Uniform

Uniform is the 2003 feature film debut of director Diao Yi'nan, who had previously worked as an established screenwriter for directors such as Zhang Yang and Shi Runjiu. The film, produced by Hu Tong Communications, was distributed via DVD in the United States by First Run Features as part of the Global Film Initiative.

Synopsis from Wikipedia, CC BY-SA 4.0. Everything below written here.

Poster © the film's rights holders.