java小程序自动报告内网服务器的公网IP地址

公司搭了一SVN服务器，由于没有固定IP地址。在公司记下IP往邮件一发，回家想通过这个IP连上服务器，发现在IP不对。所以想一办法，写一小程序，让服务器自动检测外网IP地址发到邮箱。这样就可以回家取下邮件拿到IP，就可连上SVN服务器（注已做好端口映射）。
说下原理：
1.用URL连上一可查看IP地址的网址，取下当前服务器的公网IP地址
2.进行下判断，看拿到的IP地址，是否有变，没变不处理，有变发邮件
3.将取得的公网IP地址发指定邮箱
4.使用定时器，定时执行2步骤
5.通过IDE（本人采用Eclipse）生成可执行jar
话不多说上代码:

package com.huzy.autoip;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Date;
import java.util.Properties;
import java.util.Timer;
import java.util.TimerTask;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.mail.Authenticator;
import javax.mail.Message;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;

public class AutoIP {

	private static String localIP = "127.0.0.1";
	
	public static void main(String[] args) throws Exception {
		timer();
	}

	private static String getLocalIp() {
		URL url = null;
		try {
			url = new URL("http://www.ip138.com/ip2city.asp");
		} catch (MalformedURLException e) {
			e.printStackTrace();
		}
		BufferedInputStream bis;
		try {
			bis = new BufferedInputStream(url.openStream());
			InputStreamReader isr = new InputStreamReader(bis);
			BufferedReader reader = new BufferedReader(isr);
			String s = null;
			while ((s = reader.readLine()) != null) {
				if (s.trim().equals(""))
					continue;
				String regEx = "(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9])\\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9]|0)\\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9]|0)\\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[0-9])";
				Pattern pat = Pattern.compile(regEx);
				Matcher mat = pat.matcher(s);
				boolean rs = mat.find();
				if (rs)
					return mat.group(0);
			}
			bis.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return null;
	}

	public static void sendMail(String content) throws Exception {
		Properties props = System.getProperties();
		props.setProperty("mail.smtp.auth", "true");
		props.setProperty("mail.host", "smtp.163.com");
		Session session = Session.getInstance(props, new Authenticator() {
			@Override
			protected PasswordAuthentication getPasswordAuthentication() {
				return new PasswordAuthentication("[e-mail]", "your_password");
			}
		});
		Message message = new MimeMessage(session);
		message.setSubject("hello");
		message.setRecipients(Message.RecipientType.TO, InternetAddress.parse("[e-mail]"));
		message.setFrom(new InternetAddress("[e-mail]"));
		message.setText("the time " + new Date() + " IP " + content);
		Transport.send(message);
	}
	
	public static void timer(){
        Timer timer = new Timer();
        timer.schedule(new MyTask(), 0, 10 * 1000);
    }
	
	public static class MyTask extends TimerTask {

		private String newIP = null;
		@Override
		public void run() {
			try {
				newIP = getLocalIp();
				if(newIP != null) {
					if (!newIP.equals(localIP)) {
						localIP = newIP;
						sendMail(localIP);
					}
				}
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
	}
}