@Test public void date(){ LocalDateTime dateTime = LocalDateTime.now(); DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"); String format = dateTime.format(formatter); System.out.println("format:" + format);//2023-09-25 19:53:41 Date date = new Date(); System.out.println("date:" + date);//Mon Sep 25 20:12:59 CST 2023 String string = date.toString(); System.out.println("string:" + string);//Mon Sep 25 19:55:45 CST 2023 Date date1 = new Date(); SimpleDateFormat ft = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); String format1 = ft.format(date1); System.out.println("format1:" + format1);//2023-09-25 19:58:20 String dateStr1 = "2016-05-18"; String dateStr2 = "2016-05-17 12:37:56"; Date date3 = null; Date date2 = null; try { date3 = new SimpleDateFormat("yyyy-MM-dd").parse(dateStr1); date2 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse(dateStr2); } catch (ParseException e) { e.printStackTrace(); } System.out.println(date3);//Wed May 18 00:00:00 CST 2016 System.out.println(date2);//Tue May 17 12:37:56 CST 2016 //String dateStr = "2020-12-30 11:25:33"; DateTimeFormatter inputFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"); LocalDateTime datetime = LocalDateTime.parse(format1, inputFormatter); System.out.println("datetime : " + datetime);//2023-09-25T20:00:48 long l = System.currentTimeMillis(); System.out.println("l:" + l);//1695643386795 Date datel = new Date(l); System.out.println(datel);//Mon Sep 25 20:05:25 CST 2023 long time = datel.getTime(); System.out.println("time:" + time);//1695643630057 }