java将pdf文件转成图片，并且在转了之后删除pdf文件

/**

   * 将pdf转成img

   */

public static void changePdfToImg() {

    try {

      File file = new File("E:\\test\\baseInfo_2.pdf");

      RandomAccessFile raf = new RandomAccessFile(file, "r");

      FileChannel channel = raf.getChannel();

      MappedByteBuffer buf = channel.map(FileChannel.MapMode.READ_ONLY, 0, channel.size());

      PDFFile pdffile = new PDFFile(buf);

      for (int i = 1; i <= pdffile.getNumPages(); i++) {

        PDFPage page = pdffile.getPage(i);

        Rectangle rect = new Rectangle(0, 0, ((int) page.getBBox().getWidth()), ((int) page.getBBox().getHeight()));

        Image img = page.getImage(rect.width, rect.height, 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("E:\\test\\img\\" + i + ".jpg"); // 输出到文件流

        JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);

        JPEGEncodeParam param2 = encoder.getDefaultJPEGEncodeParam(tag);

        param2.setQuality(1f, false);// 1f是提高生成的图片质量

        encoder.setJPEGEncodeParam(param2);

        encoder.encode(tag); // JPEG编码

        out.close();

      }

      channel.close();

      raf.close();

      unmap(buf);//如果要在转图片之后删除pdf，就必须要这个关闭流和清空缓冲的方法

    } catch (FileNotFoundException e) {

      e.printStackTrace();

    } catch (IOException e) {

      e.printStackTrace();

    }

  }

/**

   * 清空缓冲

   * @param buffer

   */

  public static void unmap(final Object buffer) {

    AccessController.doPrivileged(new PrivilegedAction() {

      public Object run() {

        try {

          Method getCleanerMethod = buffer.getClass().getMethod("cleaner", new Class[0]);

          getCleanerMethod.setAccessible(true);

          sun.misc.Cleaner cleaner = (sun.misc.Cleaner) getCleanerMethod.invoke(buffer, new Object[0]);

          cleaner.clean();

        } catch (Exception e) {

          e.printStackTrace();

        }

        return null;

      }

    });

  }