Java 添加骑缝章到PDF 文档中

骑缝章常见于一些重要的合同或标书中，它具有防止他人增减文件页数的作用，能保证文件的完整性和有效性。本文将介绍如何借助Free Spire.PDF for Java 在Java应用程序中添加骑缝章到PDF格式的合同文件中。

产品导入

方法一：下载Free Spire.PDF for Java包并解压缩，然后将lib文件夹下的Spire.Pdf.jar包作为依赖项导入到Java应用程序中

方法二：直接通过Maven仓库安装JAR包，配置pom.xml文件的代码如下：

<repositories>
    <repository>
        <id>com.e-iceblue</id>
        <url>http://repo.e-iceblue.cn/repository/maven-public/</url>
    </repository>
</repositories>
<dependencies>
    <dependency>
        <groupId>e-iceblue</groupId>
        <artifactId>spire.pdf.free</artifactId>
        <version>3.9.0</version>
    </dependency>
</dependencies>

添加骑缝章：

import com.spire.pdf.*;
import com.spire.pdf.graphics.*;
import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.geom.Point2D;
import java.awt.image.BufferedImage;
import java.io.*;

public class addSeamSeals {
    public static void main(String[] args) throws IOException {

        //加载示例文档
        PdfDocument doc = new PdfDocument();
        doc.loadFromFile("采购合同.pdf");

        PdfUnitConvertor convert = new PdfUnitConvertor();
        PdfPageBase pageBase = null;

        //获取分割后的印章图片
        BufferedImage[] images = GetImage(doc.getPages().getCount());
        float x = 0;
        float y = 0;

        //将图片画到PDF页面上的指定位置
        for (int i = 0; i < doc.getPages().getCount(); i++)
        {
            BufferedImage image= images[ i ];
            pageBase = doc.getPages().get(i);
            x = (float)(pageBase.getSize().getWidth()) - convert.convertUnits(image.getWidth(), PdfGraphicsUnit.Pixel, PdfGraphicsUnit.Point);
            y = (float) pageBase.getSize().getHeight()/ 2;
            pageBase.getCanvas().drawImage(PdfImage.fromImage(image), new Point2D.Float(x, y));
        }
        //保存PDF
        doc.saveToFile("Result.pdf");
    }
    //定义GetImage方法，根据PDF页数分割印章图片
    static BufferedImage[] GetImage(int num) throws IOException {
        String originalImg = "C:\Users\Administrator\Desktop\z.png";
        BufferedImage image = ImageIO.read(new File(originalImg));
        int rows = 1;
        int cols = num;
        int chunks = rows * cols;
        int chunkWidth = image.getWidth() / cols;
        int chunkHeight = image.getHeight() / rows;
        int count = 0;
        BufferedImage[] imgs = new BufferedImage[ chunks ];
        for (int x = 0; x < rows; x++) {
            for (int y = 0; y < cols; y++) {
                imgs[ count ] = new BufferedImage(chunkWidth, chunkHeight, image.getType());
                Graphics2D gr = imgs[ count++ ].createGraphics();
                gr.drawImage(image, 0, 0, chunkWidth, chunkHeight,
                        chunkWidth * y, chunkHeight * x,
                        chunkWidth * y + chunkWidth, chunkHeight * x + chunkHeight, Color.WHITE,null);
                gr.dispose();
            }
        }
        return imgs;
    }
}

代码运行结果：