检测IP输入是否合法

/**
* 檢測IP輸入是否合法
* @param ip
* @return
*/
private boolean checkIp(String ip)
{
StringTokenizer st = new StringTokenizer(ip,".");
int count = st.countTokens();

if (count != 4)
return false;
for (int i = 0; i < 4; i++)
{
int ipInt = Integer.parseInt(st.nextToken());
if (ipInt >= 0 && ipInt <= 255)
continue;
else
return false;
}
return true;
}