一、maven安装

<dependency>
    <groupId>org.icepdf.os</groupId>
    <artifactId>icepdf-core</artifactId>
    <version>6.2.2</version>
</dependency>

二、Java代码实现

import org.icepdf.core.pobjects.Document;
import org.icepdf.core.pobjects.Page;
import org.icepdf.core.util.GraphicsRenderingHints;

import javax.imageio.IIOImage;
import javax.imageio.ImageIO;
import javax.imageio.ImageWriter;
import javax.imageio.stream.ImageOutputStream;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;
import java.util.Iterator;


public class CapturePdfFirstPageUtil {
    /**
     * 生成一本书的缩略图
     *
     * @param inputFile  需要生成缩略图的书籍的完整路径
     * @param outputFile 生成缩略图的放置路径
     */
    public static void generateBookIamge(String inputFile, String outputFile) {
        Document document = null;

        try {
            float rotation = 0f;
            // 缩略图显示倍数，1表示不缩放，0.5表示缩小到50%
            float zoom = 0.8f;

            document = new Document();
            document.setFile(inputFile);
            // maxPages = document.getPageTree().getNumberOfPages();

            BufferedImage p_w_picpath = (BufferedImage) document.getPageImage(0, GraphicsRenderingHints.SCREEN,
                    Page.BOUNDARY_CROPBOX, rotation, zoom);

            Iterator iter = ImageIO.getImageWritersBySuffix("jpg");
            ImageWriter writer = (ImageWriter) iter.next();

            FileOutputStream out = new FileOutputStream(new File(outputFile));
            ImageOutputStream outImage = ImageIO.createImageOutputStream(out);

            writer.setOutput(outImage);
            writer.write(new IIOImage(p_w_picpath, null, null));

        } catch (Exception e) {
            System.out.println("生成书的缩略图失败 : " + inputFile);
            System.out.println(e);
        }
    }

    public static void main(String[] args) {
        CapturePdfFirstPageUtil.generateBookIamge("C:\\Users\\Downloads\\我是帅子男一号.pdf", "C:\\Users\\Desktop\\帅子男一号.jpg");
    }
}