How to extract text from a PDF file with Apache PD

问题:

I would like to extract text from a given PDF file with Apache PDFBox.

I wrote this code:

PDFTextStripper pdfStripper = null;
PDDocument pdDoc = null;
COSDocument cosDoc = null;
File file = new File(filepath);

PDFParser parser = new PDFParser(new FileInputStream(file));
parser.parse();
cosDoc = parser.getDocument();
pdfStripper = new PDFTextStripper();
pdDoc = new PDDocument(cosDoc);
pdfStripper.setStartPage(1);
pdfStripper.setEndPage(5);
String parsedText = pdfStripper.getText(pdDoc);
System.out.println(parsedText);

However, I got the following error:

Exception in thread "main" java.lang.NullPointerException
at org.apache.fontbox.afm.AFMParser.main(AFMParser.java:304)

I added pdfbox-1.8.5.jar and fontbox-1.8.5.jar to the class path.

Edit

I added System.out.println("program starts"); to the beginning of the program.

I ran it, then I got the same error as mentioned above and program starts did not appear in the console.

Thus, I think I have a problem with the class path or something.

Thank you.

回答1:

I executed your code and it worked properly. Maybe your problem is related to FilePath that you have given to file. I put my pdf in C drive and hard coded the file path.here is my code:

// PDFBox 2.0.8 require org.apache.pdfbox.io.RandomAccessRead
// import org.apache.pdfbox.io.RandomAccessFile;

public class PDFReader{
    public static void main(String args[]) {
        PDFTextStripper pdfStripper = null;
        PDDocument pdDoc = null;
        COSDocument cosDoc = null;
        File file = new File("C:/my.pdf");
        try {
            // PDFBox 2.0.8 require org.apache.pdfbox.io.RandomAccessRead 
            // RandomAccessFile randomAccessFile = new RandomAccessFile(file, "r");
            // PDFParser parser = new PDFParser(randomAccessFile);

            PDFParser parser = new PDFParser(new FileInputStream(file));
            parser.parse();
            cosDoc = parser.getDocument();
            pdfStripper = new PDFTextStripper();
            pdDoc = new PDDocument(cosDoc);
            pdfStripper.setStartPage(1);
            pdfStripper.setEndPage(5);
            String parsedText = pdfStripper.getText(pdDoc);
            System.out.println(parsedText);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } 
    }
}

回答2:

Using PDFBox 2.0.7, this is how I get the text of a PDF:

static String getText(File pdfFile) throws IOException {
    PDDocument doc = PDDocument.load(pdfFile);
    return new PDFTextStripper().getText(doc);
}

Call it like this:

try {
    String text = getText(new File("/home/me/test.pdf"));
    System.out.println("Text in PDF: " + text);
} catch (IOException e) {
    e.printStackTrace();
}

---

Since user oivemaria asked in the comments:

You can use PDFBox in your application by adding it to your dependencies in build.gradle:

dependencies {
  compile group: 'org.apache.pdfbox', name: 'pdfbox', version: '2.0.7'
}

Here's more on dependency management using Gradle.

---

If you want to keep the PDF's format in the parsed text, give PDFLayoutTextStripper a try.

回答3:

PdfBox 2.0.3 has a command line tool as well.

1. Download jar file
2. java -jar pdfbox-app-2.0.3.jar ExtractText [OPTIONS] <inputfile> [output-text-file]

Options:
  -password  <password>        : Password to decrypt document
  -encoding  <output encoding> : UTF-8 (default) or ISO-8859-1, UTF-16BE, UTF-16LE, etc.
  -console                     : Send text to console instead of file
  -html                        : Output in HTML format instead of raw text
  -sort                        : Sort the text before writing
  -ignoreBeads                 : Disables the separation by beads
  -debug                       : Enables debug output about the time consumption of every stage
  -startPage <number>          : The first page to start extraction(1 based)
  -endPage <number>            : The last page to extract(inclusive)
  <inputfile>                  : The PDF document to use
  [output-text-file]           : The file to write the text to

回答4:

Maven dep:

    <dependency>
        <groupId>org.apache.pdfbox</groupId>
        <artifactId>pdfbox</artifactId>
        <version>2.0.9</version>
    </dependency>

Then the fucntion to get the pdf text as String.

private static String readPDF(File pdf) throws InvalidPasswordException, IOException {
    try (PDDocument document = PDDocument.load(pdf)) {

        document.getClass();

        if (!document.isEncrypted()) {

            PDFTextStripperByArea stripper = new PDFTextStripperByArea();
            stripper.setSortByPosition(true);

            PDFTextStripper tStripper = new PDFTextStripper();

            String pdfFileInText = tStripper.getText(document);
            // System.out.println("Text:" + st);

            // split by whitespace
            String lines[] = pdfFileInText.split("\\r?\\n");
            List<String> pdfLines = new ArrayList<>();
            StringBuilder sb = new StringBuilder();
            for (String line : lines) {
                System.out.println(line);
                pdfLines.add(line);
                sb.append(line + "\n");
            }
            return sb.toString();
        }

    }
    return null;
}

回答5:

This works fine to extract data from a PDF file that has text content using pdfbox 2.0.6

import java.io.File;
import java.io.IOException;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.text.PDFTextStripper;
import org.apache.pdfbox.text.PDFTextStripperByArea;

public class PDFTextExtractor {
   public static void main(String[] args) throws IOException {
       System.out.println(readParaFromPDF("C:\\sample1.pdf",3, "Enter Start Text Here", "Enter Ending Text Here"));
    //Enter FilePath, Page Number, StartsWith, EndsWith
   }
   public static String readParaFromPDF(String pdfPath, int pageNo, String strStartIndentifier, String strEndIdentifier) {
       String returnString = "";
       try {
           PDDocument document = PDDocument.load(new File(pdfPath));
           document.getClass();        
           if (!document.isEncrypted()) {
               PDFTextStripperByArea stripper = new PDFTextStripperByArea();
               stripper.setSortByPosition(true);
               PDFTextStripper tStripper = new PDFTextStripper();
               tStripper.setStartPage(pageNo);
               tStripper.setEndPage(pageNo);
               String pdfFileInText = tStripper.getText(document);
               String strStart = strStartIndentifier;
               String strEnd = strEndIdentifier;
               int startInddex = pdfFileInText.indexOf(strStart);
               int endInddex = pdfFileInText.indexOf(strEnd);
               returnString = pdfFileInText.substring(startInddex, endInddex) + strEnd;
           }
          } catch (Exception e) {
              returnString = "No ParaGraph Found";
       }
            return returnString;
   }
}