Inet4Address (Java 2 Platform SE v1.4.1) - JDK 5 Documentation v1.4.1, Java 2 SDK 英文文档

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Java^TM 2 Platform
Std. Ed. v1.4.1

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java.net
Class Inet4Address

java.lang.Object
  |
  +--java.net.InetAddress
        |
        +--java.net.Inet4Address

All Implemented Interfaces:: Serializable

public final class Inet4Address
extends InetAddress

This class represents an Internet Protocol version 4 (IPv4) address. Defined by RFC 790: Assigned Numbers, RFC 1918: Address Allocation for Private Internets, and RFC 2365: Administratively Scoped IP Multicast

Textual representation of IP addresses

Textual representation of IPv4 address used as input to methods takes one of the following forms:

d.d.d.d

d.d.d

d.d

d

When four parts are specified, each is interpreted as a byte of data and assigned, from left to right, to the four bytes of an IPv4 address.

When a three part address is specified, the last part is interpreted as a 16-bit quantity and placed in the right most two bytes of the network address. This makes the three part address format convenient for specifying Class B net- work addresses as 128.net.host.

When a two part address is supplied, the last part is interpreted as a 24-bit quantity and placed in the right most three bytes of the network address. This makes the two part address format convenient for specifying Class A network addresses as net.host.

When only one part is given, the value is stored directly in the network address without any byte rearrangement.

For methods that return a textual representation as output value, the first form, i.e. a dotted-quad string, is used.

The Scope of a Multicast Address

Historically the IPv4 TTL field in the IP header has doubled as a multicast scope field: a TTL of 0 means node-local, 1 means link-local, up through 32 means site-local, up through 64 means region-local, up through 128 means continent-local, and up through 255 are global. However, the administrative scoping is preferred. Please refer to RFC 2365: Administratively Scoped IP Multicast

See Also:: Serialized Form

Method Summary

boolean equals(Object obj)
          Compares this object against the specified object.

byte[] getAddress()
          Returns the raw IP address of this InetAddress object.

String getHostAddress()
          Returns the IP address string in textual presentation form.

int hashCode()
          Returns a hashcode for this IP address.

boolean isAnyLocalAddress()
          Utility routine to check if the InetAddress in a wildcard address.

boolean isLinkLocalAddress()
          Utility routine to check if the InetAddress is an link local address.

boolean isLoopbackAddress()
          Utility routine to check if the InetAddress is a loopback address.

boolean isMCGlobal()
          Utility routine to check if the multicast address has global scope.

boolean isMCLinkLocal()
          Utility routine to check if the multicast address has link scope.

boolean isMCNodeLocal()
          Utility routine to check if the multicast address has node scope.

boolean isMCOrgLocal()
          Utility routine to check if the multicast address has organization scope.

boolean isMCSiteLocal()
          Utility routine to check if the multicast address has site scope.

boolean isMulticastAddress()
          Utility routine to check if the InetAddress is an IP multicast address.

boolean isSiteLocalAddress()
          Utility routine to check if the InetAddress is a site local address.

Methods inherited from class java.net.InetAddress

getAllByName, getByAddress, getByAddress, getByName, getCanonicalHostName, getHostName, getLocalHost, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Method Detail

isMulticastAddress

public boolean isMulticastAddress()

Utility routine to check if the InetAddress is an IP multicast address. IP multicast address is a Class D address i.e first four bits of the address are 1110.

Overrides:: isMulticastAddress in class InetAddress

Returns:: a boolean indicating if the InetAddress is an IP multicast address
Since:: JDK1.1

isAnyLocalAddress

public boolean isAnyLocalAddress()

Utility routine to check if the InetAddress in a wildcard address.

Overrides:: isAnyLocalAddress in class InetAddress

Returns:: a boolean indicating if the Inetaddress is a wildcard address.
Since:: 1.4

isLoopbackAddress

public boolean isLoopbackAddress()

Description copied from class: InetAddress

Utility routine to check if the InetAddress is a loopback address.

Overrides:: isLoopbackAddress in class InetAddress

Returns:: a boolean indicating if the InetAddress is a loopback address; or false otherwise.

isLinkLocalAddress

public boolean isLinkLocalAddress()

Utility routine to check if the InetAddress is an link local address.

Overrides:: isLinkLocalAddress in class InetAddress

Returns:: a boolean indicating if the InetAddress is a link local address; or false if address is not a link local unicast address.
Since:: 1.4

isSiteLocalAddress

public boolean isSiteLocalAddress()

Utility routine to check if the InetAddress is a site local address.

Overrides:: isSiteLocalAddress in class InetAddress

Returns:: a boolean indicating if the InetAddress is a site local address; or false if address is not a site local unicast address.
Since:: 1.4

isMCGlobal

public boolean isMCGlobal()

Utility routine to check if the multicast address has global scope.

Overrides:: isMCGlobal in class InetAddress

Returns:: a boolean indicating if the address has is a multicast address of global scope, false if it is not of global scope or it is not a multicast address
Since:: 1.4

isMCNodeLocal

public boolean isMCNodeLocal()

Utility routine to check if the multicast address has node scope.

Overrides:: isMCNodeLocal in class InetAddress

Returns:: a boolean indicating if the address has is a multicast address of node-local scope, false if it is not of node-local scope or it is not a multicast address
Since:: 1.4

isMCLinkLocal

public boolean isMCLinkLocal()

Utility routine to check if the multicast address has link scope.

Overrides:: isMCLinkLocal in class InetAddress

Returns:: a boolean indicating if the address has is a multicast address of link-local scope, false if it is not of link-local scope or it is not a multicast address
Since:: 1.4

isMCSiteLocal

public boolean isMCSiteLocal()

Utility routine to check if the multicast address has site scope.

Overrides:: isMCSiteLocal in class InetAddress

Returns:: a boolean indicating if the address has is a multicast address of site-local scope, false if it is not of site-local scope or it is not a multicast address
Since:: 1.4

isMCOrgLocal

public boolean isMCOrgLocal()

Utility routine to check if the multicast address has organization scope.

Overrides:: isMCOrgLocal in class InetAddress

Returns:: a boolean indicating if the address has is a multicast address of organization-local scope, false if it is not of organization-local scope or it is not a multicast address
Since:: 1.4

getAddress

public byte[] getAddress()

Returns the raw IP address of this InetAddress object. The result is in network byte order: the highest order byte of the address is in getAddress()[0].

Overrides:: getAddress in class InetAddress

Returns:: the raw IP address of this object.

getHostAddress

public String getHostAddress()

Returns the IP address string in textual presentation form.

Overrides:: getHostAddress in class InetAddress

Returns:: the raw IP address in a string format.
Since:: JDK1.0.2

hashCode

public int hashCode()

Returns a hashcode for this IP address.

Overrides:: hashCode in class InetAddress

Returns:: a hash code value for this IP address.

equals

public boolean equals(Object obj)

Compares this object against the specified object. The result is true if and only if the argument is not null and it represents the same IP address as this object.

Two instances of InetAddress represent the same IP address if the length of the byte arrays returned by getAddress is the same for both, and each of the array components is the same for the byte arrays.

Overrides:: equals in class InetAddress

Parameters:: obj - the object to compare against.
Returns:: true if the objects are the same; false otherwise.
See Also:: InetAddress.getAddress()