Find Text in PDF by Regular Expression in Java

import com.spire.pdf.*;
import com.spire.pdf.texts.*;
import java.awt.*;
import java.util.*;
import java.util.List;

public class FindText {
    public static void main(String[] args) {
        //Load a PDF document
        PdfDocument pdf = new PdfDocument();
        pdf.loadFromFile("C:\\Users\\Administrator\\Desktop\\test.pdf");

        //Create a object of PdfTextFind collection
        PdfTextFindOptions findOptions = new PdfTextFindOptions();

        //Loop through the pages
        for (Object page : (Iterable) pdf.getPages()) {
            PdfPageBase pageBase = (PdfPageBase) page;

            //Define a regular expression
            String pattern = "\\#\\w+\\b";
            // Set search parameter to use regular expression
            findOptions.setTextFindParameter(EnumSet.of(TextFindParameter.Regex));

            // Create a text finder object for the page
            PdfTextFinder textFinder = new PdfTextFinder(pageBase);

            // Find text fragments that match the pattern
            List<PdfTextFragment> finds = textFinder.find(pattern, findOptions);

            //Highlight the search results with yellow
            for (PdfTextFragment find : finds) {
                find.highLight(Color.yellow);
            }
        }

        //Save to file
        pdf.saveToFile("FindByPattern.pdf");
    }
}