Java枚举

枚举概念

枚举的引入：

1.传统方式

改进

2.新技术，使用枚举

enum关键字实现枚举注意事项

常用方法：

枚举概念

枚举是一组常量的集合

可以理解为：枚举属于一种特殊的类，里面只包含一组有限的特定的对象

枚举的引入：

要求创建季节Season对象，请设计并完成

1.传统方式


package com.cs.enum_;
 
public class Enumeration01 {
    public static void main(String[] args) {
        //使用
        Season season = new Season("春天", "温暖");
        Season winter = new Season("冬天", "寒冷");
        Season summer = new Season("夏天", "炎热");
        Season autumn = new Season("秋天", "凉爽");
        Season other = new Season("红天","~~~");
    }
}
 
class Season {//类
    private String name;
    private String desc;//描述
 
    public Season(String name, String desc) {
        this.name = name;
        this.desc = desc;
    }
 
    public String getName() {
        return name;
    }
 
    public void setName(String name) {
        this.name = name;
    }
 
    public String getDesc() {
        return desc;
    }
 
    public void setDesc(String desc) {
        this.desc = desc;
    }
}

Season对象特点：

(1)季节的值是有限的几个

(2)只读，不需要修改

改进


public class Enumeration02 {
    public static void main(String[] args) {
        System.out.println(Season.SPRING);
        System.out.println(Season.SUNNER);
        System.out.println(Season.AUTUMN);
        System.out.println(Season.WINTER);
    }
}
 
 
//演示定义枚举实现
class Season {//类
    private String name;
    private String desc;//描述
 
    //定义了四个对象,固定
    public static final Season SPRING = new Season("春天", "温暖");
    public static final Season WINTER = new Season("冬天", "寒冷");
    public static final Season AUTUMN = new Season("秋天", "凉爽");
    public static final Season SUNNER = new Season("夏天", "炎热");
    
    private Season(String name, String desc) {
        this.name = name;
        this.desc = desc;
    }
 
    public String getName() {
        return name;
    }
 
 
    public String getDesc() {
        return desc;
    }
 
    @Override
    public String toString() {
        return "Season{" +
                "name='" + name + '\'' +
                ", desc='" + desc + '\'' +
                '}';
    }
}

2.新技术，使用枚举

构造器私有化

去掉Set相关方法


public class Enumeration03 {
    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);
        //Enum
    }
}
 
//演示定义枚举实现
enum Season {//类
    SPRING("春天", "温暖"),
    WINTER("冬天", "寒冷"),
    AUTUMN("秋天", "凉爽"),
    SUMMER("夏天", "炎热"), WHAT();
 
    private String name;
    private String desc;//描述
 
 
    private Season() {
 
    }
 
    private Season(String name, String desc) {
        this.name = name;
        this.desc = desc;
    }
 
    public String getName() {
        return name;
    }
 
 
    public String getDesc() {
        return desc;
    }
 
    @Override
    public String toString() {
        return "Season{" +
                "name='" + name + '\'' +
                ", desc='" + desc + '\'' +
                '}';
    }
}