枚举类型

声明枚举后，我们可以使用switch语句检查相应的值。

Rank a = Rank.SOLDIER;

switch(a) {
    case SOLDIER:
    System.out.println("Soldier says hi!");
    break;
    case SERGEANT:
    System.out.println("Sergeant says Hello!");
    break;
    case CAPTAIN:
    System.out.println("Captain says Welcome!");
    break;
}
//输出 "Soldier says hi!"