хочеть? Um, I guess you've meant хотеть.

Both genetive and accusative are possible for a direct object of this verb with a subtle to none change of meaning. Dative? I don't think so.

Example.

Я хочу воду - Я хочу воды - both are the same. The last one is genitive and it kind of implies that you want some water, not all the water in the world. This genitive case is assumed to be really a partitive case in this case.

But я хочу стол not я хочу стола. However both я хочу столы and я хочу столов are possible. I think it's due to the partitive case in there. While стол is considered to be a solid and not usually divided object you can't use partitive here. But if you go for plural столов you can use partitive because those столов can be a part of a larger group of tables.

I hope this helps.