How to stop being a friend?

gsi300024v

I've a friend I made through a class we took, so we'd chat for a few minutes before and after the class only.
Then we started meeting up sometimes for tea and a chat for an hour or two.
The thing is, after about 5 minutes this person gets really negative about life and I really don't want to meet up. I try not to be rude. I feel I don't owe the person anything as we've only really met up 5 or 6 times. While I've empathy for them, I'd say they're not very happy with life, I don't feel it's my responsibility to have to listen to this negative stream over conversation for hours.
It's not a judgement on this person either. It's just I do not enjoy meeting up so don't want to. Any suggestions? I bump into them once or twice a month and they ring or text about meeting up.
I'm not sure what to do?

Tokyo

Stop making yourself so available to them.

You say that you are meeting up for tea and two-hour-long chats, which would indicate that at some stage you are giving into his/her requests, I'm guessing in an attempt not to be rude. Seeing as you don't know the person very well outside of this class, they have no idea what else is going on in your life. So tell them that you are too busy to meet up, that you have other things going on, be it another class, or family stuff.

If it persists, then you might have to be more forthright about it further down the line, but hopefully they will get the hint before that.

Meathlass

Make excuses as to why you can't meet. They'll eventually get the hint and stop contacting you.