Add Default Port to a URL If Missing : URL « Network Protocol « Java

Add Default Port to a URL If Missing


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import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Utils {
  public static String addDefaultPortIfMissing(String urlString, String defaultPort) {
    URL url = null;
    try {
        url = new URL(urlString);
    } catch (MalformedURLException e) {
        return urlString;
    if (url.getPort() != -1) {
        return urlString;
    String regex = "http://([^/]+)";        
    String found = getFirstFound(urlString, regex);
    String replacer = "http://" + found + ":" + defaultPort;
    if (!isEmpty(found)) {
        urlString = urlString.replaceFirst(regex, replacer);
    return urlString;
  public static String getFirstFound(String contents, String regex) {
    List<String> founds = getFound(contents, regex);
    if (isEmpty(founds)) {
        return null;
    return founds.get(0);
  public static List<String> getFound(String contents, String regex) {
      if (isEmpty(regex) || isEmpty(contents)) {
          return null;
      List<String> results = new ArrayList<String>();
      Pattern pattern = Pattern.compile(regex, Pattern.UNICODE_CASE);
      Matcher matcher = pattern.matcher(contents);
      while (matcher.find()) {
          if (matcher.groupCount() > 0) {
          } else {
      return results;
  public static boolean isEmpty(List<String> list) {
    if (list == null || list.size() == 0) {
        return true;
    if (list.size() == 1 && isEmpty(list.get(0))) {
        return true;
    return false;
  public static boolean isEmpty(String str) {
      if (str != null && str.trim().length() > 0) {
          return false;
      return true;


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