使用icepdf将pdf文件转换成照片(以及隐藏的一个bug)

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

public class PdfToImg {
    public static void main(String[] args) {
        String filePath = "E:\\data\\pdf\\1.pdf";
        List<String> imageList = pdfToImagePath(filePath);
        Iterator<String> iterator = imageList.iterator();
        while (iterator.hasNext()) {

            System.out.println(iterator.next());
        }
        System.out.println(imageList);
    }

    public static List<String> pdfToImagePath(String filePath) {
        List<String> list = new ArrayList<>();
        String fileDirectory = filePath.substring(0, filePath.lastIndexOf("."));//获取去除后缀的文件路径

        String imagePath;
        File file = new File(filePath);
        try {
            File f = new File(fileDirectory);
            if (!f.exists()) {
                f.mkdir();
            }
            PDDocument doc = PDDocument.load(file);
            PDFRenderer renderer = new PDFRenderer(doc);
            int pageCount = doc.getNumberOfPages();
            for (int i = 0; i < pageCount; i++) {
                // 方式1,第二个参数是设置缩放比(即像素)
                BufferedImage image = renderer.renderImageWithDPI(i, 296);
                // 方式2,第二个参数是设置缩放比(即像素)
                BufferedImage images = renderer.renderImage(i, 1.25f);  //第二个参数越大生成图片分辨率越高，转换时间也就越长
                imagePath = fileDirectory + "/" + i + ".jpg";
                ImageIO.write(images, "PNG", new File(imagePath));
                list.add(imagePath);
                return list;
            }
            doc.close();              //关闭文件,不然该pdf文件会一直被占用。
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }
}