【Java入门】枚举

枚举

枚举也是一个类。枚举是一个特殊的类，枚举是用来一一列举出有限的的值的集合。

枚举也可以有构造器，在枚举常量初始化的时候被调用

public enum Week {
Monday("周一"), Tuesday("周二"), Wednesday("周三"), Thursday("周四"), Friday("周五"), Saturday("周六"), Sunday("周天");
private String week;

Week(String week) {
this.week = week;
}

public String getWeek() {
return week;
}
}

public class Test {
public static void main(String[] args) {
//Enum的静态函数valueOf 将字符串转换为对应的枚举类 参数一：目标枚举类 参数二：枚举常量名
Week week = (Week) Enum.valueOf(Week.class, "Sunday");

//将枚举类的值（常量名）转换为字符串
System.out.println(week.toString());

//返回该常量在枚举常量中的位置 从0开始
System.out.println("该常量在所有常量中排第n位" + week.ordinal());

//如果常量出现在other之前，则返回一个负值，如果位置相等返回0，否则返回正值
System.out.println(week.compareTo(Enum.valueOf(Week.class, "Monday")));

System.out.println(week.getWeek());
}
}