我尝试执行此代码，获取java.lang.NullPointerException
writer = PdfWriter.getInstance(document, new FileOutputStream("D:\\Test.pdf"));
document.open();
XMLWorkerHelper.getInstance().parseXHtml(writer, document, new FileInputStream("D:\\work\\iTextPDF\\index.html"));
document.close();
错误：
Exception in thread "main" java.lang.NullPointerException at
com.itextpdf.tool.xml.net.FileRetrieveImpl.read(FileRetrieveImpl.java:182)
at
com.itextpdf.tool.xml.net.FileRetrieveImpl.processFromHref(FileRetrieveImpl.java:150)
at
com.itextpdf.tool.xml.css.StyleAttrCSSResolver.addCssFile(StyleAttrCSSResolver.java:289)
at com.itextpdf.tool.xml.html.head.Link.start(Link.java:78) at
com.itextpdf.tool.xml.html.AbstractTagProcessor.startElement(AbstractTagProcessor.java:136)
at
com.itextpdf.tool.xml.pipeline.html.HtmlPipeline.open(HtmlPipeline.java:96)
at com.itextpdf.tool.xml.XMLWorker.startElement(XMLWorker.java:165)
at
com.itextpdf.tool.xml.parser.XMLParser.startElement(XMLParser.java:320)
at
com.itextpdf.tool.xml.parser.state.SelfClosingTagState.process(SelfClosingTagState.java:70)
at
com.itextpdf.tool.xml.parser.XMLParser.parseStream(XMLParser.java:184)
at com.itextpdf.tool.xml.parser.XMLParser.parse(XMLParser.java:138)
at
com.itextpdf.tool.xml.XMLWorkerHelper.parseXHtml(XMLWorkerHelper.java:181)
at
org.open.word.test.TestOpenWord.convertHTMLtoPDFCase2(TestOpenWord.java:55)
at org.open.word.test.TestOpenWord.main(TestOpenWord.java:19)