枚举

自定义类实现枚举

//    1.将构造器私有化，防止直接new
//    2.去掉set方法，防止属性被修改
//    3.再Season内部直接创建固定的对象
//    4.优化，可以加入final修饰符
//	  5.可以提供get方法，但不能提供set方法

public class Enumeration_02 {
    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);
    }
}

class Season {
    private String name;
    private String desc;//描述

    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 SUMMER = new Season("夏天", "炎热");
    public static final Season AUTUMN = new Season("秋天", "凉爽");

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

enum关键字实现枚举

public class Enumeration_03 {
    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);
        System.out.println(Season.What);
    }
}
enum Season {
//    1.使用enum代替class
//    2.public static final Season SPRING = new Season("春天","温暖")
//    直接使用SPRING("春天", "温暖")替代
//    常量名(实参列表)
//    3.如果有多个常量（对象），使用“,”间隔即可
//    4.如果使用enum来实现枚举，要求将定义的常量对象写在前面
//    5.如果使用的是无参构造器，创建常量对象则可以省略()
    SPRING("春天", "温暖"),
    SUMMER("夏天", "火热"),
    AUTUMN("秋天","凉爽"),
    WINTER("冬天","寒冷"),
    What;
    private String name;
    private String desc;//描述

    Season() {
        System.out.println("无参构造器");
    }

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

注意事项

1.使用enum关键字开发一个枚举时，默认会继承Enum类[ 通过javap可知]