java 获取ipv4主网的随机子网段代码

以下是Java获取IPv4主网的随机子网段的代码示例：

import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.Random;

public class RandomSubnet {
    public static void main(String[] args) {
        try {
            // 获取本机IP地址
            InetAddress inetAddress = InetAddress.getLocalHost();
            String ipAddress = inetAddress.getHostAddress();

            // 将IP地址转换为字节数组
            byte[] ipBytes = inetAddress.getAddress();

            // 随机生成子网掩码
            Random random = new Random();
            int subnetMask = 24 + random.nextInt(8); // 生成24-32之间的随机整数作为子网掩码

            // 计算子网掩码对应的子网地址
            int mask = 0xffffffff << (32 - subnetMask);
            byte[] maskBytes = new byte[] { (byte) (mask >>> 24), (byte) (mask >> 16 & 0xff), (byte) (mask >> 8 & 0xff), (byte) (mask & 0xff) };
            byte[] subnetBytes = new byte[] { (byte) (ipBytes[0] & maskBytes[0]), (byte) (ipBytes[1] & maskBytes[1]), (byte) (ipBytes[2] & maskBytes[2]), 0 };

            // 输出随机生成的子网段地址
            InetAddress subnet = InetAddress.getByAddress(subnetBytes);
            System.out.println("IP地址: " + ipAddress);
            System.out.println("子网掩码: " + subnetMask);
            System.out.println("子网段地址: " + subnet.getHostAddress());
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }
    }
}

该程序首先获取本机IP地址，然后通过随机生成子网掩码的方式计算出对应的子网段地址，并输出结果。