JAVA学习笔记之 Date类和Calendar类的使用

1、Date类的使用

        /**
         * Date类的使用
         * */
        Date date = new Date();
        SimpleDateFormat dateFormat = new SimpleDateFormat();
        dateFormat.applyPattern("yyyy'年'MM'月'dd'日'");
        //或者SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy'年'MM'月'dd'日'");
        String formatDate = dateFormat.format(date);
        System.out.println(formatDate);

2、Calendar类的使用

        /**
         * Calendar类基本的获取时间的方法
         * */

        Calendar calendar = Calendar.getInstance();
        int year = calendar.get(Calendar.YEAR);
        int month = calendar.get(Calendar.MONTH)+1;        //月数加一才可得到当前月份，因为Calendar中以0为第一个月
        int dayOfWeek = calendar.get(Calendar.DATE);
//或者  int dayOfWeek = calendar.get(Calendar.DAY_OF_WEEK)-1;//需要减一，国际上大多数国家以星期日为一周的第一天，中国以星期一为一周的第一天
        int hour12 = calendar.get(Calendar.HOUR);             //十二小时制的小时数
        int hour24 = calendar.get(Calendar.HOUR_OF_DAY);      //二十四小时制的小时数
        int minute = calendar.get(Calendar.MINUTE);
        int second = calendar.get(Calendar.SECOND);
        int milliSecond = calendar.get(Calendar.MILLISECOND);
        System.out.println(year+"年"+month+"月"+dayOfWeek+"日"+hour24+"时"+minute+"分"+second+"秒"+milliSecond+"毫秒");

        /**
         * Calendar类获取某一日期对应这一年的星期几、第几天、第几周、第几月
         * */
        SimpleDateFormat dateFormat1 = new SimpleDateFormat("yyyy:MM:dd");
        Date date1 = dateFormat1.parse("2012:12:01");
        calendar.setFirstDayOfWeek(Calendar.MONDAY);         //系统默认星期天是一周的第一天，设置这个不会改变dayOfWeek的值，但会改变weekOfYear的值
        calendar.setTime(date1);

        int dayOfWeek1 = calendar.get(Calendar.DAY_OF_WEEK) - 1;          //星期几
        int dayOfMonth = calendar.get(Calendar.DAY_OF_MONTH);             //day of month
        int dayOfYear = calendar.get(Calendar.DAY_OF_YEAR);               //day of year
        int weekOFMonth = calendar.get(Calendar.WEEK_OF_MONTH);           //week of month
        int weekOfYear = calendar.get(Calendar.WEEK_OF_YEAR);             //week of year
        System.out.println("dayOfWeek: "+dayOfWeek1);
        System.out.println("dayOfMonth: "+dayOfMonth);
        System.out.println("dayOfYear: "+dayOfYear);
        System.out.println("weekOFMonth: "+weekOFMonth);
        System.out.println("weekOfYear: "+weekOfYear);