题解 | #整数与IP地址间的转换#

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

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner scanner = new Scanner(System.in);
        while (scanner.hasNext()) {
            String ip = scanner.next();
            String address = scanner.next();
            // 将IP地址转换成字节数组
            byte[] bytes;
            try {
                bytes = InetAddress.getByName(ip).getAddress();
            } catch (UnknownHostException e) {
                e.printStackTrace();
                return;
            }
            // 将字节数组转换成长整数
            long result = 0;
            for (byte b : bytes) {
                result <<= 8;
                result |= b & 0xFF;
            }
            // 输出结果
            System.out.println(result);
            System.out.println(InetAddress.getByName(address).getHostAddress());
        }
    }
}