发邮件的问题

写一个发邮件的方法代码如下，不过不知道为什么一直报错，请高手帮忙！
public void sendMail(String mes,int i){

SimpleEmail email = new SimpleEmail();
email.setTLS(true);
email.setHostName("smtp.163.com");
email.setAuthentication("[email protected]", "880529123");

try {
email.addTo("[email protected]");
email.setFrom("[email protected]");
email.setSubject("This is the title!");
email.setCharset("GBK");
email.setMsg(mes+"看看能不能成功！"+" "+i);
email.send();
} catch (EmailException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

}错误如下：Caused by: java.net.UnknownHostException: smtp.163.com
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:177)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
at java.net.Socket.connect(Socket.java:519)
at java.net.Socket.connect(Socket.java:469)
at com.sun.mail.util.SocketFetcher.createSocket(SocketFetcher.java:232)
at com.sun.mail.util.SocketFetcher.getSocket(SocketFetcher.java:189)
at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1250)
... 12 more
找不到服务器地址