Java8中LocalDateTime与时间戳timestamp的互相转换

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));
    //=============================================================================================
    /*
                   年:1
                   月:13
                   日:396
                   半日:792
                   小时:9506
                   分钟:570362
                   秒:34221720
                   毫秒:34221720000
    */
  }

  @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"));
    //=============================================================================================
    /*
                    2017年07月22日 22:53
                    2019年07月22日 22:33
     */
  }

  @Test
  public void dayStart_test() {
    System.out.println(getDayStart(LocalDateTime.now()));
    System.out.println(getDayEnd(LocalDateTime.now()));
    //=============================================================================================
    /*
                    2017-07-22T00:00
                2017-07-22T23:59:59.999999999
     */
  }

}

总结

到此这篇关于Java8中LocalDateTime与时间戳timestamp互相转换的文章就介绍到这了,更多相关Java8 LocalDateTime与timestamp转换内容请搜索服务器之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持服务器之家！

原文链接：https://blog.csdn.net/czx2018/article/details/85005466