Wyodrębnij tekst i obrazy z pliku PDF za pomocą iText5

Question

Potrzebuję pomocy w wyodrębnianiu tekstu i obrazów z pliku PDF za pomocą odwzorowań lub odniesień do obrazów w wyodrębnionym tekście przy użyciu biblioteki Java iText5. Jeśli iText5 jest niewłaściwym narzędziem do tego, proszę doradzić mi, polecając inną bibliotekę Java, która wykonuje tę samą funkcję.

To jest tak daleko, co mam zrobić

import java.io.IOException; 
import com.itextpdf.text.Document; 
import com.itextpdf.text.DocumentException; 
import com.itextpdf.text.pdf.PdfReader; 
import com.itextpdf.text.pdf.parser.PdfReaderContentParser; 
import com.itextpdf.text.pdf.parser.PdfTextExtractor; 
import com.itextpdf.text.Paragraph; 

public class Iconverter { 

    /** 
    * @param args 
    */ 
    static int PAGE_NUMBER; 


    /** The new document to which we've added a border rectangle. */ 
    public static final String RESULT = "/home/sarah/Java for Dummies 4th Edition/Img%s.%s"; 
    public static void main(String[] args) { 
     String docText = ""; 
     String pdfName = "/home/sarah/Java for Dummies 4th Edition.pdf"; 
     Document document = new Document(); 
     document.open(); 
     try { 
      PdfReader reader = new PdfReader(pdfName); 
      PAGE_NUMBER = reader.getNumberOfPages(); 
      for(int i = 1; i <=PAGE_NUMBER; i++){ 
       docText = PdfTextExtractor.getTextFromPage(reader, i); 
      } 
      extractImages(pdfName);  
      document.add(new Paragraph("..")); 
     } catch (Exception e) { 
      e.printStackTrace(); 
     } 
     document.close(); 
    } 
    /** 
    * Parses a PDF and extracts all the images. 
    * @param src the source PDF 
    * @param dest the resulting PDF 
    */ 
    public static void extractImages(String filename) throws IOException, DocumentException { 
     PdfReader reader = new PdfReader(filename); 
     PdfReaderContentParser parser = new PdfReaderContentParser(reader); 
     MyImageRenderListener listener = new MyImageRenderListener(RESULT); 
     for (int i = 1; i <= PAGE_NUMBER; i++) { 
      parser.processContent(i, listener); 
     } 
    } 
} 

import java.awt.image.BufferedImage; 
import java.io.FileOutputStream; 
import java.io.IOException; 

import javax.imageio.ImageIO; 

import com.itextpdf.text.pdf.PdfName; 
import com.itextpdf.text.pdf.parser.ImageRenderInfo; 
import com.itextpdf.text.pdf.parser.PdfImageObject; 
import com.itextpdf.text.pdf.parser.RenderListener; 
import com.itextpdf.text.pdf.parser.TextRenderInfo; 

public class MyImageRenderListener implements RenderListener { 

    /** The new document to which we've added a border rectangle. */ 
    protected String path = ""; 

    /** 
    * Creates a RenderListener that will look for images. 
    */ 
    public MyImageRenderListener(String path) { 
     this.path = path; 
    } 

    /** 
    * @see com.itextpdf.text.pdf.parser.RenderListener#beginTextBlock() 
    */ 
    public void beginTextBlock() { 
    } 

    /** 
    * @see com.itextpdf.text.pdf.parser.RenderListener#endTextBlock() 
    */ 
    public void endTextBlock() { 
    } 

    /** 
    * @see com.itextpdf.text.pdf.parser.RenderListener#renderImage(
    *  com.itextpdf.text.pdf.parser.ImageRenderInfo) 
    */ 
    public void renderImage(ImageRenderInfo renderInfo) { 
     try { 
      String filename; 
      FileOutputStream os; 
      PdfImageObject image = renderInfo.getImage(); 
      PdfName filter = (PdfName)image.get(PdfName.FILTER); 
      if (PdfName.DCTDECODE.equals(filter)) { 
       filename = String.format(path, renderInfo.getRef().getNumber(), "JPG"); 
       os = new FileOutputStream(filename); 
       os.write(image.getStreamBytes()); 
       os.flush(); 
       os.close(); 
      } 
      else if (PdfName.JPXDECODE.equals(filter)) { 
       filename = String.format(path, renderInfo.getRef().getNumber(), "jp2"); 
       os = new FileOutputStream(filename); 
       os.write(image.getStreamBytes()); 
       os.flush(); 
       os.close(); 
      } 
      else if (PdfName.JBIG2DECODE.equals(filter)) { 
       // ignore: filter not supported. 
      } 
      else { 
       BufferedImage awtimage = renderInfo.getImage().getBufferedImage(); 
       if (awtimage != null) { 
        filename = String.format(path, renderInfo.getRef().getNumber(), "png"); 
        ImageIO.write(awtimage, "png", new FileOutputStream(filename)); 
       } 
      } 
     } catch (IOException e) { 
      e.printStackTrace(); 
     } 
    } 

    /** 
    * @see com.itextpdf.text.pdf.parser.RenderListener#renderText(
    *  com.itextpdf.text.pdf.parser.TextRenderInfo) 
    */ 
    public void renderText(TextRenderInfo renderInfo) { 
    } 
} 

Answer 1

Jako alternatywę dla iText, Apache PDFBox może pomóc.

Spójrz na tych klas:

org.apache.pdfbox.ExtractImages

org.apache.pdfbox.ExtractText