解決：PDFBox報的java.io.IOException: Missing root object specification in trailer

文章目錄

• 問題描述
• 原因分析
• 解決方案

問題描述

使用pdfbox類庫操作pdf檔案時，遇到下面的報錯資訊：

java.io.IOException: Missing root object specification in trailer

PDFBox參考：

https://pdfbox.apache.org/

Apache PDFBox 庫是一個開源的用于處理 PDF 文檔的 Java 工具。

原因分析

目前看下來有兩種原因：

1. pdf檔案格式有損壞，無法讀取
2. 使用的pdfbox版本有相關漏洞

解決方案

針對上面的 原因一，檢查pdf檔案格式，再操作。

針對上面的 原因二，可以通過更新pdfbox版本來解決：

Apache PDFBox 2.0.6 釋出了，這個版本是基于 2.0.5 版本的增量式 bug 修複版本，包含了幾個修複和小改進，在下面的release notes中就可以看到，修複了該問題：

Apache PDFBox 2.0.6 Release Notes

内容如下：

Sub-task
[PDFBOX-3302] - Explicit support for certification signatures
Bug
[PDFBOX-3313] - Java 9 InaccessibleObjectException
[PDFBOX-3318] - IllegalArgumentException in PDPageTree constructor: root cannot be null
[PDFBOX-3347] - COSName parsing doesn't handle ISO-8859-1 encoded bytes
[PDFBOX-3519] - COSName is not ascii
[PDFBOX-3545] - COSParser.parseXref failing if startXrefOffset over pdf size
[PDFBOX-3687] - PDFBox doesn't respect different setting of /DA at PDAnnotationWidget level to /DA at PDField level
[PDFBOX-3717] - java.io.IOException: Missing root object specification in trailer
[PDFBOX-3723] - FDFField.getValue() doesn't return the values in line with the Javadoc.
[PDFBOX-3724] - Wrong size in rendering of some artifacts
[PDFBOX-3726] - NPE when setting the field value in an AcroForm and the NormalAppearance entry exists but is COSNull
[PDFBOX-3727] - "premature EOF, image will be incomplete"
[PDFBOX-3728] - org.apache.pdfbox.cos.COSDictionary cannot be cast to org.apache.pdfbox.cos.COSStream
[PDFBOX-3731] - IOException: Found Token[kind=NAME, text=bind] but expected ND at offset 91
[PDFBOX-3732] - IllegalArgumentException when refreshing an appearance and no font resources are defined
[PDFBOX-3733] - image added to pdf by tool AddImageToPDF is turn-overed
[PDFBOX-3738] - Signature not visible on Acrobat
[PDFBOX-3739] - ImageWriterIterator.next() and ImageReaderIterator.next() can return null
[PDFBOX-3740] - Standard 14 and Encoding
[PDFBOX-3741] - usage of default colorspace not checked by preflight
[PDFBOX-3742] - Unknown dir object c='>' cInt=62 peek='>' peekInt=62
[PDFBOX-3743] - Running GC between signing and saving document closes stream
[PDFBOX-3745] - Wrong character width
[PDFBOX-3747] - CmapSubtable#getCharCodes provides values in random order
[PDFBOX-3748] - java.lang.UnsupportedOperationException: Kerning table version 0 format 2 not yet supported.
[PDFBOX-3750] - java.util.zip.DataFormatException when parsing a PDF
[PDFBOX-3751] - Flattening a pdf with refreshAppearances set to true causes a NullPointerException
[PDFBOX-3752] - PDVariableText text color changes to be the same as the background color after flattening
[PDFBOX-3753] - setting a RadioButton with export values does not update the appearance
[PDFBOX-3754] - Skip << >> in type1 font parser
[PDFBOX-3755] - ClassCastException in PDColor constructor: org.apache.pdfbox.cos.COSNull cannot be cast to org.apache.pdfbox.cos.COSNumber
[PDFBOX-3757] - TTFSubsetter scrambles PostScript names and unicode codepoints when subset contains diaeresis
[PDFBOX-3761] - Exception in thread "main" java.lang.NullPointerException
[PDFBOX-3769] - Cannot read JBIG2 image when JBIG2-Image-Decoder is in path
[PDFBOX-3775] - Merge documents fails due to IllegalArgumentException
[PDFBOX-3781] - Existing AcroForm default resources is overwritten by signing code
[PDFBOX-3783] - java.io.IOException: Expected root dictionary, but got this: COSNull{}
[PDFBOX-3784] - Inline image incorrectly parsed
[PDFBOX-3788] - java.lang.RuntimeException: java.io.IOException: Catalog cannot be found
[PDFBOX-3789] - Some text missing in rendering
[PDFBOX-3791] - Long rendering time
[PDFBOX-3837] - PDFBox does not maintain the font appearence of a field if it appears severraly in a PDF Form
Improvement
[PDFBOX-2684] - Javadoc for COSBase.setNeedToBeUpdate
[PDFBOX-3614] - Directly use the BouncyCastleProvider rather than installing it
[PDFBOX-3716] - Read images from byte array
[PDFBOX-3722] - make font cache error message less scary
[PDFBOX-3730] - Encapsulate outputStream into BufferedOutputStream in PDDocument.save()
[PDFBOX-3763] - Optimize SampledImageReader.getStencilImage()
[PDFBOX-3768] - Optimize SampledImageReader.from1Bit()
[PDFBOX-3770] - provide set of page indexes that have page label ranges
[PDFBOX-3772] - Add COSBoolean(false) as option in PDDocumentCatalog's getOpenAction
[PDFBOX-3779] - Add dpi and border parameter to PrintPDF command line utility