IdHttp获取服务器文件

[xiao_zhao]

procedure TForm1.DownLoadFile(URL:String;FileName:String;Resume:Boolean);
var
  tStream : TFileStream ;
begin
  if FileExists(FileName) then
      tStream := TFileStream.Create(FileName,fmOpenReadWrite)
  else
      tStream := TFileStream.Create(FileName,fmCreate);

  if Resume then  //断点续传
  begin
    IdHttp1.Request.ContentRangeStart := tStream.Size - 1 ;
    tStream.Position := tStream.Size - 1 ;
    IdHttp1.Head(URL);
    IdHttp1.Request.ContentRangeEnd := IdHttp1.Response.ContentLength ;
  end
  else
    IdHttp1.Request.ContentRangeStart := 0 ;

  try
    IdHttp1.Get(URL,tStream);
  finally
    tStream.Free ;
  end;

end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  DownLoadFile('http://10.136.72.121:2000/updateimage/renderingsimages/0000000001/','O1016448851703512.jpg',false);
end;

如何服务器上文件不存在，在执行IdHttp1.Get(URL,tStream)的时候会报错
HTTP/1.1 404 Not Found

请问该如何处理

[bdmh]

不存在当然报错了，不报错你想干嘛

[xiao_zhao]

那如何判断文件是否存在？？？

[yabaiking]

捕获异常
然后就可以判断文件不存在