java中的枚举

[code ]import java.util.Date;

public class EnumTest {

 /**

  * @param args

  */

 public static void main(String[] args) {

  // TODO Auto-generated method stub

  WeekDay1 weekDay = WeekDay1.MON;

  System.out.println(weekDay.nextDay());

  WeekDay weekDay2 = WeekDay.FRI;

  System.out.println(weekDay2);

  System.out.println(weekDay2.name());

  System.out.println(weekDay2.ordinal());

  System.out.println(WeekDay.valueOf("SUN").toString());

  System.out.println(WeekDay.values().length);

  new Date(300){};

 }

 public enum WeekDay{

  SUN(1),MON(),TUE,WED,THI,FRI,SAT;

  private WeekDay(){System.out.println("first");}

  private WeekDay(int day){System.out.println("second");}

 }

 public enum TrafficLamp{

  RED(30){

   public  TrafficLamp nextLamp(){

    return GREEN;

   }

  },

  GREEN(45){

   public  TrafficLamp nextLamp(){

    return YELLOW;

   }  

  },

  YELLOW(5){

   public  TrafficLamp nextLamp(){

    return RED;

   }  

  };

  public abstract TrafficLamp nextLamp();

  private int time;

  private TrafficLamp(int time){this.time = time;}

 }

}[/code]