java8时间处理

/**
* Instant：瞬时实例
* LocalDate：本地日期 不包含具体时间 例如 2020-02-02 可以用来记录纪念日
* LocalDTime：本地时间 不包含日期
* LocalDateTime：结合了日期和时间 但不包含时差和时区
* ZonedDateTime：完整的日期时间，包含时区和相对UTC或格林威治的视察
*
* ZoneOffSet,ZoneId：操作时区
*
* DateTimeFormatter:格式化时间
*
* LocalDate等许多类为 final 线程安全不可变， plusHour withDay等操作后要用新的对象来接收
*/
public static void main(String[] args) {
LocalDate today = LocalDate.now();
System.out.println(today); // 2020-05-30

/* 处理特定日期  */
LocalDate birthday = LocalDate.of(1994,8,11);
System.out.println(birthday); // 1994-08-11

/* 日期比较  */
if (today.equals(birthday)) {
System.out.println("日期形同");
}

/* MonthDay 和 YearMonth 用来检查某一天是不是生日这种周期性时间 */
MonthDay myBithday = MonthDay.of(birthday.getMonth(), birthday.getDayOfMonth());
MonthDay currentMonDay = MonthDay.from(today);
if (myBithday.equals(currentMonDay)) {
System.out.println("今天是你的生日");
}

/* 在现有时间基础上囧算之前之后的年、月、周、时、分、秒 */
LocalDateTime nowTime = LocalDateTime.now();
LocalDateTime afterTime = nowTime.plusHours(3);
LocalDateTime beforeTime = nowTime.minusYears(2);
System.out.println("afterTime:"+afterTime+"- beforeTime:"+beforeTime);
// afterTime:2020-05-30T15:09:28.013- beforeTime:2018-05-30T12:09:28.013

/* 在现有时间基础上修改年、月、周、时、分、秒 */
LocalDateTime localDateTime = nowTime.withHour(11);
System.out.println("with 11 Time:"+localDateTime); // with 11 Time:2020-05-30T11:09:28.013

/* 使用java8的Clock时钟类获取时间戳 */
Clock clock = Clock.systemUTC();
System.out.println(clock.millis()); // 1590811768013
System.out.println(System.currentTimeMillis()); // 1590811768013

Clock defalutClock = Clock.systemDefaultZone();
System.out.println(defalutClock.millis()); // 1590811768013
System.out.println(defalutClock.getZone()); // Asia/Shanghai

/* 判断早于某时还是晚于某时 */
LocalDateTime tomorrow = nowTime.plusDays(1);
if (tomorrow.isEqual(nowTime)) {
//时间一样
} else if (tomorrow.isAfter(nowTime)) {
//是否在当前之后
} else if (tomorrow.isBefore(nowTime)) {
//之前
} else {
//
}

/* 时区处理 */
ZoneId beijing = ZoneId.of("America/New_York");
LocalDateTime timenow = LocalDateTime.now();

ZonedDateTime zonedDateTime = ZonedDateTime.of(timenow, beijing);
System.out.println("纽约时间" + zonedDateTime);
// 纽约时间2020-05-30T12:22:38.102-04:00[America/New_York]

/* 检测闰年 */
LocalDate leafYear = LocalDate.now();
if (leafYear.i
56c
sLeapYear()){
//闰年
}

/* 计算两个时间之间的天数和月数 */
LocalDate current = LocalDate.now();
LocalDate yourBirthday = LocalDate.of(1996, 8, 11);
Period between = Period.between(yourBirthday, current);
System.out.println(between.getYears()+"年"+between.getMonths()+"月"+between.getDays()+"天");
// 23年9月19天

/* 包含时差信息的日期和时间
*  ZoneOffset 表示时差 印度与GMT或者UTC飙车事件时差+5:30
* */
LocalDateTime dateTime = LocalDateTime.now();
ZoneOffset offset = ZoneOffset.of("+05:30");
OffsetDateTime offsetDateTime = OffsetDateTime.of(dateTime, offset);
System.out.println(offsetDateTime); //2020-05-30T12:48:54.655+05:30
System.out.println(OffsetDateTime.now()); //2020-05-30T12:48:54.655+08:00

/* 格式化时间 */

DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
System.out.println(formatter.format(LocalDateTime.now()));//2020-05-30 12:55:40

}