package com.zj.tool;public enum WeekDay {    Mon("Monday",1),    Tue("Tuesday",2),    Wed("Wednesday",3),    Thu("Thursday",4),    Fri("Friday",5),    Sat("Saturday",6),    Sun("Sunday",7);    /**定义枚举类型自己的属性**/    private final String day;    private final int dayNum;    private WeekDay(String day,int dayNum) {        this.day = day;        this.dayNum = dayNum;    }        public int getDayNum()    {        return dayNum;    }    /**定义枚举类型自己的方法**/    public static void printDay(int i){        switch(i){            case 1: System.out.println(WeekDay.Mon); break;            case 2: System.out.println(WeekDay.Tue);break;            case 3: System.out.println(WeekDay.Wed);break;            case 4: System.out.println(WeekDay.Thu);break;            case 5: System.out.println(WeekDay.Fri);break;            case 6: System.out.println(WeekDay.Sat);break;            case 7: System.out.println(WeekDay.Sun);break;            default:System.out.println("wrong number!");        }    }    public String getDay() {        return day;    }    public static void main(String args[]) {        for (WeekDay day : WeekDay.values()) {            System.out.println(day + "====>" + day.getDay()+ "====>" + day.getDayNum());        }        WeekDay.printDay(5);    }}

一个很实际的问题,数据库里面存的是数字但是页面要显示字符串,此时就i显示出enum的好处了