枚举类型详解

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枚举类型：

原理：

publicabstract class WeekDay{

privateWeekDay(){};

publicfinal static WeekDay SUN = new WeekDay(){

publicWeekDay nextDay(){

returnMON

}

publicfinal static WeekDay MON = new WeekDay(){

publicWeekDay nextDay(){

returnSUN

}

publicString toString(){

returnthis == SUN?"sun":"mon"

}

publicstatic void main(String[]args){

WeekDayweekday = WeekDay.SUN;

syso(weekday.nextDay());

}

具体应用：

publicstatic void main(String[]args){

WeedDayweedDay = WeeKDay.SUN;

syso(weekDay);

syso(WeedDay.valueOf("SUN"));

WeekDay[]w = WeekDay.values();

}

publicenum WeekDay{

SUN(1),MON(),TUE,WED,THI,FRI,SAT

privateWeekDay(){syso(1)};

privateWeekDay(int day){syso(2)};

}

带有抽象方法的枚举(交通灯)

publicenum TrafficLamp{

继承了TrafficLamp的匿名类对象,

必须实现父类的抽象方法。然后作为类的属性程序

RED(21){//在匿名类对象传参，会调用父类的带参数的构造方法

public TrafficLamp nextLamp(){

returnGREEN;

}

GREEN(30){

public TrafficLamp nextLamp(){

retrunYELLOW

}

YELLOW(5){

public TrafficLamp nextLamp(){

returnRED;

}

};

publicabstract TrafficLamp nextLamp();

}

publicstatic void main(String[]args){

TrafficLamplamp = TrafficLamp.RED;

syso(lamp.nextLamp());

privateint time;

privateTrafficLamp(int time){this.time = time;}

}