【Java SE】时区,LocalDate,LocalDateTime

https://blog.csdn.net/qq_44749491/article/details/130123065

 

中国一共分了5个时区

哈尔滨 Asia/Harbin 长白时区GMT+8:30
上海 Asia/Shanghai 标准时区 GMT+8
重庆 Asia/Chongqing 陇蜀时区GMT+7
乌鲁木齐 Asia/Urumqi 藏时区GMT+6
喀什 Asia/Kashgar 昆仑时区GMT+5:30

获取时区

// 指定时区，推荐
ZoneId zoneId = TimeZone.getTimeZone("Asia/Shanghai").toZoneId();
// 系统默认时区，不推荐
ZoneId zoneId = ZoneId.systemDefault()

获取当前系统日期和时间

ZoneId zoneId = TimeZone.getTimeZone("Asia/Shanghai").toZoneId();
LocalDate localDate = LocalDate.now(zoneId);
LocalDateTime localDateTime = LocalDateTime.now(zoneId);

获取中国标准日期和时间

ZoneId zoneId = TimeZone.getTimeZone("Asia/Shanghai").toZoneId();
LocalDate localDate = LocalDate.now(zoneId);
String date = DateTimeFormatter.ofPattern("yyyy-MM-dd").format(localDate);
LocalDateTime localDateTime = LocalDateTime.now(zoneId);
String dateTime = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss").format(localDateTime);

毫秒转日期时间

ZoneId zoneId = TimeZone.getTimeZone("Asia/Shanghai").toZoneId();
// 推荐
LocalDateTime ldt = Instant.ofEpochMilli(1777280940692L).atZone(zoneId).toLocalDateTime();
// 不推荐
LocalDateTime ldt2 = LocalDateTime.ofInstant(Instant.ofEpochMilli(1777280940692L), zoneId);
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
String formattedDateTime = formatter.format(ldt);

当月

String yearMonth = DateTimeFormatter.ofPattern("yyyy-MM").format(localDate);
startTime = yearMonth + "-01 00:00:00";
// 当前天
endTime = DateTimeFormatter.ofPattern("yyyy-MM-dd").format(localDate) + " 23:59:59";
// 最后一天
endTime = yearMonth + "-" + month.length(localDate.isLeapYear()) + " 23:59:59";

过去一年

startTime = DateTimeFormatter.ofPattern("yyyy-MM-dd").format(localDate.minusYears(1).plusDays(1)) + " 00:00:00";
endTime = DateTimeFormatter.ofPattern("yyyy-MM-dd").format(localDate) + " 23:59:59";

格式化

String value = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss").format(localDate);
String value = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss").format(localDateTime);

LocalDateTime转Date

ZoneId zoneId = TimeZone.getTimeZone("Asia/Shanghai").toZoneId();
LocalDateTime localDateTime = LocalDateTime.parse("2022-10-24 23:59:59", DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
ZonedDateTime zonedDateTime = localDateTime.atZone(zoneId);
Date date = Date.from(zonedDateTime.toInstant());