我无法在pdf文件中检测到空白页。我已经在互联网上搜索了它，但是找不到一个好的解决方案。
我试过了
if(xobjects==null || textcontent==null || size <20 bytes )
then "blank"
else
not blank
但是最长的时间它返回错误的答案。我用过 Itextsharp
代码在下面...
我正在使用 Itextsharp Librabry
对于xobjects
PdfDictionary xobjects = resourceDic.GetAsDict(PdfName.XOBJECT);
//here resourceDic is PdfDictionary type
//I know that if Xobjects is null then page is blank. But sometimes blank page gives xobjects which is not null.
对于内容流
RandomAccessFileOrArray f = reader.SafeFile;
//here reader = new PdfReader(filename);
byte[] contentBytes = reader.GetPageContent(pageNum, f);
//I have measured the size of contentbytes but sometimes it gives more than 20 bytes for blank page
用于文本内容
String extractedText = PdfTextExtractor.GetTextFromPage(reader, pageNum, new LocationTextExtractionStrategy());
// sometimes blank page give a text more than 20 char length .
最佳答案
发现空页面的一种非常简单的方法是:使用Ghostscript命令行调用bbox设备。
Ghostscript的bbox会计算该最小矩形“边界框”的坐标，该矩形包围页面中将要渲染像素的所有点:
gs \
-o /dev/null \
-sDEVICE=bbox \
input.pdf
在Windows上:
gswin32c.exe ^
-o nul ^
-sDEVICE=bbox ^
input.pdf
结果:
GPL Ghostscript 9.05 (2012-02-08)
Copyright (C) 2010 Artifex Software, Inc. All rights reserved.
This software comes with NO WARRANTY: see the file PUBLIC for details.
Processing pages 1 through 6.
Page 1
%%BoundingBox: 27 281 548 804
%%HiResBoundingBox: 27.000000 281.000000 547.332031 804.000000
Page 2
%%BoundingBox: 0 0 0 0
%%HiResBoundingBox: 0.000000 0.000000 0.000000 0.000000
Page 3
%%BoundingBox: 27 302 568 814
%%HiResBoundingBox: 27.949219 302.000000 567.332031 814.000000
Page 4
%%BoundingBox: 27 302 568 814
%%HiResBoundingBox: 27.949219 302.000000 567.332031 814.000000
Page 5
%%BoundingBox: 27 302 568 814
%%HiResBoundingBox: 27.949219 302.000000 567.332031 814.000000
Page 6
%%BoundingBox: 27 302 568 814
%%HiResBoundingBox: 27.949219 302.000000 567.332031 814.000000
如您所见，输入文档的第2页为空。