Java8 格式化时间

DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyyMMddHHmmss");
LocalDateTime.now().format(formatter);

格式：

 Symbol  Meaning                     Presentation      Examples
 ------  -------                     ------------      -------
  G       era                         text              AD; Anno Domini; A
  u       year                        year              2004; 04
  y       year-of-era                 year              2004; 04
  D       day-of-year                 number            189
  M/L     month-of-year               number/text       7; 07; Jul; July; J
  d       day-of-month                number            10
  Q/q     quarter-of-year             number/text       3; 03; Q3; 3rd quarter
  Y       week-based-year             year              1996; 96
  w       week-of-week-based-year     number            27
  W       week-of-month               number            4
  E       day-of-week                 text              Tue; Tuesday; T
  e/c     localized day-of-week       number/text       2; 02; Tue; Tuesday; T
  F       week-of-month               number            3
  a       am-pm-of-day                text              PM
  h       clock-hour-of-am-pm (1-12)  number            12
  K       hour-of-am-pm (0-11)        number            0
  k       clock-hour-of-am-pm (1-24)  number            0
  H       hour-of-day (0-23)          number            0
  m       minute-of-hour              number            30
  s       second-of-minute            number            55
  S       fraction-of-second          fraction          978
  A       milli-of-day                number            1234
  n       nano-of-second              number            987654321
  N       nano-of-day                 number            1234000000
  V       time-zone ID                zone-id           America/Los_Angeles; Z; -08:30
  z       time-zone name              zone-name         Pacific Standard Time; PST
  O       localized zone-offset       offset-O          GMT+8; GMT+08:00; UTC-08:00;
  X       zone-offset 'Z' for zero    offset-X          Z; -08; -0830; -08:30; -083015; -08:30:15;
  x       zone-offset                 offset-x          +0000; -08; -0830; -08:30; -083015; -08:30:15;
  Z       zone-offset                 offset-Z          +0000; -0800; -08:00;
  p       pad next                    pad modifier      1
  '       escape for text             delimiter
  ''      single quote                literal           '
  [       optional section start
  ]       optional section end
  #       reserved for future use
  {       reserved for future use
  }       reserved for future use