You can bring alcohol into your hotel room if you are staying at Disney World. If you want to pack beer or cocktails into a cooler and take them to Magic Kingdom, than no, that isn't allowed.

You are not permitted to bring your own alcoholic beverages into any of the four Walt Disney World or two Disneyland theme parks. Security checkpoints at the park entrances are very thorough, and any alcohol found in coolers or bags will be confiscated or must be returned to your vehicle or hotel room. The only major exception on Disney property is at the Resort Hotels, where guests are allowed to have alcohol in their private rooms. Additionally, you can purchase wine at Disney Springs to be consumed at select table-service restaurants, though a corkage fee usually applies. While you cannot "bring" it in, alcohol is widely available for purchase inside most parks (with Magic Kingdom being the most restrictive, serving it only at sit-down table-service locations). For a safe and seamless day, it is best to leave the private stash at the hotel and enjoy the uniquely themed "adult beverages" offered at places like Oga’s Cantina in Galaxy’s Edge or the various pavilions in EPCOT’s World Showcase.