Jasperreports xls shows in splitted format

Question

I am using Jasperreports 3.7.2, iReport and JRExporter. I tested with JExcelAPI as well. The generated report is shown in MSExcel in splitted format. I run the report using Spring MVC Controller -> forwarding to a Servlet. The Servlet does the logic. This issue does not appear if I run directly the Servlet, bypassing the spring controller. Any suggestions or solutions are appreciated. thanks