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 + '\'' +
'}';
}
}
