Java中没有IP API连接，连接问题

Question

我正在尝试使用其网站提供的链接在no-IP API上发出GET请求。 这是我的Java代码，由于明显的原因，用户名，密码，主机名和IP地址当然被隐藏了

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class Connector 
{
    private static URL url;
    private static HttpURLConnection connection;
    private static BufferedReader bufferedReader;
    private static String line;

    public Connector() 
    {

    }

    public static void main(String[] args)
    {
        System.out.println(connectTo("http://username:password@dynupdate.no-ip.com/nic/update?hostname=hostname.ddns.net&myip=xxx.xxx.xxx.xxx"));
    }

    public static int connectTo(String u)
    {
          try
          {
               url = new URL(u);
               connection = (HttpURLConnection) url.openConnection();

               connection.setRequestMethod("GET");
               connection.setConnectTimeout(5000);
               connection.setReadTimeout(5000);

               System.out.println("Connection status: " + connection.getResponseMessage());


               bufferedReader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
               while((line = bufferedReader.readLine()) != null)
               {
                   System.out.println(line);
               }
                   bufferedReader.close();

               connection.disconnect();
               return 0;
          }
          catch(Exception e)
          {
              System.out.println(e.getMessage());
              return -1;
          }
    }
}

我收到“连接被拒绝：连接”错误，但找不到任何有关为什么发生这种情况的信息。关于如何解决它的任何想法？