Calendar 对象的使用实例

1.Calendar demo例子

Java Calendar 类时间操作，示范代码。

public class CalendarDemo {

    private static SimpleDateFormat date_format = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");

    public static void main(String[] args) {

        //获取calendar实例;

        Calendar calendar = Calendar.getInstance();

        //判断calendar是不是GregorianCalendar类的实例;

        if(calendar instanceof GregorianCalendar){

            System.out.println("属于GregorianCalendar类的实例!");

        }

        //从calendar对象中获得date对象，当前时间;

        Date dates =  calendar.getTime();

        //格式化时间;

        String date_str= date_format.format(dates);

        System.out.println(date_str);

        //设置月份05；代表日历的月份6月，因为月份从0开始。

        calendar.set(Calendar.MONTH, 05);

        int months = calendar.get(Calendar.MONTH);

        System.out.println(months);  //输出05;

        //设置日期为2011-07-24 09：59:50

        calendar.set(2011, 06, 24, 9, 59, 50);

        String getDate = date_format.format(calendar.getTime());

        System.out.println(getDate);   //输出2011-07-24 09:59:50;

        //比较日前大小;

        if(new Date().getTime() > calendar.getTimeInMillis()){

            System.out.println("当前日期在后!");

        }else{

            System.out.println("当前日期在前!");

        }

        //设置当前时间为:2011-07-24 11:06:00

        calendar.setTime(new Date());

        int year   = calendar.get(Calendar.YEAR);   //获取年;

        int month  = calendar.get(Calendar.MONTH);  //获取月;

        int date   = calendar.get(Calendar.DATE);   //获取天;

        int hour   = calendar.get(Calendar.HOUR);   //获取小时;

        int minute = calendar.get(Calendar.MINUTE); //获取分钟;

        int second = calendar.get(Calendar.SECOND); //获取秒钟;

        int hour_of_day = calendar.get(Calendar.HOUR_OF_DAY);    //第几个小时，

        int day_of_month  = calendar.get(Calendar.DAY_OF_MONTH); //这天，在一个月内是第几天.

        int day_of_week = calendar.get(Calendar.DAY_OF_WEEK);    //这天，在一周内，是第几天.

        int day_of_year = calendar.get(Calendar.DAY_OF_YEAR);    //这天，在一年内，是第几天。

        int week_of_year = calendar.get(Calendar.WEEK_OF_YEAR);  //这周，在一年内是第几周;

        int week_of_month = calendar.get(Calendar.WEEK_OF_MONTH);//这周，在这个月是第几周;以以星为标准；

        int zone_offset = calendar.get(Calendar.ZONE_OFFSET);    //获取时区;

        int day_of_week_in_month = calendar.get(Calendar.DAY_OF_WEEK_IN_MONTH);  //某月中第几周，按这个月1号算，1号起就是第1周，8号起就是第2周。以月份天数为标准

        int r = calendar.get(Calendar.AM_PM);

        if(r==calendar.AM){

            System.out.println("现在是上午");

        }

        if(r==calendar.PM){

            System.out.println("现在是下午");

        }

        System.out.println("==================================================");

        System.out.println(year);

        System.out.println(month);

        System.out.println(date);

        System.out.println(hour);

        System.out.println(minute);

        System.out.println(second);

        System.out.println(hour_of_day);

        System.out.println(day_of_month);

        System.out.println(day_of_week);

        System.out.println(day_of_year);

        System.out.println(week_of_year);

        System.out.println(week_of_month);

        System.out.println(zone_offset);

        System.out.println(day_of_week_in_month);

    }

}

2.项目中应用

@RequestMapping(method = RequestMethod.GET, produces = { "application/json" })

    @ResponseBody

    public ListWithTotalCount<AuctionsDTO> aucLotQuery(@ModelAttribute("selectedAgency") SysAgencyDto selectedAgency,

        int page, int rows, String order, String sort) {

        Pageable pageable;

        String agencyId = selectedAgency.getId().toString();

        if (sort != null && !sort.isEmpty()) {

            pageable = new PageRequest(page - 1, rows, Direction.fromStringOrNull(order), sort);

        } else {

            pageable = new PageRequest(page - 1, rows);

        }

        Calendar cal = Calendar.getInstance();

        cal.set(Calendar.HOUR_OF_DAY, 0);

        cal.set(Calendar.MINUTE, 0);

        cal.set(Calendar.SECOND, 0);

        cal.set(Calendar.MILLISECOND, 0);

        Date less = cal.getTime();

        cal.set(Calendar.HOUR_OF_DAY, 23);

        cal.set(Calendar.MINUTE, 59);

        cal.set(Calendar.SECOND, 59);

        cal.set(Calendar.MILLISECOND, 999);

        Date great = cal.getTime();

        Specification<Auction> spec = (root, query, cb) -> {

            List<Predicate> predicates = new ArrayList<Predicate>();

            if (agencyId != null && !agencyId.isEmpty() && !"0".equals(agencyId)) {

                Predicate predicate = cb.equal(root.get(Auction_.agencyId), agencyId);

                predicates.add(predicate);

            }

            Predicate published = cb.equal(root.get(Auction_.isPublished), Auction.AUCLOT_ISPUBLISHED_FINISH);

            predicates.add(published);


　　　　　　  //获取当天的检索条件

            Predicate time =cb.between(root.get(Auction_.startTime),less,great);

            predicates.add(time);

            return cb.and(predicates.toArray(new Predicate[0]));

        };

        Page<Auction> pageresult = auctionRepository.findAll(spec, pageable);

        List<AuctionsDTO> dtoList = (new AuctionsDTOAssembler()).toDTOList(pageresult.getContent());

        return new ListWithTotalCount<AuctionsDTO>(dtoList, (int) pageresult.getTotalElements());

    }