获取局域网外网Ip的方法

StringBuffer sb = new StringBuffer();
  try {
   System.out.println("IP:"+InetAddress.getLocalHost().getHostAddress());

//   URL url = new URL("http://fw.qq.com/ipaddress");
   URL url = new URL("http://www.ip138.com/ip2city.asp");
   String s = null;
   sb = new StringBuffer();
   BufferedReader in = new BufferedReader(new InputStreamReader(url
     .openStream(),"gb2312"));
   while ((s = in.readLine()) != null) {
 
    sb.append(s);
   }
   System.out.println(sb.toString());
   System.out.println(sb.substring(sb.toString().indexOf("[")+1,sb.toString().indexOf("]")));
   String str=sb.toString();
//   System.out.println(str.substring(str.indexOf('"')+1,str.indexOf(',')-1));
   
   
  } catch (MalformedURLException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  } catch (IOException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }