java中的枚举

最新推荐文章于 2025-03-27 15:30:52 发布

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本文通过两个具体的例子展示了Java中枚举类型的使用方法。第一个例子是定义一周中的日子，并演示了如何使用枚举来表示星期几及其实现的简单逻辑。第二个例子则更进一步，通过枚举类型实现了一个交通信号灯的抽象状态机，每个状态都有自己的持续时间，并且能够切换到下一个状态。

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;}
}
}