If terminal change do i need a transit visa?

Haru, you do not have any problem in this regard. When traveling on 24 hour visa free transit as you will since your layover in Shanghai will be less than 24 hours, you have a right to travel absolutely visa free even if you have to change terminals or even airports. In other words, you do not need a visa of any kind at all.

I strongly advise you to print out your tickets and to have those printouts at hand, ready to be presented to relevant authorities. So, when you land in Shanghai, you will first approach a transit counter where you will apply for a temporary entry permit by presenting your flight tickets. This application is free of any charge. After your permit is granted, you will cross the immigration and proceed to another terminal in order to catch your flight to Hungary.

You should just ask, when performing a check-in in Japan if your luggage will be tagged all the way to Hungary, so that you can make your transfer in Shanghai with a complete peace of mind. I am certain that this will be the case, but just ask to be 100% certain about this detail. Also, I encourage you to use correct terminology because this is not 24 hours visa, but 24 hour visa free transit!