It's better to use jxl frame work when working with excel/ java as jxl has lots of features which can be explored.
http://jexcelapi.sourceforge.net/ WritableWorkbook samplebook = Workbook.createWorkbook(out);
WritableSheet sample = highTransBook.createSheet("Sample", 0);
sample.setPageSetup(PageOrientation.LANDSCAPE);
WritableFont times20font = new WritableFont(WritableFont.TIMES, 20, WritableFont.BOLD, true);
WritableCellFormat times20format = new WritableCellFormat(times20font);
Label label1 = new Label(0,0, "Sample Ref", times20format);
sample.addCell(label1);