Java EE (Java Enterprise Edition) General Discussion

hi,
I have used this statement before send files to client in my servlet code:
response.setHeader("Content-Disposition", "attachment;filename=\"" + file.getName() +"\"");
It's sure that the "File Download" dialog will be forced at client's side,and user can choose these choices:"open","save as","cancel","more info";
But when i chick "open" this choice,for example,i want to open a file of PDF type,the "Acrobat Reader" will be called and the right file will be opened.
Now, i want to let the opened file displayed in the region i set in IE or other browers.
What should i do ? Please help me.
Thanx very much !