判断某IP是否在某个网段

package filereader;

public class ipTest {
boolean i;

public static boolean ipIsValid(String ipSection, String ip) {
if (ipSection == null)
throw new NullPointerException("IP段不能为空！");
if (ip == null)
throw new NullPointerException("IP不能为空！");
ipSection = ipSection.trim();
ip = ip.trim();
final String REGX_IP = "((25[0-5]|2[0-4]//d|1//d{2}|[1-9]//d|//d)//.){3}(25[0-5]|2[0-4]//d|1//d{2}|[1-9]//d|//d)";
final String REGX_IPB = REGX_IP + "//-" + REGX_IP;
if (!ipSection.matches(REGX_IPB) || !ip.matches(REGX_IP))
return false;
int idx = ipSection.indexOf('-');
String[] sips = ipSection.substring(0, idx).split("//.");
String[] sipe = ipSection.substring(idx + 1).split("//.");
String[] sipt = ip.split("//.");
long ips = 0L, ipe = 0L, ipt = 0L;
for (int i = 0; i < 4; ++i) {
ips = ips << 8 | Integer.parseInt(sips[i]);
ipe = ipe << 8 | Integer.parseInt(sipe[i]);
ipt = ipt << 8 | Integer.parseInt(sipt[i]);
}
if (ips > ipe) {
long t = ips;
ips = ipe;
ipe = t;
}
return ips <= ipt && ipt <= ipe;
}

public static void main(String[] args) {
if (ipIsValid("192.168.1.1-192.168.36.1", "192.168.3.54")) {
System.out.println("ip属于该网段");
} else
System.out.println("ip不属于该网段");
}
}