可能重复:
将pdf文件转换为jpg格式的asp.net程序
public class Pdf2Image {
private Image image;
int length;
public int convertPdf2Image(String pdfname) {
File file = new File(pdfname);
RandomAccessFile raf;
try {
raf = new RandomAccessFile(file, "r");
FileChannel channel = raf.getChannel();
ByteBuffer buf = channel.map(FileChannel.MapMode.READ_ONLY, 0, channel.size());
PDFFile pdffile = new PDFFile(buf);
// draw the first page to an image
int num = pdffile.getNumPages();
length=num;
for (int i = 0; i <= num; i++) {
PDFPage page = pdffile.getPage(i);
//get the width and height for the doc at the default zoom
int width = (int) page.getBBox().getWidth();
int height = (int) page.getBBox().getHeight();
Rectangle rect = new Rectangle(0, 0, width, height);
int rotation = page.getRotation();
Rectangle rect1 = rect;
if (rotation == 90 || rotation == 270) {
rect1 = new Rectangle(0, 0, rect.height, rect.width);
}
//generate the image
BufferedImage img = (BufferedImage) page.getImage(
rect.width, rect.height, //width & height
rect1, // clip rect
null, // null for the ImageObserver
true, // fill background with white
true // block until drawing is done
);
ImageIO.write(img, "png", new File("src\\downloadedFiles\\aa" + i + ".png"));
}
} catch (FileNotFoundException e1) {
System.err.println(e1.getLocalizedMessage());
} catch (IOException e) {
System.err.println(e.getLocalizedMessage());
}
return length;
}
public static void main(String[] args) {
Pdf2Image p = new Pdf2Image();
p.convertPdf2Image("src\\downloadedFiles\\todaypdf.pdf");
}
}
我正在使用这段代码将PDF文件转换为图片。对于大多数PDF文件,它都可以正常工作,但在某些PDF文件中会出现异常。异常信息如下:
Expected 'xref' at start of table.
有人能告诉我为什么会出现这样的异常吗?