一 简单应用

package cn.xy.Enum;

public enum TrafficLamp
{
 RED,GREEN,YELLOW;
}

TrafficLamp red = TrafficLamp.RED;
System.out.println(red);
System.out.println(red.name());
System.out.println(red.ordinal());
System.out.println(TrafficLamp.valueOf("YELLOW"));
TrafficLamp[] ts = TrafficLamp.values();
for (TrafficLamp t : ts)
{
 System.out.println(t.name());
}

结果

RED
RED
0
YELLOW
RED
GREEN
YELLOW

二 复杂应用

package cn.xy.Enum;

public enum TrafficLampComplex
{

// 元素列表必须放在枚举类的最上面
 RED(10)
 {
  @Override
  public TrafficLampComplex nextLamp()
  {
   return GREEN;
  }

@Override
  public String getValue()
  {
   return "红灯，时长" + this.getTime();
  }
 },
 GREEN(10)
 {
  @Override
  public TrafficLampComplex nextLamp()
  {
   return YELLOW;
  }

@Override
  public String getValue()
  {
   return "绿灯，时长" + this.getTime();
  }
 },
 YELLOW(5)
 {
  @Override
  public TrafficLampComplex nextLamp()
  {
   return YELLOW;
  }

@Override
  public String getValue()
  {
   return "黄灯，时长" + this.getTime();
  }
 };

/**
  * 时长
  */
 private int time;

TrafficLampComplex()
 {
 }

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

/**
  * 下一个灯
  * @return
  */
 public abstract TrafficLampComplex nextLamp();

/**
  * 取值
  * @return
  */
 public abstract String getValue();

public int getTime()
 {
  return time;
 }

public void setTime(int time)
 {
  this.time = time;
 }

}

TrafficLampComplex tcRed = TrafficLampComplex.RED;
System.out.println(tcRed.nextLamp());
System.out.println(tcRed.getValue());

结果

GREEN
红灯，时长10

三 提示

如果理解该例子有困难，请参看本博客的《jdk1.5新特性5之枚举之模拟枚举类型》