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关于LocalDateTime最常用方法和时间转换方式

作者:大脑补丁

Java8版本引入了LocalDateTime和LocalDate类,极大地方便了日期和时间的处理,本文主要介绍了字符串与LocalDateTime的互转,Long型时间戳与UTC时间字符串的转换,获取今天、某天的起止时间,自定义时间的设置,以及LocalDateTime与Date的相互转换等常用方法

LocalDateTime最常用方法和时间转换

Java 8 版本以后,新增了了LocalDateTime和了LocalDate类,转换方便不亚于jodaTIme。

LocalDateTime方法有很多,本文将开发中最常用的一些时间转换列举出来,并给出转换后的示例,希望大家可以转换时参考使用。

字符串转LocalDateTime

public static LocalDateTime parseStringToDateTime(String time, String format) {
  DateTimeFormatter df = DateTimeFormatter.ofPattern(format);
  return LocalDateTime.parse(time, df);
}

LocalDateTime转字符串

public static String getDateTimeToString(LocalDateTime localDateTime, String format) {
  DateTimeFormatter formatter = DateTimeFormatter.ofPattern(format);
  return localDateTime.format(formatter);
}

测试:

若毫秒位不为000则显示毫秒

String utc = getUTCMillisecondFromTimestamp(1539718265123);
System.out.println(utc);

输出:2018-10-16T19:31:05.123Z

若毫秒为000则不显示毫秒,

String utc = getUTCMillisecondFromTimestamp(1539718265000);
System.out.println(utc);

输出:2018-10-16T19:31:05Z

Long型时间戳(15位)转UTC时间字符串

/**
	 * 将UTC时间戳转为UTC字符串(精确到秒)
	 *
	 * @param timestamp
	 * @return
	 */
	public static String getUTCStrFromTimestamp(long timestamp) {
		DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss'Z'");
		// 北京时间:ZoneId.of("UTC+8");系统默认时间:ZoneId.systemDefault() 
		LocalDateTime localDateTime = LocalDateTime.ofInstant(Instant.ofEpochMilli(timestamp), ZoneId.of("UTC"));
		String utc = localDateTime.format(formatter);
		return utc;
	}

测试:

String utc = getUTCStrFromTimestamp(1539718265123);
System.out.println(utc);

输出:2018-10-16T19:31:05Z

Long型时间戳(15位)转UTC时间字符串

	/**
	 * 将时间戳转为UTC字符串(若毫秒为000则不显示毫秒,若毫秒位不为000则显示毫秒)
	 * 
	 * 返回格式:2018-10-16T19:31:05.123Z
	 * 
	 * @param timestamp
	 * @return
	 */
	public static String getUTCMillisecondFromTimestamp(long timestamp) {
		Instant instant = Instant.ofEpochMilli(timestamp);
		String utcString = instant.toString();
		return utcString;
	}

获取今天的起止时间

DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss'Z'");

String startTime = LocalDateTime.now().withHour(0).withMinute(0).withSecond(0).withNano(0).format(formatter);

String endTime = LocalDateTime.now().withHour(23).withMinute(59).withSecond(59).withNano(999_999_999).format(formatter);

返回目标月份的最后一天

/**
	 * 返回目标月份的最后一天
	 *
	 * @param sourceDate  目标月份
	 * @param monthOffset 月份偏移量
	 * @return
	 */
	private LocalDate getLastDateOfMonth(LocalDate sourceDate, int monthOffset) {
		return sourceDate.plusMonths(monthOffset).with(TemporalAdjusters.lastDayOfMonth());
	}

获取某天的起止时间(优雅)

LocalDate date = LocalDate.of(2021, 4, 20);
LocalDateTime startTime = LocalDateTime.of(date, LocalTime.MIN);
LocalDateTime endTime = LocalDateTime.of(date, LocalTime.MAX);

LocalDateTime设置自定义时间

/**
	 * 获得一个(毫秒)时间戳的十分钟起始时间戳
	 * 
	 * 如:输入1534930875000(2018-08-22 17:41:15)的时间戳返回1534930800000(2018-08-22 17:40:00)的时间戳
	 * 
	 * @param timestrap
	 * 
	 * 
	 * @return
	 */
	public static long getTenMinuteStartTimestrap(long timestamp) {
		LocalDateTime localDateTime = getLocalDateTimeByTimestamp(timestamp);
		int minute = localDateTime.getMinute();
		// 分钟个位数置为0
		int minute_floor = minute / 10 * 10;
		LocalDateTime startLocalDateTime = localDateTime.withMinute(minute_floor).withSecond(0).withNano(0);
		long startTimestamp = getTimestampByLocalDateTime(startLocalDateTime);
		return startTimestamp;
	}

Long毫秒时间戳转LocalDateTime

	/**
	 * Long毫秒时间戳转LocalDateTime
	 */
	public static LocalDateTime getLocalDateTimeByTimestamp(long timestamp) {
		Instant instant = Instant.ofEpochMilli(timestamp);
		LocalDateTime localDateTime = LocalDateTime.ofInstant(instant, ZoneOffset.UTC);
		return localDateTime;
	}

根据LocalDateTime获取毫秒时间戳

	/**
	 * 根据毫秒时间戳获取LocalDateTime
	 * @param localDateTime
	 * @return
	 */
	public static long getTimestampByLocalDateTime(LocalDateTime localDateTime) {
		long timestamp = localDateTime.atZone(ZoneId.of("UTC")).toInstant().toEpochMilli();
		return timestamp;
	}

Long时间戳根据时区转为当地日期

/**
	 * 时间戳根据时区转为当地日期
	 * @param timestamp
	 * @param timezone
	 * @return
	 */
	public static Date getLocalDateByTimezone(long timestamp, int timezone) {
		Instant instant = Instant.ofEpochMilli(timestamp);
		LocalDateTime localDateTime = LocalDateTime.ofInstant(instant, ZoneOffset.UTC);
		// 当地时间
		LocalDateTime localDate = localDateTime.plusHours(timezone);
		DateTimeFormatter df = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss'Z'");
		String localDateTimeStr = df.format(localDate);
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
		Date date = null;
		try {
			date = sdf.parse(localDateTimeStr);
		} catch (ParseException e) {
			e.printStackTrace();
		}
		return date;
	}

LocalDateTime转Date

注意:系统所在时区

Date date = Date.from(LocalDateTime.now().atZone(ZoneId.systemDefault()).toInstant());

Date转LocalDateTime

Date todayDate = new Date();
LocalDateTime ldt = todayDate.toInstant()
        .atZone( ZoneId.systemDefault() )
        .toLocalDateTime();

毫秒转秒(时间戳)

long second = Instant.ofEpochMilli(1636338645000L).getEpochSecond();

秒转毫秒(时间戳)

long second = Instant.ofEpochSecond(1636338645L).toEpochMilli();

总结

以上为个人经验,希望能给大家一个参考,也希望大家多多支持脚本之家。

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