Enum:具有名的值的有限集合
enum Shrubbery {GROUND, CRAWLING, HANGING}
print(s + " ordinal: " + s.ordinal());
Shrubbery shrub = Enum.valueOf(Shrubbery.class, "GROUND");
enum Shrubbery {GROUND, CRAWLING, HANGING}
print(s + " ordinal: " + s.ordinal());
Shrubbery shrub = Enum.valueOf(Shrubbery.class, "GROUND");