java实现pdf按页切分成图片

package com.ces.component.pictrueCut.entity;

import java.awt.Image;

import java.awt.Rectangle;

import java.awt.image.BufferedImage;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.RandomAccessFile;

import java.lang.reflect.Method;

import java.nio.MappedByteBuffer;

import java.nio.channels.FileChannel;

import java.security.AccessController;

import java.security.PrivilegedAction;  

import com.sun.image.codec.jpeg.JPEGCodec;

import com.sun.image.codec.jpeg.JPEGEncodeParam;

import com.sun.image.codec.jpeg.JPEGImageEncoder;

import com.sun.pdfview.PDFFile;

import com.sun.pdfview.PDFPage;

public class pdfToImage {

    public static int changePdfToImg(String instructiopath,String picturepath) {

        int countpage =0;

        try {

            //instructiopath ="D:/instructio/2015-05-16/Android 4编程入门经典.pdf"

            //picturepath = "D:/instructio/picture/2015-05-16/";  

            File file = new File(instructiopath);

            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);

            //创建图片文件夹

            File dirfile = new File(picturepath);

               if(!dirfile.exists()){

                     dirfile.mkdirs();

                }

            //获得图片页数

            countpage = pdffile.getNumPages();

            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()));

                int n = 2;

                /** 图片清晰度（n>0且n<7）【pdf放大参数】 */

                Image img = page.getImage(rect.width * n, rect.height * n,

                        rect, /** 放大pdf到n倍，创建图片。 */

                        null, /** null for the ImageObserver */

                        true, /** fill background with white */

                        true /** block until drawing is done */

                );

                BufferedImage tag = new BufferedImage(rect.width * n,

                        rect.height * n, BufferedImage.TYPE_INT_RGB);

                tag.getGraphics().drawImage(img, 0, 0, rect.width * n,

                        rect.height * n, null);

                /**

                 * File imgfile = new File("D:\\work\\mybook\\FilesNew\\img\\" +

                 * i + ".jpg"); if(imgfile.exists()){

                 * if(imgfile.createNewFile()) { System.out.println("创建图片："+

                 * "D:\\work\\mybook\\FilesNew\\img\\" + i + ".jpg"); } else {

                 * System.out.println("创建图片失败！"); } }

                 */

                FileOutputStream out = new FileOutputStream(picturepath+"/" + i

                        + ".png");

                /** 输出到文件流 */

                JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);

                JPEGEncodeParam param2 = encoder.getDefaultJPEGEncodeParam(tag);

                param2.setQuality(1f, true);

                /** 1f~0.01f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();

        }

        return countpage;  

    }  

    @SuppressWarnings("unchecked")

    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;

            }

        });

    }

}