騎縫章常見於一些重要的合同或標書中，它具有防止他人增減檔案頁數的作用，能保證檔案的完整性和有效性。本文將介紹如何藉助Free Spire.PDF for Java 在Java應用程式中新增騎縫章到PDF格式的合同檔案中。

產品匯入

方法一：下載Free Spire.PDF for Java包並解壓縮，然後將lib資料夾下的Spire.Pdf.jar包作為依賴項匯入到Java應用程式中

方法二：直接通過Maven倉庫安裝JAR包，配置pom.xml檔案的程式碼如下：

<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>

新增騎縫章：

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 {

        //載入示例文件
        PdfDocument doc = new PdfDocument();
        doc.loadFromFile("採購合同.pdf");

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

        //獲取分割後的印章圖片
        BufferedImage[] images = GetImage(doc.getPages().getCount());
        float x = 0;
        float y = 0;

        //將圖片畫到PDF頁面上的指定位置
        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));
        }
        //儲存PDF
        doc.saveToFile("Result.pdf");
    }
    //定義GetImage方法，根據PDF頁數分割印章圖片
    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;
    }
}

程式碼執行結果：