String can't be cast to an Integer and Integer can't be cast to a String

Question

The getHttpPort method returns an Object type derived from a JSON data query. The value of the Object could be a blank string or an Integer value. To be on the safe side I thought I could represent it as a String like this:

String port = (String)getHttpPort(param);

But this sometimes generates the error:

Integer cannot be cast to a String.

So I tried this:

String port = ((Integer)getHttpPort(param).toString();

But now I get the reverse error:

String cannot be cast to an Integer.

What's the proper way to represent the returned result of the getHttpPort method as a String?