Java8 LocalDateTime日常轉換

/*LocalDateTime與時間戳互轉*/
// LocalDateTime轉時間戳
long timestamp = LocalDateTime.now().atZone(ZoneId.systemDefault()).toInstant().toEpochMilli();
System.out.println(String.format("timestamp => %s",timestamp));
// 時間戳轉LocalDateTime
LocalDateTime now = LocalDateTime.ofInstant(Instant.ofEpochMilli(timestamp), TimeZone.getDefault().toZoneId());

/*LocalDateTime與指定格式時間日期字符串互轉*/
// DateTimeFormatter.ISO_DATE相當於DateTimeFormatter.ofPattern("yyyy-MM-dd") 相應的還有DateTimeFormatter.ISO_DATE_TIME/DateTimeFormatter.ISO_TIME
format = now.format(DateTimeFormatter.ISO_DATE);
System.out.println(String.format("DateTimeFormatter.ISO_DATE => %s",format));
format = now.format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSS"));
System.out.println(String.format("'yyyy-MM-dd HH:mm:ss.SSS' => %s",format));
// 時間日期字符串轉LocalDateTime
LocalDateTime parse = LocalDateTime.parse(format, DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSS"));