Jasper报告无法生成PDF

Question

这是我第一次使用Jasper Report，我需要使用Java Server Face JSF生成PDF，所以，PDF生成后，它应该由浏览器下载

我使用netbeans代码生成Web应用程序，使用java服务器面框架和primefaces

public void createPDF() throws IOException {
    List<Pelanggan> asdf = pelangganFacade.findAll();
    try {
        ServletContext ctx = (ServletContext)FacesContext.getCurrentInstance()
                .getExternalContext().getContext();
        String ReportTemplate = ctx.getRealPath("/WEB-INF/Blank_A4.jasper");
        Map<String, Object> parameters = new HashMap<String, Object>();
        parameters.put("nama", asdf.get(1));
        HttpServletResponse response = (HttpServletResponse)FacesContext.getCurrentInstance()
                .getExternalContext().getContext();  
        response.addHeader("Content-disposition", "attachment; filename=testing.pdf");
        ServletOutputStream outputStream = response.getOutputStream();
        JasperPrint jasperPrint = JasperFillManager.fillReport(ReportTemplate, parameters);
        JasperExportManager.exportReportToPdfStream(jasperPrint, outputStream);
        outputStream.flush();
        outputStream.close();
        FacesContext.getCurrentInstance().responseComplete();
    } catch (JRException ex) {
        Logger.getLogger(TestReport.class.getName()).log(Level.SEVERE, null, ex);
    }
}

但它没有工作，给我一个错误

java.lang.ClassCastException: org.apache.catalina.core.ApplicationContextFacade cannot be      cast to javax.servlet.http.HttpServletResponse
Caused by: java.lang.ClassCastException: org.apache.catalina.core.ApplicationContextFacade     cannot be cast to javax.servlet.http.HttpServletResponse
at com.joandilee.TestReport.createPDF(TestReport.java:55)

是否有任何简单的方法来使用Jasper报告生成PDF报告，然后将其下载到浏览器?

Answer 1

这不是Jasper的错误

代替

HttpServletResponse response = (HttpServletResponse)FacesContext
             .getCurrentInstance().getExternalContext().getContext();  

HttpServletResponse response = (HttpServletResponse) FacesContext
            .getCurrentInstance().getExternalContext().getResponse();