Java8中LocalDateTime与时间戳timestamp的互相转换

public LocalDateTime timestamToDatetime( long timestamp){

   Instant instant = Instant.ofEpochMilli(timestamp);

   return LocalDateTime.ofInstant(instant, ZoneId.systemDefault());

  }

public long datatimeToTimestamp(LocalDateTime ldt){

   long timestamp = ldt.toInstant(ZoneOffset.of( "+8" )).toEpochMilli();

   return timestamp;

  }

ZoneId zone = ZoneId.systemDefault();

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

package com.kingboy测试数据mon.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 );

   }

}

package com.kingboy测试数据mon.localdatetimeutils;

import com.kingboy测试数据mon.utils.date.LocalDateTimeUtils;

import org.junit.Test;

import java.time.LocalDateTime;

import java.time.temporal.ChronoUnit;

import static com.kingboy测试数据mon.utils.date.LocalDateTimeUtils.getDayEnd;

import static com.kingboy测试数据mon.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

      */

   }

}