按照堆栈跟踪中的说明获取NPE。该代码适用于某些html文件。因此，我可以确认该问题是间歇性的。
如果仔细观察，html会有一个根标记，其中包括标头图像和页码，其余部分位于中。其背后的原因是，我希望在生成的pdf的每个页面上都包含图像和页面编号。
下面是我正在使用的示例代码：
``````
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
ConverterProperties converterProperties = new ConverterProperties();
converterProperties.setCharset(StandardCharsets.UTF_8.name());
converterProperties.setImmediateFlush(false);
converterProperties.setCreateAcroForm(false);
FontProvider fontProvider = new DefaultFontProvider();
FontProgram fontProgram =
FontProgramFactory.createFont("/fonts/arialuni.ttf");
fontProvider.addFont(fontProgram);
converterProperties.setFontProvider(fontProvider);
HtmlConverter.convertToPdf(html, outputStream, converterProperties);
outputStream.close();
``````
错误跟踪strace：
ERROR com.itextpdf.layout.renderer.TableRenderer - Occupied area has not been initialized. Some of the cell's content might not end up placed correctly.
java.lang.NullPointerException
at com.itextpdf.layout.renderer.BlockRenderer.applyVerticalAlignment(BlockRenderer.java:630)
at com.itextpdf.layout.renderer.TableRenderer.correctRowCellsOccupiedAreas(TableRenderer.java:1718)
at com.itextpdf.layout.renderer.TableRenderer.correctLayoutedCellsOccupiedAreas(TableRenderer.java:1670)
at com.itextpdf.layout.renderer.TableRenderer.layout(TableRenderer.java:736)
at com.itextpdf.layout.renderer.TableRenderer.layout(TableRenderer.java:439)
at com.itextpdf.layout.renderer.BlockRenderer.layout(BlockRenderer.java:219)
at com.itextpdf.layout.renderer.BlockRenderer.layout(BlockRenderer.java:219)
at com.itextpdf.layout.renderer.BlockRenderer.layout(BlockRenderer.java:219)
at com.itextpdf.layout.renderer.BlockRenderer.layout(BlockRenderer.java:219)
at com.itextpdf.layout.renderer.BlockRenderer.layout(BlockRenderer.java:219)
at com.itextpdf.layout.renderer.BlockRenderer.layout(BlockRenderer.java:219)
at com.itextpdf.layout.renderer.TableRenderer.layout(TableRenderer.java:570)
at com.itextpdf.layout.renderer.BlockRenderer.layout(BlockRenderer.java:219)
at com.itextpdf.layout.renderer.RootRenderer.addChild(RootRenderer.java:134)
at com.itextpdf.html2pdf.attach.impl.layout.HtmlDocumentRenderer.addChild(HtmlDocumentRenderer.java:173)
at com.itextpdf.layout.RootElement.createAndAddRendererSubTree(RootElement.java:377)
at com.itextpdf.layout.RootElement.add(RootElement.java:106)
at com.itextpdf.layout.Document.add(Document.java:160)
at com.itextpdf.html2pdf.attach.impl.tags.HtmlTagWorker.processBlockChild(HtmlTagWorker.java:183)
at com.itextpdf.html2pdf.attach.impl.tags.HtmlTagWorker.processTagChild(HtmlTagWorker.java:149)
at com.itextpdf.html2pdf.attach.impl.tags.BodyTagWorker.processTagChild(BodyTagWorker.java:111)
at com.itextpdf.html2pdf.attach.impl.DefaultHtmlProcessor.visit(DefaultHtmlProcessor.java:353)
已使用HTML：
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8" />
<title>My Report</title>
<style> #remaining_sections tr, td {text-align:left;border-bottom:#ffffff 1.00pt SOLID;height:15pt;} #header span div{position: relative;text-align:left;width:100pt;} @page {size: portrait ;padding:5pt; margin:0.3in;border-top:1pt solid black;border-left:1pt solid black;border-bottom:1pt solid black;border-right:1pt solid black;} table { page-break-after:auto } th { page-break-inside:avoid; page-break-after:auto } tr { page-break-inside:avoid; page-break-after:auto } td { page-break-inside:avoid; page-break-after:auto } thead { display:table-header-group} tfoot { display:table-footer-group }#element { position: expression(fixed); top: 0in; left:0.1in;right:0.1in;bottom:0.1in; z-index: 10;} a[href]:after { content: none !important; } #element { position: fixed; top: 0in; left:0.1in;right:0.1in;bottom:0.1in; z-index: 10} body{ background-color:#FFFFFF;font-family:"Arial Unicode MS";white-space:nowrap;font-size:9pt;} .headers { font-size:12pt; font-weight:bold; color:#555555;text-align:center;} .bold {font-weight:bold;} #remaining_sections {top:255pt;width:540pt;} #main {top:13pt;left:22pt;width:568pt;} #remaining_sections table { border: none;white-space: nowrap;font-family: "Arial Unicode MS";font-size: 9pt;border-collapse: collapse;width: 100%;height: auto;} .theading { background-color:#FFFFFF;font-family: "Arial Unicode MS";font-size: 8pt;font-weight: bold;color: #555555;} #remaining_sections th {padding:15px;} #remaining_sections td {padding-left:15px;padding-right:15px;}#remaining_sections tbody tr:nth-child(odd) {background-color:#FFFFFF;} #remaining_sections .total_td { white-space: nowrap;font-family: "Arial Unicode MS";font-size: 9pt;color: #2B446E;background-color:#FFFFFF;border:none;} #remaining_sections .summary_td {white-space: nowrap;font-family: "Arial Unicode MS";font-size: 9pt;font-weight: bold;color: #2B446E;border:#828282 1.00pt SOLID; text-align:right;} .no_background {background-color:#FFFFFF;} .header_line_1 {border-top:#000000 2.00pt OUTSET;} .aligning {border-collapse: inherit;text-align:left;padding-left:60px;} #summary_details_tr tr td {border-bottom:none;background-color:#FFFFFF;}#remaining_sections td { border-bottom:#828282 1.00pt SOLID;}#head_image {left:22pt;top:12pt;width:135pt;height:60pt;margin-right: auto; display: block;}#pageNoHead { left:22pt;top:2pt;width:110pt;height:8pt;margin-left: auto; display: block;}#pageNoHead:after { counter-increment: page; content: "Page " counter(page) " of " counter(pages) ; }</style>
</head>
<body style="OVERFLOW: auto">
<div id="main">
<table style="repeat-header: yes;repeat-footer: yes;">
<thead>
<tr>
<th>
<div>
<div id='pageNoHead'/><img id=head_image src='data:image/jpeg;base64,/image/2Q=='/></div>
</th>
</tr>
</thead>
<tbody>
<tr>
<td>
<div id="header">
<div style='top:72pt;left:22pt; text-align:right;margin-right:30pt'><span style='text-align:right;margin-right:74pt;'>MY INVOICE</span></div>
<span>
<div style="top:20pt;left:263pt;text-align:right;">DATE:</div>
<div style="top:7pt;left:388pt;text-align:right;">31MAY18</div>
<div style="top:6pt;left:290pt;text-align:right;">NUM:</div>
<div style="top:-6pt;left:431pt;text-align:right;">1234567890</div>
<div style="top:-6pt;left:290pt;text-align:right;">HEAD:</div>
<div style="top:-17pt;left:369pt;text-align:right;">39</div>
<div style="top:-6pt;left:285pt;text-align:right; color:white;">SEQUENCE:</div>
<div style="top:-17pt;left:369pt;text-align:right; color:white;">39</div>
</span>
<span>
<div style="top:15pt;left:20pt;">MY COMPANY LIMITED</div>
<div style="top:17pt;left:20pt;">MY FARM</div>
<div style="top:15pt;left:20pt;">MY TOWN</div>
<div style="top:13pt;left:20pt;">MY CITY</div>
<div style="top:11pt;left:20pt;">MY PIN</div>
<div style="top:9pt;left:20pt;"></div>
</span>
<div style="left:5pt;width:520pt;text-align:right;padding-bottom: 35pt;">RANDOM HEADER</div>
</div>
<div id="remaining_sections">
<div id="introduction">
FOR ADVICE ONLY - ALL CHANGES HAVE BEEN APPLIED AT ZERO LEVEL</br></br>THIS DETAILS CHANGES FOR YOUR MOTOR INDUSTRY AND RECEIVED BY BUS FOR </br>THE PERIOD OF 01 MAY 2018 TO 31 MAY 2018.</br></br>
</br>
<div id="summary_of_charges">
<table cellspacing='0' cellpadding='0'>
<tbody id='summary_details_tr'>
<tr>
<td colspan='8'>HEAD </td>
</tr>
<tr>
<td>1234567890 </td>
<td>HEAD TO CAR </td>
<td>INR </td>
<td>1234567890 </td>
<td>1234567890 </td>
<td style='text-align:right;'>4,160.10 </td>
<td>1234567890 </td>
<td>DR </td>
</tr>
</tbody>
</table>
</div>
</br>
<div id="summary_of_vat">
<table cellspacing='0' cellpadding='0'>
<tbody id='summary_details_tr'>
<tr>
<td colspan='8'>HEAD OF GST </td>
</tr>
<tr height='30'>
<td>1234567890 </td>
<td>GST NO: </td>
<td>1234567890 </td>
<td>1234567890 </td>
<td>1234567890 </td>
<td>1234567890 </td>
<td>1234567890 </td>
<td>1234567890 </td>
<td>1234567890 </td>
<tr>
</tbody>
</table>
</br>
<div>GST IS APPLIED AT 18.0000% TO SOME CHARGES SHOWN ABOVE. ALL OTHER CHARGES ARE GST EXEMPT AND NO</div>
<div>INPUT TAX MAY BE RECLAIMED.</div>
</div>
</br></br>
<div id="transaction">
<table id='trans_dtaa' cellspacing='0' cellpadding='0'>
<thead>
<tr>
<th colspan='8' class='no_background' style='padding:0pt;border:none;'>
<div class='header_line_1 headers'>HEADER</div>
<div class='header_line_1'></div>
</br>
</th>
</tr>
<tr class='theading'>
<th>HEAD</th>
<th>HEAD NO</th>
<th style='text-align:right;'>HEAD</th>
<th style='text-align:right;'>HEAD</th>
<th style='text-align:right;'>HEAD</th>
<th style='text-align:right;'>NON-HEAD</th>
<th style='text-align:right;'>HEAD</th>
<th style='text-align:right;'>HEAD</th>
</tr>
</thead>
<tbody id='transaction_details_tr'>
<tr>
<td>18-MAY-18 </td>
<td>1234567890 </td>
<td style='text-align:right;'>80 </td>
<td style='text-align:right;'>4,206.61 </td>
<td style='text-align:right;'>39.48 </td>
<td style='text-align:right;'>0.00 </td>
<td style='text-align:right;'>0.00 </td>
<td style='text-align:right;'>4,167.13 </td>
</tr>
</tbody>
</table>
</div>
</br></br>
<div id="transaction_item_summary">
<table id='deposit_summary_table' cellspacing='0' cellpadding='0'>
<thead>
<tr>
<th colspan='7' class='no_background' style='padding:0pt;border:none;'>
<div class='header_line_1 headers'>NEW HEADER</div>
<div class='header_line_1'></div>
</br>
<div style='border-top:#FFFFFF 1.00pt OUTSET;'></div>
</th>
</tr>
</thead>
<tbody id='deposit_summary_tr'>
<tr>
<td class='summary_td'>SALES: </td>
<td class='summary_td'>7,805 </td>
<td class='summary_td'>338,939.07 </td>
<td class='summary_td'>DB: </td>
<td class='summary_td'>0 </td>
<td class='summary_td'>0.00 </td>
</tr>
<tr>
<td class='summary_td'>RETURN: </td>
<td class='summary_td'>61 </td>
<td class='summary_td'>2,355.86 </td>
<td class='summary_td'>CR : </td>
<td class='summary_td'>0 </td>
<td class='summary_td'>0.00 </td>
</tr>
<tr>
<td class='total_td summary_td'>TOTAL: </td>
<td class='total_td summary_td'>7,866 </td>
<td class='total_td summary_td'>336,583.21 </td>
<td class='total_td summary_td'>TOTAL: </td>
<td class='total_td summary_td'>0 </td>
<td class='total_td summary_td'>0.00 </td>
</tr>
</tbody>
</table>
</div>
</br></br>
<div id="card_summary">
<table cellspacing='0' cellpadding='0'>
<thead>
<tr>
<th colspan='8' class='no_background' style='padding:0pt;border:none;'>
<div class='header_line_1 headers'>HEADER</div>
<div class='header_line_1'></div>
</br>
</th>
</tr>
<tr class='theading'>
<th>HEAD</th>
<th style='text-align:center;'>HEAD</th>
<th style='text-align:right;'>HEAD</th>
<th style='text-align:right;'> HEAD</th>
<th style='text-align:right;'>HEAD</th>
<th style='text-align:right;'>HEAD</th>
<th style='text-align:right;'>HEAD</th>
</tr>
</thead>
<tbody id='card_summary_details_tr'>
<tr>
<td>1234567890 </td>
<td style='text-align:center;'>358.31 </td>
<td style='text-align:right;'>2,298.60 </td>
<td style='text-align:right;'>0.00 </td>
<td style='text-align:right;'>0.00 </td>
<td style='text-align:right;'>0.00 </td>
<td style='text-align:right;'>0.00 </td>
</tr>
</tbody>
</table>
</div>
</br></br>
<div id="transaction_charges">
<table cellspacing='0' cellpadding='0'>
<thead>
<tr>
<th colspan='8' class='no_background' style='padding:0pt;border:none;'>
<div class='header_line_1 headers'>HEADER</div>
<div class='header_line_1'></div>
</br>
</th>
</tr>
</thead>
</table>
<table cellspacing='0' cellpadding='0'>
<thead>
<tr>
<td colspan='8' class='no_background headers' style='text-align:left;padding:0pt;border:none;'>INR </td>
</tr>
<tr class='theading'>
<th>HEAD</th>
<th> HEAD</th>
<th style='text-align:right;'>HEAD</th>
<th style='text-align:right;'>HEAD</th>
<th>HEAD<br> HEAD</th>
<th>HEAD <br>HEAD</th>
<th style='text-align:right;'>HEAD</th>
<th style='text-align:right;'>HEAD</th>
</tr>
</thead>
<tbody id='deposit_details_tr'>
<tr>
<td>TEXT </td>
<td style='text-align:right;'>2 </td>
<td style='text-align:right;'>330.40 </td>
<td style='text-align:right;'>165.20 </td>
<td>1.3240 </td>
<td>0.0000 </td>
<td style='text-align:right;'>4.37 </td>
<td style='text-align:right;'>INR </td>
</tr>
</tbody>
</table>
</br>
</div>
</br></br>
<div id="interchange_and_other_charges">
<table cellspacing='0' cellpadding='0'>
<thead>
<tr>
<th colspan='8' class='no_background' style='padding:0pt;border:none;'>
<div class='header_line_1 headers'>HEADER</div>
<div class='header_line_1'></div>
</br>
</th>
</tr>
</thead>
</table>
<table cellspacing='0' cellpadding='0'>
<thead>
<tr>
<td colspan='8' class='no_background headers' style='text-align:left;padding:0pt;border:none;'>INR </td>
</tr>
<tr class='theading'>
<th>HEAD</th>
<th style='text-align:right;'>HEAD</th>
<th style='text-align:right;'>HEAD</th>
<th style='text-align:right;'>HEAD </th>
<th style='text-align:right;'>HEAD</th>
</tr>
</thead>
<tbody id='interchange_and_other_charges_details_tr'>
<tr>
<td>MY HEAD </td>
<td style='text-align:right;'>50 </td>
<td style='text-align:right;'>3,246.63 </td>
<td style='text-align:right;'>1.95 </td>
<td style='text-align:right;'>INR </td>
</tr>
</tbody>
</table>
</br>
</div>
</br></br>
<div id="chargebacks_rejects"></div>
</br></br>
<div id="other_fees_section">
<table cellspacing='0' cellpadding='0'>
<thead>
<tr>
<th colspan='8' class='no_background' style='padding:0pt;border:none;'>
<div class='header_line_1 headers'>HEADER</div>
<div class='header_line_1'></div>
</br>
</th>
</tr>
</thead>
<tbody></tbody>
</table>
<table cellspacing='0' cellpadding='0'>
<thead>
<tr>
<th colspan='8' class='no_background' style='padding:0pt;border:none;'>
<div style='text-align:left;' class='headers'>GST APPLICABLE FEES</div>
</th>
</tr>
<tr class='theading'>
<th>CARD</th>
<th>CARD</th>
<th>CARD</th>
<th style='text-align:right;'>CARD</th>
<th style='text-align:left;' >CARD</th>
<th style='text-align:right;'>CARD</th>
<th style='text-align:right;'>CARD</th>
</tr>
</thead>
<tbody id='vat_applicable_fees_details_tr'>
<tr>
<td> </td>
<td>1234567890 </td>
<td>GST </td>
<td style='text-align:right;'>2 </td>
<td>3.5000 </td>
<td style='text-align:right;'>7.00 </td>
<td style='text-align:center;'>INR </td>
</tr>
</tbody>
</table>
</br>
</div>
<div id="other_fees_section2">
<table cellspacing='0' cellpadding='0'>
<thead>
<div style='text-align:left;' class='headers'>HEADER</div>
</th></tr>
<tr class='theading'>
<th>CARD</th>
<th>CARD</th>
<th>CARD</th>
<th style='text-align:right;'>CARD</th>
<th style='text-align:left;' >CARD</th>
<th style='text-align:right;'>CARD</th>
<th style='text-align:right;'>CARD</th>
</tr>
</thead>
<tbody id='non_vat_applicable_fees_details_tr'>
<tr>
<td> </td>
<td>1234567890 </td>
<td>CARD </td>
<td style='text-align:right;'>0 </td>
<td>000.0000 </td>
<td style='text-align:right;'>-0.32 </td>
<td style='text-align:center;'>INR </td>
</tr>
<tr class='total_td'>
<td colspan='4'> </td>
<td>SUB TOTAL </td>
<td style='text-align:right;'>305.53 </td>
<td style='text-align:center;'>INR </td>
</tr>
<tr class='total_td'>
<td colspan='4'> </td>
<td>TOTAL </td>
<td style='text-align:right;'>586.33 </td>
<td style='text-align:center;'>INR </td>
</tr>
</tbody>
</table>
</div>
</br></br>
</div>
</div>
</td>
</tr>
</tbody>
</table>
</div>
<div id="vertical_border" style="left:600pt;" height="(doc_height+15)px;" class="thick_border"></div>
<div id="horizontal_border" style="left:0pt; width:600pt;" height="(doc_height+25)px;" class="thick_border"></div>
</body>
</HTML>
答案 0 :(得分：0)
当我将HTML放入HTML检查器（例如https://validator.w3.org/nu/#textarea）时，我会看到许多错误。特别是，它不喜欢自动关闭的62638: "/azure-pipelines.yml: Could not get the latest source version for repository MySolution hosted on Azure Repos using ref refs/heads/$(Build.SourceBranch)."
：
<div />如果您用结尾的 <div>
<div id='pageNoHead'/><img id=head_image src='data:image/jpeg;base64,/image/2Q=='/></div>
显式关闭<div id='pageNoHead'/>，会发生什么？例如：
</div>此外，我将检查并修复您的HTML其余部分。其中一些是：
<div>
<div id='pageNoHead'></div>
<img id=head_image src='data:image/jpeg;base64,/image/2Q=='/>
</div>
is not correct，应为</br>或<br>。<br/>）的表主体。<tbody id='summary_details_tr'>（看起来您应该关闭上一行，即<tr> </tbody>。可能还有其他错误，我在您拥有的某些表结构上链接到barfs的HTML检查器。我认为问题出在HTML格式错误，而不是您的代码。