Consegue refatorar?

Conversor.java

package br.com.caelum.gnarus.apostila;

import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import br.com.caelum.gnarus.apostila.dominio.Exercicio;
import br.com.caelum.gnarus.apostila.dominio.Secao;
import br.com.caelum.gnarus.apostila.dominio.SecaoConvertida;

public class Conversor {

	private StringBuilder convertido;

	public Conversor() {
	}
	
	public SecaoConvertida converte(Secao s) {
		convertido = new StringBuilder();

		convertido.append("[chapter " + s.getTitulo() + "]\n\n");
		toAfc(s.getId(), s.getTexto());
		exercicios(s);
		
		return new SecaoConvertida(s.getNumero(), convertido.toString());
	}

	private void exercicios(Secao s) {
		
		if(s.getExercicios().isEmpty()) return;
		
		convertido.append("\n\n[section Exercícios]\n\n");
		convertido.append("[exercise]\n");
		for(Exercicio e : s.getExercicios()) {
			convertido.append("[question]\n");
			toAfc(s.getId(), e.getEnunciado());
			convertido.append("[answer]\n");
			toAfc(s.getId(), e.getResposta());
			convertido.append("[/answer]\n");
			convertido.append("[/question]\n\n");
		}
		convertido.append("[/exercise]\n");
		
	}

	private String toAfc(int secaoId, String textoOriginal) {
		
		String texto = textoOriginal.replace("<b>", "**").replace("</b>", "**");
		texto = texto.replace("<br/>", "\n\n").replace("<br>", "\n\n").replace("<br />", "\n\n");
		texto = texto.replace("<i>", "::").replace("</i>", "::");
		texto = texto.replace("<h1>", "[section ").replace("</h1>", "]");
		texto = texto.replace("<h2>", "[section ").replace("</h2>", "]");
		texto = texto.replace("<code>", "%%").replace("</code>", "%%");
		texto = texto.replace("[java]", "[code java]").replace("[/java]", "[/code]");
		texto = texto.replace("[xml]", "[code xml]").replace("[/xml]", "[/code]");
		texto = texto.replace("[ruby]", "[code ruby]").replace("[/ruby]", "[/code]");

		Pattern pattern = Pattern.compile("<img src=\"([a-zA-Z0-9.:/-]*)\" />");
		Matcher matcher = pattern.matcher(texto);
		
		int i = 0;
		while(matcher.find()) {
			String originalImg = matcher.group(0);
			String imgUrl = matcher.group(1);
			
			String imgFileName = "s" + secaoId + "i" + i + "." + extensao(imgUrl);
			download(imgUrl, imgFileName);
			
			texto = texto.replace(originalImg, "[img " + imgFileName + " w=60%]");
			i++;
		}
		
		convertido.append(texto);
		
		
		
		return convertido.toString();
	}

	private String extensao(String imgUrl) {
		String[] ponto = imgUrl.split("\\.");
		return ponto[ponto.length-1];
	}

	private void download(String imageUrl, String destinationFile) {
		try {
			URL url = new URL(imageUrl);
			
			InputStream is = url.openStream();
			OutputStream os = new FileOutputStream(destinationFile);

			byte[] b = new byte[2048];
			int length;

			while ((length = is.read(b)) != -1) {
				os.write(b, 0, length);
			}

			is.close();
			os.close();
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
		
	}

}