Java Extracting Text Between Tags and Attributes

I am trying to extract text between particular tags and attributes. For now, I tried to extract for tags. I am reading a ".gexf" file which has XML data inside. Then I am saving this data as a string. Then I am trying to extract text between "nodes" tag. Here is my code so far:

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {
    private static String filePath = "src/babel.gexf";

    public String readFile(String filePath) throws IOException {
        BufferedReader br = new BufferedReader(new FileReader(filePath));
        try {
            StringBuilder sb = new StringBuilder();
            String line = br.readLine();
            while (line != null) {
                sb.append(line);
                sb.append("\n");
                line = br.readLine();
            }
            return sb.toString();
        } finally {
            br.close();
        }
    }

    public void getNodesContent(String content) throws IOException {
        final Pattern pattern = Pattern.compile("<nodes>(\\w+)</nodes>", Pattern.MULTILINE);
        final Matcher matcher = pattern.matcher(content);
        while (matcher.find()) {
            System.out.println(matcher.group(1));
        }
    }

    public static void main(String [] args) throws IOException {
        Main m = new Main();
        String result = m.readFile(filePath);
        m.getNodesContent(result);
    }
}