Date，DateTime，String等日期格式的相互转化

来源：互联网发布：ubuntu传文件编辑：程序博客网时间：2024/05/22 09:38
日期之间的转化关系：        1，获取当前系统时间   Date date = new Date();2，Date转为DateTime   DateTime dateTime = new DateTime(date.getTime());3，DateTime转为Date   Date date = dateTime.toDate();4，获取日期格式,   DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");5，Date转换为String类型格式   String dateStr = df.format(new Date());工具类/** * 返回当前日期时间字符串<br> * 默认格式:yyyy-mm-dd hh:mm:ss * * @return String 返回当前字符串型日期时间 */public static String getCurrentTime() {        String returnStr = null;        SimpleDateFormat f = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");        Date date = new Date();        returnStr = f.format(date);        return returnStr;        }/** * 返回当前日期时间字符串<br> * 默认格式:yyyymmddhhmmss * * @return String 返回当前字符串型日期时间 */public static BigDecimal getCurrentTimeAsNumber() {        String returnStr = null;        SimpleDateFormat f = new SimpleDateFormat("yyyyMMddHHmmss");        Date date = new Date();        returnStr = f.format(date);        return new BigDecimal(returnStr);        }/** * 返回自定义格式的当前日期时间字符串 * * @param format *            格式规则 * @return String 返回当前字符串型日期时间 */public static String getCurrentTime(String format) {        String returnStr = null;        SimpleDateFormat f = new SimpleDateFormat(format);        Date date = new Date();        returnStr = f.format(date);        return returnStr;        }/** * 返回当前字符串型日期 * * @return String 返回的字符串型日期 */public static String getCurDate() {        Calendar calendar = Calendar.getInstance();        SimpleDateFormat simpledateformat = new SimpleDateFormat("yyyy-MM-dd");        String strDate = simpledateformat.format(calendar.getTime());        return strDate;        }/** * 返回指定格式的字符型日期 * @param date * @param formatString * @return */public static String Date2String(Date date, String formatString) {        if (G4Utils.isEmpty(date)) {        return null;        }        SimpleDateFormat simpledateformat = new SimpleDateFormat(formatString);        String strDate = simpledateformat.format(date);        return strDate;        }/** * 返回当前字符串型日期 * * @param format *            格式规则 * * @return String 返回的字符串型日期 */public static String getCurDate(String format) {        Calendar calendar = Calendar.getInstance();        SimpleDateFormat simpledateformat = new SimpleDateFormat(format);        String strDate = simpledateformat.format(calendar.getTime());        return strDate;        }/** * 返回TimeStamp对象 * * @return */public static Timestamp getCurrentTimestamp() {        Object obj = TypeCaseHelper.convert(getCurrentTime(), "Timestamp", "yyyy-MM-dd HH:mm:ss");        if (obj != null)        return (Timestamp) obj;        else        return null;        }/** * 将字符串型日期转换为日期型 * * @param strDate *            字符串型日期 * @param srcDateFormat *            源日期格式 * @param dstDateFormat *            目标日期格式 * @return Date 返回的util.Date型日期 */public static Date stringToDate(String strDate, String srcDateFormat, String dstDateFormat) {        Date rtDate = null;        Date tmpDate = (new SimpleDateFormat(srcDateFormat)).parse(strDate, new ParsePosition(0));        String tmpString = null;        if (tmpDate != null)        tmpString = (new SimpleDateFormat(dstDateFormat)).format(tmpDate);        if (tmpString != null)        rtDate = (new SimpleDateFormat(dstDateFormat)).parse(tmpString, new ParsePosition(0));        return rtDate;        }/** * dp转px * * @param context * @param * @return */public static float dp2px(Context context, int dpVal) {        return TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,        dpVal, context.getResources().getDisplayMetrics());        }/** * sp转px * * @param context * @param spVal * @return */public static float sp2px(Context context, float spVal) {        return TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP,        spVal, context.getResources().getDisplayMetrics());        }/** * 屏幕宽度 * * @param context * @return */public static int getDisplayWidth(Context context) {        return context.getResources().getDisplayMetrics().widthPixels;        }/** * 屏幕高度 * * @param context * @return */public static int getDisplayHeight(Context context) {        return context.getResources().getDisplayMetrics().heightPixels;        }//是否同月public static boolean isEqualsMonth(DateTime dateTime1, DateTime dateTime2) {        return dateTime1.getMonthOfYear() == dateTime2.getMonthOfYear();        }/** * 第一个是不是第二个的上一个月,只在此处有效 * * @param dateTime1 * @param dateTime2 * @return */public static boolean isLastMonth(DateTime dateTime1, DateTime dateTime2) {        DateTime dateTime = dateTime2.plusMonths(-1);        return dateTime1.getMonthOfYear() == dateTime.getMonthOfYear();        }/** * 第一个是不是第二个的下一个月，只在此处有效 * @param dateTime1 * @param dateTime2 * @return */public static boolean isNextMonth(DateTime dateTime1, DateTime dateTime2) {        DateTime dateTime = dateTime2.plusMonths(1);        return dateTime1.getMonthOfYear() == dateTime.getMonthOfYear();        }/** * 获得两个日期距离几个月 * @return */public static int getIntervalMonths(DateTime dateTime1, DateTime dateTime2) {        return (dateTime2.getYear() - dateTime1.getYear()) * 12 + (dateTime2.getMonthOfYear() - dateTime1.getMonthOfYear());        }/** * 获得两个日期距离几周 * * @param dateTime1 * @param dateTime2 * @return */public static int getIntervalWeek(DateTime dateTime1, DateTime dateTime2) {        DateTime sunFirstDayOfWeek1 = getSunFirstDayOfWeek(dateTime1);        DateTime sunFirstDayOfWeek2 = getSunFirstDayOfWeek(dateTime2);        int days = Days.daysBetween(sunFirstDayOfWeek1, sunFirstDayOfWeek2).getDays();        if (days > 0) {        return (days + 1) / 7;        } else if (days < 0) {        return (days - 1) / 7;        } else {        return days;        }        }/** * 是否是今天 * @param dateTime * @return */public static boolean isToday(DateTime dateTime) {        return new DateTime().toLocalDate().equals(dateTime.toLocalDate());        }/** * 某月第一天是周几 * * @return */public static int getFirstDayOfWeekOfMonth(int year, int month) {        int dayOfWeek = new DateTime(year, month, 1, 0, 0, 0).getDayOfWeek();        if (dayOfWeek == 7) {        return 0;        }        return dayOfWeek;        }//转化一周从周日开始public static DateTime getSunFirstDayOfWeek(DateTime dateTime) {        if (dateTime.dayOfWeek().get() == 7) {        return dateTime;        } else {        return dateTime.minusWeeks(1).withDayOfWeek(7);        }        }/** * 通过年份和月份 得到当月的日子 * * @param year * @param month * @return */public static int getMonthDays(int year, int month) {        month++;        switch (month) {        case 1:        case 3:        case 5:        case 7:        case 8:        case 10:        case 12:        return 31;        case 4:        case 6:        case 9:        case 11:        return 30;        case 2:        if (((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0)) {        return 29;        } else {        return 28;        }default:        return -1;        }        }/** * 获取这个月有几行 * * @param year * @param month * @return */public static int getMonthRows(int year, int month) {        int size = getFirstDayOfWeekOfMonth(year, month) + getMonthDays(year, month) - 1;        return size % 7 == 0 ? size / 7 : (size / 7) + 1;        }/** * 返回当前月份1号位于周几 * * @param year  年份 * @param month 月份，传入系统获取的，不需要正常的 * @return 日：1    一：2       二：3       三：4       四：5       五：6       六：7 */public static int getFirstDayWeek(int year, int month) {        Calendar calendar = Calendar.getInstance();        calendar.set(year, month, 1);        return calendar.get(Calendar.DAY_OF_WEEK);        }public static int getYearByTimeStamp(long timeStamp) {        String date = timeStampToDate(timeStamp);        String year = date.substring(0, 4);        return Integer.parseInt(year);        }public static String timeStampToDate(long timeStamp) {        Date date = new Date(timeStamp);        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");        String dateStr = simpleDateFormat.format(date);        return dateStr;        }/** * 获取当前日期是星期几<br> * * @param dt * @return 当前日期是星期几 */public static Integer getWeekOfDate(DateTime dt) {//        String[] weekDays = {"星期日", "星期一", "星期二", "星期三", "星期四", "星期五", "星期六"};        Integer[] weekDays = {0, 1, 2, 3, 4, 5, 6};        Calendar cal = Calendar.getInstance();        cal.setTime(dt.toDate());        int w = cal.get(Calendar.DAY_OF_WEEK) - 1;        if (w < 0)        w = 0;        return weekDays[w];        }/** * 获取一个日期加上天数得到最后的日期 * * @param d   日期 * @param day 加的天数 如果天数是负数，即是减 * @return 当前日期是星期几 */public static Date addDate(Date d, long day) {        long time = d.getTime();        day = day * 24 * 60 * 60 * 1000;        time += day;        return new Date(time);        }
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