这篇文章主要介绍“Java枚举enum如何实现”,在日常操作中,相信很多人在Java枚举enum如何实现问题上存在疑惑,小编查阅了各式资料,整理出简单好用的操作方法,希望对大家解答”Java枚举enum如何实现”的疑惑有所帮助!接下来,请跟着小编一起来学习吧!
1.枚举是一组常量的集合
2.理解:美剧属于一种特殊的类,里面只包含一组有限的特定的对象
1.不需要提供Set方法,枚举对象值通常为只读。
2.对枚举对象/属性使用final和static关键字修饰,实现底层优化
3.枚举对象名通常使用全部大写,常量的命名规范
4.枚举·对象根据需要,可以有一到多个属性
package com.demo;
import javax.sound.midi.Soundbank;
/**
* @version 1.0
* @auther Demo龙
*/
public class Enum01 {
public static void main(String[] args) {
System.out.println(Season.SPRING);
System.out.println(Season.SUMMER);
System.out.println(Season.AUTUMN);
System.out.println(Season.WINTER);
}
}
//演示自定义枚举实现
class Season{
private String name;
private String desc;//描述特性
//1.将构造器私有化,目的防止直接new出来
private Season(String name, String desc) {
this.name = name;
this.desc = desc;
}
//2.去掉set方法,只能读取,不能修改属性
public String getName() {
return name;
}
public String getDesc() {
return desc;
}
//3.在season内部创建固定的对象
//定义了四个对象
// public static Season SPRING=new Season("春天","温暖");
// public static Season SUMMER=new Season("夏天","炎热");
// public static Season AUTUMN=new Season("秋天","凉爽");
// public static Season WINTER=new Season("冬天","寒冷");
//最终优化,加入final
public static final Season SPRING=new Season("春天","温暖");
public static final Season SUMMER=new Season("夏天","炎热");
public static final Season AUTUMN=new Season("秋天","凉爽");
public static final Season WINTER=new Season("冬天","寒冷");
//重写toString方法
@Override
public String toString() {
return "Season{" +
"name='" + name + '\'' +
", desc='" + desc + '\'' +
'}';
}
}
如果使用enum关键字来实现枚举类
1.使用关键字enum替换class
2.public static final Season02 SPRING=new Season02(“春天”,“温暖”);可替换为 SPRING(“春天”,“温暖”),//解读:常量名(实参列表)
3.如果有多个常量使用逗号间隔即可
4.如果使用enum关键字实现枚举,要求将定义的常量对象写下前面
package com.demo;
/**
* @version 1.0
* @auther Demo龙
*/
public class Enum02 {
public static void main(String[] args) {
System.out.println(Season.SPRING);
System.out.println(Season.SUMMER);
System.out.println(Season.AUTUMN);
System.out.println(Season.WINTER);
}
}
//演示使用enum关键字来实现枚举类
enum Season02{
//如果使用enum关键字来实现枚举类
//1.使用关键字enum替换class
//2.public static final Season02 SPRING=new Season02("春天","温暖");可替换为
SPRING("春天","温暖"),//解读:常量名(实参列表)
//3.如果有多个常量使用逗号间隔即可
SUMMER("夏天","炎热"),
AUTUMN("秋天","凉爽"), WINTER("冬天","寒冷");
//4.如果使用enum关键字实现枚举,要求将定义的常量对象写下前面
private String name;
private String desc;//描述特性
//1.将构造器私有化,目的防止直接new出来
private Season02(String name, String desc) {
this.name = name;
this.desc = desc;
}
//2.去掉set方法,只能读取,不能修改属性
public String getName() {
return name;
}
public String getDesc() {
return desc;
}
//3.在season内部创建固定的对象
//定义了四个对象
// public static Season SPRING=new Season("春天","温暖");
// public static Season SUMMER=new Season("夏天","炎热");
// public static Season AUTUMN=new Season("秋天","凉爽");
// public static Season WINTER=new Season("冬天","寒冷");
//最终优化,加入final
// public static final Season02 SPRING=new Season02("春天","温暖");
// public static final Season02 SUMMER=new Season02("夏天","炎热");
// public static final Season02 AUTUMN=new Season02("秋天","凉爽");
// public static final Season02 WINTER=new Season02("冬天","寒冷");
//重写toString方法
@Override
public String toString() {
return "Season{" +
"name='" + name + '\'' +
", desc='" + desc + '\'' +
'}';
}
}
1.当我i们使用enum关键字开发一个枚举类时,默认会继承Enum类
2.传统的public static final Season02 SPRING=new Season02("春天","温暖");
,这里要知道他调用的是哪个构造器
3.如果使用无参构造器创建枚举对象,则实参列表和小括号都可以省略.
4.当有多个枚举对象时,使用逗号间隔,最后有一个分号结尾
5.枚举对象必须放在枚举类的行首
package com.demo;
/**
* @version 1.0
* @auther Demo龙
*/
public class Enum02 {
public static void main(String[] args) {
System.out.println(Season.SPRING);
System.out.println(Season.SUMMER);
System.out.println(Season.AUTUMN);
System.out.println(Season.WINTER);
}
}
//演示使用enum关键字来实现枚举类
enum Season02{
//如果使用enum关键字来实现枚举类
//1.使用关键字enum替换class
//2.public static final Season02 SPRING=new Season02("春天","温暖");可替换为
SPRING("春天","温暖"),//解读:常量名(实参列表)
//3.如果有多个常量使用逗号间隔即可
SUMMER("夏天","炎热"),
AUTUMN("秋天","凉爽"), WINTER("冬天","寒冷"),
//3.如果使用无参构造器创建枚举对象,则实参列表和小括号都可以省略.两种写法
HAHA,//调用无参构造器
HAHAHA();//调用无参构造器
//4.如果使用enum关键字实现枚举,要求将定义的常量对象写下前面
private String name;
private String desc;//描述特性
//1.将构造器私有化,目的防止直接new出来
private Season02(String name, String desc) {
this.name = name;
this.desc = desc;
}
private Season02() {
//无参构造器
}
//2.去掉set方法,只能读取,不能修改属性
public String getName() {
return name;
}
public String getDesc() {
return desc;
}
//3.在season内部创建固定的对象
//定义了四个对象
// public static Season SPRING=new Season("春天","温暖");
// public static Season SUMMER=new Season("夏天","炎热");
// public static Season AUTUMN=new Season("秋天","凉爽");
// public static Season WINTER=new Season("冬天","寒冷");
//最终优化,加入final
// public static final Season02 SPRING=new Season02("春天","温暖");
// public static final Season02 SUMMER=new Season02("夏天","炎热");
// public static final Season02 AUTUMN=new Season02("秋天","凉爽");
// public static final Season02 WINTER=new Season02("冬天","寒冷");
//重写toString方法
@Override
public String toString() {
return "Season{" +
"name='" + name + '\'' +
", desc='" + desc + '\'' +
'}';
}
}
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