java枚举（enum）

自定义枚举类

1. 私有化类的构造器，保证不能在类的外部创建其对象

2. 在类的内部创建枚举类的实例。声明为：public static final

3. 对象如果有实例变量，应该声明为private final，并在构造器中初始化

class Season{
    private final String SEASONNAME;//季节的名称
    private final String SEASONDESC;//季节的描述
    private Season(String seasonName,String seasonDesc){
        this.SEASONNAME = seasonName;
        this.SEASONDESC = seasonDesc;
    }
    public static final Season SPRING = new Season("春天", "春暖花开");
    public static final Season SUMMER = new Season("夏天", "夏日炎炎");
    public static final Season AUTUMN = new Season("秋天", "秋高气爽");
    public static final Season WINTER = new Season("冬天", "白雪皑皑");
}

使用enum定义枚举类

使用 enum 定义的枚举类默认继承了 java.lang.Enum类，因此不能再 继承其他类

枚举类的构造器只能使用 private 权限修饰符

枚举类的所有实例必须在枚举类中显式列出(, 分隔 ; 结尾)。列出的 实例系统会自动添加 public static final 修饰

必须在枚举类的第一行声明枚举类对象

public enum SeasonEnum {
    SPRING("春天","春风又绿江南岸"),
    SUMMER("夏天","映日荷花别样红"),
    AUTUMN("秋天","秋水共长天一色"),
    WINTER("冬天","窗含西岭千秋雪");
    private final String seasonName;
    private final String seasonDesc;
    private SeasonEnum(String seasonName, String seasonDesc) {
        this.seasonName = seasonName;
        this.seasonDesc = seasonDesc;
    }
    public String getSeasonName() {
        return seasonName;
    }
    public String getSeasonDesc() {
        return seasonDesc;
    }
}