• java ip number to string


    package com.awkj;
    
    import java.math.BigInteger;
    import java.net.InetAddress;
    import java.net.UnknownHostException;
    
    public class App {
    
        private static BigInteger MIN_IP = new BigInteger("0");
        private static BigInteger MAX_IP = new BigInteger("4294967295");
    
        static String inet_ntoa(BigInteger raw) {
            int minFlag = raw.compareTo(MIN_IP);
            int maxFlag = raw.compareTo(MAX_IP);
            if (minFlag < 0 || maxFlag > 0) {
                return null;
            } else {
                try {
                    long rawLong = raw.longValue();
                    byte[] b = new byte[]{(byte) (rawLong >> 24),
                            (byte) (rawLong >> 16),
                            (byte) (rawLong >> 8),
                            (byte) rawLong};
                    return InetAddress.getByAddress(b).getHostAddress();
                } catch (UnknownHostException e) {
                    e.printStackTrace();
                    return null;
                }
            }
    
        }
    
        public static void main(String[] args) {
            /*
            MYSQL result:
            SELECT
            INET_NTOA(-1); --> NULL
    
            SELECT
            INET_NTOA(0);  --> 0.0.0.0
    
            SELECT
            INET_NTOA(134744072);  --> 8.8.8.8
    
            SELECT
            INET_NTOA(4294967295);  --> 255.255.255.255
    
            SELECT
            INET_ATON(4294967296);  --> NULL
            */
    
            System.out.println(inet_ntoa(new BigInteger("-1")));
            System.out.println(inet_ntoa(new BigInteger("0")));
            System.out.println(inet_ntoa(new BigInteger("134744072")));
            System.out.println(inet_ntoa(new BigInteger("4294967295")));
            System.out.println(inet_ntoa(new BigInteger("4294967296")));
        }
    }
    

      

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  • 原文地址:https://www.cnblogs.com/shenwenkai/p/10497573.html
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