在Java代码中使用pdfBox将PDF转换为图片

// 生成图片
PDDocument pd = PDDocument.load(new File(filePath));
PDFRenderer pdfRenderer = new PDFRenderer(pd);
BufferedImage combined = null;
for (int page = 0; page < pd.getNumberOfPages(); ++page)
{
BufferedImage bim = pdfRenderer.renderImageWithDPI(page, 96, ImageType.RGB);
if (page == 0) {
combined = bim;
} else {
combined = merge(combined, bim);
}
}
ImageIOUtil.writeImage(combined, filePath + ".png", 96);
pd.close();

private static BufferedImage merge(BufferedImage image1, BufferedImage image2) {
BufferedImage combined = new BufferedImage(
image1.getWidth(),
image1.getHeight() + image2.getHeight(),
BufferedImage.TYPE_INT_RGB);

Graphics g = combined.getGraphics();
g.drawImage(image1, 0, 0, null);
g.drawImage(image2, 0, image1.getHeight(), null);
g.dispose();
return combined;
}