本文实例为大家分享了java实现Img与PDF相互转换的具体代码，供大家参考，具体内容如下
不善于表达，就直接贴出代码吧。请大牛忽视我。
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.util.Map;
import java.util.Map.Entry;
import java.util.TreeMap;
import com.Utils.ImgFileTool;
import com.lowagie.text.document;
import com.lowagie.text.Image;
import com.lowagie.text.Rectangle;
import com.lowagie.text.pdf.PdfCopy;
import com.lowagie.text.pdf.PdfimportedPage;
import com.lowagie.text.pdf.PdfReader;
import com.lowagie.text.pdf.PdfWriter;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
import com.sun.pdfview.PDFFile;
import com.sun.pdfview.PDFPage;
@SuppressWarnings("unused")
public class ImgPdfUtils {
public static void main(String[] args) throws Exception {
//PDF包提取 pdf
//pdfExtraction();
//pdf转jpg
//pdfToJpg("E:\java\资料pdf\1.pdf","E:\java\资料pdf\1.jpg",1);
//将多个jpg直接合并成pdf包
//extractionPdf("F:\temp\Project\数据\dfdsfds\巴黎公社活动家传略_img","F:\temp\Project\数据\dfdsfds\巴黎公社活动家传略_img.pdf");
//jpg转pdf
//jpgToPdf();
//文件排序
//listOrder();
ImgFileTool.imgMerageToPdf(new File("F:\temp\Project\数据\dfdsfds\巴黎公社活动家传略_img").listFiles(),new File("F:\temp\Project\数据\dfdsfds\","巴黎公社活动家传略.pdf"));
}
private static void listOrder() {
File[] listFiles = new File("F:\temp\Project\数据\dfdsfds\巴黎公社活动家传略_img").listFiles();
TreeMap tree = new TreeMap();
for(File f : listFiles)
{
tree.put(Integer.parseInt(f.getName().replaceAll(".jpg$", "")), f);
}
for(Entry eif : tree.entrySet())
{
System.out.println(eif.getKey()+"="+eif.getValue().toString());
}
}
public static boolean imgMerageToPdf(File[] list, File file)throws Exception {
//1：对图片文件通过TreeMap以名称进行自然排序
Map mif = new TreeMap();
for(File f : list)
mif.put(Integer.parseInt(f.getName().replaceAll(".jpg$", "")), f);
//2：获取第一个Img的宽、高做为PDF文档标准
ByteArrayOutputStream baos = new ByteArrayOutputStream(2048*3);
InputStream is = new FileInputStream(mif.get(1));
for(int len;(len=is.read())!=-1;)
baos.write(len);
baos.flush();
Image image = Image.getInstance(baos.toByteArray());
float width = image.width();
float height = image.height();
baos.close();
//3:通过宽高 ，实例化PDF文档对象。
document document = new document(new Rectangle(width,height));
PdfWriter pdfWr = PdfWriter.getInstance(document, new FileOutputStream(file));
document.open();
//4：获取每一个图片文件，转为IMG对象。装载到document对象中
for(Entry eif : mif.entrySet())
{
//4.1:读取到内存中
baos = new ByteArrayOutputStream(2048*3);
is = new FileInputStream(eif.getValue());
for(int len;(len=is.read())!=-1;)
baos.write(len);
baos.flush();
//4.2通过byte字节生成IMG对象
image = Image.getInstance(baos.toByteArray());
Image.getInstance(baos.toByteArray());
image.setAbsolutePosition(0.0f, 0.0f);
//4.3：添加到document中
document.add(image);
document.newPage();
baos.close();
}
//5：释放资源
document.close();
pdfWr.close();
return true;
}
private static void pdfToJpg(String source,String target,int x) throws Exception {
//创建从中读取和向其中写入（可选）的随机访问文件流，R表示对其只是访问模式
RandomAccessFile rea = new RandomAccessFile(new File(source), "r");
//将流读取到内存中，然后还映射一个PDF对象
FileChannel channel = rea.getChannel();
ByteBuffer buf = channel.map(FileChannel.MapMode.READ_ONLY,0, channel.size());
PDFFile pdfFile = new PDFFile(buf);
PDFPage page = pdfFile.getPage(x);
// get the width and height for the doc at the default zoom
java.awt.Rectangle rect = new java.awt.Rectangle(0, 0, (int) page.getBBox()
.getWidth(), (int) page.getBBox().getHeight());
// generate the image
java.awt.Image img = page.getImage(rect.width, rect.height, // width &
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(target); // 输出到文件流
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
encoder.encode(tag); // JPEG编码
out.close();
}
private static void pdfExtraction(String source,String target,int pageNum) throws Exception{
//1：创建PDF读取对象
PdfReader pr = new PdfReader(source);
System.out.println("this document "+pr.getNumberOfPages()+" page");
//2：将第page页转为提取，创建document对象
document doc = new document(pr.getPageSize(pageNum));
//3：通过PdfCopy转其单独存储
PdfCopy copy = new PdfCopy(doc, new FileOutputStream(new File(target)));
doc.open();
doc.newPage();
//4：获取第1页，装载到document中。
PdfimportedPage page = copy.getimportedPage(pr,pageNum);
copy.addPage(page);
//5：释放资源
copy.close();
doc.close();
pr.close();
}
private static void jpgToPdf(File pdfFile,File imgFile) throws Exception {
//文件转img
InputStream is = new FileInputStream(pdfFile);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
for(int i;(i=is.read())!=-1;)
{
baos.write(i);
}
baos.flush();
//取得图像的宽和高。
Image img = Image.getInstance(baos.toByteArray());
float width = img.width();
float height = img.height();
img.setAbsolutePosition(0.0F, 0.0F);//取消偏移
System.out.println("width = "+width+"theight"+height);
//img转pdf
document doc = new document(new Rectangle(width,height));
PdfWriter pw = PdfWriter.getInstance(doc,new FileOutputStream(imgFile));
doc.open();
doc.add(img);
//释放资源
System.out.println(doc.newPage());
pw.flush();
baos.close();
doc.close();
pw.close();
}
}
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持考高分网。
