Class InetSocketAddress

java.lang.Object
java.net.SocketAddress
java.net.InetSocketAddress
All Implemented Interfaces:
Serializable
public class InetSocketAddress extends SocketAddress
This class implements an IP Socket Address (IP address + port number) It can also be a pair (hostname + port number), in which case an attempt will be made to resolve the hostname. If resolution fails then the address is said to be unresolved but can still be used on some circumstances like connecting through a proxy.

It provides an immutable object used by sockets for binding, connecting, or as returned values.

The wildcard is a special local IP address. It usually means "any" and can only be used for bind operations.

Since:
1.4
See Also:

Constructor Summary

Constructor Description
InetSocketAddress(int port)
Creates a socket address where the IP address is the wildcard address and the port number a specified value.
InetSocketAddress(String hostname, int port)
Creates a socket address from a hostname and a port number.
InetSocketAddress(InetAddress addr, int port)
Creates a socket address from an IP address and a port number.

Method Summary

Modifier and Type Method Description
static InetSocketAddress createUnresolved(String host, int port)
Creates an unresolved socket address from a hostname and a port number.
final boolean equals(Object obj)
Compares this object against the specified object.
final InetAddress getAddress()
Gets the InetAddress.
final String getHostName()
Gets the hostname.
final String getHostString()
Returns the hostname, or the String form of the address if it doesn't have a hostname (it was created using a literal).
final int getPort()
Gets the port number.
final int hashCode()
Returns a hashcode for this socket address.
final boolean isUnresolved()
Checks whether the address has been resolved or not.
String toString()
Constructs a string representation of this InetSocketAddress.

Methods declared in class java.lang.Object

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

Constructor Details

InetSocketAddress

public InetSocketAddress(int port)
Creates a socket address where the IP address is the wildcard address and the port number a specified value.

A valid port value is between 0 and 65535. A port number of zero will let the system pick up an ephemeral port in a bind operation.

Parameters:
port - The port number
Throws:
IllegalArgumentException - if the port parameter is outside the specified range of valid port values.

InetSocketAddress

public InetSocketAddress(InetAddress addr, int port)
Creates a socket address from an IP address and a port number.

A valid port value is between 0 and 65535. A port number of zero will let the system pick up an ephemeral port in a bind operation.

A null address will assign the wildcard address.

Parameters:
addr - The IP address
port - The port number
Throws:
IllegalArgumentException - if the port parameter is outside the specified range of valid port values.

InetSocketAddress

public InetSocketAddress(String hostname, int port)
Creates a socket address from a hostname and a port number.

An attempt will be made to resolve the hostname into an InetAddress. If that attempt fails, the address will be flagged as unresolved.

If there is a security manager, its checkConnect method is called with the host name as its argument to check the permission to resolve it. This could result in a SecurityException.

A valid port value is between 0 and 65535. A port number of zero will let the system pick up an ephemeral port in a bind operation.

Parameters:
hostname - the Host name
port - The port number
Throws:
IllegalArgumentException - if the port parameter is outside the range of valid port values, or if the hostname parameter is null.
SecurityException - if a security manager is present and permission to resolve the host name is denied.
See Also:

Method Details

createUnresolved

public static InetSocketAddress createUnresolved(String host, int port)
Creates an unresolved socket address from a hostname and a port number.

No attempt will be made to resolve the hostname into an InetAddress. The address will be flagged as unresolved.

A valid port value is between 0 and 65535. A port number of zero will let the system pick up an ephemeral port in a bind operation.

Parameters:
host - the Host name
port - The port number
Returns:
an InetSocketAddress representing the unresolved socket address
Throws:
IllegalArgumentException - if the port parameter is outside the range of valid port values, or if the hostname parameter is null.
Since:
1.5
See Also:

getPort

public final int getPort()
Gets the port number.
Returns:
the port number.

getAddress

public final InetAddress getAddress()
Gets the InetAddress.
Returns:
the InetAddress or null if it is unresolved.

getHostName

public final String getHostName()
Gets the hostname. Note: This method may trigger a name service reverse lookup if the address was created with a literal IP address.
Returns:
the hostname part of the address.

getHostString

public final String getHostString()
Returns the hostname, or the String form of the address if it doesn't have a hostname (it was created using a literal). This has the benefit of not attempting a reverse lookup.
Returns:
the hostname, or String representation of the address.
Since:
1.7

isUnresolved

public final boolean isUnresolved()
Checks whether the address has been resolved or not.
Returns:
true if the hostname couldn't be resolved into an InetAddress.

toString

public String toString()
Constructs a string representation of this InetSocketAddress. This string is constructed by calling InetAddress.toString() on the InetAddress and concatenating the port number (with a colon).

If the address is an IPv6 address, the IPv6 literal is enclosed in square brackets, for example: "localhost/[0:0:0:0:0:0:0:1]:80". If the address is unresolved, <unresolved> is displayed in place of the address literal, for example "foo/<unresolved>:80".

To retrieve a string representation of the hostname or the address, use getHostString(), rather than parsing the string returned by this toString() method.

Overrides:
toString in class Object
Returns:
a string representation of this object.

equals

public final 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 address as this object.

Two instances of InetSocketAddress represent the same address if both the InetAddresses (or hostnames if it is unresolved) and port numbers are equal. If both addresses are unresolved, then the hostname and the port number are compared. Note: Hostnames are case insensitive. e.g. "FooBar" and "foobar" are considered equal.

Overrides:
equals in class Object
Parameters:
obj - the object to compare against.
Returns:
true if the objects are the same; false otherwise.
See Also:

hashCode

public final int hashCode()
Returns a hashcode for this socket address.
Overrides:
hashCode in class Object
Returns:
a hash code value for this socket address.
See Also:

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https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/net/InetSocketAddress.html