ireport 导出html

Question

<%
String transId = (String) request.getParameter("transId");
System.out.println("transId--" + transId);
%>
<%
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver"); Connection conn = DriverManager
.getConnection("jdbc:sqlserver://192.168.1.12:1433;User=sa;Password=tongxiweb2008;DatabaseName=EETransWeb"); File reportFile = new File(application
.getRealPath("/reports/classic.jasper")); JasperReport jasperReport = (JasperReport) JRLoader
.loadObject(reportFile.getPath());
System.out.println("reportFile.getPath()--" + reportFile.getPath());
Map parameters = new HashMap();
parameters.put("allotId", transId); JasperPrint jasperPrint = JasperFillManager.fillReport(
jasperReport, parameters, conn); JRHtmlExporter exporter = new JRHtmlExporter(); Map imagesMap = new HashMap();
session.setAttribute("IMAGES_MAP", imagesMap); exporter
.setParameter(JRExporterParameter.JASPER_PRINT, jasperPrint);
exporter.setParameter(JRExporterParameter.OUTPUT_WRITER, out);
exporter
.setParameter(JRHtmlExporterParameter.IMAGES_MAP, imagesMap);
exporter.setParameter(JRHtmlExporterParameter.IMAGES_URI,
"output/transView..jsp?image="); exporter.setParameter(JRExporterParameter.CHARACTER_ENCODING,
"GB2312"); exporter.exportReport();
%>
我导出到html，什么反应也没有，也没有报错！！不知道什么原因！！
改成导出pdf，就报错！
byte[] bytes=JasperRunManager.runReportToPdf(reportFile.getPath(),parameters,conn);
response.sendRedirect("/imsWeb/output/image.html");
response.setContentType("application/pdf");
response.setContentLength(bytes.length);
ServletOutputStream outputStream=response.getOutputStream();
outputStream.write(bytes,0,bytes.length);
outputStream.flush();
outputStream.close();
异常：
java.lang.NoClassDefFoundError: com/lowagie/text/DocumentException
at net.sf.jasperreports.engine.JasperExportManager.exportReportToPdf(JasperExportManager.java:183)
at net.sf.jasperreports.engine.JasperRunManager.runReportToPdf(JasperRunManager.java:205)
at org.apache.jsp.output.transView_jsp._jspService(transView_jsp.java:151)