Java8 LocalDateTime与timestamp转换

将timestamp转为LocalDateTime

public LocalDateTime timestamToDatetime(long timestamp){ Instant instant = Instant.ofEpochMilli(timestamp); return LocalDateTime.ofInstant(instant, ZoneId.systemDefault()); }

将LocalDataTime转为timestamp

public long datatimeToTimestamp(LocalDateTime ldt){ long timestamp = ldt.toInstant(ZoneOffset.of("+8")).toEpochMilli(); return timestamp; }

我在网上还找到了另一个将datetime转为时间戳的方法：

ZoneId zone = ZoneId.systemDefault();long timestamp = ldt.atZone(zone).toInstant().toEpochMilli();

Java8的时间转为时间戳的大概的思路就是LocalDateTime先转为Instant，设置时区，然后转timestamp。

附一个Java8中的LocalDateTime工具类

工具类

package com.kingboy.common.utils.date;import java.time.*;import java.time.format.DateTimeFormatter;import java.time.temporal.ChronoUnit;import java.time.temporal.TemporalUnit;import java.util.Date;/* * @author kingboy * @Date 2017/7/22 下午2:12 * @Description LocalDateTimeUtils is used to Java8中的时间类 */public class LocalDateTimeUtils { //获取当前时间的LocalDateTime对象 //LocalDateTime.now(); //根据年月日构建LocalDateTime //LocalDateTime.of(); //比较日期先后 //LocalDateTime.now().isBefore(), //LocalDateTime.now().isAfter(), //Date转换为LocalDateTime public static LocalDateTime convertDateToLDT(Date date) { return LocalDateTime.ofInstant(date.toInstant(), ZoneId.systemDefault()); } //LocalDateTime转换为Date public static Date convertLDTToDate(LocalDateTime time) { return Date.from(time.atZone(ZoneId.systemDefault()).toInstant()); } //获取指定日期的毫秒 public static Long getMilliByTime(LocalDateTime time) { return time.atZone(ZoneId.systemDefault()).toInstant().toEpochMilli(); } //获取指定日期的秒 public static Long getSecondsByTime(LocalDateTime time) { return time.atZone(ZoneId.systemDefault()).toInstant().getEpochSecond(); } //获取指定时间的指定格式 public static String formatTime(LocalDateTime time,String pattern) { return time.format(DateTimeFormatter.ofPattern(pattern)); } //获取当前时间的指定格式 public static String formatNow(String pattern) { return formatTime(LocalDateTime.now(), pattern); } //日期加上一个数,根据field不同加不同值,field为ChronoUnit.* public static LocalDateTime plus(LocalDateTime time, long number, TemporalUnit field) { return time.plus(number, field); } //日期减去一个数,根据field不同减不同值,field参数为ChronoUnit.* public static LocalDateTime minu(LocalDateTime time, long number, TemporalUnit field){ return time.minus(number,field); } /** * 获取两个日期的差 field参数为ChronoUnit.* * @param startTime * @param endTime * @param field 单位(年月日时分秒) * @return */ public static long betweenTwoTime(LocalDateTime startTime, LocalDateTime endTime, ChronoUnit field) { Period period = Period.between(LocalDate.from(startTime), LocalDate.from(endTime)); if (field == ChronoUnit.YEARS) return period.getYears(); if (field == ChronoUnit.MONTHS) return period.getYears() * 12 + period.getMonths(); return field.between(startTime, endTime); } //获取一天的开始时间，2017,7,22 00:00 public static LocalDateTime getDayStart(LocalDateTime time) { return time.withHour(0) .withMinute(0) .withSecond(0) .withNano(0); } //获取一天的结束时间，2017,7,22 23:59:59.999999999 public static LocalDateTime getDayEnd(LocalDateTime time) { return time.withHour(23) .withMinute(59) .withSecond(59) .withNano(999999999); }}

测试类

package com.kingboy.common.localdatetimeutils;import com.kingboy.common.utils.date.LocalDateTimeUtils;import org.junit.Test;import java.time.LocalDateTime;import java.time.temporal.ChronoUnit;import static com.kingboy.common.utils.date.LocalDateTimeUtils.getDayEnd;import static com.kingboy.common.utils.date.LocalDateTimeUtils.getDayStart;/** * @author kingboy * @Date 2017/7/22 下午7:16 * @Description LocaDateTimeUtilsTest is used to 测试LocalDateTime工具 */public class LocaDateTimeUtilsTest { @Test public void format_test() { System.out.println(LocalDateTimeUtils.formatNow("yyyy年MM月dd日 HH:mm:ss")); } @Test public void betweenTwoTime_test() { LocalDateTime start = LocalDateTime.of(1993, 10, 13, 11, 11); LocalDateTime end = LocalDateTime.of(1994, 11, 13, 13, 13); System.out.println("年:" + LocalDateTimeUtils.betweenTwoTime(start, end, ChronoUnit.YEARS)); System.out.println("月:" + LocalDateTimeUtils.betweenTwoTime(start, end, ChronoUnit.MONTHS)); System.out.println("日:" + LocalDateTimeUtils.betweenTwoTime(start, end, ChronoUnit.DAYS)); System.out.println("半日:" + LocalDateTimeUtils.betweenTwoTime(start, end, ChronoUnit.HALF_DAYS)); System.out.println("小时:" + LocalDateTimeUtils.betweenTwoTime(start, end, ChronoUnit.HOURS)); System.out.println("分钟:" + LocalDateTimeUtils.betweenTwoTime(start, end, ChronoUnit.MINUTES)); System.out.println("秒:" + LocalDateTimeUtils.betweenTwoTime(start, end, ChronoUnit.SECONDS)); System.out.println("毫秒:" + LocalDateTimeUtils.betweenTwoTime(start, end, ChronoUnit.MILLIS)); //============================================================================================= } @Test public void plus_test() { //增加二十分钟 System.out.println(LocalDateTimeUtils.formatTime(LocalDateTimeUtils.plus(LocalDateTime.now(), 20, ChronoUnit.MINUTES), "yyyy年MM月dd日 HH:mm")); //增加两年 System.out.println(LocalDateTimeUtils.formatTime(LocalDateTimeUtils.plus(LocalDateTime.now(), 2, ChronoUnit.YEARS), "yyyy年MM月dd日 HH:mm")); //============================================================================================= } @Test public void dayStart_test() { System.out.println(getDayStart(LocalDateTime.now())); System.out.println(getDayEnd(LocalDateTime.now())); //============================================================================================= }}

总结

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