What does the national integrity in Mei Lanfang's story mean?

The "national integrity" in Mei Lanfang's Beard refers to the fact that during the Anti-Japanese War, Mei Lanfang grew a beard and refused to perform for the Japanese, making a living by writing and selling paintings. He is a great patriot. He said to his friend, "Don't look at my beard. It will be useful in the future. If the Japanese are unreasonable and insist that I come out to sing, then he will have to go to jail and be beheaded. "

National integrity is a belief pursuit, civilized standard and value scale that a nation adheres to, including noble morality and excellent quality.