引入依赖

<dependency>
    <groupId>org.apache.pdfbox</groupId>
    <artifactId>fontbox</artifactId>
    <version>2.0.1</version>
</dependency>
<dependency>
    <groupId>org.apache.pdfbox</groupId>
    <artifactId>pdfbox</artifactId>
    <version>2.0.1</version>
</dependency>

代码实现

import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPageTree;
import org.apache.pdfbox.rendering.PDFRenderer;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.*;

public class Pdf {
    public static void main(String[] args) throws Exception {
        pdfToImageFile();
    }

    static void pdfToImageFile() throws Exception {
        PDDocument doc = null;
        ByteArrayOutputStream os = null;
        InputStream stream = null;
        OutputStream out = null;
        try {
            // pdf路径
            stream = new FileInputStream("D:\\download\\pdf.pdf");
            // 加载解析PDF文件
            doc = PDDocument.load(stream);
            PDFRenderer pdfRenderer = new PDFRenderer(doc);
            PDPageTree pages = doc.getPages();
            int pageCount = pages.getCount();
            for (int i = 0; i < pageCount; i++) {
                BufferedImage bim = pdfRenderer.renderImageWithDPI(i, 200);
                os = new ByteArrayOutputStream();
                ImageIO.write(bim, "jpg", os);
                byte[] dataList = os.toByteArray();
                // jpg文件转出路径
                File file = new File("D:\\download\\pdf\\hello_" + i + ".jpg");
                if (!file.getParentFile().exists()) {
                    // 不存在则创建父目录及子文件
                    file.getParentFile().mkdirs();
                    file.createNewFile();
                }
                out = new FileOutputStream(file);
                out.write(dataList);
            }
        } catch (Exception e) {
            e.printStackTrace();
            throw e;
        } finally {
            if (doc != null) doc.close();
            if (os != null) os.close();
            if (stream != null) stream.close();
            if (out != null) out.close();
        }
    }
}

成功截图