您可以通过
DateTimeFormatterBuilder.parseDefaulting以下方式为不可用字段设置默认值：
DateTimeFormatter formatter = new DateTimeFormatterBuilder() .appendPattern("dd/MM/yyyy a") .parseDefaulting(ChronoField.HOUR_OF_AMPM, 0) // this is required .parseDefaulting(ChronoField.MINUTE_OF_HOUR, 0) // optional, but you can set other value .parseDefaulting(ChronoField.SECOND_OF_MINUTE, 0) // optional as well .toFormatter();System.out.println(LocalDateTime.parse("17/02/2015 PM", formatter)); // 2015-02-17T12:00System.out.println(LocalDateTime.parse("17/02/2015 AM", formatter)); // 2015-02-17T00:00
