JExcel

[jcamp]

I have the following code which produces an excel spreadsheet to my browser. what i want to do is to use JExcel to manipulate the spreadsheet before presenting to the browser. can someone please tell me how to do this.
here is the current working code:

byte buf[] = output.getBytes();
ServletOutputStream sos = resp.getOutputStream();
//resp.setHeader("Content-disposition", "inline; filename=" + ra + dtStr + ".xls");
resp.setHeader("Content-disposition", "inline; filename="+ viewName + time + ".xls");
resp.setHeader("Pragma", "Public");
resp.setContentType("appilication/vnd.ms-excel");
resp.setContentLength(buf.length);
sos.write(buf);
sos.flush();
sos.close();