PDF 处理指南

概览

本指南介绍如何使用 Python 库与命令行工具完成核心 PDF 操作。若需高级功能、JavaScript 库或更详细示例，请查阅 reference.md。若要填写 PDF 表单，请阅读 forms.md 并严格遵循其中的说明。

快速上手

from pypdf import PdfReader, PdfWriter

# 读取 PDF
reader = PdfReader("document.pdf")
print(f"Pages: {len(reader.pages)}")

# 抽取文本
text = ""
for page in reader.pages:
    text += page.extract_text()

Python 库

pypdf —— 基础操作

合并 PDF

from pypdf import PdfWriter, PdfReader

writer = PdfWriter()
for pdf_file in ["doc1.pdf", "doc2.pdf", "doc3.pdf"]:
    reader = PdfReader(pdf_file)
    for page in reader.pages:
        writer.add_page(page)

with open("merged.pdf", "wb") as output:
    writer.write(output)

拆分 PDF

reader = PdfReader("input.pdf")
for i, page in enumerate(reader.pages):
    writer = PdfWriter()
    writer.add_page(page)
    with open(f"page_{i+1}.pdf", "wb") as output:
        writer.write(output)

抽取元数据

reader = PdfReader("document.pdf")
meta = reader.metadata
print(f"Title: {meta.title}")
print(f"Author: {meta.author}")
print(f"Subject: {meta.subject}")
print(f"Creator: {meta.creator}")

旋转页面

reader = PdfReader("input.pdf")
writer = PdfWriter()

page = reader.pages[0]
page.rotate(90)  # 顺时针旋转 90°
writer.add_page(page)

with open("rotated.pdf", "wb") as output:
    writer.write(output)

pdfplumber —— 文本与表格抽取

抽取保留排版的文本

import pdfplumber

with pdfplumber.open("document.pdf") as pdf:
    for page in pdf.pages:
        text = page.extract_text()
        print(text)

抽取表格

with pdfplumber.open("document.pdf") as pdf:
    for i, page in enumerate(pdf.pages):
        tables = page.extract_tables()
        for j, table in enumerate(tables):
            print(f"Table {j+1} on page {i+1}:")
            for row in table:
                print(row)

高级表格抽取

import pandas as pd

with pdfplumber.open("document.pdf") as pdf:
    all_tables = []
    for page in pdf.pages:
        tables = page.extract_tables()
        for table in tables:
            if table:  # 确保表格非空
                df = pd.DataFrame(table[1:], columns=table[0])
                all_tables.append(df)

# 合并所有表格
if all_tables:
    combined_df = pd.concat(all_tables, ignore_index=True)
    combined_df.to_excel("extracted_tables.xlsx", index=False)

reportlab —— 创建 PDF

基础 PDF 创建

from reportlab.lib.pagesizes import letter
from reportlab.pdfgen import canvas

c = canvas.Canvas("hello.pdf", pagesize=letter)
width, height = letter

# 添加文本
c.drawString(100, height - 100, "Hello World!")
c.drawString(100, height - 120, "This is a PDF created with reportlab")

# 添加线条
c.line(100, height - 140, 400, height - 140)

# 保存
c.save()

创建多页 PDF

from reportlab.lib.pagesizes import letter
from reportlab.platypus import SimpleDocTemplate, Paragraph, Spacer, PageBreak
from reportlab.lib.styles import getSampleStyleSheet

doc = SimpleDocTemplate("report.pdf", pagesize=letter)
styles = getSampleStyleSheet()
story = []

# 添加内容
title = Paragraph("Report Title", styles['Title'])
story.append(title)
story.append(Spacer(1, 12))

body = Paragraph("This is the body of the report. " * 20, styles['Normal'])
story.append(body)
story.append(PageBreak())

# 第二页
story.append(Paragraph("Page 2", styles['Heading1']))
story.append(Paragraph("Content for page 2", styles['Normal']))

# 构建 PDF
doc.build(story)

命令行工具

pdftotext（poppler-utils）

# 抽取文本
pdftotext input.pdf output.txt

# 保留排版抽取
pdftotext -layout input.pdf output.txt

# 抽取特定页
pdftotext -f 1 -l 5 input.pdf output.txt  # 第 1-5 页

qpdf

# 合并 PDF
qpdf --empty --pages file1.pdf file2.pdf -- merged.pdf

# 拆分页面
qpdf input.pdf --pages . 1-5 -- pages1-5.pdf
qpdf input.pdf --pages . 6-10 -- pages6-10.pdf

# 旋转页面
qpdf input.pdf output.pdf --rotate=+90:1  # 第 1 页旋转 90°

# 移除密码
qpdf --password=mypassword --decrypt encrypted.pdf decrypted.pdf

pdftk（如环境可用）

# 合并
pdftk file1.pdf file2.pdf cat output merged.pdf

# 拆分
pdftk input.pdf burst

# 旋转
pdftk input.pdf rotate 1east output rotated.pdf

常见任务

抽取扫描 PDF 的文本

# 依赖：pip install pytesseract pdf2image
import pytesseract
from pdf2image import convert_from_path

# 将 PDF 转为图像
images = convert_from_path('scanned.pdf')

# 对每页执行 OCR
text = ""
for i, image in enumerate(images):
    text += f"Page {i+1}:\n"
    text += pytesseract.image_to_string(image)
    text += "\n\n"

print(text)

添加水印

from pypdf import PdfReader, PdfWriter

# 创建或加载水印页
watermark = PdfReader("watermark.pdf").pages[0]

# 应用于所有页面
reader = PdfReader("document.pdf")
writer = PdfWriter()

for page in reader.pages:
    page.merge_page(watermark)
    writer.add_page(page)

with open("watermarked.pdf", "wb") as output:
    writer.write(output)

抽取图片

# 使用 pdfimages（poppler-utils）
pdfimages -j input.pdf output_prefix

# 将抽取的图片保存为 output_prefix-000.jpg、output_prefix-001.jpg 等

设置密码保护

from pypdf import PdfReader, PdfWriter

reader = PdfReader("input.pdf")
writer = PdfWriter()

for page in reader.pages:
    writer.add_page(page)

# 添加密码
writer.encrypt("userpassword", "ownerpassword")

with open("encrypted.pdf", "wb") as output:
    writer.write(output)

快速参考表

后续步骤

• 进阶 pypdfium2 用法请参阅 reference.md
• 若要使用 JavaScript 库（pdf-lib），请参阅 reference.md
• 如需填写 PDF 表单，请严格按照 forms.md 操作
• 排障指南亦汇总于 reference.md