java 根据日期计算当前周一和周日，及根据秒数计算天小时分钟秒数等相关日期

日期工具类

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

public class DateUtil {
    public static final String[] DATE_FORMAT = { "yyyy-MM-dd", "yyyy-MM-dd HH:mm:ss", "yyyy-MM-dd HH:mm:ss.SSS", "yyyyMMdd", "yyyyMMddHHmmss", "yyyyMMddHHmmssSSS", "HH:mm", "HH:mm:ss" };

    private final static SimpleDateFormat shortSdf = new SimpleDateFormat("yyyy-MM-dd");
    private final static SimpleDateFormat longSdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    
    public static Date getWeekDayStartTime(Date startDate) {
        Calendar c = Calendar.getInstance();
        c.setTime(startDate);
        try {
            int weekday = c.get(Calendar.DAY_OF_WEEK) - 2;
            c.add(Calendar.DATE, -weekday);
            c.setTime(longSdf.parse(shortSdf.format(c.getTime()) + " 00:00:00"));
        } catch (Exception e) {
            e.printStackTrace();
        }
        return c.getTime();
    }

    
    public static Date getWeekDayEndTime(Date endDate) {
        Calendar c = Calendar.getInstance();
        c.setTime(endDate);
        try {
            int weekday = c.get(Calendar.DAY_OF_WEEK);
            c.add(Calendar.DATE, 8 - weekday);
            c.setTime(longSdf.parse(shortSdf.format(c.getTime()) + " 23:59:59"));
        } catch (Exception e) {
            e.printStackTrace();
        }
        return c.getTime();
    }

    
    public static Date getCurrentWeekDayStartTime() {
        Calendar c = Calendar.getInstance();
        try {
            int weekday = c.get(Calendar.DAY_OF_WEEK) - 2;
            c.add(Calendar.DATE, -weekday);
            c.setTime(longSdf.parse(shortSdf.format(c.getTime()) + " 00:00:00"));
        } catch (Exception e) {
            e.printStackTrace();
        }
        return c.getTime();
    }

    
    public static Date getCurrentWeekDayEndTime() {
        Calendar c = Calendar.getInstance();
        try {
            int weekday = c.get(Calendar.DAY_OF_WEEK);
            c.add(Calendar.DATE, 8 - weekday);
            c.setTime(longSdf.parse(shortSdf.format(c.getTime()) + " 23:59:59"));
        } catch (Exception e) {
            e.printStackTrace();
        }
        return c.getTime();
    }
    
    public static Date getCurrentDayStartTime() {
        Date now = new Date();
        try {
            now = shortSdf.parse(shortSdf.format(now));
        } catch (Exception e) {
            e.printStackTrace();
        }
        return now;
    }

    
    public static Date getCurrentDayEndTime() {
        Date now = new Date();
        try {
            now = longSdf.parse(shortSdf.format(now) + " 23:59:59");
        } catch (Exception e) {
            e.printStackTrace();
        }
        return now;
    }

    
    public static String parseSeconds(long totalSeconds) {
        long day = 0;
        long hour = 0;
        long minute = 0;
        long second = 0;
        if (totalSeconds > 0) {
            second = totalSeconds;
            if (second >= 60) {
                minute = second / 60;
                second = second % 60;
                if (minute >= 60) {
                    hour = minute / 60;
                    minute = minute % 60;
                    if (hour > 24) {
                        day = hour / 24;
                        hour = hour % 24;
                    }
                }
            }
        }
        return (day >= 10 ? (day + "") : ("0" + day) +":"+ (hour >= 10 ? (hour + ""): ("0" + hour))+ ":" + (minute >= 10 ? (minute + "") : ("0" + minute)) + ":" + (second >= 10 ? (second + "") : ("0" + second)));

    }
    
    public static double getDistanceOfTwoDate(Date before, Date after) {
        long beforeTime = before.getTime();
        long afterTime = after.getTime();
        return (afterTime - beforeTime) / (1000 * 60 * 60 * 24);
    }
    
    public static int daysBetween(Date smdate, Date bdate)
            throws ParseException {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        smdate = sdf.parse(sdf.format(smdate));
        bdate = sdf.parse(sdf.format(bdate));
        Calendar cal = Calendar.getInstance();
        cal.setTime(smdate);
        long time1 = cal.getTimeInMillis();
        cal.setTime(bdate);
        long time2 = cal.getTimeInMillis();
        long between_days = (time2 - time1) / (1000 * 3600 * 24);

        return Integer.parseInt(String.valueOf(between_days));
    }
    
    public static double getDistanceHoursOfTwoDate(Date before, Date after) {
        long beforeTime = before.getTime();
        long afterTime = after.getTime();
        return (afterTime - beforeTime) / (1000 * 60 * 60 );  }
    
    public static long getDistanceSecondOfTwoDate(Date before, Date after) {
        long beforeTime = before.getTime();
        long afterTime = after.getTime();
        return (afterTime - beforeTime) / 1000 ;
    }
    
    public static boolean isEffectiveDate(Date nowTime, Date startTime, Date endTime) {
        if (nowTime.getTime() == startTime.getTime()
                || nowTime.getTime() == endTime.getTime()) {
            return true;
        }

        Calendar date = Calendar.getInstance();
        date.setTime(nowTime);

        Calendar begin = Calendar.getInstance();
        begin.setTime(startTime);

        Calendar end = Calendar.getInstance();
        end.setTime(endTime);

        if (date.after(begin) && date.before(end)) {
            return true;
        } else {
            return false;
        }
    }
    
    public static String dateToWeek(String datetime)  {
        SimpleDateFormat f = new SimpleDateFormat("yyyyMMdd");
        String[] weekDays = { "星期日", "星期一", "星期二", "星期三", "星期四", "星期五", "星期六" };
        Calendar cal = Calendar.getInstance(); // 获得一个日历
        Date datet = null;
        try {
            datet = f.parse(datetime);
            cal.setTime(datet);
        } catch (Exception e) {
            e.printStackTrace();
        }
        int w = cal.get(Calendar.DAY_OF_WEEK) - 1; // 指示一个星期中的某天。
        if (w < 0)
            w = 0;
        return weekDays[w];
    }
}