枚举

枚举

是一些常量值的集合，以 enum 关键字定义，可以声明在类的内部，也可以声明到独立的类中，但不能定义在方法内

优点

• 写错单词会有提示，减少代码中的 bug
• 语义明了，增加代码可读性

写法

// WeekDemo.java 定义在类内
public class WeekDemo {
    enum Week {MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY, SUNDAY}
    public static void main(String[] args) {
        System.out.println(Week.MONDAY);
    }
}

// WeekDemo.java 定义在类外
enum Week {MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY, SUNDAY}
public class WeekDemo {
    public static void main(String[] args) {
        System.out.println(Week.MONDAY);
    }
}

// 在其他类中定义枚举
public class WeekEnum{
    enum Week {MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY, SUNDAY}
}

// 使用
public class WeekDemo{
    public static void main(String[] args){
        System.out.print(WeekEnum.Week.TUESDAY)
    }
}