java 日期与周数月数互相转换方法

你的名字 2022-05-11 03:20 311阅读 0赞

import java.text.ParseException;
    import java.text.SimpleDateFormat;
    import java.util.Calendar;
    import java.util.Date;
    
    /**
     * data:2018-6-22
     * author:qixin
     * descriptor:日期常用方法
     * */
    public class DateUtil {
    
        private static SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
    
        private static SimpleDateFormat dayFormat = new SimpleDateFormat("yyyy-MM-dd");
    
        private static SimpleDateFormat weekFormat = new SimpleDateFormat("yyyy-ww");
    
        private static SimpleDateFormat monthFormat = new SimpleDateFormat("yyyy-MM");
    
      
    
        /**
         * Turn date into week.
         * @author yinfuyuan <yinfuyuan@renrenche.com>
         * @param day The date that needs to be converted into the week.
         * @return The week corresponding to the date or empty string.
         */
        public static String dayToWeek(String day) {
            try {
                Date date = dayFormat.parse(day);
                Calendar calendar = Calendar.getInstance();
                calendar.setTime(date);
                calendar.setFirstDayOfWeek(Calendar.MONDAY);
                String year =  (new SimpleDateFormat("yyyy")).format(calendar.getTime());
                String week = String.valueOf(calendar.get(Calendar.WEEK_OF_YEAR));
                return year + "-" + week;
            } catch (ParseException pe) {
                return "";
            }
        }
    
        /**
         * Turn date into month.
         * @author yinfuyuan <yinfuyuan@renrenche.com>
         * @param day The date that needs to be converted into the month.
         * @return The month corresponding to the date or empty string.
         */
        public static String dayToMonth(String day) {
            try {
                Date date = dayFormat.parse(day);
                Calendar calendar = Calendar.getInstance();
                calendar.setTime(date);
                return monthFormat.format(calendar.getTime());
            } catch (ParseException pe) {
                return "";
            }
        }
    
        /**
         * Turn first day of the week into day.
         * @author yinfuyuan <yinfuyuan@renrenche.com>
         * @param week The week that needs to be converted into a day.
         * @return The day corresponding to first of the week or empty string.
         */
        public static String weekToFirstDay(String week) {
            try {
                Date date = weekFormat.parse(week);
                Calendar calendar = Calendar.getInstance();
                calendar.setTime(date);
                calendar.setFirstDayOfWeek(Calendar.MONDAY);
                calendar.add(Calendar.DATE, 1);
                return dayFormat.format(calendar.getTime());
            } catch (ParseException pe) {
                return "";
            }
        }
    
        /**
         * Turn last day of the week into day.
         * @author yinfuyuan <yinfuyuan@renrenche.com>
         * @param week The week that needs to be converted into a day.
         * @return The day corresponding to last day of the week or empty string.
         */
        public static String weekToLastDay(String week) {
            try {
                Date date = weekFormat.parse(week);
                Calendar calendar = Calendar.getInstance();
                calendar.setTime(date);
                calendar.add(Calendar.DATE, 7);
                calendar.setFirstDayOfWeek(Calendar.MONDAY);
                return dayFormat.format(calendar.getTime());
            } catch (ParseException pe) {
                return "";
            }
        }
    
        /**
         * Turn week into month.
         * @author yinfuyuan <yinfuyuan@renrenche.com>
         * @param week The week that needs to be converted into a month.
         * @return The month corresponding to the week or empty string.
         */
        public static String weekToMonth(String week) {
            try {
                Date date = weekFormat.parse(week);
                Calendar calendar = Calendar.getInstance();
                calendar.setTime(date);
                calendar.setFirstDayOfWeek(Calendar.MONDAY);
                return monthFormat.format(calendar.getTime());
            } catch (ParseException pe) {
                return "";
            }
        }
    
        /**
         * Turn first day of the month into day.
         * @author yinfuyuan <yinfuyuan@renrenche.com>
         * @param month The month that needs to be converted into a date.
         * @return The first day of the month or empty string.
         */
        public static String monthToFirstDay(String month) {
            try {
                Date date = monthFormat.parse(month);
                Calendar calendar = Calendar.getInstance();
                calendar.setTime(date);
                return dayFormat.format(calendar.getTime());
            } catch (ParseException pe) {
                return "";
            }
        }
    
        /**
         * Turn last day of the month into day.
         * @author yinfuyuan <yinfuyuan@renrenche.com>
         * @param month The month that needs to be converted into a date.
         * @return The last day of the month or empty string.
         */
        public static String monthToLastDay(String month) {
            try {
                Date date = monthFormat.parse(month);
                Calendar calendar = Calendar.getInstance();
                calendar.setTime(date);
                calendar.add(Calendar.MONTH, 1);
                calendar.add(Calendar.DATE, -1);
                return dayFormat.format(calendar.getTime());
            } catch (ParseException pe) {
                return "";
            }
        }
    
        /**
         * Turn first week of the month into week.
         * @author yinfuyuan <yinfuyuan@renrenche.com>
         * @param month The month that needs to be converted into a first week.
         * @return The first week of the month corresponding to the week or empty string.
         */
        public static String monthToFirstWeek(String month) {
            try {
                Date date = monthFormat.parse(month);
                Calendar calendar = Calendar.getInstance();
                calendar.setTime(date);
                return weekFormat.format(calendar.getTime());
            } catch (ParseException pe) {
                return "";
            }
        }
    
        /**
         * Turn last week of the month into week.
         * @author yinfuyuan <yinfuyuan@renrenche.com>
         * @param month The month that needs to be converted into a last week.
         * @return The last week of the month corresponding to the week or empty string.
         */
        public static String monthToLastWeek(String month) {
            try {
                Date date = monthFormat.parse(month);
                Calendar calendar = Calendar.getInstance();
                calendar.setTime(date);
                calendar.add(Calendar.MONTH, 1);
                calendar.add(Calendar.DATE, -1);
                return weekFormat.format(calendar.getTime());
            } catch (ParseException pe) {
                return "";
            }
        }
    
        /**
         * 返回天数double类型
         * @author qixin
         * @param startTime,
         * @param endTime,
         * @return  返回天数double类型 天数小于1的都归为1（默认1天即汇总）
         */
        public static Double getDayNum(String startTime,String endTime) {
            SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
            Double dayNum=1.00d;
            try{
                Calendar cal = Calendar.getInstance();
                cal.setTime(sdf.parse(startTime));
                long time1 = cal.getTimeInMillis();
                cal.setTime(sdf.parse(endTime));
                long time2 = cal.getTimeInMillis();
                long between_days=(time2-time1)/(1000*3600*24);
                if (between_days>1){
                    String day=between_days+"";
                    dayNum=Double.valueOf(day);
                }else {
                    dayNum=1.00d;
                }
            }catch (Exception e){
                e.printStackTrace();
                System.out.println(e.getMessage());
            }
            return dayNum;
        }
    
    }

感谢观看