使用jsf abd ireport生成的空白pdf，xls，docs ppt页面

Question

我正在尝试使用简单的代码生成pdf，xls，docs和ppt文件。我可以生成它，但它给出了一个blak页面，并且在Stacktrace中没有错误。我认为它不会从数据库中获取数据。

这是代码，Bean页面：

@ManagedBean   
@SessionScoped   

public class CompteRapport implements  Serializable{  

private static final long serialVersionUID = 1L;

private List<Users>listusers;
UsersDAO uDao= new UsersDAOImp();
JasperPrint jasperPrint;  

public void init() throws JRException{  
   JRBeanCollectionDataSource beanCollectionDataSource=new JRBeanCollectionDataSource(listusers);  
String  reportPath=  FacesContext.getCurrentInstance().getExternalContext().getRealPath("/Report/users.jasper");     
jasperPrint=JasperFillManager.fillReport(reportPath, new HashMap(),beanCollectionDataSource);   
}

public void PDF(ActionEvent actionEvent) throws JRException, IOException{  
   init();  
   HttpServletResponse httpServletResponse=(HttpServletResponse)FacesContext.getCurrentInstance().getExternalContext().getResponse();  
  httpServletResponse.addHeader("Content-disposition", "attachment; filename=users.pdf");  
   ServletOutputStream servletOutputStream=httpServletResponse.getOutputStream();  
   JasperExportManager.exportReportToPdfStream(jasperPrint, servletOutputStream);  
   FacesContext.getCurrentInstance().responseComplete();  


}  
public void DOCX(ActionEvent actionEvent) throws JRException, IOException{  
    init();  
   HttpServletResponse httpServletResponse=(HttpServletResponse)FacesContext.getCurrentInstance().getExternalContext().getResponse();  
   httpServletResponse.addHeader("Content-disposition", "attachment; filename=report.docx");  
   ServletOutputStream servletOutputStream=httpServletResponse.getOutputStream();  
   JRDocxExporter docxExporter=new JRDocxExporter();  
   docxExporter.setParameter(JRExporterParameter.JASPER_PRINT, jasperPrint);  
   docxExporter.setParameter(JRExporterParameter.OUTPUT_STREAM, servletOutputStream);  
   docxExporter.exportReport();

   FacesContext.getCurrentInstance().responseComplete();  

  }  
   public void XLSX(ActionEvent actionEvent) throws JRException, IOException{  
    init();  
   HttpServletResponse httpServletResponse=(HttpServletResponse)FacesContext.getCurrentInstance().getExternalContext().getResponse();  
  httpServletResponse.addHeader("Content-disposition", "attachment; filename=report.xlsx");  
   ServletOutputStream servletOutputStream=httpServletResponse.getOutputStream();  
   JRXlsxExporter docxExporter=new JRXlsxExporter();  
   docxExporter.setParameter(JRExporterParameter.JASPER_PRINT, jasperPrint);  
   docxExporter.setParameter(JRExporterParameter.OUTPUT_STREAM, servletOutputStream);  
   docxExporter.exportReport();  
   FacesContext.getCurrentInstance().responseComplete();  
}  
  public void ODT(ActionEvent actionEvent) throws JRException, IOException{  
   init();  
   HttpServletResponse httpServletResponse=(HttpServletResponse)FacesContext.getCurrentInstance().getExternalContext().getResponse();  
  httpServletResponse.addHeader("Content-disposition", "attachment; filename=report.odt");  
   ServletOutputStream servletOutputStream=httpServletResponse.getOutputStream();  
   JROdtExporter docxExporter=new JROdtExporter();  
   docxExporter.setParameter(JRExporterParameter.JASPER_PRINT, jasperPrint);  
   docxExporter.setParameter(JRExporterParameter.OUTPUT_STREAM, servletOutputStream);  
   docxExporter.exportReport();  
   FacesContext.getCurrentInstance().responseComplete();  
}  
   public void PPT(ActionEvent actionEvent) throws JRException, IOException{  
   init();  
   HttpServletResponse httpServletResponse=(HttpServletResponse)FacesContext.getCurrentInstance().getExternalContext().getResponse();  
  httpServletResponse.addHeader("Content-disposition", "attachment; filename=report.pptx");  
   ServletOutputStream servletOutputStream=httpServletResponse.getOutputStream();  
   JRPptxExporter docxExporter=new JRPptxExporter();  
   docxExporter.setParameter(JRExporterParameter.JASPER_PRINT, jasperPrint);  
   docxExporter.setParameter(JRExporterParameter.OUTPUT_STREAM, servletOutputStream);  
   docxExporter.exportReport();  
   FacesContext.getCurrentInstance().responseComplete();  
}  

public List<Users> getListusers() {
    return listusers;
}

public void setListusers(List<Users> listusers) {
    this.listusers = listusers;
}

public UsersDAO getuDao() {
    return uDao;
}

public void setuDao(UsersDAO uDao) {
    this.uDao = uDao;
}

}