Delphi中实现文件Copy的三种方法

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Delphi中实现文件Copy的三种方法

　核心提示：1．调用API函数 procedure CopyFile(FromFileName,ToFileName:string); var f1,f2:file; Begin AssignFile(f1,Fro...

1．调用API函数

1. procedure CopyFile(FromFileName,ToFileName:string);
   
2. var
   
3. f1,f2:file;
   
4. Begin
   
5. AssignFile(f1,FromFileName); file://指定源文件名
   
6. AssignFile(f2,ToFileName); file://指定目标文件名
   
7. Reset(f1);
   
8. Try
   
9. Rewrite(f2);
   
10. Try
    
11. If Lzcopy(TfileRec(f1).handle,TfileRec(f2).Handle)<0
    
12. Then
    
13. Raise EinoutError.creat(’文件复制错误’)
    
14. Finally
    
15. CloseFile(f2); file://关闭 f2
    
16. End;
    
17. Finally
    
18. Until length(sLine)<=0;
    
19. End;
    
20. End;

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2.文件流

1. procedure copyfile;
   
2. var f1,f2: tfilestream ;
   
3. begin
   
4. f1:=Tfilestream.Create(sourcefilename,fmopenread);
   
5. try
   
6. f2:=Tfilestream.Create(targetfilename,fmopenwrite or fmcreate);
   
7. try
   
8. f2.CopyFrom(f1,f1.size);
   
9. finally
   
10. f2.Free;
    
11. end;
    
12. finally
    
13. f1.Free;
    
14. end;
    
15. end;

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3．利用内存块读写buffer实现

1. Procudure FileCopy(const Fromfile,Tofile:string);
   
2. Var
   
3. F1,F2:file;
   
4. NumRead,Numwritten:word;
   
5. Buf:array [1..2048] of char;
   
6. Begin
   
7. AssignFile(F1,Fromfile);
   
8. Reset(F1,1);
   
9. AssignFile(F2,Tofile);
   
10. Rewrite(F2,1);
    
11. Repeat
    
12. BlockRead(F1,buf,sizeof(buf),NumRead);
    
13. BlockWrite(F2,buf,Numread,NumWritten);
    
14. Until (NumRead=0) or (NumWritten<>NumRead);
    
15. CloseFile(F1);
    
16. CloseFile(F2);
    
17. End;

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