java后台获取服务器的公网地址

    private String getIpAddress() {
    	SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy");
        URL url = null;
        URLConnection urlconn = null;
        BufferedReader br = null;
        try {
            url = new URL("http://"+dateFormat.format(new Date())+".ip138.com/ic.asp");//爬取的网站是百度搜索ip时排名第一的那个
            urlconn = url.openConnection();
            br = new BufferedReader(new InputStreamReader(
                    urlconn.getInputStream()));
            String buf = null;
            String get= null;
            while ((buf = br.readLine()) != null) {
                get+=buf;
            }
            int where,end;
            for(where=0;where<get.length()&&get.charAt(where)!='[';where++);
            for(end=where;end<get.length()&&get.charAt(end)!=']';end++);
            get=get.substring(where+1,end);
            return get;
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                br.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return null;
    }

 

获取本机的公网地址.