[转]java实现ip检查

以前项目用到的要求实现IP访问控制,具体转自哪里忘记了,以为拿过来后自己又改了点。直接上代码

public class ipTest {
    /**
     * 判断IP是否在指定范围；
     */
    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("10.118.128.0-10.118.255.255", "10.118.202.2")) {
            System.out.println("ip属于该网段");
        } else
            System.out.println("ip不属于该网段");
    }
}

简单说下思路，ipv4是长度为32位划分成4段。那么就把起止IP及要校验的IP的每段分别升位，不足8位末尾补0，全部升位后，在需要校验的IP是否在此段中即可。