Java中Enum的使用

package com.zoer.src;public enum WeekDay {Mon_("Monday"), Tue_("Tuesday"), Wed_("Wednesday"), Thu_("Thursday"), Fri_("Friday"), Sat_("Saturday"), Sun_("Sunday");private final String day;private WeekDay(String day) {System.out.println(day);this.day = day;}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;}}

上面的代码中生明了一个enum，枚举类型用来表示一组相同类型的常量。

代码中使用了private的构造函数【enum仅允许private的构造函数】。

Tue_("Tuesday")，括号内的内容就是构造函数中的参数，比如传入Tuesday，则经过构造函数执行之后，Tue的day值就是Tuesday了。

ps：整个enum初始化的过程中，生明了几个值，则构造函数需要执行相应次数。

package com.zoer.src;public class T {/** * @param args */public static void main(String args[]) {for (int i = 0; i < WeekDay.values().length; i++) {WeekDay d = WeekDay.values()[i];p(d);}}public static void p(WeekDay d) {System.out.println(d + "->" + d.getDay());}}

输出：

Mon_->MondayTue_->TuesdayWed_->WednesdayThu_->ThursdayFri_->FridaySat_->SaturdaySun_->Sunday