Java Requires Chilkat v11.7.0+

Get Every Occurrence of a Label in a PDF

See more PDF Text Extraction Examples

Demonstrates the "labelOccurrence" option. When the same label appears more than once (for example "Total:" on each of several receipts), "first" (the default) uses the first occurrence, "all" returns every occurrence with its page, and a number selects one occurrence. Java

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    boolean success = false;

    //  This example requires the Chilkat API to have been previously unlocked.
    //  See Global Unlock Sample for sample code.

    //  The PDF used in this example (three receipts, one per page) is available at three_receipts.pdf

    CkPdf pdf = new CkPdf();
    success = pdf.LoadFile("qa_data/pdf/three_receipts.pdf");
    if (success == false) {
        System.out.println(pdf.lastErrorText());
        return;
        }

    CkJsonObject json = new CkJsonObject();
    CkJsonObject jsonOut = new CkJsonObject();

    //  Each of the three pages is a receipt with a "Total:" line.
    json.UpdateString("label","Total");
    json.UpdateString("labelValue","right");

    //  By default only the first occurrence (in reading order) is used.
    success = pdf.ExtractText("text",json,jsonOut);
    if (success == false) {
        System.out.println(pdf.lastErrorText());
        return;
        }

    System.out.println("First total: " + jsonOut.stringOf("text"));

    //  labelOccurrence "all" returns every occurrence.  The "text" member holds the values joined
    //  by line breaks, and labelMatches has one entry per occurrence with its page.
    json.UpdateString("labelOccurrence","all");
    success = pdf.ExtractText("text",json,jsonOut);
    if (success == false) {
        System.out.println(pdf.lastErrorText());
        return;
        }

    int i = 0;
    int count_i = jsonOut.SizeOfArray("labelMatches");
    while (i < count_i) {
        jsonOut.put_I(i);
        System.out.println("Page " + jsonOut.IntOf("labelMatches[i].page") + " total: " + jsonOut.stringOf("labelMatches[i].text"));
        i = i+1;
        }

    //  A number selects one occurrence: 2 is the second.
    json.UpdateInt("labelOccurrence",2);
    success = pdf.ExtractText("text",json,jsonOut);
    if (success == false) {
        System.out.println(pdf.lastErrorText());
        return;
        }

    System.out.println("Second total: " + jsonOut.stringOf("text"));

    //  The occurrences are counted over the selected pages, so combining "pages" with the label
    //  is another way to pick one receipt:
    json.UpdateString("labelOccurrence","first");
    json.UpdateString("pages","3");
    json.UpdateString("label","Receipt No.");
    success = pdf.ExtractText("text",json,jsonOut);
    if (success == false) {
        System.out.println(pdf.lastErrorText());
        return;
        }

    System.out.println("Receipt number on page 3: " + jsonOut.stringOf("text"));

    //  Sample output:

    //  First total: $19.86
    //  Page 1 total: $19.86
    //  Page 2 total: $17.34
    //  Page 3 total: $23.62
    //  Second total: $17.34
    //  Receipt number on page 3: 1003
  }
}