java实现pdf按页转换为图片

package core.util;

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 pdfchangtoimage {

  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 ;

  }

  });

  }

}