1.LocalDateTime以及DateTimeFormatter
public static void main(String[] args) {
LocalDate date = LocalDate.now();
LocalTime time = LocalTime.now();
LocalDateTime dateTime = LocalDateTime.now();
System.out.println(date); //2020-05-21
System.out.println(time); //18:54:01.650
System.out.println(dateTime);//2020-05-21T18:54:01.650
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
//字符串转LocalDateTime
dateTime = LocalDateTime.parse("2020-02-23 11:23:55",formatter);
//LocalDateTime转字符串
System.out.println(dateTime.format(formatter));//2020-02-23 11:23:55
}