android IP地址连接改成域名连接

[siren28]

求解啊！为何用IP连接时可以连接！当我用该IP所绑的域名来连接却是无法连接啊！如何做？？本人刚接触安卓开发啊！！
String sip =etIp.getText().toString().trim();
String sport =etPort.getText().toString().trim();

Pattern pa=Pattern.compile("^(\\d{1,2}|1\\d\\d|2[0-4]\\d|25[0-5])\\.(\\d{1,2}|1\\d\\d|2[0-4]\\d|25[0-5])\\.(\\d{1,2}|1\\d\\d|2[0-4]\\d|25[0-5])\\.(\\d{1,2}|1\\d\\d|2[0-4]\\d|25[0-5])$");
Matcher ma=pa.matcher(sip);
if(ma.matches()==false)
{
RelayCtrlActivity.showMessage(mct.getString(R.string.msg6));
//连接不成功！
return;
}