Spring MVC - ブラウザに空白のPDFを開きます。

Question

私のアプリケーションではブラウザに空のPDFを開きます。 Spring Web model-view-controller（MVC）フレームワークを使用しています。ここで

コード

@Override 
     public ModelAndView handleRequest(HttpServletRequest request, 
       HttpServletResponse response) throws Exception { 
    byte[] data = "No file attached".getBytes(); 
    String fileName = "NofileFound.pdf"; 
      response.setHeader("Content-Disposition","attachment; filename="+fileName); 
      response.setContentType("application/pdf");   
      OutputStream out = response.getOutputStream();  

Document document = new Document();   
      PdfWriter writer = PdfWriter.getInstance(new Document(), new FileOutputStream("NofileFound.pdf")); 
      document.open(); 
      document.add(new Paragraph("test")); 
      document.close(); 
      writer.close(); 

      ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream(); 
      PdfWriter.getInstance(document, byteArrayOutputStream);   
      data = byteArrayOutputStream.toByteArray(); 

      out.write(data); 
      out.flush(); 
      out.close();   
      return null; 
    } 

しかし、私はこのエラーを得たファイルを開くとき：

not a supported file type 

Answer 1

@Override 
     public ModelAndView handleRequest(HttpServletRequest request, 
       HttpServletResponse response) throws Exception { 

    response.setContentType("application/pdf"); 
    Document document = new Document(); 
    PdfWriter.getInstance(document, response.getOutputStream()); 
    document.open(); 
    document.add(new Paragraph("empty pdf")); 
    document.close(); 

    return null 
}