java8 LocalDateTime

Posted 2020-12-23 几多心中创伤 —《谁伴我闯荡》

在多并发情况下使用SimpleDateFormat需格外注意 ：SimpleDateFormat除了format是线程不安全以外，parse方法也是线程不安全的。

LocalDate

只获取年月日

LocalDate localDate = LocalDate.now();  //localDate：2020-06-01
LocalDate localDate1 = LocalDate.of(2020, 01, 01); //localDate1：2020-01-01

获取年、月、日、星期几

int year = localDate.getYear();  //2020
int year1 = localDate.get(ChronoField.YEAR);  //2020
Month month = localDate.getMonth();  //JUNE
int month1 = localDate.get(ChronoField.MONTH_OF_YEAR);  //6
int day = localDate.getDayOfMonth();   //1
int day1 = localDate.get(ChronoField.DAY_OF_MONTH);  //1
DayOfWeek dayOfWeek = localDate.getDayOfWeek();  //MONDAY
int dayOfWeek1 = localDate.get(ChronoField.DAY_OF_WEEK); //1

LocalTime

只获取时分秒

LocalTime localTime = LocalTime.of(23, 11, 11);  //23:11:11
LocalTime localTime1 = LocalTime.now(); //23:15:51.710

获取时分秒

int hour = localTime.getHour();  //23
int hour1 = localTime.get(ChronoField.HOUR_OF_DAY);  //23 
int minute = localTime.getMinute();  //11
int minute1 = localTime.get(ChronoField.MINUTE_OF_HOUR);  //11
int second = localTime.getSecond();  //11
int second1 = localTime.get(ChronoField.SECOND_OF_MINUTE); //11

LocalDateTime

LocalDateTime localDateTime = LocalDateTime.now(); //2020-06-01T23:23:50.559

Instant

获取秒数、获取毫秒数

Instant instant = Instant.now(); //2020-06-01T15:27:18.608Z
long currentSecond = instant.getEpochSecond(); //1591025238
long currentMilli = instant.toEpochMilli(); //1591025238608
System.currentTimeMillis(); //1591025406619

 

//2020