Java获取本机外网IP

一种可行的获取方法，是通过http请求从网站中取出ip字段。例如: http://ip.chinaz.com/
通过这个网址，加上简单的正则表达式，即可得到

public static String getV4IP(){
	String ip = "";
	String chinaz = "http://ip.chinaz.com";
	
	StringBuilder inputLine = new StringBuilder();
	String read = "";
	URL url = null;
	HttpURLConnection urlConnection = null;
	BufferedReader in = null;
	try {
		url = new URL(chinaz);
		urlConnection = (HttpURLConnection) url.openConnection();
	    in = new BufferedReader( new InputStreamReader(urlConnection.getInputStream(),"UTF-8"));
		while((read=in.readLine())!=null){
			inputLine.append(read+"\r\n");
		}
		//System.out.println(inputLine.toString());
	} catch (MalformedURLException e) {
		e.printStackTrace();
	} catch (IOException e) {
		e.printStackTrace();
	}finally{
		if(in!=null){
			try {
				in.close();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}
	
	
	Pattern p = Pattern.compile("\\<dd class\\=\"fz24\">(.*?)\\<\\/dd>");
	Matcher m = p.matcher(inputLine.toString());
	if(m.find()){
		String ipstr = m.group(1);
		ip = ipstr;
		//System.out.println(ipstr);
	}
	return ip;
}