枚举类代替 ifelse

枚举类可以用来代替 ifelse 语句，可以提高代码的可读性和可维护性。枚举类可以定义一组常量，每个常量都有一个对应的值，可以通过枚举类来判断变量的取值，从而避免使用 ifelse 语句。

例如，我们可以定义一个枚举类来表示一周的天数：

public enum DayOfWeek {
    MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY, SUNDAY
}

然后可以使用 switch 语句来判断变量的取值：

DayOfWeek day = DayOfWeek.MONDAY;
switch (day) {
    case MONDAY:
        System.out.println("Today is Monday");
        break;
    case TUESDAY:
        System.out.println("Today is Tuesday");
        break;
    case WEDNESDAY:
        System.out.println("Today is Wednesday");
        break;
    case THURSDAY:
        System.out.println("Today is Thursday");
        break;
    case FRIDAY:
        System.out.println("Today is Friday");
        break;
    case SATURDAY:
        System.out.println("Today is Saturday");
        break;
    case SUNDAY:
        System.out.println("Today is Sunday");
        break;
}

这样就可以避免使用 ifelse 语句来判断变量的取值。