princess cruise visits Thailand to Taipai then 2 days in Japan then finishes in Shanghai flight out

Maree, you will be eligible for 24 or 144 hour visa free transit in direct relation to your entire transit time in Shanghai and you don't need any kind of visa. Anyway, to be perfectly certain about your visa free eligibility, you will check whether your itinerary fulfills the following conditions:

- Your last port of call, immediately before Shanghai, is not allowed to be in mainland China port
- Your flight from Shanghai to, I assume Australia, is not allowed to have any additional landing within mainland China and in the country where your cruise will have its last port of call, immediately before Shanghai

So, if the above conditions are fulfilled, you will be eligible for 24 or 144 hour visa free transit in Shanghai area. Whether you will be eligible for 24 or 144 hour visa free transit depends on your entire transit time calculated from your scheduled arrival by cruise, until your scheduled departure by plane. If your entire transit time will be less than 24 hours, you will be eligible for 24 hour visa free transit and if your entire transit time will be just a minute longer than 24 hours, you will be eligible for 144 hour visa free transit. Basically, in both cases it is absolutely the same for you because you will transit through Shanghai visa free.