如何在Java中将十六进制转换为IP地址？

Question

I have a problem converting hex to IP address. For example, I have two string "b019e85" an "ac12accf" which represent IP of "11.1.158.133" and "172.18.172.207". Is there a convenient way of converting such hex string to ip address? I have read a number of answers, such as onvert-hexadecimal-string-to-ip-address and java-convert-int-to-inetaddress . But both of them do not work. Either it throws exception of "java.net.UnknownHostException: addr is of illegal length" or "java.lang.IllegalArgumentException: hexBinary needs to be even-length: b019e85 " Sample code as follows:

            InetAddress vipAddress = InetAddress.getByAddress(DatatypeConverter.parseHexBinary("b019e85"));

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I write a small utility method to convert hex to ip(only ipv4). It does not do the validity check.

private String getIpByHex(String hex) {
    Long ipLong = Long.parseLong(hex, 16);
    String ipString = String.format("%d.%d.%d.%d", ipLong >> 24, 
        ipLong >> 16 & 0x00000000000000FF, 
        ipLong >> 8 & 0x00000000000000FF, 
        ipLong & 0x00000000000000FF);

    return ipString;
}

Answer 1

Not pretty, but should work.

public class IpTest {
  public static void main(String[] args) throws Exception {
    String hexAddrString1 = "b019e85";
    String hexAddrString2 = "ac12accf";
    System.out.println("ip:" + getIpFromHex(hexAddrString1));
    System.out.println("ip:" + getIpFromHex(hexAddrString2));
    //To get InetAddress
    InetAddress vipAddress1 = InetAddress.getByName(getIpFromHex(hexAddrString1));
    InetAddress vipAddress2 = InetAddress.getByName(getIpFromHex(hexAddrString2));
  }

  public static String getIpFromHex(String hexAddrString) {
    if (hexAddrString.length() % 2 != 0) {
      hexAddrString = "0" + hexAddrString;
    }
    if (hexAddrString.length() != 8) {
      //error..
    }
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < hexAddrString.length(); i = i + 2) {
      final String part = hexAddrString.substring(i, i + 2);
      final int ipPart = Integer.parseInt(part, 16);
      if (ipPart < 0 || ipPart > 254) {
        //Error...
      }
      sb.append(ipPart);
      if (i + 2 < hexAddrString.length()) {
        sb.append(".");
      }
    }
    return sb.toString();
  }
}