Java日期周模式

按照公司某项目的需求，定义周模式：每周从周一开始，至少四天在当年的才算第一周 。
定义周实体类:

public class Week {
    private String weekNum;
    private int beginYear;
    private int endYear;
    // 周开始日期 格式: MM/dd
    private String weekBegin;
    // 周结束日期 格式: MM/dd
    private String weekEnd;

    /**
     * 获取周开始日期 (yyyy/MM/dd)
     * @return
     */
    public Date getWeekBeginDate() {
        SimpleDateFormat formatter = new SimpleDateFormat("yyyy/MM/dd");
        String strDate = beginYear + "/" + weekBegin;
        Date date = new Date();
        try {
            date = formatter.parse(strDate);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        return date;
    }

    /**
     * 获取周结束日期 (yyyy/MM/dd)
     * @return
     */
    public Date getWeekEndDate() {
        SimpleDateFormat formatter = new SimpleDateFormat("yyyy/MM/dd");
        String strDate = endYear + "/" + weekEnd;
        Date date = new Date();
        try {
            date = formatter.parse(strDate);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        return date;
    }

    public String getWeekNum() {
        return weekNum;
    }

    public void setWeekNum(String weekNum) {
        this.weekNum = weekNum;
    }

    public int getBeginYear() {
        return beginYear;
    }

    public void setBeginYear(int beginYear) {
        this.beginYear = beginYear;
    }

    public int getEndYear() {
        return endYear;
    }

    public void setEndYear(int endYear) {
        this.endYear = endYear;
    }

    public String getWeekBegin() {
        return weekBegin;
    }

    public void setWeekBegin(String weekBegin) {
        this.weekBegin = weekBegin;
    }

    public String getWeekEnd() {
        return weekEnd;
    }

    public void setWeekEnd(String weekEnd) {
        this.weekEnd = weekEnd;
    }

    @Override
    public String toString() {
       return beginYear + "/" + weekBegin + " ~ " + endYear + "/" + weekEnd + "(第" + weekNum + "周)";
    }

}

周模式帮助类WeekHelper:

public class WeekHelper {

    private static SimpleDateFormat sdf = new SimpleDateFormat("MM/dd");
    private static SimpleDateFormat sdf2 = new SimpleDateFormat("yyyy/MM/dd");

    /**
     * 获取某一年所有周
     * @param currentYear
     * @return
     */
    public static List<Week> getWeeksByYear(int currentYear) {
        ArrayList<Week> weekList = new ArrayList<>();
        Date lastDay = DateUtil.getLastDayOfYear(currentYear);
        boolean result = DateUtil.isLastDayInYearLastWeek(lastDay);
        // 一年最多有53个星期
        for(int i = 0;i < 53 ; i++){
            Date firstDayOfWeek = DateUtil.getFirstDayOfWeek(currentYear, i);
            Date lastDayOfWeek = DateUtil.getLastDayOfWeek(currentYear, i);

            Calendar startCal = Calendar.getInstance();
            startCal.setTime(firstDayOfWeek);
            Calendar endCal = Calendar.getInstance();
            endCal.setTime(lastDayOfWeek);
            String WeekNumStr = String.valueOf(i + 1);
            if (i < 9) {
                WeekNumStr = "0" + (i + 1);
            }
            Week everyWeek = new Week();
            everyWeek.setBeginYear(startCal.get(Calendar.YEAR));
            everyWeek.setEndYear(endCal.get(Calendar.YEAR));
            everyWeek.setWeekBegin(sdf.format(startCal.getTime()));
            everyWeek.setWeekEnd(sdf.format(endCal.getTime()));
            everyWeek.setWeekNum(WeekNumStr);
            if(i <= 50){
                weekList.add(everyWeek);
            }
            if(i > 50){
                // 判断最后一天是否在这区间内
                if(DateUtil.isEffectiveDate(lastDay,firstDayOfWeek,lastDayOfWeek)){
                    // 判断该年的最后一天(xxxx年12月31日)所在的周是不是当年的最后一周
                    if(result){
                        weekList.add(everyWeek);
                    }
                    break;
                }else{
                    weekList.add(everyWeek);
                }
            }

        }
        return weekList;
    }

    /**
     * 获取当前时间所在的年份
     * @param nowCal
     * @return
     */
    public static int getSelectYear(Calendar nowCal){
        int currentYear = nowCal.get(Calendar.YEAR);
        int currentYear1 = currentYear + 1;
        int currentYear2 = currentYear - 1;
        Date[] resultDate = getYearMinDayAndMasDay(currentYear);
        if(DateUtil.isEffectiveDate(nowCal.getTime(),resultDate[0],resultDate[1])){
            return currentYear;
        }else{
            resultDate = getYearMinDayAndMasDay(currentYear1);
            if(DateUtil.isEffectiveDate(nowCal.getTime(),resultDate[0],resultDate[1])){
                return currentYear1;
            }else{
                resultDate = getYearMinDayAndMasDay(currentYear2);
                if(DateUtil.isEffectiveDate(nowCal.getTime(),resultDate[0],resultDate[1])){
                    return currentYear2;
                }
            }
        }
        return 0;
    }

    /**
     * 获取一年第一周的第一天 和 最后一周的最后一天
     * @param currentYear
     * @return
     */
    public static Date[] getYearMinDayAndMasDay(int currentYear){
        Date[] resultDate = new Date[2];
        List<Week> weeks = getWeeksByYear(currentYear);
        Week week0 = weeks.get(0);
        Week week1 = weeks.get(weeks.size()-1);
        Date minDate = week0.getWeekBeginDate();
        Date maxDate = week1.getWeekEndDate();
        resultDate[0] = minDate;
        resultDate[1] = maxDate;
        return resultDate;
    }

    /**
     * 根据当前日期算出所在周的开始时间和结束时间
     * @param currentDate
     * @return
     */
    public static String[] getWeekStartAndEndDay(Date currentDate) {
        String[] weekDay = new String[2];
        Date firstDayOfWeek = DateUtil.getFirstDayOfWeek(currentDate);
        Date lastDayOfWeek = DateUtil.getLastDayOfWeek(currentDate);
        weekDay[0] = sdf2.format(firstDayOfWeek.getTime());
        weekDay[1] = sdf2.format(lastDayOfWeek.getTime());
        return weekDay;
    }

}

日期帮助类DateUtil ：

public class DateUtil {
    public static final long SEC_MILL_SECONDS = 1000;
    public static final long MINUTE_MILL_SECONDS = 60 * SEC_MILL_SECONDS;
    public static final long HOUR_MILL_SECONDS = 60 * MINUTE_MILL_SECONDS;
    public static final long DAY_MILL_SECONDS = 24 * HOUR_MILL_SECONDS;

    // 获取某年的第几周的开始日期
    public static Date getFirstDayOfWeek(int year, int week) {
        Calendar c = getFirstDayOfWeek(year);
        Calendar cal = (GregorianCalendar) c.clone();
        cal.add(Calendar.DATE, week * 7);

        return getFirstDayOfWeek(cal.getTime());
    }

    // 获取某年的第几周的结束日期
    public static Date getLastDayOfWeek(int year, int week) {
        Calendar c = getFirstDayOfWeek(year);
        Calendar cal = (GregorianCalendar) c.clone();
        cal.add(Calendar.DATE, week * 7);

        return getLastDayOfWeek(cal.getTime());
    }

    /** 获取一年开始的第一周的周一
     *  第一周如果有四天或以上就算是该年的第一周,
     *  否则就是上一年的最后一周(用于跨年判断第一周开始时间)
     * @param year
     * @return
     */
    public static Calendar getFirstDayOfWeek(int year){
        Calendar c = new GregorianCalendar();
        c.set(year, Calendar.JANUARY, 1, 0, 0, 0);
        int dayOfWeek = c.get(Calendar.DAY_OF_WEEK);
        // 如果1月1日是周五，周六或者周日，那么这一周是上一年最后一周，重新计算今年的第一周开始的周一
        if(dayOfWeek == Calendar.FRIDAY || dayOfWeek == Calendar.SATURDAY || dayOfWeek == Calendar.SUNDAY){
            while(c.get(Calendar.DAY_OF_WEEK) != Calendar.MONDAY){
                c.add(Calendar.DAY_OF_YEAR, 1);
            }
        }
        return c;
    }

    // 获取当前时间所在周的开始日期
    public static Date getFirstDayOfWeek(Date date) {
        Calendar c = new GregorianCalendar();
        c.setFirstDayOfWeek(Calendar.MONDAY);
        c.setTime(date);
        c.set(Calendar.DAY_OF_WEEK, c.getFirstDayOfWeek()); // Monday
        return c.getTime();
    }

    // 获取当前时间所在周的结束日期
    public static Date getLastDayOfWeek(Date date) {
        Calendar c = new GregorianCalendar();
        c.setFirstDayOfWeek(Calendar.MONDAY);
        c.setTime(date);
        c.set(Calendar.DAY_OF_WEEK, c.getFirstDayOfWeek() + 6); // Sunday
        return c.getTime();
    }

    /**
     * 判断该年的最后一天(xxxx年12月31日)所在的周是不是当年的最后一周,
     * 否则就是下一年的第一周
     */
    public static boolean isLastDayInYearLastWeek(Date lastDate){
        boolean result = false;
        Calendar c = new GregorianCalendar();
        c.setTime(lastDate);
        int lastDay = c.get(Calendar.DAY_OF_WEEK);
        // 当lastDay是周四、五、六、日， 它所在周就是是该年的最后一周
        if(lastDay == Calendar.THURSDAY || lastDay == Calendar.FRIDAY || lastDay == Calendar.SATURDAY || lastDay == Calendar.SUNDAY){
            result = true;
        }
        return result;
    }

    // 获取一年的最后一天
    public static Date getLastDayOfYear(int year) {
        Calendar c = new GregorianCalendar();
        c.set(year, Calendar.DECEMBER, 31, 0, 0, 0);
        return c.getTime();
    }

    /**
     * 判断当前时间是否在[startTime, endTime]区间，注意时间格式要一致
     *
     * @param nowTime 当前时间
     * @param startTime 开始时间
     * @param endTime 结束时间
     * @return
     */
    public static boolean isEffectiveDate(Date nowTime, Date startTime, Date endTime) {
        if(Math.abs(nowTime.getTime() - startTime.getTime()) < 1000 ||
                Math.abs(nowTime.getTime() - endTime.getTime()) < 1000){
            return true;
        }

        Calendar date = new GregorianCalendar();
        date.setTime(nowTime);

        Calendar begin = new GregorianCalendar();
        begin.setTime(startTime);

        Calendar end = new GregorianCalendar();
        end.setTime(endTime);

        if (date.after(begin) && date.before(end)) {
            return true;
        } else {
            return false;
        }
    }
}

Main方法入口：

public class Main {

    public static void main(String[] args) {
        int currentYear = 2019;
        List<Week> weeks = WeekHelper.getWeeksByYear(currentYear);
        System.out.println("当前选择的年份:" + currentYear);
        for(Week week:weeks){
            System.out.println(week.toString());
        }
    }

}

打印的结果如下：

当前选择的年份:2019
2018/12/31 ~ 2019/01/06(第01周)
2019/01/07 ~ 2019/01/13(第02周)
2019/01/14 ~ 2019/01/20(第03周)
2019/01/21 ~ 2019/01/27(第04周)
2019/01/28 ~ 2019/02/03(第05周)
2019/02/04 ~ 2019/02/10(第06周)
2019/02/11 ~ 2019/02/17(第07周)
2019/02/18 ~ 2019/02/24(第08周)
2019/02/25 ~ 2019/03/03(第09周)
2019/03/04 ~ 2019/03/10(第10周)
2019/03/11 ~ 2019/03/17(第11周)
2019/03/18 ~ 2019/03/24(第12周)
2019/03/25 ~ 2019/03/31(第13周)
2019/04/01 ~ 2019/04/07(第14周)
2019/04/08 ~ 2019/04/14(第15周)
2019/04/15 ~ 2019/04/21(第16周)
2019/04/22 ~ 2019/04/28(第17周)
2019/04/29 ~ 2019/05/05(第18周)
2019/05/06 ~ 2019/05/12(第19周)
2019/05/13 ~ 2019/05/19(第20周)
2019/05/20 ~ 2019/05/26(第21周)
2019/05/27 ~ 2019/06/02(第22周)
2019/06/03 ~ 2019/06/09(第23周)
2019/06/10 ~ 2019/06/16(第24周)
2019/06/17 ~ 2019/06/23(第25周)
2019/06/24 ~ 2019/06/30(第26周)
2019/07/01 ~ 2019/07/07(第27周)
2019/07/08 ~ 2019/07/14(第28周)
2019/07/15 ~ 2019/07/21(第29周)
2019/07/22 ~ 2019/07/28(第30周)
2019/07/29 ~ 2019/08/04(第31周)
2019/08/05 ~ 2019/08/11(第32周)
2019/08/12 ~ 2019/08/18(第33周)
2019/08/19 ~ 2019/08/25(第34周)
2019/08/26 ~ 2019/09/01(第35周)
2019/09/02 ~ 2019/09/08(第36周)
2019/09/09 ~ 2019/09/15(第37周)
2019/09/16 ~ 2019/09/22(第38周)
2019/09/23 ~ 2019/09/29(第39周)
2019/09/30 ~ 2019/10/06(第40周)
2019/10/07 ~ 2019/10/13(第41周)
2019/10/14 ~ 2019/10/20(第42周)
2019/10/21 ~ 2019/10/27(第43周)
2019/10/28 ~ 2019/11/03(第44周)
2019/11/04 ~ 2019/11/10(第45周)
2019/11/11 ~ 2019/11/17(第46周)
2019/11/18 ~ 2019/11/24(第47周)
2019/11/25 ~ 2019/12/01(第48周)
2019/12/02 ~ 2019/12/08(第49周)
2019/12/09 ~ 2019/12/15(第50周)
2019/12/16 ~ 2019/12/22(第51周)
2019/12/23 ~ 2019/12/29(第52周)

源码地址：https://github.com/michael19900101/javaWeekDemo

最后编辑于 ：
©著作权归作者所有,转载或内容合作请联系作者
平台声明：文章内容（如有图片或视频亦包括在内）由作者上传并发布，文章内容仅代表作者本人观点，简书系信息发布平台，仅提供信息存储服务。

推荐阅读更多精彩内容

  • Android - 收藏集
    Android 自定义View的各种姿势1 Activity的显示之ViewRootImpl详解 Activity...
    passiontim阅读 173,842评论 25赞 709
  • Java必会技能之基础篇
    一、Java 简介 Java是由Sun Microsystems公司于1995年5月推出的Java面向对象程序设计...
    子非鱼_t_阅读 4,310评论 1赞 44
  • 身在京都的一日随想
    ❶，京都的夜，很有香格里拉的味道。 今天来京都逛街之时，顺便去千年古寺清水寺溜了个弯。如同去任何一个景点一样，以避...
    RWBY阅读 351评论 0赞 1
  • 坚持
    今天情绪不是很好，世贸天阶越热闹越觉得孤单，受了冷眼遭到拒绝。此刻在回家的路上，想想曾经生活的苦难，这些算得了什么...
    雅娣阅读 156评论 0赞 0
  • 我的第一简书——儿童节快乐
    —、儿童节的由来 旧中国的儿童节 硝烟中的童年难免痛苦和愤怒，但苦难的童年也有明快和热情。中国抗日儿童团的建立，让...
    王XianSen阅读 229评论 1赞 0