前言
最近老被小伙伴戳；其实这些都是些很基础的东西，一边完善工具类；一边整理一下关于date的常见运用；以后使用起来就不需要到处去找了；争取做到想要的这儿都有。
正文
private static final String TYPE = "yyyy-MM-dd HH:mm"; public static final long ONEDAY_TIME=24*60*60*1000L; /** * 返回当前时间+天数 * @param nowTime 2019-01-01) * @param number 3 * @return 2019-01-04 00:00:00 */ public static String after(String nowTime, Integer number) { String time = ""; String pattern = "yyyy-MM-dd"; SimpleDateFormat sdf = new SimpleDateFormat(pattern); Date now = null; try { now = sdf.parse(nowTime); } catch (ParseException e) { e.printStackTrace(); } Calendar c = Calendar.getInstance(); c.setTime(now); c.add(Calendar.DAY_OF_MONTH, number); time = c.get(c.YEAR) + "-" + ((c.get(Calendar.MONTH) + 1) < 10 ? "0" + (c.get(Calendar.MONTH) + 1) : (c.get(Calendar.MONTH) + 1)) + "-" + (c.get(Calendar.DAY_OF_MONTH) < 10 ? "0" + c.get(Calendar.DAY_OF_MONTH) : c.get(Calendar.DAY_OF_MONTH)) + " " + (c.get(Calendar.HOUR_OF_DAY) < 10 ? "0" + c.get(Calendar.HOUR_OF_DAY) : c.get(Calendar.HOUR_OF_DAY)) + ":" + (c.get(Calendar.MINUTE) < 10 ? "0" + c.get(Calendar.MINUTE) : c.get(Calendar.MINUTE)) + ":" + (c.get(Calendar.SECOND) < 10 ? "0" + c.get(Calendar.SECOND) : c.get(Calendar.SECOND)); return time; } /** * 当前时间 * * @param data * @return */ public static String timeToString(Date date) { String pattern = "yyyy-MM-dd HH:mm:ss"; SimpleDateFormat sdf = new SimpleDateFormat(pattern); return sdf.format(date); } /** * String转成规定格式 * * @param data * @param pattern * @return */ public static String stringToTime(String data, String pattern) throws Exception { DateFormat fmt = new SimpleDateFormat(pattern); Date date = fmt.parse(data); return fmt.format(date); } /** * 两个时间相减 * * @param startTime * @param endTime * @return */ public static double jisuan(String startTime, String endTime, String pattern) throws Exception { SimpleDateFormat sdf = new SimpleDateFormat(pattern); Date start = sdf.parse(startTime); Date end = sdf.parse(endTime); long cha = end.getTime() - start.getTime(); double result = cha * 1.0 / (1000 * 60 * 60); return result; } /** * 返回固定长度的数字 * * @param strLength * @return */ public static String getFixLenthString(int strLength) { Random rm = new Random(); // 获得随机数 double pross = (1 + rm.nextDouble()) * Math.pow(10, strLength); // 将获得的获得随机数转化为字符串 String fixLenthString = String.valueOf(pross); // 返回固定的长度的随机数 return fixLenthString.substring(1, strLength + 1); } /** * 生成随即的名字 * * @param fileName * @return */ public static String generateFileName(String fileName) { String formatDate = new SimpleDateFormat("yyMMddHHmmss").format(new Date()); int random = new Random().nextInt(10000); int position = fileName.lastIndexOf("."); String extension = fileName.substring(position); return formatDate + random + extension; } /** * 把时间格式字符串转化为date * @param date * @param pattern * @return * @throws ParseException */ public static Date formateDate (String date, String pattern) throws ParseException { return new SimpleDateFormat(pattern).parse(date); } /** * 获取当前年月，格式：yyyyMM * @return java.lang.String */ public static String getYearAndMonth() { SimpleDateFormat formatter = new SimpleDateFormat("yyyyMM"); Date currentTime = new Date(); String date = formatter.format(currentTime); return date; } /** * 获取当前年月，格式：yyyyMM * @return java.lang.String */ public static String getYearAndMonth(Date date) { SimpleDateFormat formatter = new SimpleDateFormat("yyyyMM"); String sdate = formatter.format(date); return sdate; } /** * 获取当前年月，格式：yyyy-MM * @return java.lang.String */ public static String getYearAndMonthForSql() { SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM"); Date currentTime = new Date(); String date = formatter.format(currentTime); return date; } /** * 获取当前年月，格式：yyyy-MM * @return java.lang.String */ public static String getYearAndMonthForSql(Date currentTime) { SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM"); String date = formatter.format(currentTime); return date; } /** * 获取当前年月，格式：yyyyMMdd * @return java.lang.String */ public static String getYearAndMonthAndDay() { SimpleDateFormat formatter = new SimpleDateFormat("yyyyMMdd"); Date currentTime = new Date(); String date = formatter.format(currentTime); return date; } /** * 将传入日期转换为"yyyy-MM-dd HH:mm:ss" * @return java.lang.String */ public static String DateToLongString(Date date) { SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); String dateStr = formatter.format(date); return dateStr; } /** * 将传入日期转换为"yyyy-MM-dd" * @return java.lang.String */ public static String DateToShortString(Date dateStr) { SimpleDateFormat clsFormat = new SimpleDateFormat("yyyy-MM-dd"); String returnString = new String(""); returnString = clsFormat.format(dateStr); return returnString; } /** * 将传入日期转换为"MM-dd" * @return java.lang.String */ public static String DateToMonthAndDayString(Date dateStr) { SimpleDateFormat clsFormat = new SimpleDateFormat("MM-dd"); String returnString = new String(""); returnString = clsFormat.format(dateStr); return returnString; } /** * 将传入日期转换为"MM月dd日" * @return java.lang.String */ public static String DateToMonthAndDayStringForZhCn(Date dateStr) { SimpleDateFormat clsFormat = new SimpleDateFormat("MM月dd日"); String returnString = new String(""); returnString = clsFormat.format(dateStr); return returnString; } /** * 将传入日期转换为"yyyyMMdd" * @return java.lang.String */ public static String DateToStringByName(Date dateStr) { SimpleDateFormat clsFormat = new SimpleDateFormat("yyyyMMdd"); String returnString = new String(""); returnString = clsFormat.format(dateStr); return returnString; } /** * 将传入String("yyyy-MM-dd")转换为java.util.Date * @throws ParseException * @return java.util.Date */ public static Date stringToDate(String str) throws ParseException { Date date = new Date(); SimpleDateFormat formater = new SimpleDateFormat("yyyy-MM-dd"); date = formater.parse(str); return date; } /** * 将传入String("yyyy-MM-dd HH:mm:ss")转换为java.util.Date * @throws ParseException * @return java.util.Date */ public static Date stringToDatetime(String str) throws ParseException { Date date = new Date(); SimpleDateFormat formater = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); date = formater.parse(str); return date; } /** * 将传入String("EEE MMM dd HH:mm:ss z yyyy", Locale.US)转换为java.util.Date * 主要用于Excel导入时日期格式的转化 * @throws ParseException * @return java.util.Date */ public static Date stringToDateForUS(String str) throws ParseException { Date date = new Date(); SimpleDateFormat formater = new SimpleDateFormat("EEE MMM dd HH:mm:ss z yyyy", Locale.US); date = formater.parse(str); return date; } /** * 当前日期+days天 * @return java.util.Date */ public static Date getDateByAfter(int days) { Calendar cal = Calendar.getInstance(); // int day=cal.get(Calendar.DATE); cal.add(Calendar.DAY_OF_YEAR, days); return cal.getTime(); } /** * 获取时间戳，格式："yyyyMMddHHmmssSSS" * @return java.lang.String */ public static String getCurrTimestampForString() { SimpleDateFormat formatter = new SimpleDateFormat("yyyyMMddHHmmssSSS"); Date currentTime = new Date(); String dateString = formatter.format(currentTime); return dateString; } /** * 获取时间戳，格式："yyyyMMddddhhmmssSSS" * @return java.lang.Integer */ public static Integer getCurrTimestampForInteger() { SimpleDateFormat formatter = new SimpleDateFormat("yyyyMMddddhhmmssSSS"); Date currentTime = new Date(); String dateString = formatter.format(currentTime); Integer res=Integer.parseInt(dateString); return res; } /** * 当前时期+month月 * @return java.util.Date */ public static Date datePlusMonth(int month) { Calendar cal = Calendar.getInstance(); cal.add(Calendar.MONTH, month); return cal.getTime(); } /** * 返回时间 * @param str * @return * @throws ParseException */ public static String stringToTime(String str){ try { SimpleDateFormat formater = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); Date date = formater.parse(str); SimpleDateFormat fmt = new SimpleDateFormat("HH:mm:ss"); String dateString = fmt.format(date); return dateString; } catch (ParseException e) { e.printStackTrace(); return null; } } /** * 返回日期 * @param str * @return * @throws ParseException */ public static String stringToDateString(String str){ try { SimpleDateFormat formater = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); Date date = formater.parse(str); SimpleDateFormat fmt = new SimpleDateFormat("yyyy-MM-dd"); String dateString = fmt.format(date); return dateString; } catch (ParseException e) { e.printStackTrace(); return null; } } /** * 返回日期 时分 * @param str * @return * @throws ParseException */ public static String stringToDateAndHourAndMinString(String str){ try { SimpleDateFormat formater = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); Date date = formater.parse(str); SimpleDateFormat fmt = new SimpleDateFormat("yyyy-MM-dd HH:mm"); String dateString = fmt.format(date); return dateString; } catch (ParseException e) { e.printStackTrace(); return null; } } /** * 返回日期及星期 * @param str * @return * @throws ParseException */ public static String stringToDateAndWeek(String str){ try { SimpleDateFormat formater = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); Date date = formater.parse(str); SimpleDateFormat fmt = new SimpleDateFormat("yyyy-MM-dd / E"); String dateString = fmt.format(date); return dateString; } catch (ParseException e) { e.printStackTrace(); return null; } } /** * 将秒转换为时分秒格式 * @param second * @return */ public static String secondToDateTimeForMp3(int second){ String result=""; GregorianCalendar gc = new GregorianCalendar(); gc.setTimeInMillis(second * 1000); if(second<3600){ SimpleDateFormat format = new SimpleDateFormat("mm:ss"); result=format.format(gc.getTime()); }else{ SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss"); result=format.format(gc.getTime()); } return result; } /** * 返回MM.dd * @param str * @return * @throws ParseException */ public static String stringToMonthAndDay(String str){ try { SimpleDateFormat formater = new SimpleDateFormat("yyyy-MM-dd"); Date date = formater.parse(str); SimpleDateFormat fmt = new SimpleDateFormat("MM.dd"); String dateString = fmt.format(date); return dateString; } catch (ParseException e) { e.printStackTrace(); return null; } } /** * 返回MM月dd日 * @param str * @return * @throws ParseException */ public static String stringToFormatMonthAndDay(String str){ try { SimpleDateFormat formater = new SimpleDateFormat("yyyy-MM-dd"); Date date = formater.parse(str); SimpleDateFormat fmt = new SimpleDateFormat("MM月dd日"); String dateString = fmt.format(date); return dateString; } catch (ParseException e) { e.printStackTrace(); return null; } } /** * 返回yyyy.MM.dd * @param str * @return * @throws ParseException */ public static String stringToFormatYearAndMonthAndDay(String str){ try { SimpleDateFormat formater = new SimpleDateFormat("yyyy-MM-dd"); Date date = formater.parse(str); SimpleDateFormat fmt = new SimpleDateFormat("yyyy.MM.dd"); String dateString = fmt.format(date); return dateString; } catch (ParseException e) { e.printStackTrace(); return null; } } /** * 返回日期是第几天 * @param str * @return * @throws ParseException */ public static Integer stringToDay(String str) { try { Date date = new Date(); SimpleDateFormat formater = new SimpleDateFormat("yyyy-MM-dd"); date = formater.parse(str); Calendar calendar = Calendar.getInstance(); calendar.setTime(date); return calendar.get(Calendar.DAY_OF_MONTH); } catch (ParseException e) { e.printStackTrace(); return -1; } } /** * 返回星期几 * 星期一 1 ~ 星期六 6 * 星期日 0 * @param str * @return * @throws ParseException */ public static Integer stringToWeekNum(String str) { try { Date date = new Date(); SimpleDateFormat formater = new SimpleDateFormat("yyyy-MM-dd"); date = formater.parse(str); Calendar calendar = Calendar.getInstance(); calendar.setTime(date); return calendar.get(Calendar.DAY_OF_WEEK)-1; } catch (ParseException e) { e.printStackTrace(); return -1; } } /** * 获取当前年月，格式：yyyy * @return java.lang.String */ public static String getYear() { SimpleDateFormat formatter = new SimpleDateFormat("yyyy"); Date currentTime = new Date(); String date = formatter.format(currentTime); return date; } /** * 返回某一段日期内的所有日期 * */ public static List getAllInDateRange(String start_date, String end_date) { if(StringUtils.isEmpty(start_date) || StringUtils.isEmpty(end_date)){ return null; } DateFormat formatter = new SimpleDateFormat("yyyy-MM-dd"); List listDate = new ArrayList(); listDate.add(start_date); try{ Calendar calBegin = Calendar.getInstance(); calBegin.setTime(formatter.parse(start_date)); Calendar calEnd = Calendar.getInstance(); calEnd.setTime(formatter.parse(end_date)); while (formatter.parse(end_date).after(calBegin.getTime())) { calBegin.add(Calendar.DAY_OF_MONTH, 1); listDate.add(formatter.format(calBegin.getTime())); } return listDate; } catch (ParseException e){ e.printStackTrace();; } return null; } /* * 当前日期后n天的日期 * */ public static String afterNDay(int n){ Calendar c=Calendar.getInstance(); DateFormat df=new SimpleDateFormat("yyyy-MM-dd"); c.setTime(new Date()); c.add(Calendar.DATE,n); Date d2=c.getTime(); String s=df.format(d2); return s; } public static String getDateDiff (String selfDate) { if(selfDate == null || selfDate=="") { return ""; }else { DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); Date date = null; try { date = dateFormat.parse(selfDate); } catch (ParseException e) { e.printStackTrace(); } long diff = new Date().getTime() - date.getTime(); long day = diff/(1000*60*60*24); long hour = (diff - day*(1000*60*60*24))/(1000*60*60); long minutes = (diff - day*(1000*60*60*24) - hour*(1000*60*60))/(1000*60); String timeDiff = day+"天"+hour+"小时"+minutes+"分"; return timeDiff; } } /** * 字符串类型的时间转换时间戳 * @param date "2018-3-19 13:09:00" * @return 1470154736000 */ public static long getTimeLong (String date) { SimpleDateFormat sdf = new SimpleDateFormat( "yyyy-MM-dd HH:mm:ss" ); Date d; long time = 0; try { d = sdf.parse(date); time = d.getTime(); //System.out.println(d + ": " + time); } catch (ParseException e) { e.printStackTrace(); } return time; } /** * 获取星期 * @param weekday * @return */ public static String getStringWeekday(int weekday){ if(weekday == 1){ return "周日"; } else if(weekday == 2){ return "周一"; } else if(weekday == 3){ return "周二"; } else if(weekday == 4){ return "周三"; } else if(weekday == 5){ return "周四"; } else if(weekday == 6){ return "周五"; } else if(weekday == 7){ return "周六"; } return ""; } /** * 计算两个时间 间隔了多少天 * @param beforeTime * @param afterTime * @return */ public static int getIntervalDay(long beforeTime, long afterTime){ Calendar calendar1=Calendar.getInstance(); calendar1.setTimeInMillis(beforeTime); calendar1.set(Calendar.MILLISECOND,0); calendar1.set(Calendar.SECOND,0); calendar1.set(Calendar.MINUTE,0); calendar1.set(Calendar.HOUR,0); Calendar calendar2=Calendar.getInstance(); calendar2.setTimeInMillis(afterTime); calendar2.set(Calendar.MILLISECOND,0); calendar2.set(Calendar.SECOND,0); calendar2.set(Calendar.MINUTE,0); calendar2.set(Calendar.HOUR,0); return (int)((calendar2.getTimeInMillis()-calendar1.getTimeInMillis())/ONEDAY_TIME); } /** * 当月1日0点 * @param * @param * @return */ public static long getCurrentMonthStartTime(){ Calendar calendar=Calendar.getInstance(); calendar.set(Calendar.MILLISECOND,0); calendar.set(Calendar.SECOND,0); calendar.set(Calendar.MINUTE,0); calendar.set(Calendar.HOUR_OF_DAY,0); calendar.set(Calendar.DAY_OF_MONTH,1); return calendar.getTimeInMillis(); } /** * 指定月份 最后一天 0点时刻； * @return */ public static long getMonthLastDayZeroTime(String month){ try { SimpleDateFormat simpleDateFormat=new SimpleDateFormat("yyyy-MM"); Date date= simpleDateFormat.parse(month); Calendar calendar= Calendar.getInstance(); calendar.setTimeInMillis(date.getTime()); calendar.set(Calendar.DAY_OF_MONTH, 1); calendar.set(Calendar.HOUR_OF_DAY, 0); calendar.set(Calendar.MINUTE,0); calendar.set(Calendar.SECOND,0); calendar.add(Calendar.MONTH,1); calendar.add(Calendar.DAY_OF_MONTH,-1); return calendar.getTimeInMillis(); }catch (Exception e){ throw new RuntimeException(e); } } /** * 获取第二天0点时刻 * @param day * @return */ public static long getNextDayZeroTime(String day){ try { SimpleDateFormat simpleDateFormat=new SimpleDateFormat("yyyy-MM-dd"); Date date= simpleDateFormat.parse(day); Calendar calendar= Calendar.getInstance(); calendar.setTimeInMillis(date.getTime()); calendar.set(Calendar.HOUR_OF_DAY, 0); calendar.set(Calendar.MINUTE,0); calendar.set(Calendar.SECOND,0); calendar.add(Calendar.DAY_OF_MONTH,1); return calendar.getTimeInMillis(); }catch (Exception e){ throw new RuntimeException(e); } } /** * * @param day * @return */ public static long getDayZeroTime(String day){ try { SimpleDateFormat simpleDateFormat=new SimpleDateFormat("yyyy-MM-dd"); Date date= simpleDateFormat.parse(day); Calendar calendar= Calendar.getInstance(); calendar.setTimeInMillis(date.getTime()); calendar.set(Calendar.HOUR_OF_DAY, 0); calendar.set(Calendar.MINUTE,0); calendar.set(Calendar.SECOND,0); return calendar.getTimeInMillis(); }catch (Exception e){ throw new RuntimeException(e); } } /** * * 获取下一个月的第一天. * * @return */ public static String getPerFirstDayOfMonth() { SimpleDateFormat dft = new SimpleDateFormat("yyyy-MM-dd"); Calendar calendar = Calendar.getInstance(); calendar.add(Calendar.MONTH, 1); calendar.set(Calendar.DAY_OF_MONTH, calendar.getActualMinimum(Calendar.DAY_OF_MONTH)); return dft.format(calendar.getTime()); }/** * 今天的路径 * @return */ public static String addressRadom() { Date date = new Date(); String uploadMM = DateUtil.timeToString(date, "yyyy/MM"); String uploadDD = DateUtil.timeToString(date, "dd"); String uploadDir = uploadMM + "/" + uploadDD + "/"; return uploadDir; } /** * 补0 * @param zero * @param nikeo * @return */ public static String haoAddOne(String zero,String nikeo) { Integer n = Integer.parseInt(nikeo); DecimalFormat df = new DecimalFormat(zero); return df.format(n); }