如何用struts2 导出jsp页面上显示的内容？


这是我的jsp页面 希望能点击导出excel后导出那些报表内容
现在只能导出空excel以下是ExcelServiceImpl：
public class ExcelServiceImpl implements IExcelService{
HttpServletResponse response = ServletActionContext.getResponse(); 
HttpServletRequest request = ServletActionContext.getRequest(); 
public InputStream getExcelInputStream() {
 //将OutputStream转化为InputStream           ByteArrayOutputStream out = new ByteArrayOutputStream();           putDataOnOutputStream(out);           return new ByteArrayInputStream(out.toByteArray());   
}
private void putDataOnOutputStream(OutputStream os) {           jxl.write.Label label;           WritableWorkbook workbook;           try {               workbook = Workbook.createWorkbook(os);               WritableSheet sheet = workbook.createSheet("银弹的第一页", 0);                 label = new jxl.write.Label(0, 0, "我是银弹我怕谁");               sheet.addCell(label);                              workbook.write();               workbook.close();           } catch (Exception e) {               e.printStackTrace();           }       }   }
请问下大神们要如何改？详细点 本人程度较差Struts