我在問題「Append PDF at the available space of another PDF file」之前問過，並且我已經在一個頁面中將原生iText和JFreeChart組合成PDF。JFreeChart沒有在生成的Spring MVC和iText中顯示PDF
我使用教程「Spring Web MVC with PDF View Example (using iText 5.x)」將此設置合併到我的Spring MVC應用程序中。
據我所知，使用Spring的AbstractView，進而爲
@Override
protected void buildPdfDocument(Map<String, Object> map, Document document,
PdfWriter pdfWriter, HttpServletRequest request,
HttpServletResponse response) throws Exception {
// do iText and JFreeCharts
}
和顯示JFreeChart實例需要現有的PDF文件中插入它作爲「Creating an iText pdf with embedded JFreeChart」證明實施：
// get the direct pdf content
PdfContentByte dc = docWriter.getDirectContent();
// get a pdf template from the direct content
PdfTemplate tp = dc.createTemplate(width, height);
// create an AWT renderer from the pdf template
Graphics2D g2 = tp.createGraphics(width, height, new DefaultFontMapper());
Rectangle2D r2D = new Rectangle2D.Double(0,0, width,height);
chart.draw(g2,r2D,null);
g2.dispose();
// add the rendered pdf template to the direct content
// you will have to play around with this because the chart is absolutely positioned.
// 38 is just a typical left margin
// docWriter.getVerticalPosition(true) will approximate the position that the content above the chart ended
dc.addTemplate(tp, 38, docWriter.getVerticalPosition(true)-height);
現在我的問題是，每當我調用擴展的方法AbstractView（請參閱第二個鏈接），它顯示插入JFreeChart之前的PDF而不是具有創建評論圖表。我沒有遇到任何錯誤，但我想知道是否有解決此問題的方法。
我只想讓用戶使用JFreeChart查看PDF，就像Spring MVC中的普通PDF實現一樣。
正如你所看到的，我只是按照上面的教程進行組合。他們在一個單獨的項目中完美地工作，但是當我與Spring合併時，JFreeChart沒有顯示，特別是顯示了錯誤的PDF文件。
我知道我可以只放一個鏈接到正確的文件調用生成的PDF使用JFreeChart，有點攔截觀看，但我保持我的希望了這種設置，因爲這將是一個方便的方法使用這三種技術完全沒有文件I/O在服務器（我有麻煩）中的麻煩。
下面是類AbstractITextPdfView從「Spring Web MVC with PDF View Example (using iText 5.x)」，我使用的一個片段。
有人能告訴我如何直接打開PDF文件到圖表，即在buildPdfDocument()內？
@Override
protected void renderMergedOutputModel(Map<String, Object> model,
HttpServletRequest request, HttpServletResponse response)
throws Exception {
// IE workaround: write into byte array first.
ByteArrayOutputStream baos = createTemporaryOutputStream();
// Apply preferences and build metadata.
Document document = newDocument();
PdfWriter writer = newWriter(document, baos);
prepareWriter(model, writer, request);
buildPdfMetadata(model, document, request);
// Build PDF document.
document.open();
buildPdfDocument(model, document, writer, request, response);
document.close();
// Flush to HTTP response.
writeToResponse(response, baos);
}
更新
我通過保存到文件後JFreeChart 「武官」 本身的iText PDF截獲ByteArrayOutputStream。
@Override
protected void renderMergedOutputModel(Map<String, Object> model,
HttpServletRequest request, HttpServletResponse response)
throws Exception {
// IE workaround: write into byte array first.
ByteArrayOutputStream baos = createTemporaryOutputStream();
// Apply preferences and build metadata.
Document document = newDocument();
PdfWriter pdfWriter = newWriter(document, baos);
prepareWriter(model, pdfWriter, request);
buildPdfMetadata(model, document, request);
// Build PDF document.
document.open();
buildPdfDocument(model, document, pdfWriter, request, response);
document.close();
FileOutputStream fos = null;
try {
fos = new FileOutputStream(new File("D:/MUST-HAVE-CHART.pdf"));
baos.writeTo(fos);
} catch (IOException ioe) {
// Handle exception here
ioe.printStackTrace();
} finally {
fos.close();
}
System.out.println(baos.toString());
// Flush to HTTP response.
writeToResponse(response, baos);
}
發生了什麼事是MUST-HAVE-CHART.PDF沒有圖表，同創建後由Spring MVC提供了一個。與圖表的一個但是被保存在其他地方，如在代碼：
@Override
protected void buildPdfDocument(Map<String, Object> map, Document document,
PdfWriter pdfWriter, HttpServletRequest request,
HttpServletResponse response) throws Exception {
logger.info("Start of PDF creation");
Domain domain = (Domain) map.get("domain");
ServletContext servletContext = request.getSession()
.getServletContext();
File servletTempDir = (File) servletContext
.getAttribute("javax.servlet.context.tempdir");
if (servletTempDir == null)
throw new IllegalStateException(
"Container does not provide a temp dir");
File targetFile = new File(servletTempDir, NAME_FILE);
pdfWriter = PdfWriter.getInstance(document, new FileOutputStream(
targetFile));
logger.info("PDF file path: " + targetFile.getAbsolutePath().toString());
document.open();
PdfBuilder.assemble(document, pdfWriter, domain);
document.close();
pdfWriter.close();
logger.info("End of PDF creation");
map.put("file", targetFile.getAbsolutePath().toString());
}
正確的保存在javax.servlet.context.tempdir或C:/tomcat/work/Catalina/localhost/my_spring_app/pdf_file.pdf。