计算IP地址是否在Java中的指定范围内 [英] Calculate whether an IP address is in a specified range in Java

问题描述

我希望能够返回true / false，具体取决于IP在两个其他IP的范围内。

I want to be able to return true/false depending on an IP being in range of two other IPs.

例如：

ip 192.200.3.0

范围从192.200。 0.0

范围为192.255.0.0

应该为真。

其他例子：

assert 192.200.1.0 == true
assert 192.199.1.1 == false
assert 197.200.1.0 == false

推荐答案

检查范围的最简单方法可能是将IP地址转换为32位整数，然后只比较整数。

The easiest way to check the range is probably to convert the IP addresses to 32-bit integers and then just compare the integers.

public class Example {
    public static long ipToLong(InetAddress ip) {
        byte[] octets = ip.getAddress();
        long result = 0;
        for (byte octet : octets) {
            result <<= 8;
            result |= octet & 0xff;
        }
        return result;
    }

    public static void main(String[] args) throws UnknownHostException {
        long ipLo = ipToLong(InetAddress.getByName("192.200.0.0"));
        long ipHi = ipToLong(InetAddress.getByName("192.255.0.0"));
        long ipToTest = ipToLong(InetAddress.getByName("192.200.3.0"));

        System.out.println(ipToTest >= ipLo && ipToTest <= ipHi);
    }
}

而不是 InetAddress.getByName （），您可能希望查看具有 InetAddresses 帮助程序类，可避免DNS查找的可能性。

Rather than InetAddress.getByName(), you may want to look at the Guava library which has an InetAddresses helper class that avoids the possibility of DNS lookups.

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