Miscommunication between the Captain and the flight attendants regarding expected turbulence and passenger beverage services resulted in wet floors; wet clothing and exposure to possible injury on the part of those in the cabin.

Narrative

About ten minutes after the 10;000 FT chime the Captain called us to ask if we were finished with our cabin service. The 'A' Flight Attendant and I told the Captain that we are on our first tray of drinks. We weren't able to take drink orders and pass out peanuts on the ground because as soon as the last passenger boarded the Operations Agent closed the front door. The Captain told us in five minutes it was reported we will fly into turbulence. We (flight attendants) asked the Captain do we need to stop beverage service. The Captain told us to continue to serve the passenger and he will call us back to let us know if it was safe to continue beverage service. Five minutes later the Captain called us and told us to continue service.After the 'A' Flight Attendant finished her last tray; she made a final descent announcement. The 'C' Flight Attendant and I hadn't finished our service. But when 'A' Flight Attendant made the final descent announcement; we stopped serving and went to the aft galley to clean up so we could be seated.The Captain called us and told the 'A' Flight Attendant that he heard her announcement and that we can continue to serve beverages. So the 'C' Flight Attendant and I re-poured our drinks. We (me and 'C' Flight Attendant) didn't realize how close to the ground we were when the Captain called and told us to finish our service. We were past the final descent stage of the flight; but yet the Captain told us to finish beverage service.The Captain never chimed for final descent in the final descent stage of the flight; but yet he chimed us to tell us to finish our beverage service. About two minutes after the captain called us to tell us to finish beverage service; we hit code four turbulence.We had a jumpseater on the jump seat; so the 'C' Flight Attendant got to the other side of the jump seat and I sat on the floor. Meanwhile the trays of beverages started to fall on me. Because we were in the approach stage of the flight with code four turbulence; it caused the trays of beverages to fall on me. The 'C' Flight Attendant made an attempt to make it to the front jump seat.As the plane was going forward; toward the ground; the can of beverages started falling out of the cabinets hitting me. I tried to close the cabinet doors so that the cans of beverages would not hit the jumpseater. Needless to say; I got drench by the drinks that were on the trays; I got hit multiple times by cans of beverages; and the aft galley floor was flooded with beverages.I'm not sure why the Captain told us to finish beverage service while we were in final descent stage of the flight. Maybe he was trying to impress (name) because he was on our flight. But whatever the reason was for the Captain to make such a reckless decision doing a crucial stage of the flight it caused a safety breach because while trying to close the cabinet doors we landed. If it is a 55 minute flight with expected turbulence; then the flight attendants need to remain seated and not do beverages service.