【转】用java将pdf转换成jpg图片的代码

这段代码将能够将pdf转换成jpg图片，虽然图片不是很清晰，但已经够用了，因为我只想要封面的图片做文档的缩略图。

package pdf;

import java.awt.Image;
import java.awt.Rectangle;
import java.awt.image.BufferedImage;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import javax.swing.SwingUtilities;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
import com.sun.pdfview.PDFFile;
import com.sun.pdfview.PDFPage;

public class PdfToJpgTest {
	public static void setup() throws IOException {

		// load a pdf from a byte buffer
		File file = new File(
				"c://xxxxx.pdf");
		RandomAccessFile 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);

		System.out.println("页数： " + pdffile.getNumPages());

		for (int i = 1; i <= pdffile.getNumPages(); i++) {
			// draw the first page to an image
			PDFPage page = pdffile.getPage(i);

			// get the width and height for the doc at the default zoom
			Rectangle rect = new Rectangle(0, 0, (int) page.getBBox()
					.getWidth(), (int) page.getBBox().getHeight());

			// generate the image
			Image img = page.getImage(rect.width, rect.height, // width &
																// height
					rect, // clip rect
					null, // null for the ImageObserver
					true, // fill background with white
					true // block until drawing is done
					);

			BufferedImage tag = new BufferedImage(rect.width, rect.height,
					BufferedImage.TYPE_INT_RGB);
			tag.getGraphics().drawImage(img, 0, 0, rect.width, rect.height,
					null);
			FileOutputStream out = new FileOutputStream(
					"c://picture//"
							+ i + ".jpg"); // 输出到文件流
			JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
			encoder.encode(tag); // JPEG编码

			out.close();
		}

		// show the image in a frame
		// JFrame frame = new JFrame("PDF Test");
		// frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		// frame.add(new JLabel(new ImageIcon(img)));
		// frame.pack();
		// frame.setVisible(true);
	}

	public static void main(final String[] args) {
		SwingUtilities.invokeLater(new Runnable() {
			public void run() {
				try {
					PdfToJpgTest.setup();
				} catch (IOException ex) {
					ex.printStackTrace();
				}
			}
		});
	}

}

文章来源：http://blog.csdn.net/kiss_the_java/article/details/4538105

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