獲取當前時間的毫秒值

class Demo{
 public static void main(String[] args) throws ParseException   {
        //獲取當前時間到毫秒值
        Date d = new Date();
        System.out.println("當前時間為:" + d);
        //建立日期格式化物件(把日期轉成字串)
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy年MM月dd日HH時mm分s秒");
        String str = sdf.format(d);
        System.out
 
.println(str);

        //解析(將字串轉換為日期都物件)
        String str2 = "2021-12-12";
        SimpleDateFormat sdf2 = new SimpleDateFormat("yyyy-MM-dd");
        Date d1 = sdf2.parse(str2);
        System.out.println(d1);
    }
}

獲取日曆類

//日曆類Calendar
        //獲取Calendar日曆物件
        Calendar c = Calendar.getInstance
 
();
        int year = c.get(Calendar.YEAR);  //獲取指定的日曆欄位的值
        int month = c.get(Calendar.MONTH);
        int date = c.get(Calendar.DATE);
        System.out.print(year + "年 ");
        System.out.print(month+"月 ");
        System.out.print( date +"日");