Apache fop：生成空白pdf输出

Question

我试图使用Apache Fop和Java生成PDF，但生成的PDF始终是空白页。 它全部嵌套在Web应用程序中，Sever是glassfish。

有人有建议吗？

这里是我的xsl：

<?xml version="1.0" encoding="UTF-8"?> 
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:fo="http://www.w3.org/1999/XSL/Format"> 
    <xsl:output method="xml" encoding="utf-8" /> 
    <xsl:template match="/"> 
     <fo:root> 
      <fo:layout-master-set> 
       <fo:simple-page-master master-name="DealerOverview"> 
        <fo:region-body margin-top="4cm" margin-bottom="2cm" /> 
        <fo:region-before extent="3.5" /> 
        <fo:region-after extent="3.5" /> 
       </fo:simple-page-master> 
      </fo:layout-master-set> 
      <xsl:apply-templates select="DealerOverview" /> 
      </fo:root> 
     </xsl:template> 
     <xsl:template match="DealerOverview"> 
     <fo:page-sequence master-reference="DealerOverview"> 
      <fo:flow flow-name="xsl-region-body"> 
       <fo:block> 
        <fo:table table-layout="fixed"> 
         <fo:table-body> 
          <fo:table-row> 
           <fo:table-cell text-align="center" font-weight="bold"> 
            <fo:block>Brand</fo:block> 
           </fo:table-cell> 
           <fo:table-cell text-align="center" font-weight="bold"> 
            <fo:block>TargetYear</fo:block> 
           </fo:table-cell> 
           <fo:table-cell text-align="center" font-weight="bold"> 
            <fo:block>TargetPrevYear</fo:block> 
           </fo:table-cell> 
          </fo:table-row> 
          <xsl:for-each select="DealerOverview/Brands/Brand"> 
            <fo:table-row> 
             <fo:table-cell border="solid 1px black" text-align="center"> 
              <fo:block> 
               <xsl:value-of select="BrandId" /> 
              </fo:block> 
             </fo:table-cell> 
             <fo:table-cell border="solid 1px black" text-align="center"> 
              <fo:block> 
               <xsl:value-of select="TargetYear" /> 
              </fo:block> 
             </fo:table-cell> 
             <fo:table-cell border="solid 1px black" text-align="center"> 
              <fo:block> 
               <xsl:value-of select="TargetPrevYear" /> 
              </fo:block> 
             </fo:table-cell> 
            </fo:table-row> 
           </xsl:for-each> 
         </fo:table-body> 
        </fo:table> 
       </fo:block> 
      </fo:flow> 
     </fo:page-sequence> 
     </xsl:template> 
     <!-- TODO: Auto-generated template --> 
</xsl:stylesheet> 

和示例-XML的文件看起来是这样的：

<?xml version="1.0" encoding="UTF-8"?> 
<DealerOverview> 
    <DealerDetails> 
     <Version>testForDealer</Version> 
     <Date>Oct, 1, 2013</Date> 
     <State>Released to Dealer</State> 
     <Dealer>Ungeheuer Automobile GmBH</Dealer> 
     <BrandOverview>All</BrandOverview> 
    </DealerDetails> 
    <Brands> 
     <Brand id="BM"> 
      <BrandId>BM</BrandId> 
      <TargetYear>500</TargetYear> 
      <TargetPrevYear>1000</TargetPrevYear> 
     </Brand> 
    </Brands> 
</DealerOverview> 

编辑： Java的代码应生成PDF ...

public void createPdfWithFop(File xmlString) throws IOException { 

     FacesContext context = FacesContext.getCurrentInstance(); 
     ServletContext servletContext = (ServletContext) context.getExternalContext().getContext(); 
     HttpServletResponse response = (HttpServletResponse) context.getExternalContext().getResponse(); 

     pathToXsl = servletContext.getRealPath("/resources/reporting/PrintDealersOverview.xsl"); 

     File xslFile = new File(pathToXsl); 
     String tempString = FileUtils.readFileToString(xmlString); 
     System.out.println("Das XML-File in der Fop: " + tempString + " ende"); 
     StreamSource source = new StreamSource(xmlString); 
     StreamSource transformSource = new StreamSource(xslFile); 

     FopFactory fopFactory = FopFactory.newInstance(); 
     FOUserAgent userAgent = fopFactory.newFOUserAgent(); 

     ByteArrayOutputStream outStream = new ByteArrayOutputStream(); 

     TransformerFactory factory = TransformerFactory.newInstance(); 
     try { 

      Transformer transformer = factory.newTransformer(transformSource); 
      Fop fop = fopFactory.newFop(MimeConstants.MIME_PDF, outStream); 
      Result res = new SAXResult(fop.getDefaultHandler()); 

      transformer.transform(source, res); 

      byte[] pdfBytes = outStream.toByteArray(); 
      response.setContentType("application/pdf"); 
      response.addHeader("Content-Disposition", "attachment; filename=\"DealersOverview.pdf\""); 
      response.getOutputStream().write(pdfBytes); 
//   response.getOutputStream().flush(); 

     } catch (TransformerConfigurationException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } catch (FOPException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } catch (TransformerException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } catch (IOException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } 
    } 

第二编辑：

我发现，我的outputStream出了问题。 我想显示一个另存为对话框，以便从我的Web应用程序下载生成的文件。 我没有看到，我的输出有什么问题...

Answer 1

我不确定你说的是什么意思，当你得到一个空白页面，因为运行上述转换确实会为我生成一些输出。

但是，我确实注意到你的for-each不正确。您的选择正在寻找DealerOverview/Brands/Brand，但因为您已经在DealerOverview模板中，所以select会在此位置寻找一个元素DealerOverview/DealerOverview/Brands/Brand，该元素不存在。因此，如果您从选择中删除DealerOverview，则会在输出中获得更多信息。