Java枚举类的使用

当类的对象是有限个并且是确定的，需要定义一组常量时强烈建议使用枚举类。

话不多说直接进入正题

如何定义枚举类

方法一（jdk5.0之前自定义枚举类）：

package kk.java.enumtest;

/**
 * <p>
 * 自定义枚举类
 * </P>
 *
 * @author Kk
 * @since 2022/7/24 11:47
 */
public class SeasonTest {
    public static void main(String[] args) {
        //使用枚举类实例化一个对象
        Season autumn = Season.AUTUMN;
        System.out.println(autumn);
    }
}
class Season {
    //定义属性
    private final String seasonName;
    private final String seasonDesc;

    //私有化构造器并给属性赋值
    private Season(String seasonName, String seasonDesc) {
        this.seasonName = seasonName;
        this.seasonDesc = seasonDesc;
    }

    //提供多个枚举类对象
    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", "丰收时节");
    public static final Season WINTER = new Season("冬天", "天寒地冻");

    public String getSeasonName() {
        return seasonName;
    }

    public String getSeasonDesc() {
        return seasonDesc;
    }

    @Override
    public String toString() {
        return "Season{" +
                "seasonName='" + seasonName + '\'' +
                ", seasonDesc='" + seasonDesc + '\'' +
                '}';
    }
}

运行结果如下：

 

方法二（jdk5.0，可以使用enum关键字定义枚举类）：

package kk.java.enumtest;

/**
 * <p>
 * 使用enum定义枚举类
 * 说明：定义的枚举类默认继承java.lang.Enum类
 * </P>
 *
 * @author Kk
 * @since 2022/7/24 12:08
 */
public class SeasonTest1 {
    public static void main(String[] args) {
        Season1 spring = Season1.SPRING;
        System.out.println(spring);
    }
}

enum Season1 {
    //1.提供枚举类的对象，对象前面的修饰关键字可以省略，对象之间使用 "," 隔开，使用 ";" 结尾
    SPRING("春天", "春暖花开"),
    SUMMER("夏天", "夏日炎炎"),
    AUTUMN("秋天", "秋高气爽"),
    WINTER("冬天", "冰天雪地");

    private final String seasonName;
    private final String seasonDesc;

    Season1(String seasonName, String seasonDesc) {
        this.seasonName = seasonName;
        this.seasonDesc = seasonDesc;
    }

    public String getSeasonName() {
        return seasonName;
    }

    public String getSeasonDesc() {
        return seasonDesc;
    }
}

运行结果如下： 

 枚举类的方法（Enum类中的常用方法）：

 使用enum关键字定义的枚举类实现接口

package kk.java.enumtest;

/**
 * <p>
 * 使用enum定义枚举类
 * 说明：定义的枚举类默认继承java.lang.Enum类
 * </P>
 *
 * @author Kk
 * @since 2022/7/24 12:08
 */
public class SeasonTest1 {
    public static void main(String[] args) {
        Season1 spring = Season1.SPRING;
        System.out.println(spring);
        //调用重写的show方法
        spring.show();
    }
}

//让枚举类的对象分别实现接口中的方法，当然也可以只是在枚举类中实现一次
interface info {
    void show();
}

enum Season1 implements info {
    //1.提供枚举类的对象，对象前面的修饰关键字可以省略，对象之间使用 "," 隔开，使用 ";" 结尾
    SPRING("春天", "春暖花开") {
        @Override
        public void show() {
            System.out.println("春天来咯");
        }
    },
    SUMMER("夏天", "夏日炎炎") {
        @Override
        public void show() {
            System.out.println("夏天来咯");
        }
    },
    AUTUMN("秋天", "秋高气爽") {
        @Override
        public void show() {
            System.out.println("秋天天来咯");
        }
    },
    WINTER("冬天", "冰天雪地") {
        @Override
        public void show() {
            System.out.println("冬天来咯");
        }
    };

    private final String seasonName;
    private final String seasonDesc;

    Season1(String seasonName, String seasonDesc) {
        this.seasonName = seasonName;
        this.seasonDesc = seasonDesc;
    }

    public String getSeasonName() {
        return seasonName;
    }

    public String getSeasonDesc() {
        return seasonDesc;
    }
}