NetUtil (Netty API Reference (4.0.56.Final))

java.lang.Object
- io.netty.util.NetUtil

```
public final class NetUtil
extends java.lang.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 Summary

Fields
Modifier and Type	Field and Description
`static java.net.InetAddress`	`LOCALHOST` The `InetAddress` that represents the loopback address.
`static java.net.Inet4Address`	`LOCALHOST4` The `Inet4Address` that represents the IPv4 loopback address '127.0.0.1'
`static java.net.Inet6Address`	`LOCALHOST6` The `Inet6Address` that represents the IPv6 loopback address '::1'
`static java.net.NetworkInterface`	`LOOPBACK_IF` The loopback `NetworkInterface` of the current machine
`static int`	`SOMAXCONN` The SOMAXCONN value of the current machine.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static byte[]`	`createByteArrayFromIpAddressString(java.lang.String ipAddressString)` Creates an byte[] based on an ipAddressString.
`static java.net.Inet6Address`	`getByName(java.lang.CharSequence ip)` Returns the `Inet6Address` representation of a `CharSequence` IP address.
`static java.net.Inet6Address`	`getByName(java.lang.CharSequence ip, boolean ipv4Mapped)` Returns the `Inet6Address` representation of a `CharSequence` IP address.
`static boolean`	`isIpV4StackPreferred()` Returns `true` if ipv4 should be prefered on a system that supports ipv4 and ipv6.
`static boolean`	`isValidIpV4Address(java.lang.String ip)` Takes a string and parses it to see if it is a valid IPV4 address.
`static boolean`	`isValidIpV6Address(java.lang.String ip)`
`static java.lang.String`	`toAddressString(java.net.InetAddress ip)` Returns the `String` representation of an `InetAddress`.
`static java.lang.String`	`toAddressString(java.net.InetAddress ip, boolean ipv4Mapped)` Returns the `String` representation of an `InetAddress`.
`static java.lang.String`	`toSocketAddressString(java.net.InetSocketAddress addr)` Returns the `String` representation of an `InetSocketAddress`.
`static java.lang.String`	`toSocketAddressString(java.lang.String host, int port)` Returns the `String` representation of a host port combo.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - LOCALHOST4
```
public static final java.net.Inet4Address LOCALHOST4
```
    The Inet4Address that represents the IPv4 loopback address '127.0.0.1'
  - LOCALHOST6
```
public static final java.net.Inet6Address LOCALHOST6
```
    The Inet6Address that represents the IPv6 loopback address '::1'
  - LOCALHOST
```
public static final java.net.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 java.net.NetworkInterface LOOPBACK_IF
```
    The loopback NetworkInterface of the current 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 or 128 for others.
- Method Detail
  - isIpV4StackPreferred
```
public static boolean isIpV4StackPreferred()
```
    Returns true if ipv4 should be prefered on a system that supports ipv4 and ipv6.
  - createByteArrayFromIpAddressString
```
public static byte[] createByteArrayFromIpAddressString(java.lang.String ipAddressString)
```
    Creates an byte[] based on an ipAddressString. No error handling is performed here.
  - isValidIpV6Address
```
public static boolean isValidIpV6Address(java.lang.String ip)
```
  - isValidIpV4Address
```
public static boolean isValidIpV4Address(java.lang.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 java.net.Inet6Address getByName(java.lang.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 java.net.Inet6Address getByName(java.lang.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 java.lang.String toSocketAddressString(java.net.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 java.lang.String toSocketAddressString(java.lang.String host,
                                                     int port)
```
    Returns the String representation of a host port combo.
  - toAddressString
```
public static java.lang.String toAddressString(java.net.InetAddress ip)
```
    Returns the String representation of an InetAddress.
    - Inet4Address results are identical to InetAddress.getHostAddress()
    - Inet6Address results adhere to rfc 5952 section 4
    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 java.lang.String toAddressString(java.net.InetAddress ip,
                                               boolean ipv4Mapped)
```
    Returns the String representation of an InetAddress.
    - Inet4Address results are identical to InetAddress.getHostAddress()
    - Inet6Address results adhere to rfc 5952 section 4 if ipv4Mapped is false. If ipv4Mapped is true then "IPv4 mapped" format from rfc 4291 section 2 will be supported. The compressed result will always obey the compression rules defined in rfc 5952 section 4
    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

Class NetUtil

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

LOCALHOST4

LOCALHOST6

LOCALHOST

LOOPBACK_IF

SOMAXCONN

Method Detail

isIpV4StackPreferred

createByteArrayFromIpAddressString

isValidIpV6Address

isValidIpV4Address

getByName

getByName

toSocketAddressString

toSocketAddressString

toAddressString

toAddressString