[Java] Date String Parsing and Formatting

1. Parsing String to LocalDateTime with DateTimeFormatter

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static void parseStringToLocasDateTime() { String dateStr = "2018-03-20 13:54:26"; DateTimeFormatter df = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"); LocalDateTime result = LocalDateTime.parse(dateStr, df); System.out.println(result); }

Result:

2018-03-20T13:54:26

2. Formatting LocalDateTime to String with DateTimeFormatter

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static void formatLocasDateTimeToString() { DateTimeFormatter df = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"); LocalDateTime date = LocalDateTime.now(); String dateStr = df.format(date); System.out.println(dateStr); System.out.println(date.toString()); }

Result:

2018-03-29 22:22:23
2018-03-29T22:22:23.262

3. Parsing String to Date with SimpleDateFormat

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void parseStringToDate() { String dateStr = "2018-03-20 13:54:26"; DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); Date result; try { result = df.parse(dateStr); System.out.println(result); } catch (ParseException e) { e.printStackTrace(); } }

Result:

Tue Mar 20 13:54:26 KST 2018

4. Formatting Date to String with SimpleDateFormat

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void formatDateToString() { DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); Date date = new Date(); String dateStr = df.format(date); System.out.println(dateStr); System.out.println(date.toString()); }

Result:

2018-03-21 01:25:45
Wed Mar 21 01:25:45 KST 2018