package com.taosdata.example.jdbcTaosdemo.utils; import java.text.ParseException; import java.text.SimpleDateFormat; import java.time.Duration; import java.time.Instant; import java.util.Date; public class TimeStampUtil { private static final String datetimeFormat = "yyyy-MM-dd HH:mm:ss.SSS"; public static long datetimeToLong(String dateTime) { SimpleDateFormat sdf = new SimpleDateFormat(datetimeFormat); try { return sdf.parse(dateTime).getTime(); } catch (ParseException e) { throw new RuntimeException(e); } } public static String longToDatetime(long time) { SimpleDateFormat sdf = new SimpleDateFormat(datetimeFormat); return sdf.format(new Date(time)); } public static void main(String[] args) throws ParseException { // Instant now = Instant.now(); // System.out.println(now); // Instant years20Ago = now.minus(Duration.ofDays(365)); // System.out.println(years20Ago); } }