1.整体实现步骤
在日常办公中，我们可能会有一个需求，需要将多个pdf文件合并成一个文件。例如：需要将每个章节的pdf文件学习资料合并成一个pdf文件，便于我们进行学习资料的归档与整理。如何才能合并多个pdf文件呢？我查了一下网上现有的资料(详见参考资料1)，发现python中有一个第三方库PyPDF2用起来真香。但是，网上现有的程序仅仅实现多个pdf文件，并未实现按序合并。下面谈谈我的整体实现步骤：(1).既然有轮子了，那就直接开干吧。win+R键打开cmd，执行pip install PyPDF2安装PyPDF2第三方库。由于我之前已经安装该第三方库，所以实际安装结果以你电脑安装结果为准。
(2).解决PyPDF2第三方库产生的编码问题，此解决方法来源于参考资料2。
Traceback (most recent call last):
File "D:\python35\Lib\site-packages\PyPDF2\generic.py", line 484, in readFromStream
return NameObject(name.decode('utf-8'))
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xcb in position 8: invalid continuation byte
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "D:\python35\Lib\apps\backstage\views\busi_contract_manage_view.py", line 703, in post
merge_pdf_result = merge_pdf(final_files, pdf_path)
File "D:\python35\Lib\apps\utils\doc_convert_util.py", line 86, in merge_pdf
pdf_writer.write(new_file)
File "D:\python35\Lib\site-packages\PyPDF2\pdf.py", line 482, in write
self._sweepIndirectReferences(externalReferenceMap, self._root)
File "D:\python35\Lib\site-packages\PyPDF2\pdf.py", line 571, in _sweepIndirectReferences
self._sweepIndirectReferences(externMap, realdata)
File "D:\python35\Lib\site-packages\PyPDF2\pdf.py", line 547, in _sweepIndirectReferences
value = self._sweepIndirectReferences(externMap, value)
File "D:\python35\Lib\site-packages\PyPDF2\pdf.py", line 571, in _sweepIndirectReferences
self._sweepIndirectReferences(externMap, realdata)
File "D:\python35\Lib\site-packages\PyPDF2\pdf.py", line 547, in _sweepIndirectReferences
value = self._sweepIndirectReferences(externMap, value)
File "D:\python35\Lib\site-packages\PyPDF2\pdf.py", line 556, in _sweepIndirectReferences
value = self._sweepIndirectReferences(externMap, data[i])
File "D:\python35\Lib\site-packages\PyPDF2\pdf.py", line 571, in _sweepIndirectReferences
self._sweepIndirectReferences(externMap, realdata)
File "D:\python35\Lib\site-packages\PyPDF2\pdf.py", line 547, in _sweepIndirectReferences
value = self._sweepIndirectReferences(externMap, value)
File "D:\python35\Lib\site-packages\PyPDF2\pdf.py", line 547, in _sweepIndirectReferences
value = self._sweepIndirectReferences(externMap, value)
File "D:\python35\Lib\site-packages\PyPDF2\pdf.py", line 547, in _sweepIndirectReferences
value = self._sweepIndirectReferences(externMap, value)
File "D:\python35\Lib\site-packages\PyPDF2\pdf.py", line 577, in _sweepIndirectReferences
newobj = data.pdf.getObject(data)
File "D:\python35\Lib\site-packages\PyPDF2\pdf.py", line 1611, in getObject
retval = readObject(self.stream, self)
File "D:\python35\Lib\site-packages\PyPDF2\generic.py", line 66, in readObject
return DictionaryObject.readFromStream(stream, pdf)
File "D:\python35\Lib\site-packages\PyPDF2\generic.py", line 579, in readFromStream
value = readObject(stream, pdf)
File "D:\python35\Lib\site-packages\PyPDF2\generic.py", line 60, in readObject
return NameObject.readFromStream(stream, pdf)
File "D:\python35\Lib\site-packages\PyPDF2\generic.py", line 492, in readFromStream
raise utils.PdfReadError("Illegal character in Name Object")
PyPDF2.utils.PdfReadError: Illegal character in Name Object 分析上面报错部分，可以看出错误来源于D:\python35\Lib\site-packages\PyPDF2\generic.py", line 484。generic.py文件第484行，原始内容为：try:
return NameObject(name.decode('utf-8'))
except (UnicodeEncodeError, UnicodeDecodeError) as e:
# Name objects should represent irregular characters
# with a '#' followed by the symbol's hex number
if not pdf.strict:
warnings.warn("Illegal character in Name Object", utils.PdfReadWarning)
return NameObject(name)
else:
raise utils.PdfReadError("Illegal character in Name Object") 需要将上述原始内容，修改为如下内容：try:
return NameObject(name.decode('utf-8'))
except (UnicodeEncodeError, UnicodeDecodeError) as e:
# Name objects should represent irregular characters
# with a '#' followed by the symbol's hex number
try:
return NameObject(name.decode('gbk'))
except (UnicodeEncodeError, UnicodeDecodeError) as e:
if not pdf.strict:
warnings.warn("Illegal character in Name Object", utils.PdfReadWarning)
return NameObject(name)
else:
raise utils.PdfReadError("Illegal character in Name Object") 接着，修改utils.py文件中的第238行。utils.py文件中的第238行原始内容如下所示：
r = s.encode('latin-1')
if len(s) < 2:
bc[s] = r
return r 需要将上述原始内容，修改为如下内容： try:
r = s.encode('latin-1')
except Exception as e:
r = s.encode('utf-8')
if len(s) < 2:
bc[s] = r
return r (3).对需要合并的多个pdf文件进行重命名，文件命名为1.pdf、2.pdf、3.pdf，依次类推。此处仍可以优化，欢迎各位大佬提出宝贵意见。(4).将需要合并的多个pdf文件放置在同一个文件夹下，程序执行结束后输出合并后的文件名为merge.pdf(可以在程序中自定义该文件名)。
2.按序合并的整体思路[完整程序见最后]
(1).对所有待合并的pdf文件名以1、2、3等数字来进行重命名。进行对于实现多个pdf文件按序合并，我想了一些方法。例如：根据文件的创建时间进行排序，根据原始的文件名称进行排序。最终，想了一个很简单的方法。即对原始文件手动以数字来重命名，这样做是为了便于以文件名来排序。之前想直接以原始的文件名来重命名，但是考虑到中文名称的pdf文件与英文名称的pdf文件没法直接通过比较文件名来实现排序后合并，因此将所有待合并的pdf文件统一以数字来重命名。此处，应该有更好的方法，欢迎各位大佬提出宝贵意见。
(2).提取当前文件夹下以.pdf后缀结束的所有文件。既然所有待合并的pdf文件名都被重命名成了数字，那直接对这些数字排序，排序后直接合并就好啦。
(3).从文件完整名称中，提取出文件名(不包括文件的.pdf后缀部分)。由于我们利用的是文件名字来实现排序，用来排序的文件名字是不含文件后缀名.pdf的。所以，必须想办法(通过切片操作实现)将.pdf后缀给弄掉。
(4).对文件名字进行排序。注意一下：提取处理的文件名字是str类型的，需要转成int类型后再排序一下。
(5).利用字符串拼接对排序后的文件名字与.pdf后缀进行拼接，拼接成一个含有文件后缀名的文件名。此处应该有更好的方法，字符串拼接比较慢，占内存！有其他更好的方法，欢迎各位大佬提出。(6).直接利用现有轮子PyPDF2库中的PdfFileMerger()类实例化出一个file_merger对象，调用已有API实现多个pdf文件的按序合并。注意：此时的文件已经是按照文件名排好序啦。
import os
from PyPDF2 import PdfFileMerger
target_path = 'E:\\Flask\\'
pdf_lst = [f for f in os.listdir(target_path) if f.endswith('.pdf')]
tmp = []
for item in pdf_lst:
tmp.append(item[:-4])
res = [int(i) for i in tmp if isinstance(i, str)]
ss = sorted(res)
ll = []
for j in ss:
sj = str(j) + ".pdf"
ll.append(sj)
pdf_lst = [os.path.join(target_path, filename) for filename in ll]
file_merger = PdfFileMerger()
for pdf in pdf_lst:
file_merger.append(pdf) # 合并pdf文件
file_merger.write("E://Flask//merge.pdf") 3.参考资料
(1).PyPDF2库官方说明(https://pypi.org/project/PyPDF2/)
(2).PyPDF2编码问题解决方法(https://blog.csdn.net/kmesky/article/details/102695520)
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