无法使用Java剥离pdf中的页面行

Question

i want to strip 1st page and 3rd page but why does it is stripping only 1st page and displaying same output twice.I am using pdfbox here.It is unable to strip 3rd page even though i have written it as stripper.setStartPage( 3 )

import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.text.PDFTextStripper;
import org.apache.pdfbox.text.TextPosition;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.util.ArrayList;
import java.util.List;

public class GetlinesFromPDF extends PDFTextStripper {

    static List<String> lines = new ArrayList<String>();    
    public GetlinesFromPDF() throws IOException {
    }

    public static void main( String[] args ) throws IOException    {
        PDDocument document = null;
        String fileName = "C://Users//policy.pdf"; 
        try {
            document = PDDocument.load( new File(fileName) );
            PDFTextStripper stripper = new GetlinesFromPDF();                             
            stripper.setSortByPosition( true );


            stripper.setStartPage( 1 );
            stripper.setEndPage( 1);
            Writer dummy = new OutputStreamWriter(new ByteArrayOutputStream());
            stripper.writeText(document, dummy);
             String qoute_number = lines.get(2);
            System.out.println(qoute_number);

            stripper.setStartPage( 3 );
            stripper.setEndPage( 3);
            Writer dummy1 = new OutputStreamWriter(new ByteArrayOutputStream());
            stripper.writeText(document, dummy1);
            String qoute_number1 = lines.get(2);
            System.out.println(qoute_number1);       
        }

        finally {
            if( document != null ) {
                document.close();
            }
        }
    }

    @Override
    protected void writeString(String str, List<TextPosition> textPositions) throws IOException {
     lines.add(str);

}}

Answer 1

The stripping works perfectly. Your problem is that lines adds all your results - stripping of page one and page three. Therefore, printing out the same index ( get(2) ) always contains content from page one. If you add a clear call between the two strippings, you should see the correct result.

stripper.setStartPage( 1 );
stripper.setEndPage( 1);
Writer dummy = new OutputStreamWriter(new ByteArrayOutputStream());
stripper.writeText(document, dummy);
String qoute_number = lines.get(2);
System.out.println(qoute_number);

lines.clear();

stripper.setStartPage( 3 );
stripper.setEndPage( 3);