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Excel插入多行VBA实现

王远洋 2024-05-24 阅读 35

Java Enum 枚举类

概述

  • 枚举类型本质上也是一种类,只不过是这个类的对象是有限的、固定的几个,不能让用户随意创建。

枚举类的实现

细节

  • 使用enum关键字定义的枚举类,默认其父类时java.lang.Enum类
  • 使用enum关键字定义的枚举类,不要再显示的定义其父类,否则报错

enum类中的方法

已经定义了enum类

enum Season {
    SPRING("春季","春风又绿江南岸"),
    SUMMER("夏季","映日荷花别样红"),
    AUTUMN("秋季","秋水共长天一色"),
    WINTER("冬季","千里冰封,万里雪飘");
    private final String seasonName;    //季节名称
    private final String seasonDesc;    //季节描述

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

    public String getSeasonName() {
        return seasonName;
    }

    public String getSeasonDesc() {
        return seasonDesc;
    }
}
  • toString() 默认返回的是常量名(对象名),可以继续手动重写该方法!

    public class SeasonTest{
        public static void main(String []args){
            System.out.println(Season.SPRING.toString());	//输出:SPRING
            System.out.println(Season.SUMMER.toString());	//输出:SUMMER
            System.out.println(Season.AUTUMN.toString());	//输出:AUTUMN
            System.out.println(Season.WINTER.toString());	//输出:WINTER
            System.out.println(Season.SPRING); 				//输出:SPRING
            System.out.println(Season.SUMMER);				//输出:SUMMER
            System.out.println(Season.AUTUMN);				//输出: AUTUMN
            System.out.println(Season.WINTER);				//输出:WINTER
        }
    }
    //未重写toSpring()的结果
    String toString(): 默认返回的是常量名(对象名),可以继续手动重写该方法!
    
  • name() 得到当前枚举常量的名称。建议优先使用toString()。

    public class SeasonTest{
        public static void main(String []args){
            System.out.println(Season.SPRING.name());
            System.out.println(Season.SUMMER.name());
            System.out.println(Season.AUTUMN.name());
            System.out.println(Season.WINTER.name());
        }
    }
    //输出结果
    //SPRING
    //SUMMER
    //AUTUMN
    //WINTER
    String name():得到当前枚举常量的名称。建议优先使用toString()
  • values()

    public class SeasonTest{
        public static void main(String []args){
            Season[] values = Season.values();
            for (int i = 0; i < values.length; i++) {
                System.out.println(values[i]);
            }
        }
    }
    //输出结果
    //SPRING
    //SUMMER
    //AUTUMN
    //WINTER
    static 枚举类型[] values():返回枚举类型的对象数组。该方法可以很方便地遍历所有的枚举值,是一个静态方法
    
  • valueOf(String objName)

    static 枚举类型 valueOf(String name):可以把一个字符串转为对应的枚举类对象。要求字符串必须是枚举类对象的“名字”。如不是,会有运行时异常:IllegalArgumentExceptionpublic class SeasonTest{
        public static void main(String []args){
            String objName = "SPRING";
            Season season1 = Season.valueOf(objName);
            System.out.println(season1);	//SPRING
            Season season2 = Season.valueOf("WINTER");
            System.out.println(season2);	//WINTER
        }
    }
    //若重写了toSpring()方法,则按照重写后的来输出
    
  • int ordinal( )

    public class SeasonTest{
        public static void main(String []args){
            System.out.println(Season.SPRING.ordinal());
            System.out.println(Season.SUMMER.ordinal());
            System.out.println(Season.AUTUMN.ordinal());
            System.out.println(Season.WINTER.ordinal());
        }
    }
    //int ordinal():返回当前枚举常量的次序号,默认从0开始
    //输出结果 
    //0
    //1
    //2
    //3
    

枚举类实现接口操作

  • 枚举类实现接口,在枚举类中重写接口中的抽象方法。当通过不同的枚举类对象调用此方法时,执行的是同一个方法

    enum Season implements Info{
        SPRING("春天","春暖花开"),
        SUMMER("夏天","烈日炎炎"),
        AUTUMN("秋天","秋高气爽"),
        WINTER("冬天","白雪皑皑");
        private final String seasonName;	//季节名称
        private final String seasonDesc;	//季节描述
        private Season(String seasonName,String seasonDesc){
            this.seasonName = seasonName;
            this.seasonDesc = seasonDesc;
        }
        public String getSeasonName(){
            returtn this.seasonName;
        }
        public String getSeasonDesc(){
            return this.seasonName;
        }
        
        public void show(){
            System.out.println("这是一个季节");
        }
    }
    interface Info{
        void show();
    }
    
    public class SeasonTest{
        public static void main(String []args){
            Season.SPRING.show();
            Season.SUMMER.show();
        }
    }
    //此时,重写方法是在Season类中
    //输出结果:
    // 这是一个季节
    // 这是一个季节
    
  • 让枚举类的每一个对象都重写接口中的抽象方法,当通过不同的枚举类对象调用此方法时,执行的是不同的方法

    interface Info{
        void show();
    }
    
    enum Season implements Info{
        SPRING("春天","春意盎然"){
            public void show(){
                System.out.println("春风又绿江南岸");
            }
        },
        SUMMER("夏天","烈日炎炎"){
            public void show(){
                System.out.println("映日荷花别样红");
            }
        },
        AUTUMN("秋天","秋高气爽"){
            public void show(){
                System.out.println("秋水共长天一色");
            }
        },
        WINTER("冬天","白雪皑皑"){
            public void show(){
                System.out.println("窗含西岭千秋雪");
            }
        };
        private final String seasonName;
        private final String seasonDesc;
        private Season(String seasonName,String seasonDesc){
            this.seasonName = seasonName;
            this.seasonDesc = seasonDesc;
        }
        public String getSeasonName(){
            return this.seasonName;
        }
        public String getSeasonDesc(){
            return this.seasonDesc;
        }
        
    }
    public class SeasonTest{
        public static void main(String []args){
            Season []seasons = Season.values();
            for(int i = 0; i < seasons.length;i++){
                seasons[i].show();
            }
        }
    }
    
    //输出
    春风又绿江南岸
    映日荷花别样红
    秋水共长天一色
    窗含西岭千秋雪
    
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