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，因此，在生成 PDF 后，它应该由浏览器下载

我使用 netbeans 代码生成的 Web 应用程序，带有 java server faces 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);
    }
}

但它不起作用并给我一个错误

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)

有没有什么简单的方法可以使用 Jasper Report 生成 PDF 报告，然后下载到浏览器？

Answer 1

这不是 Jasper 错误

替换

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

到

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