JAVA_SE 枚举类

 

 

public class TestSeason {
	public static void main(String[] args) {
		Season spring = Season.SPRING;
		System.out.println(spring);
		spring.show();
		System.out.println(spring.getSeasonName());
	}
}
//枚举类
class Season{
	//1.提供类的属性，声明为private final 
	private final String seasonName;
	private final String seasonDesc;
	//2.声明为final的属性，在构造器中初始化。
	private Season(String seasonName,String seasonDesc){
		this.seasonName = seasonName;
		this.seasonDesc = seasonDesc;
	}
	//3.通过公共的方法来调用属性
	public String getSeasonName() {
		return seasonName;
	}
	public String getSeasonDesc() {
		return seasonDesc;
	}
	//4.创建枚举类的对象:将类的对象声明public static final
	public static final Season SPRING = new Season("spring", "春暖花开");
	public static final Season SUMMER = new Season("summer", "夏日炎炎");
	public static final Season AUTUMN = new Season("autumn", "秋高气爽");
	public static final Season WINTER = new Season("winter", "白雪皑皑");
	@Override
	public String toString() {
		return "Season [seasonName=" + seasonName + ", seasonDesc="
				+ seasonDesc + "]";
	}
	public void show(){
		System.out.println("这是一个季节");
	}
}

　　

jdk5 enum关键字创建枚举类

/*
 * 一、枚举类
 * 1.如何自定义枚举类
 * 2.如何使用enum关键字定义枚举类
 *     >常用的方法:values() valueOf(String name)
 *     >如何让枚举类实现接口:可以让不同的枚举类的对象调用被重写的抽象方法，执行的效果不同。（相当于让每个对象重写抽象方法）
 */
public class TestSeason1 {
	public static void main(String[] args) {
		Season1 spring = Season1.SPRING;
		System.out.println(spring);
		spring.show();
		System.out.println(spring.getSeasonName());
		
		System.out.println();
		//1.values()
		Season1[] seasons = Season1.values();
		for(int i = 0;i < seasons.length;i++){
			System.out.println(seasons[i]);
		}
		//2.valueOf(String name):要求传入的形参name是枚举类对象的名字。
		//否则，报java.lang.IllegalArgumentException异常
		String str = "WINTER";
		Season1 sea = Season1.valueOf(str);
		System.out.println(sea);
		System.out.println();
		
		Thread.State[] states = Thread.State.values();
		for(int i = 0;i < states.length;i++){
			System.out.println(states[i]);
		}
		sea.show();
		
	}
}
interface Info{
	void show();
}
//枚举类
enum Season1 implements Info{
	SPRING("spring", "春暖花开"){
		public void show(){
			System.out.println("春天在哪里？");
		}
	},
	SUMMER("summer", "夏日炎炎"){
		public void show(){
			System.out.println("生如夏花");
		}
	},
	AUTUMN("autumn", "秋高气爽"){
		public void show(){
			System.out.println("秋天是用来分手的季节");
		}
	},
	WINTER("winter", "白雪皑皑"){
		public void show(){
			System.out.println("冬天里的一把火");
		}
	};
	
	private final String seasonName;
	private final String seasonDesc;
	
	private Season1(String seasonName,String seasonDesc){
		this.seasonName = seasonName;
		this.seasonDesc = seasonDesc;
	}
	public String getSeasonName() {
		return seasonName;
	}
	public String getSeasonDesc() {
		return seasonDesc;
	}
	
	@Override
	public String toString() {
		return "Season [seasonName=" + seasonName + ", seasonDesc="
				+ seasonDesc + "]";
	}
//	public void show(){
//		System.out.println("这是一个季节");
//	}
}

　　

 

1. new 枚举类时，需要进行简写

2. 枚举类可以直接继承接口，与java 正常类一样。并且可以对单独的枚举类重写方法。

 

3. 主要方法

values()方法：返回枚举类型的对象数组。该方法可以很方便地遍历所有的枚举值。
valueOf(String str)：可以把一个字符串转为对应的枚举类对象。要求字符串必须是枚举类对象的“名字”。如不是，会有运行时异常。

int	ordinal()           返回枚举常量的序数（它在枚举声明中的位置，其中初始常量序数为零）。