Class NetUtil

java.lang.Object
io.netty.util.NetUtil
public final class NetUtil extends Object
A class that holds a number of network-related constants.

This class borrowed some of its methods from a modified fork of the Inet6Util class which was part of Apache Harmony.

  • Field Details

    • LOCALHOST4

      public static final Inet4Address LOCALHOST4
      The Inet4Address that represents the IPv4 loopback address '127.0.0.1'

    • LOCALHOST6

      public static final Inet6Address LOCALHOST6
      The Inet6Address that represents the IPv6 loopback address '::1'

    • LOCALHOST

      public static final InetAddress LOCALHOST
      The InetAddress that represents the loopback address. If IPv6 stack is available, it will refer to LOCALHOST6. Otherwise, LOCALHOST4.

    • LOOPBACK_IF

      public static final NetworkInterface LOOPBACK_IF
      The loopback NetworkInterface of the current machine

    • NETWORK_INTERFACES

      public static final Collection<NetworkInterface> NETWORK_INTERFACES
      An unmodifiable Collection of all the interfaces on this machine.

    • SOMAXCONN

      public static final int SOMAXCONN
      The SOMAXCONN value of the current machine. If failed to get the value, 200 is used as a default value for Windows and 128 for others.

  • Method Details

    • isIpV4StackPreferred

      public static boolean isIpV4StackPreferred()
      Returns true if IPv4 should be used even if the system supports both IPv4 and IPv6. Setting this property to true will disable IPv6 support. The default value of this property is false.
      See Also:

    • isIpV6AddressesPreferred

      public static boolean isIpV6AddressesPreferred()
      Returns true if an IPv6 address should be preferred when a host has both an IPv4 address and an IPv6 address. The default value of this property is false.
      See Also:

    • createByteArrayFromIpAddressString

      public static byte[] createByteArrayFromIpAddressString(String ipAddressString)
      Creates an byte[] based on an ipAddressString. No error handling is performed here.

    • createInetAddressFromIpAddressString

      public static InetAddress createInetAddressFromIpAddressString(String ipAddressString)
      Creates an InetAddress based on an ipAddressString or might return null if it can't be parsed. No error handling is performed here.

    • ipv4AddressToInt

      public static int ipv4AddressToInt(Inet4Address ipAddress)
      Convert Inet4Address into int

    • intToIpAddress

      public static String intToIpAddress(int i)
      Converts a 32-bit integer into an IPv4 address.

    • bytesToIpAddress

      public static String bytesToIpAddress(byte[] bytes)
      Converts 4-byte or 16-byte data into an IPv4 or IPv6 string respectively.
      Throws:
      IllegalArgumentException - if length is not 4 nor 16

    • bytesToIpAddress

      public static String bytesToIpAddress(byte[] bytes, int offset, int length)
      Converts 4-byte or 16-byte data into an IPv4 or IPv6 string respectively.
      Throws:
      IllegalArgumentException - if length is not 4 nor 16

    • isValidIpV6Address

      public static boolean isValidIpV6Address(String ip)

    • isValidIpV6Address

      public static boolean isValidIpV6Address(CharSequence ip)

    • isValidIpV4Address

      public static boolean isValidIpV4Address(CharSequence ip)
      Takes a CharSequence and parses it to see if it is a valid IPV4 address.
      Returns:
      true, if the string represents an IPV4 address in dotted notation, false otherwise

    • isValidIpV4Address

      public static boolean isValidIpV4Address(String ip)
      Takes a String and parses it to see if it is a valid IPV4 address.
      Returns:
      true, if the string represents an IPV4 address in dotted notation, false otherwise

    • getByName

      public static Inet6Address getByName(CharSequence ip)
      Returns the Inet6Address representation of a CharSequence IP address.

      This method will treat all IPv4 type addresses as "IPv4 mapped" (see getByName(CharSequence, boolean))

      Parameters:
      ip - CharSequence IP address to be converted to a Inet6Address
      Returns:
      Inet6Address representation of the ip or null if not a valid IP address.

    • getByName

      public static Inet6Address getByName(CharSequence ip, boolean ipv4Mapped)
      Returns the Inet6Address representation of a CharSequence IP address.

      The ipv4Mapped parameter specifies how IPv4 addresses should be treated. "IPv4 mapped" format as defined in rfc 4291 section 2 is supported.

      Parameters:
      ip - CharSequence IP address to be converted to a Inet6Address
      ipv4Mapped -
      • true To allow IPv4 mapped inputs to be translated into Inet6Address
      • false Consider IPv4 mapped addresses as invalid.
      Returns:
      Inet6Address representation of the ip or null if not a valid IP address.

    • toSocketAddressString

      public static String toSocketAddressString(InetSocketAddress addr)
      Returns the String representation of an InetSocketAddress.

      The output does not include Scope ID.

      Parameters:
      addr - InetSocketAddress to be converted to an address string
      Returns:
      String containing the text-formatted IP address

    • toSocketAddressString

      public static String toSocketAddressString(String host, int port)
      Returns the String representation of a host port combo.

    • toAddressString

      public static String toAddressString(InetAddress ip)
      Returns the String representation of an InetAddress.

      The output does not include Scope ID.

      Parameters:
      ip - InetAddress to be converted to an address string
      Returns:
      String containing the text-formatted IP address

    • toAddressString

      public static String toAddressString(InetAddress ip, boolean ipv4Mapped)
      Returns the String representation of an InetAddress.

      The output does not include Scope ID.

      Parameters:
      ip - InetAddress to be converted to an address string
      ipv4Mapped -
      • true to stray from strict rfc 5952 and support the "IPv4 mapped" format defined in rfc 4291 section 2 while still following the updated guidelines in rfc 5952 section 4
      • false to strictly follow rfc 5952
      Returns:
      String containing the text-formatted IP address

    • getHostname

      public static String getHostname(InetSocketAddress addr)
      Returns InetSocketAddress.getHostString().
      Parameters:
      addr - The address
      Returns:
      the host string