枚举类常用方法学习

Posted 2021-01-02

/**
     * int ordinal()
    * int compareTo(E o)
    * String name()
    * String toString()
    * <T> T valueOf(Class<T> type,String name)
    * values() 
    * 此方法虽然在JDK文档中查找不到，但每个枚举类都具有该方法，它遍历枚举类的所有枚举值非常方便
     */
    public static void main(String[] args) {
        //demo1();
//      Week2 mon = Week2.valueOf(Week2.class, "MON");      //通过字节码对象获取枚举项
//      System.out.println(mon);

        Week2[] arr = Week2.values();
        for (Week2 week2 : arr) {
            System.out.println(week2);
        }
    }

    public static void demo1() {
        Week2 mon = Week2.MON;
        Week2 tue = Week2.TUE;
        Week2 wed = Week2.WED;

        /*System.out.println(mon.ordinal());                //枚举项都是有编号的
        System.out.println(tue.ordinal());
        System.out.println(wed.ordinal());

        System.out.println(mon.compareTo(tue));         //比较的是编号
        System.out.println(mon.compareTo(wed));*/

        System.out.println(mon.name());                 //获取实例名称
        System.out.println(mon.toString());             //调用重写之后的toString方法
    }