枚举类

枚举类:类的对象只有有限个,确定的.

   当定义一组常量是,建议使用枚举类

 定义枚举类:  方式一:自定义枚举类

          单例模式视作只有一个的枚举类

public class Test {
	public static void main(String[] args) {
		System.out.println(Season.SPRING);
	}	
	
}


//自定义枚举类
class Season{
	//设置常量属性
	private final  String Season_Name;
	private final  String Season_Desc;
	
	//私有化构造器
	private Season(String seasonName,String seasonDesc) {
		this.Season_Name=seasonName;
		this.Season_Desc=seasonDesc;
				
	}
	//自定义常量
	public static final Season SPRING =new Season("春天", "气候宜人");
	public static final Season SUMER  =new Season("夏天", "气候宜人");
	public static final Season ATUMN  =new Season("秋天", "气候宜人");
	public static final Season WINTER =new Season("冬天", "气候宜人");

	@Override
	public String toString() {
		return "Season [Season_Name=" + Season_Name + ", Season_Desc=" + Season_Desc + "]";
	}
	//私有fianl属性不允许改变赋值,故只有get方法
	public String getSeason_Name() {
		return Season_Name;
	}

	public String getSeason_Desc() {
		return Season_Desc;
	}
	
	
}

                      方式二:使用enum关键字定义.-----jdk5.0新特性

//enum定义枚举类
enum Season{
	//在类的内部首行创建类的对象,多个对象使用,隔开
	  SPRING("春天", "气候宜人"),
	  SUMER("夏天", "气候宜人"),
	  ATUMN("秋天", "气候宜人"),
	  WINTER("冬天", "气候宜人");
	//设置常量属性默认权限private fianl
	 private final String Season_Name;
	 private final String Season_Desc;
	
	//私有化构造器
	private Season(String seasonName,String seasonDesc) {
		this.Season_Name=seasonName;
		this.Season_Desc=seasonDesc;
				
	}
	

	@Override
	public String toString() {
		return "Season [Season_Name=" + Season_Name + ", Season_Desc=" + Season_Desc + "]";
	}
	//私有fianl属性不允许改变赋值,故只有get方法
	public String getSeason_Name() {
		return Season_Name;
	}

	public String getSeason_Desc() {
		return Season_Desc;
	}
	
	
}

 

枚举类中的常用方法(针对方式二):

---->>>values

---->>>valueOf

---->>>toString

/*System.out.println(Season.SPRING.getSeason_Name());*/
		//values():返回当前枚举类所有对象构成的数组
		Season[] season= Season.values();
		for (int i = 0; i < season.length; i++) {
			System.out.println(season[i]);
		}
		System.out.println("*********************");
		//valuesof(String object):查找返回指定名字的枚举类对象
		Season season2 =Season.valueOf("WINTER");
		System.out.println(season2);
		
		System.out.println("*********************");
		//toString方法:如果自定义的枚举类没有toString方法,则默认继承enum当中的toString方法
		System.out.println(Season.SPRING.toString());

枚举类实现接口(针对方式二):

        枚举类的每一个对象都实现接口

 SPRING("春天", "气候宜人"){
		  public void show(){
			  System.out.println("这是春天的气息");
		  }
	  },
	  SUMER("夏天", "气候宜人"){
		  public void show(){
			  System.out.println("这是夏天的气息");
		  }
	  },
	  ATUMN("秋天", "气候宜人"){
		  public void show(){
			  System.out.println("这是秋天的气息");
		  }
	  },
	  WINTER("冬天", "气候宜人"){
		  public void show(){
			  System.out.println("这是冬天的气息");
		  }
	  };