- java.lang.Object
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- java.net.NetworkInterface
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public final class NetworkInterface extends Object
This class represents a Network Interface made up of a name, and a list of IP addresses assigned to this interface. It is used to identify the local interface on which a multicast group is joined. Interfaces are normally known by names such as "le0".- Since:
- 1.4
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Method Summary
Methods Modifier and Type Method and Description boolean
equals(Object obj)
Compares this object against the specified object.static NetworkInterface
getByIndex(int index)
Get a network interface given its index.static NetworkInterface
getByInetAddress(InetAddress addr)
Convenience method to search for a network interface that has the specified Internet Protocol (IP) address bound to it.static NetworkInterface
getByName(String name)
Searches for the network interface with the specified name.String
getDisplayName()
Get the display name of this network interface.byte[]
getHardwareAddress()
Returns the hardware address (usually MAC) of the interface if it has one and if it can be accessed given the current privileges.int
getIndex()
Returns the index of this network interface.Enumeration<InetAddress>
getInetAddresses()
Convenience method to return an Enumeration with all or a subset of the InetAddresses bound to this network interface.List<InterfaceAddress>
getInterfaceAddresses()
Get a List of all or a subset of theInterfaceAddresses
of this network interface.int
getMTU()
Returns the Maximum Transmission Unit (MTU) of this interface.String
getName()
Get the name of this network interface.static Enumeration<NetworkInterface>
getNetworkInterfaces()
Returns all the interfaces on this machine.NetworkInterface
getParent()
Returns the parent NetworkInterface of this interface if this is a subinterface, ornull
if it is a physical (non virtual) interface or has no parent.Enumeration<NetworkInterface>
getSubInterfaces()
Get an Enumeration with all the subinterfaces (also known as virtual interfaces) attached to this network interface.int
hashCode()
Returns a hash code value for the object.boolean
isLoopback()
Returns whether a network interface is a loopback interface.boolean
isPointToPoint()
Returns whether a network interface is a point to point interface.boolean
isUp()
Returns whether a network interface is up and running.boolean
isVirtual()
Returns whether this interface is a virtual interface (also called subinterface).boolean
supportsMulticast()
Returns whether a network interface supports multicasting or not.String
toString()
Returns a string representation of the object.
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Method Detail
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getName
public String getName()
Get the name of this network interface.- Returns:
- the name of this network interface
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getInetAddresses
public Enumeration<InetAddress> getInetAddresses()
Convenience method to return an Enumeration with all or a subset of the InetAddresses bound to this network interface.If there is a security manager, its
checkConnect
method is called for each InetAddress. Only InetAddresses where thecheckConnect
doesn't throw a SecurityException will be returned in the Enumeration. However, if the caller has theNetPermission
("getNetworkInformation") permission, then all InetAddresses are returned.- Returns:
- an Enumeration object with all or a subset of the InetAddresses bound to this network interface
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getInterfaceAddresses
public List<InterfaceAddress> getInterfaceAddresses()
Get a List of all or a subset of theInterfaceAddresses
of this network interface.If there is a security manager, its
checkConnect
method is called with the InetAddress for each InterfaceAddress. Only InterfaceAddresses where thecheckConnect
doesn't throw a SecurityException will be returned in the List.- Returns:
- a
List
object with all or a subset of the InterfaceAddresss of this network interface - Since:
- 1.6
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getSubInterfaces
public Enumeration<NetworkInterface> getSubInterfaces()
Get an Enumeration with all the subinterfaces (also known as virtual interfaces) attached to this network interface.For instance eth0:1 will be a subinterface to eth0.
- Returns:
- an Enumeration object with all of the subinterfaces of this network interface
- Since:
- 1.6
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getParent
public NetworkInterface getParent()
Returns the parent NetworkInterface of this interface if this is a subinterface, ornull
if it is a physical (non virtual) interface or has no parent.- Returns:
- The
NetworkInterface
this interface is attached to. - Since:
- 1.6
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getIndex
public int getIndex()
Returns the index of this network interface. The index is an integer greater or equal to zero, or-1
for unknown. This is a system specific value and interfaces with the same name can have different indexes on different machines.- Returns:
- the index of this network interface or
-1
if the index is unknown - Since:
- 1.7
- See Also:
getByIndex(int)
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getDisplayName
public String getDisplayName()
Get the display name of this network interface. A display name is a human readable String describing the network device.- Returns:
- a non-empty string representing the display name of this network interface, or null if no display name is available.
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getByName
public static NetworkInterface getByName(String name) throws SocketException
Searches for the network interface with the specified name.- Parameters:
name
- The name of the network interface.- Returns:
- A NetworkInterface with the specified name, or null if there is no network interface with the specified name.
- Throws:
SocketException
- If an I/O error occurs.NullPointerException
- If the specified name is null.
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getByIndex
public static NetworkInterface getByIndex(int index) throws SocketException
Get a network interface given its index.- Parameters:
index
- an integer, the index of the interface- Returns:
- the NetworkInterface obtained from its index, or
null
if there is no interface with such an index on the system - Throws:
SocketException
- if an I/O error occurs.IllegalArgumentException
- if index has a negative value- Since:
- 1.7
- See Also:
getIndex()
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getByInetAddress
public static NetworkInterface getByInetAddress(InetAddress addr) throws SocketException
Convenience method to search for a network interface that has the specified Internet Protocol (IP) address bound to it.If the specified IP address is bound to multiple network interfaces it is not defined which network interface is returned.
- Parameters:
addr
- The InetAddress to search with.- Returns:
- A NetworkInterface or null if there is no network interface with the specified IP address.
- Throws:
SocketException
- If an I/O error occurs.NullPointerException
- If the specified address is null.
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getNetworkInterfaces
public static Enumeration<NetworkInterface> getNetworkInterfaces() throws SocketException
Returns all the interfaces on this machine. Returns null if no network interfaces could be found on this machine. NOTE: can use getNetworkInterfaces()+getInetAddresses() to obtain all IP addresses for this node- Returns:
- an Enumeration of NetworkInterfaces found on this machine
- Throws:
SocketException
- if an I/O error occurs.
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isUp
public boolean isUp() throws SocketException
Returns whether a network interface is up and running.- Returns:
true
if the interface is up and running.- Throws:
SocketException
- if an I/O error occurs.- Since:
- 1.6
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isLoopback
public boolean isLoopback() throws SocketException
Returns whether a network interface is a loopback interface.- Returns:
true
if the interface is a loopback interface.- Throws:
SocketException
- if an I/O error occurs.- Since:
- 1.6
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isPointToPoint
public boolean isPointToPoint() throws SocketException
Returns whether a network interface is a point to point interface. A typical point to point interface would be a PPP connection through a modem.- Returns:
true
if the interface is a point to point interface.- Throws:
SocketException
- if an I/O error occurs.- Since:
- 1.6
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supportsMulticast
public boolean supportsMulticast() throws SocketException
Returns whether a network interface supports multicasting or not.- Returns:
true
if the interface supports Multicasting.- Throws:
SocketException
- if an I/O error occurs.- Since:
- 1.6
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getHardwareAddress
public byte[] getHardwareAddress() throws SocketException
Returns the hardware address (usually MAC) of the interface if it has one and if it can be accessed given the current privileges. If a security manager is set, then the caller must have the permissionNetPermission
("getNetworkInformation").- Returns:
- a byte array containing the address, or
null
if the address doesn't exist, is not accessible or a security manager is set and the caller does not have the permission NetPermission("getNetworkInformation") - Throws:
SocketException
- if an I/O error occurs.- Since:
- 1.6
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getMTU
public int getMTU() throws SocketException
Returns the Maximum Transmission Unit (MTU) of this interface.- Returns:
- the value of the MTU for that interface.
- Throws:
SocketException
- if an I/O error occurs.- Since:
- 1.6
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isVirtual
public boolean isVirtual()
Returns whether this interface is a virtual interface (also called subinterface). Virtual interfaces are, on some systems, interfaces created as a child of a physical interface and given different settings (like address or MTU). Usually the name of the interface will the name of the parent followed by a colon (:) and a number identifying the child since there can be several virtual interfaces attached to a single physical interface.- Returns:
true
if this interface is a virtual interface.- Since:
- 1.6
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equals
public boolean equals(Object obj)
Compares this object against the specified object. The result istrue
if and only if the argument is notnull
and it represents the same NetworkInterface as this object.Two instances of
NetworkInterface
represent the same NetworkInterface if both name and addrs are the same for both.- Overrides:
equals
in classObject
- Parameters:
obj
- the object to compare against.- Returns:
true
if the objects are the same;false
otherwise.- See Also:
InetAddress.getAddress()
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hashCode
public int hashCode()
Description copied from class:Object
Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided byHashMap
.The general contract of
hashCode
is:- Whenever it is invoked on the same object more than once during
an execution of a Java application, the
hashCode
method must consistently return the same integer, provided no information used inequals
comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application. - If two objects are equal according to the
equals(Object)
method, then calling thehashCode
method on each of the two objects must produce the same integer result. - It is not required that if two objects are unequal
according to the
Object.equals(java.lang.Object)
method, then calling thehashCode
method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.
As much as is reasonably practical, the hashCode method defined by class
Object
does return distinct integers for distinct objects. (This is typically implemented by converting the internal address of the object into an integer, but this implementation technique is not required by the JavaTM programming language.)- Overrides:
hashCode
in classObject
- Returns:
- a hash code value for this object.
- See Also:
Object.equals(java.lang.Object)
,System.identityHashCode(java.lang.Object)
- Whenever it is invoked on the same object more than once during
an execution of a Java application, the
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toString
public String toString()
Description copied from class:Object
Returns a string representation of the object. In general, thetoString
method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.The
toString
method for classObject
returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@
', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:getClass().getName() + '@' + Integer.toHexString(hashCode())
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Bij voorbaat dank.
Document heeft de 11/06/2005 gemaakt, de laatste keer de 04/03/2020 gewijzigd
Bron van het afgedrukte document:https://www.gaudry.be/nl/java-api-rf-java/net/NetworkInterface.html
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