Java 如何给现有PDF文档添加页码

以你之姓@ 2023-10-18 13:40 73阅读 0赞

有些PDF文档没有页码，用户在阅读的时候很不方便。这篇文章将介绍如何使用免费PDF Java组件 - **Free Spire.PDF for Java**给现有PDF文档添加页码。

**导入jar包**

首先，下载[Free Spire.PDF for Java][]组件包，并解压缩，从lib文件夹下引用以下两个.jar文件到Java应用程序中：

*  Spire.Pdf.jar
 *  Spire.Common.jar

原文档如下：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0VpY2VibHVl_size_16_color_FFFFFF_t_70][]

**AddPageNumber.java代码**

import com.spire.pdf.PdfDocument;
    import com.spire.pdf.automaticfields.PdfPageNumberField;
    import com.spire.pdf.graphics.*;
    
    import java.awt.*;
    
    public class AddPageNumber {
        public static void main(String[] args)
        {
            //加载PDF
            PdfDocument pdf = new PdfDocument();
            pdf.loadFromFile("Input.pdf");
    
            //设置页边距
            PdfUnitConvertor unitCvtr = new PdfUnitConvertor();
            PdfMargins margin = new PdfMargins();
            margin.setTop(unitCvtr.convertUnits(2.54f, PdfGraphicsUnit.Centimeter, PdfGraphicsUnit.Point));
            margin.setBottom(unitCvtr.convertUnits(2.54f, PdfGraphicsUnit.Centimeter, PdfGraphicsUnit.Point));
            margin.setLeft(unitCvtr.convertUnits(3.17f, PdfGraphicsUnit.Centimeter, PdfGraphicsUnit.Point));
            margin.setRight(unitCvtr.convertUnits(3.17f, PdfGraphicsUnit.Centimeter, PdfGraphicsUnit.Point));
    
            //调用AddPageNumber方法添加页码
            AddPageNumber(pdf, margin);
    
            //保存文档
            pdf.saveToFile("AddPageNumber.pdf");
        }
    
        /**
         *
         * @param document
         * PDF文档
         * @param margin
         * PDF文档页面的边距
         */
        public static void AddPageNumber(PdfDocument document, PdfMargins margin)
        {
            int pageCount = document.getPages().getCount();
            for(int i = 0; i < pageCount; i++)
            {
                PdfBrush brush = PdfBrushes.getBlack();
                PdfTrueTypeFont font = new PdfTrueTypeFont(new Font("Arial Unicode MS",Font.PLAIN,14),true);
                PdfStringFormat format = new PdfStringFormat(PdfTextAlignment.Left);
                int x = (int)document.getPages().get(i).getCanvas().getClientSize().getWidth() / 2;
                int y = (int)(document.getPages().get(i).getCanvas().getClientSize().getHeight() - margin.getBottom());
                Rectangle bounds = new Rectangle(x,y, 50, 20);
                PdfPageNumberField field = new PdfPageNumberField();
                field.setFont(font);;
                field.setBrush(brush);
                field.setStringFormat(format);
                field.setBounds(bounds);
                field.draw(document.getPages().get(i).getCanvas());
            }
        }
    }

运行代码，打开生成文档，结果如下：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0VpY2VibHVl_size_16_color_FFFFFF_t_70 1][]

[Free Spire.PDF for Java]: https://www.e-iceblue.cn/Downloads/Free-Spire-PDF-JAVA.html
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0VpY2VibHVl_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20190111150839738.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0VpY2VibHVl,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0VpY2VibHVl_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20190111150839779.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0VpY2VibHVl,size_16,color_FFFFFF,t_70