Links to the original text: https://blog.csdn.net/u012291108/article/details/51509988

}

• 1
• 2
• 3
• 4
• 5
• 6
• 7
• 8
• 9
• 10
• 11
• 12
• 13
• 14
• 15
• 16
• 17
• 18
• 19
• 20
• 21
• 22
• 23
• 24
• 25
• 26
• 27
• 28
• 29
• 30
• 31

1. Test

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

• 1
• 2
• 3
• 4
• 5
• 6
• 7

2.Enum Enum Class

1. Enumerated class objects must be declared on the first line of the enumerated class.
2. The difference between enumeration class and common class:
   ①Use enum Defined enumeration classes inherit by default java.lang.Enum class
   ②Enumeration class constructors can only be used private Access Controller
   ③All instances of an enumerated class must be explicitly listed in the enumerated class(, Separate ; Ending). The example system listed will be automatically added public static final Modification
3. JDK 1.5 It can be found in the switch Use in expressions Enum Objects of defined enumeration classes as expressions, case The clause can use the name of the enumerated value directly, There is no need to add enumeration classes as qualifications
4. Dome

interface info{
	void show();
}
//Enum Class
enum Season1  implements info{
	SPRING("spring", "In the warm spring, flowers are coming out with a rush"){
	public void show() {
		System.out.println("Where is spring?");
	}
	},
	SUMMER("summer", "Dog Days of Summer")
	{
		public void show() {
			System.out.println("Living like summer flowers");
		}
	}	,
	AUTUTO("Autumn", "Much has been achieved.")
	{
		public void show() {
			System.out.println("Autumn is the season for breaking up.");
		}
	},
	WINTER("winter", "Snow gleams white")
	{
		public void show() {
			System.out.println("A fire in winter");
		}
	};
<span class="token comment">//1. Provide class properties declared as 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. Attributes declared final, initialized in the constructor</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. Calling attributes through common methods</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("this season");
// }
}

• 1
• 2
• 3
• 4
• 5
• 6
• 7
• 8
• 9
• 10
• 11
• 12
• 13
• 14
• 15
• 16
• 17
• 18
• 19
• 20
• 21
• 22
• 23
• 24
• 25
• 26
• 27
• 28
• 29
• 30
• 31
• 32
• 33
• 34
• 35
• 36
• 37
• 38
• 39
• 40
• 41
• 42
• 43
• 44
• 45
• 46
• 47
• 48
• 49
• 50
• 51
• 52
• 53

1. Test
   Common methods are written in notes

public class TestEnum {
	public static void main(String[] args) {
		System.out.println("------------enum Keyword");
		//1.values(): Returns an array of enumerated classes
		Season1 [] seasons = Season1.values();
		for(int i = 0; i < seasons.length;i++) {
			System.out.println(seasons[i]);
		}
		//2.valueOf(String name): Requires the incoming parameter name to be the name of the enumerated object
		//Otherwise: Report a java.lang.IllegalArgumentException exception
		String str = "SPRING";
		Season1 sea = Season1.valueOf(str);
		System.out.println(sea);
		//Running status of threads
		Thread.State[] states = Thread.State.values();
		for (int i = 0; i < states.length; i++) {
			System.out.println(states[i]);
		}
<span class="token punctuation">}</span>

}

• 1
• 2
• 3
• 4
• 5
• 6
• 7
• 8
• 9
• 10
• 11
• 12
• 13
• 14
• 15
• 16
• 17
• 18
• 19
• 20
• 21

3. Enumeration Classes for Implementing Interfaces

1. Like ordinary Java classes, enumeration classes can implement one or more interfaces.
2. If each enumerated value is required to behave differently in the interface method invoked, then each enumerated value can be used to implement the method separately.
3. The implementation method can be seen in the demo above.

                                </div>