用delphi 实现文件下载,可以用于软件的升级

var 
    MyStream:TMemoryStream;
begin
    try
        MyStream   :=   TMemoryStream.Create;
        IdHTTP1.Get(   'http://localhost/download/j2sim.exe ',MyStream   );
        MyStream.SaveToFile(ExtractFilePath   (Application.ExeName)   +   'j2sim.exe ');
    finally
        MyStream.Free;
        Edit1.Text   :=   IdHTTP1.Response.Server   +   ':   '   +   IdHTTP1.Response.ResponseText;
    end;
end;