Java EE (Java Enterprise Edition) General Discussion

I am trying to open JSP file in excel and I get the following message: excel cannot open the file because the file format or file extension is not valid.Verify that the file has not been corrupted and that the file extension matches the format of the file. By the way, I have MS excel 2007.
here's my method:

response.setContentType("application/vnd.ms-excel");
response.setHeader("content-disposition","attachment; filename=Report.xlsx");

Also, I have add the following to web.xml:
<mime-mapping>
<extension>xlsx</extension>
<mime-type>application/vnd.ms-excel</mime-type>
</mime-mapping>

Could u pls resolve the issue asap.

smruti