ip-int-byte[]互转-使用java原生api

import java.net.InetAddress;
import java.net.UnknownHostException;

public class IpV4Util {
/**
* 将ip转为int
* @param ip
* @return int可能为负数
* @throws UnknownHostException
*/
public static int ipToInt(String ip) throws UnknownHostException {
byte[] addr = ipToBytes(ip);
//reference  java.net.Inet4Address.Inet4Address
int address  = addr[3] & 0xFF;
address |= ((addr[2] << 8) & 0xFF00);
address |= ((addr[1] << 16) & 0xFF0000);
address |= ((addr[0] << 24) & 0xFF000000);
return address;
}

/**
* 将ip转为int
* @param ip
* @return xxx.xxx.xxx.xxx
*/
public static String intToIp(int ip) {
byte[] addr = new byte[4];
addr[0] = (byte) ((ip >>> 24) & 0xFF);
addr[1] = (byte) ((ip >>> 16) & 0xFF);
addr[2] = (byte) ((ip >>> 8) & 0xFF);
addr[3] = (byte) (ip & 0xFF);
return bytesToIp(addr);
}

/**
* 将byte数组转为ip字符串
* @param src
* @return xxx.xxx.xxx.xxx
*/
public static String bytesToIp(byte[] src) {
return (src[0] & 0xff) + "." + (src[1] & 0xff) + "." + (src[2] & 0xff)
+ "." + (src[3] & 0xff);
}

/**
* 将ip字符串转为byte数组,注意:ip不可以是域名,否则会进行域名解析
* @param ip
* @return byte[]
* @throws UnknownHostException
*/
public static byte[] ipToBytes(String ip) throws UnknownHostException {
return InetAddress.getByName(ip).getAddress();
}

public static void main(String[] args) throws UnknownHostException {
String ip = "255.255.255.123";
int ipI = ipToInt(ip);
System.out.println(ip+"->"+ipI);
System.out.println(ipI+"->"+intToIp(ipI));
byte[] bytes = ipToBytes(ip);
System.out.println(ip+"->bytes.length="+bytes.length);
System.out.println("bytes->"+bytesToIp(bytes));
}
}
输出结果:
255.255.255.123->-133
-133->255.255.255.123
255.255.255.123->bytes.length=4
bytes->255.255.255.123