Depends… on the type of spray can paint… most are fast drying and will give a pretty good finish if you know how to "go back and forth" and apply the paint evenly without missing any areas… you really should lightly wipe the door with rag and lacquer thinner first to prepare it (don't wipe too hard)… recommend that you practice on another piece of material to get the "hang of it" first…

I use spray can paint on a daily basis in my furniture repair and sales hobby business, and it works very well…

However if your material is exposed to the outside weather, you should probably seal it with either a spar varnish or clear weather-proof sealer… both are also available in spray can form… Good Luck!