kendi kendime konuşayim. kendi kendimin sorusunu yanitlayayim
Daha sonra arayan arkadaşlara yardım sağlaması açısından şöyle bir kod oluşturdum;

		try{		
			JRBeanCollectionDataSource ds = new JRBeanCollectionDataSource(dataList);
			JasperReport jasperReport;
			JasperPrint jasperPrint;
			HashMap jasperParameter = new HashMap();
			ServletContext servletContext = (ServletContext) FacesContext.getCurrentInstance().getExternalContext().getContext();
			String jrxmlFile = servletContext.getRealPath("") + File.separator + "rapor/deneme.jrxml";
			JasperDesign jasperDesign = JRXmlLoader.load(jrxmlFile);
			jasperReport = JasperCompileManager.compileReport(jasperDesign);
			jasperPrint = JasperFillManager.fillReport(jasperReport,jasperParameter, ds);
			byte[] outData = JasperExportManager.exportReportToPdf(jasperPrint);
			FacesContext faces = javax.faces.context.FacesContext.getCurrentInstance();  
			HttpServletResponse response = (HttpServletResponse) faces.getExternalContext().getResponse();
			ServletOutputStream out = null; 
			response.setContentType("application/pdf");  
			response.setHeader("Content-disposition","attachment; filename=mernisformu.pdf");		
			out = response.getOutputStream();
			out.write(outData);    
			faces.responseComplete();
		}catch(JRException jr){
			jr.printStackTrace();
		}catch(IOException ioe){}