如何将Java类转换为其子类之一（SocketAddress和InetSocketAddress）

Question

I am trying to get the IP of a socket connection in string form.

I am using a framework, which returns the SocketAddress of the received message. How can i transform it to InetSocketAddress or InetAddress ?

Answer 1

If your certain that the object is an InetSocketAddress then simply cast it:

SocketAddress sockAddr = ...
InetSocketAddress inetAddr = (InetSocketAddress)sockAddr;

You can then call the getAddress() method on inetAddr to get the InetAddress object associated with it.

Answer 2

You can try casting to it. In this case this is downcasting .

InetSocketAddress isa = (InetSocketAddress) socketAddress;

However, this may throw ClassCastException if the class isn't really what you expect.

Checks can be made on this via the instanceof operator:

if (socketAddress instanceof InetSocketAddress) {
    InetSocketAddress isa = (InetSocketAddress) socketAddress;
    // invoke methods on "isa". This is now safe - no risk of exceptions
}

The same check can be done for other subclasses of SocketAddress .

Answer 3

Actually SocketAddress is an abstract class, so you receive some subclass of it. Did you try to cast returned SocketAddress to InetSocketAddress ?