JAVA 日期 一個時間段總共幾周，每一天星期幾

/**
     * 查詢一個時間段的總周數和查詢當前時間是第幾周
     * @param start
     * @param end
     * @return
     */
    private int[] selectWeekNum(Date start,Date end,int week,int flag){
        java.util.Calendar now = java.util.Calendar.getInstance();
        java.util.Calendar c_total = java.util.Calendar.getInstance();
        java.util.Calendar c_begin =  java.util.Calendar.getInstance();
        java.util.Calendar c_end = java.util.Calendar.getInstance();
        int count = 0;
        int weekTotal = 0;
        try {
            c_begin.setTime(start);
            c_end.setTime(end);
            now.setTime(new SimpleDateFormat("yyyy-MM-dd").parse(sdf.format(new Date())));
            int begin = c_begin.get(java.util.Calendar.WEEK_OF_YEAR);
            int over =c_end.get( java.util.Calendar.WEEK_OF_YEAR);
            int z = now.get( java.util.Calendar.WEEK_OF_YEAR);
            if (c_begin.getWeekYear() != c_end.getWeekYear()) {
                Date totalYear = new SimpleDateFormat("yyyy-MM-dd").parse(c_begin.getWeekYear() + "-12-31");
                c_total.setTime(totalYear);
                int x = c_total.get(java.util.Calendar.WEEK_OF_YEAR);
                while(x==1){
                    c_total.add(java.util.Calendar.DAY_OF_MONTH, -1);
                    x = c_total.get(java.util.Calendar.WEEK_OF_YEAR);
                }
                //如果結束時間剛好是星期天則不加1
                int weekNum  = this.dayForWeek(new SimpleDateFormat("yyyy-MM-dd").format(end));
                int duoyu = 0;
                if(weekNum==7) {
                     duoyu = x - begin+1;
                }else{
                    duoyu = x - begin + 1+1;
                }
                weekTotal = over + duoyu;
            } else {
                //如果結束時間剛好是星期天則不加1
                int weekNum  = this.dayForWeek(new SimpleDateFormat("yyyy-MM-dd").format(end));
                if(weekNum==7){
                    weekTotal = over - begin ;
                }else{
                    weekTotal = over - begin + 1;
                }
            }
            if (c_begin.getWeekYear() != now.getWeekYear()) {
                //計算總周數
                int x = c_total.get(java.util.Calendar.WEEK_OF_YEAR);
                while(x==1){
                    c_total.add(java.util.Calendar.DAY_OF_MONTH, -1);
                    x = c_total.get(java.util.Calendar.WEEK_OF_YEAR);
                }
                int weekNum  = this.dayForWeek(new SimpleDateFormat("yyyy-MM-dd").format(start));
                int duoyu =0;
                if(weekNum==7){
                    duoyu = x - begin + 1+1;
                }else{
                    duoyu = x - begin + 1;
                }
                count = duoyu + z;
            } else {
                int weekNum  = this.dayForWeek(new SimpleDateFormat("yyyy-MM-dd").format(start));
                if(weekNum==7){
                    count = (z - begin + 1)+1;
                }else{
                    count = (z - begin + 1);
                }
            }
            if (c_end.getTime().getTime() < now.getTime().getTime() || count < 0) {
                //如果當前時間大於學期結束時間，默然顯示第一周
                count = 1;
            }
　　　　　　　　//下拉框默認顯示的東西可根據實際情況刪除或保留
            if (week != 0 && flag == 1) {
                count = week;
            }
        }  catch (Exception e) {
              e.printStackTrace();
        }
        return new int[]{count,weekTotal};
    }

/**
     * 判斷當前日期是星期幾
     *
     * @param pTime 修要判斷的時間
     * @return dayForWeek 判斷結果
     * @Exception 發生異常
     */
    public int dayForWeek(String pTime) throws Exception {
        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
        java.util. Calendar c =  java.util. Calendar.getInstance();
        c.setTime(format.parse(pTime));
        int dayForWeek = 0;
        if(c.get( java.util. Calendar.DAY_OF_WEEK) == 1){
            dayForWeek = 7;
        }else{
            dayForWeek = c.get( java.util. Calendar.DAY_OF_WEEK) - 1;
        }
        return dayForWeek;
    }

 /**
     * 查詢一周的開始時間和結束時間
     * @param date
     * @return
     */
    private Map<String,Date>  onceWeek(Date date){
       java.util.Calendar currentDate = new GregorianCalendar();
        currentDate.setTime(date);

        currentDate.setFirstDayOfWeek( java.util.Calendar.MONDAY);
        currentDate.set( java.util.Calendar.HOUR_OF_DAY, 0); currentDate.set( java.util.Calendar.MINUTE, 0); currentDate.set( java.util.Calendar.SECOND, 0); currentDate.set( java.util.Calendar.DAY_OF_WEEK, java.util.Calendar.MONDAY); Date dBegin = (Date) currentDate.getTime().clone(); currentDate.setFirstDayOfWeek( java.util.Calendar.MONDAY); currentDate.set( java.util.Calendar.HOUR_OF_DAY, 23); currentDate.set( java.util.Calendar.MINUTE, 59); currentDate.set( java.util.Calendar.SECOND, 59); currentDate.set( java.util.Calendar.DAY_OF_WEEK, java.util.Calendar.SUNDAY); Date dEnd =(Date) currentDate.getTime().clone(); //返回星期天和一個星期的日期和周幾 Map<String,Date> map = new HashMap<>(); map.put("dBegin",dBegin); map.put("dEnd",dEnd); return map; }

/**
     * 查詢一周的時間
     * @param start
     * @param end
     * @param week
     * @param flag
     * @return
     */
    private  List< List<ScheduleVO> >  onceWeekList(Date start ,Date end,int week,int flag) {
        List< List<ScheduleVO>> list = new ArrayList<>();
        try {
            int[] total = this.selectWeekNum(start, end,week,flag);
            int weekTotal = total[1];
            java.util.Calendar currentDate = new GregorianCalendar();
            currentDate.setTime(start);
            for (int i = 0; i < weekTotal; i++) {
               Map<String,Date> map = this.onceWeek(currentDate.getTime());
                List<ScheduleVO> lDate = findDates(map.get("dBegin"),map.get("dEnd"));
                currentDate.setTime(map.get("dEnd"));
                currentDate.add(java.util.Calendar.DAY_OF_MONTH, 1);
                list.add(lDate);
            }
        }catch (Exception e){
            System.out.print(e.getMessage());
        }
        return  list;
    }

  /**
     *查詢當前日期和指定日期為星期幾
     * @param beginDate
     * @param endDate
     * @return
     */
    public static List<ScheduleVO> findDates(Date beginDate, Date endDate)
    {
        //數字轉中文
        SimpleDateFormat sif = new SimpleDateFormat("yyyy-MM-dd");
        Map<Integer,String> weekNumString = new HashMap<>();
        weekNumString.put(1,"星期一");
        weekNumString.put(2,"星期二");
        weekNumString.put(3,"星期三");
        weekNumString.put(4,"星期四");
        weekNumString.put(5,"星期五");
        weekNumString.put(6,"星期六");
        weekNumString.put(7,"星期天");

        ScheduleVO schedule1 = new ScheduleVO();
        List<ScheduleVO> lDate = new ArrayList<>();
        schedule1.setDate(sif.format(beginDate));
        schedule1.setWeekName("星期一");
        schedule1.setWeek(1);
        lDate.add(schedule1);

        java.util.Calendar cal = java.util.Calendar.getInstance();
        cal.setTime(beginDate);
        boolean bContinue = true;
        int week = 1;
        while (bContinue) {
            //根據日歷的規則，為給定的日歷字段添加或減去指定的時間量
            cal.add(java.util.Calendar.DAY_OF_MONTH, 1);
            // 測試此日期是否在指定日期之后
            if (endDate.after(cal.getTime()))
            {
                week++;
                ScheduleVO schedule = new ScheduleVO();
                schedule.setDate(sif.format(cal.getTime()));
                schedule.setWeekName(weekNumString.get(week));
                schedule.setWeek(week);
                lDate.add(schedule);
            }else {
                bContinue = false;
            }
        }
        return lDate;
    }

 

//總共有幾周 當天是這段時間的第幾周
 public static Long[] weekNum(String  begin,String  end) throws ParseException {
        Calendar cal = Calendar.getInstance();
        cal.setTime(DateUtils.parseDate(begin,DateUtils.FORMAT_DATE));
        int monday = cal.get(Calendar.DAY_OF_WEEK) - 1;
        if(monday!=1){
            cal.set(cal.DAY_OF_WEEK, cal.MONDAY);
            begin= DateUtils.format(cal.getTime(),DateUtils.FORMAT_DATE);
        }
        System.out.println("學期開始時間所在周周一日期："+begin);

        Calendar cal1 = Calendar.getInstance();
        cal1.setTime(DateUtils.parseDate(end,DateUtils.FORMAT_DATE));
        int sunday = cal1.get(Calendar.DAY_OF_WEEK) - 1;
        if(sunday!=0){
            cal1.set(Calendar.DATE, cal1.get(cal1.DATE) + 6);
            end = DateUtils.format(cal1.getTime(),DateUtils.FORMAT_DATE);
        }
        System.out.println("學期結束時間所在周周日日期："+end);

        Long totalWeek = 0l;
        Long thisWeek = 0l;
        String nowDate = DateUtils.format(new Date(),DateUtils.FORMAT_DATE);

        int ss = 1000;
        int mi = ss * 60;
        int hh = mi * 60;
        int dd = hh * 24;
        Long beginTime =DateUtils.parse(begin,DateUtils.FORMAT_DATE).getTime();
        Long endTime =DateUtils.parse(end,DateUtils.FORMAT_DATE).getTime();
        //當前時間的星期天
        Calendar cal2 = Calendar.getInstance();
        cal2.setTime(new Date());
        int thisSunDay = cal2.get(Calendar.DAY_OF_WEEK) - 1;
        if(thisSunDay!=0){
            cal2.set(Calendar.DATE, cal2.get(cal2.DATE) + 6);
            nowDate = DateUtils.format(cal2.getTime(),DateUtils.FORMAT_DATE);
        }
        System.out.println("當前時間所在周周日日期："+nowDate);

        Long now =  DateUtils.parse(nowDate,DateUtils.FORMAT_DATE).getTime();

        //得到總共的天數，因為開始時間沒有計算進去故加1
        Long totalWeekTime = (endTime-beginTime)/ dd+1;
        Long thisWeekTime = (now-beginTime)/dd+1;
        totalWeek = totalWeekTime/7;//得到總的周數


        if(now>endTime){
            thisWeek = 1l;//默認顯示第一周
        }else if(monday==0){
            thisWeek= thisWeekTime/7+1;//因英文第一天是周日故+1
        }else{
            thisWeek= thisWeekTime/7;
        }
        return new Long[]{thisWeek,totalWeek};
    }