枚举类

1、枚举类：就是对象的实例个数是确定的（例如：单例模式），也就说我们在创建枚举类的时候，会对构造器进行设置。
2、自定义创建枚举类：

package com.atguigu.java1;

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");
	}
}

3、使用enum关键字创建枚举类（必须将生命的对象放在最前面，同时去掉重复的部分）并且之间用逗号隔开。其他与我们之前创建时一致的。

//枚举类
enum Season1{
	SPRING("spring", "春暖花开"),
	SUMMER("summer", "夏日炎炎"),
	AUTUMN("autumn", "秋高气爽"),
	WINTER("winter", "白雪皑皑");
	
	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 + "]";
	}
}

4、枚举类中主要使用的两个方法：

    //1.values()：已数组的方式，获取所有的枚举成员
    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,获取枚举对象。
    //否则，报java.lang.IllegalArgumentException异常
    String str = "WINTER";
    Season1 sea = Season1.valueOf(str);

5、实现接口：特殊之处在于，当每一对象需要单独实现show方法时，可以通过{}的形式，来完成需求。

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");
		}
	};