I\'m playing around with SoapUI (the free/open source edition) to see if it could be useful at work for the kind of extensive API testing we often do because right now we do mos
Here are the steps you can follow in order to import the swagger definition into SoapUI, and make sure swagger definition is in hand or its url(basically a json ). 
Pre-condition is that, swagger plugin is installed for SoapUI as shown here
File -> Create Empty Project menu options.Import Swagger as shown below.
You are done. All the resources and its methods should appear in your project.
If you are not able to see the Import Swagger option in the right click context, then plugin is not installed. Am sure it is installed if you have installed SoapUI-5.2.1
Update
Adding some public swagger definition, so that it would be handy for someone wish to try one.
Here is the pet store swagger definition v2.0 by SwaggerUI
You would see something like below once swagger definition is imported.