枚举的接口实现

原文链接：https://blog.csdn.net/u012291108/article/details/51509988

Java 枚举类和自定义枚举类和enum声明及实现接口

• 1.枚举类
• 1.枚举类的属性
• 2.自定义枚举类
• 2.Enum枚举类
• 3.实现接口的枚举类

1.枚举类

注：
JDK1.5之前需要自定义枚举类
JDK 1.5 新增的 enum 关键字用于定义枚举类
若枚举只有一个成员, 则可以作为一种单例模式的实现方式

1.枚举类的属性

1. 枚举类对象的属性不应允许被改动, 所以应该使用 private final 修饰
2. 枚举类的使用 private final 修饰的属性应该在构造器中为其赋值
3. 若枚举类显式的定义了带参数的构造器, 则在列出枚举值时也必须对应的传入参数

2.自定义枚举类

1. 如何自定义枚举类的方法写在注释里

//自定义枚举类
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 final String getSeasonName() {
		return seasonName;
	}
	public final String getSeasonDesc() {
		return seasonDesc;
	}
	//4.创建枚举类的对象:将类的对象声明为public static final
	public static final Season SPRING = new Season("春天", "春暖花开");
	public static final Season SUMMER = new Season("夏天", "夏日炎炎");
	public static final Season FALL = new Season("秋天", "硕果累累");
	public static final Season WINTER = new Season("冬天", "白雪皑皑");
<span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> String <span class="token function">toString</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
	<span class="token keyword">return</span> <span class="token string">"Season [seasonName="</span> <span class="token operator">+</span> seasonName <span class="token operator">+</span> <span class="token string">", seasonDesc="</span> <span class="token operator">+</span> seasonDesc <span class="token operator">+</span> <span class="token string">"]"</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
<span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">show</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
	System<span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"这个一个季节"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

}

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2. Test

public static void main(String[] args) {
		Season spring = Season.SPRING;
		System.out.println(spring);
		spring.show();
		System.out.println(spring.getSeasonName() +" "+spring.getSeasonDesc());
	}
}
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2.Enum枚举类

1. 必须在枚举类的第一行声明枚举类对象。
2. 枚举类和普通类的区别：
   ①使用 enum 定义的枚举类默认继承了 java.lang.Enum 类
   ②枚举类的构造器只能使用 private 访问控制符
   ③枚举类的所有实例必须在枚举类中显式列出(, 分隔 ; 结尾). 列出的实例系统会自动添加 public static final 修饰
3. JDK 1.5 中可以在 switch 表达式中使用Enum定义的枚举类的对象作为表达式, case 子句可以直接使用枚举值的名字, 无需添加枚举类作为限定
4. Dome

interface info{
	void show();
}
//枚举类
enum Season1  implements info{
	SPRING("春天", "春暖花开"){
	public void show() {
		System.out.println("春天在哪里？");
	}
	},
	SUMMER("夏天", "夏日炎炎")
	{
		public void show() {
			System.out.println("生如夏花");
		}
	}	,
	AUTUTO("秋天", "硕果累累")
	{
		public void show() {
			System.out.println("秋天是用来分手的季节");
		}
	},
	WINTER("冬天", "白雪皑皑")
	{
		public void show() {
			System.out.println("冬天里的一把火");
		}
	};
<span class="token comment">//1.提供类的属性，声明为private final</span>
<span class="token keyword">private</span> <span class="token keyword">final</span> String seasonName<span class="token punctuation">;</span>
<span class="token keyword">private</span> <span class="token keyword">final</span> String seasonDesc<span class="token punctuation">;</span>
<span class="token comment">//2.声明为final的属性，在构造器中初始化</span>
<span class="token keyword">private</span> <span class="token function">Season1</span><span class="token punctuation">(</span>String seasonName<span class="token punctuation">,</span>String seasonDesc<span class="token punctuation">)</span> <span class="token punctuation">{</span>
	<span class="token keyword">this</span><span class="token punctuation">.</span>seasonName <span class="token operator">=</span> seasonName<span class="token punctuation">;</span>
	<span class="token keyword">this</span><span class="token punctuation">.</span>seasonDesc <span class="token operator">=</span> seasonDesc<span class="token punctuation">;</span>
<span class="token punctuation">}</span>
<span class="token comment">//3.通过公共的方法来调用属性</span>
<span class="token keyword">public</span> <span class="token keyword">final</span> String <span class="token function">getSeasonName</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
	<span class="token keyword">return</span> seasonName<span class="token punctuation">;</span>
<span class="token punctuation">}</span>
<span class="token keyword">public</span> <span class="token keyword">final</span> String <span class="token function">getSeasonDesc</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
	<span class="token keyword">return</span> seasonDesc<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token annotation punctuation">@Override</span>
<span class="token keyword">public</span> String <span class="token function">toString</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
	<span class="token keyword">return</span> <span class="token string">"Season [seasonName="</span> <span class="token operator">+</span> seasonName <span class="token operator">+</span> <span class="token string">", seasonDesc="</span> <span class="token operator">+</span> seasonDesc <span class="token operator">+</span> <span class="token string">"]"</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>

// public void show() {
// System.out.println(“这个一个季节”);
// }
}

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2. Test
   常用方法写在注释里面

public class TestEnum {
	public static void main(String[] args) {
		System.out.println("------------enum关键字");
		//1.values()：返回枚举类数组
		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是枚举对象的名字
		//否则：报java.lang.IllegalArgumentException异常
		String str = "SPRING";
		Season1 sea = Season1.valueOf(str);
		System.out.println(sea);
		//线程的运行状态
		Thread.State[] states = Thread.State.values();
		for (int i = 0; i < states.length; i++) {
			System.out.println(states[i]);
		}
<span class="token punctuation">}</span>

}

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3.实现接口的枚举类

1. 实现接口的枚举类和普通 Java 类一样，枚举类可以实现一个或多个接口
2. 若需要每个枚举值在调用实现的接口方法呈现出不同的行为方式, 则可以让每个枚举值分别来实现该方法
3. 实现方法可以看上面的demo。

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标签：String,实现,Season,seasonDesc,接口,final,枚举,public
来源： https://blog.csdn.net/weixin_44079558/article/details/100124855