Instant,LocalDate,LocalDateTime,Date,String之间转换

jdk版本：jdk11

话不多说，直接上代码，希望可以帮到大家。不喜勿喷，感谢。

public static void main(String[] args) throws InternalException, ParseException {
    Instant now = Instant.now();
    System.out.println("now:"+now);
    System.out.println("毫秒数:"+now.toEpochMilli());

    ZoneId zoneId = ZoneId.systemDefault();
    LocalDate startDatei = LocalDate.ofInstant(now, zoneId);
    System.out.println("startDatei:"+startDatei);
    LocalDateTime localDateTime = LocalDateTime.ofInstant(now,zoneId);
    System.out.println("localDateTime:"+localDateTime);
    startDatei = localDateTime.toLocalDate();
    System.out.println("startDatei:"+startDatei);
    DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSSSSSSSS");
    String dateStr = dateTimeFormatter.format(localDateTime);
    System.out.println("dateStr:"+dateStr);
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSSSSSSSS");
    Date date = sdf.parse(dateStr);
    System.out.println("date:"+date);

    LocalDate localDate = LocalDate.parse(dateStr,dateTimeFormatter);
    System.out.println("localDate:"+localDate);
}