FileSize mod BufSize)<>0 then
BufCnt:=BufCnt+1;
if Assigned(FBeforeDownLoadFile) then
FBeforeDownLoadFile(FileSize,BufSize,BufCnt);
ZeroMemory(@Buf,BufSize);
For i:=1 to (FileSize div BufSize) do
begin
BlobStream.Read(Buf,BufSize);
if Assigned(FOnDownLoadFile) then
FOnDownLoadFile(Filesize,@Buf,BufSize,BufCnt,i);
if Fstop then Break;
Ts.Write(Buf,BufSize);
Application.ProcessMessages;
end;
if ((FileSize mod BufSize)<>0) and (not FStop) then
begin
BlobStream.Read(Buf,(FileSize mod BufSize));
if Assigned(FOnDownLoadFile) then
FOnDownLoadFile(Filesize,@Buf,BufSize,BufCnt,BufCnt);
Ts.Write(Buf,(FileSize mod BufSize));
Application.ProcessMessages;
end;
if Assigned(FAfterDownLoadFile) then
FAfterDownLoadFile(FileSize,BufSize,BufCnt);
FDataSet.Next;
end;
end;


end;
end;

function TDBDownFile.Execute: boolean;
begin
result:=DownLoadFile(FFileFieldName,FTargetFileName);
end;

procedure TDBDownFile.StopDownload;
begin
FStop:=true;
end;

end.

我有例子，不过只能下
http：//www.xxx.com/xxx/xxx.xxx的；
要的话给我E_mail:wzwcn@163.com

自己搞定了:
How to download a file from the Internet. - by Borland Developer Support Staff




Abstract: Code snippit shows one way of downloading a file from the Internet.
QUESTION:
How do I download a file from a URL location?

ANSWER:

There are a number of ways to do this, below is a simple code snippit that
will give you an idea of how to do this. Make sure to add ShellApi, and UrlMon
to your uses clause.


function DownLoadInternetFile(Source, Dest : String): Boolean;
begin
try
Result := URLDownloadToFile(nil,PChar(Source),PChar(Dest),0,nil) = 0
except
Result := False;
end;
end;

procedure TForm1.Button1Click(Sender: TObject);
var
SourceString, DestinationString: string;
begin
//File location on the Internet.
SourceString := 'http://www.borland.com/images/homepage/del6homemural.gif';
//File destination.
DestinationString := 'C:Tempdel6homemural.gif';

if DownLoadInternetFile(SourceString, DestinationString) then
//This will display the file from your browser.
ShellExecute(Application.Handle, PChar('Open'), PChar(DestinationString), PChar(''), nil, SW_NORMAL)
else
ShowMessage('Error during Download ' + SourceString);
end;

用两个WebBrower
http://www.delphibbs.com/delphibbs/dispq.asp?lid=3175105

或者用id控件

URLDownloadToFile，是个api，自己查帮助吧。

多人接受答案了。