建立無參物件

public enum Direction {
    
    FRONT ,BEHIND,LEFT,RIGHT;
}

建立有參物件

public enum Directions{

    FRONT("前") {

        @Override
        public void show() {
            System.out.println("前");
        }

    },

    BEHIND("後") {

        @Override
        public void show() {
            System.out.println("後");
        }

    },

    LEFT("左") {

        @Override
        public void show() {
            System.out.println("左");
        }

    },
    RIGHT("右") {

        @Override
        public void show() {
            System.out.println("右");
        }

    };

    public abstract void show();

    private String name;

    private Directions(String name) {
        this.name = name;
    }

    public String getString() {
        return name;
    }
}
 

執行程式

public static void main(String[] args) {
    Direction d = Direction.BEHIND ;
    System.out.println(d);//BEHIND
    System.out.println("--------------------------");
        
    Directions d3 = Directions.RIGHT ;
    System.out.println(d3);//RIGHT
    d3.show();
    String name3 = d3.getString() ;
    System.out.println(name3);
        
        
    //列舉它物件都可以去呼叫toString()方法,返回宣告例項的常量名
    String str = d3.toString() ;
    System.out.println(str);//RIGHT
        
}