Java的各种时间对象互转

/**
* 将long类型的timestamp转为LocalDateTime
*/
public static LocalDateTime getDateTimeOfTimestamp(long timestamp) {
    Instant instant = Instant.ofEpochMilli(timestamp);
    ZoneId zone = ZoneId.systemDefault();
    return LocalDateTime.ofInstant(instant, zone);
}

/**
* 将LocalDateTime转为long类型的timestamp
*/

public static long getTimestampOfDateTime(LocalDateTime localDateTime) {
    ZoneId zone = ZoneId.systemDefault();
    Instant instant = localDateTime.atZone(zone).toInstant();
    return instant.toEpochMilli();
}


/**
* 字符串转 LocalDateTime
*/

DateTimeFormatter df = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
LocalDateTime lastSyncLostTime = LocalDateTime.parse("2000-01-01 00:00:00",df);


/**
* Calendar 转 Timestamp
*/
Calendar calendar = Calendar.getInstance();
new Timestamp(TimeUtil.getTimestamp(calendar.getTime())

/**
* Timestamp 转 LocalDateTime
*/
Timestamp time = Timestamp.from(Instant.now());
LocalDateTime localDateTime = time.toLocalDateTime();  
/**
* LocalDateTime 转 Timestamp
*/
Timestamp time = Timestamp.valueOf(LocalDateTime.now());
/**
* LocalDateTime 转为long类型的timestamp 再转 Calendar
*/
public static long getCalendarOfDateTimeAndTimestamp(LocalDateTime localDateTime) {
    LocalDateTime lastSyncLostTime = LocalDateTime.of(1999,1,1,0,0);
    //方法1
    long time = lastSyncLostTime.toInstant(ZoneOffset.of("+8")).toEpochMilli();、
    //方法2
    long time = lastSyncLostTime.atZone(ZoneId.systemDefault()).toInstant().toEpochMilli();
    Calendar calendar = Calendar.getInstance();
    calendar.setTimeInMillis(time);
}
         、
    // 获得某天最大时间 
    public static Date getEndOfDay(Date date) {
        LocalDateTime localDateTime = LocalDateTime.ofInstant(Instant.ofEpochMilli(date.getTime()), ZoneId.systemDefault());;
        LocalDateTime endOfDay = localDateTime.with(LocalTime.MAX);
        return Date.from(endOfDay.atZone(ZoneId.systemDefault()).toInstant());
    }
 
    // 获得某天最小时间
    public static Date getStartOfDay(Date date) {
        LocalDateTime localDateTime = LocalDateTime.ofInstant(Instant.ofEpochMilli(date.getTime()), ZoneId.systemDefault());
        LocalDateTime startOfDay = localDateTime.with(LocalTime.MIN);
        return Date.from(startOfDay.atZone(ZoneId.systemDefault()).toInstant());
    }              
//根据需求需要取得当天的零点

LocalDateTime today_start = LocalDateTime.of(LocalDate.now(), LocalTime.MIN);//当天零点
String td_st_str =
today_start.format(DateTimeFormatter.ofPattern("yyyyMMddHHmmss"));

//获取当天结束时间
LocalDateTime today_end = LocalDateTime.of(LocalDate.now(), LocalTime.MAX);//当天零点 
         
              
LocalDate today = LocalDate.now();
//本月的第一天
LocalDate firstday = LocalDate.of(today.getYear(),today.getMonth(),1);
//本月的最后一天
LocalDate lastDay =today.with(TemporalAdjusters.lastDayOfMonth());
System.out.println("本月的第一天"+firstday);
System.out.println("本月的最后一天"+lastDay);
              
// 取本月第1天：
LocalDate firstDayOfThisMonth = today.with(TemporalAdjusters.firstDayOfMonth()); // 2014-12-01
// 取本月第2天：
LocalDate secondDayOfThisMonth = today.withDayOfMonth(2); // 2014-12-02
// 取本月最后一天，再也不用计算是28，29，30还是31：
LocalDate lastDayOfThisMonth = today.with(TemporalAdjusters.lastDayOfMonth()); // 2014-12-31
// 取下一天：
LocalDate firstDayOf2015 = lastDayOfThisMonth.plusDays(1); // 变成了2015-01-01
// 取2015年1月第一个周一，这个计算用Calendar要死掉很多脑细胞：
LocalDate firstMondayOf2015 = LocalDate.parse("2015-01-01").with(TemporalAdjusters.firstInMonth(DayOfWeek.MONDAY)); // 2015-01-05
              
              
// 使用日期和时间构造日期时间对象->指定时区转换成时间戳
public static long getTodayStartTime() {
    return LocalDateTime.of(LocalDate.now(), LocalTime.MIN).toEpochSecond(ZoneOffset.of("+8"));
}

public static long getTodayEndTime() {
    return LocalDateTime.of(LocalDate.now(), LocalTime.MAX).toEpochSecond(ZoneOffset.of("+8"));
}
/**
* 获取时差
*/       
LocalDateTime from = LocalDateTime.of(2017, Month.JANUARY, 5, 10, 7, 0);    // 2017-01-05 10:07:00
LocalDateTime to = LocalDateTime.of(2017, Month.FEBRUARY, 5, 10, 7, 0);     // 2017-02-05 10:07:00
Duration duration = Duration.between(from, to);     // 表示从 2017-01-05 10:07:00 到 2017-02-05 10:07:00 这段时间

long days = duration.toDays();              // 这段时间的总天数
long hours = duration.toHours();            // 这段时间的小时数
long minutes = duration.toMinutes();        // 这段时间的分钟数
long seconds = duration.getSeconds();       // 这段时间的秒数
long milliSeconds = duration.toMillis();    // 这段时间的毫秒数
long nanoSeconds = duration.toNanos();      // 这段时间的纳秒数
Duration duration1 = Duration.of(5, ChronoUnit.DAYS);       // 5天
Duration duration2 = Duration.of(1000, ChronoUnit.MILLIS);  // 1000毫秒

/**
* 距离今天结束还有多少秒
*/     
LocalDateTime of = LocalDateTime.of(LocalDate.now(), LocalTime.MAX);
long between = ChronoUnit.SECONDS.between(LocalDateTime.now(), of);
/**
* 获取现在时间
*/ 
Long millisecond = Instant.now().toEpochMilli();  // 精确到毫秒
Long second = Instant.now().getEpochSecond();// 精确到秒
LocalDateTime now = LocalDateTime.now()//日期时间分秒
Timestamp time = Timestamp.from(Instant.now());

参数声明：

final Date date = new Date();
final Timestamp timestamp = new Timestamp(date.getTime());
final Calendar calendar = Calendar.getInstance();
final Instant instant = Instant.now();
final LocalDateTime localDateTime = LocalDateTime.now();
final ZonedDateTime zonedDateTime = ZonedDateTime.now();
final LocalDate localDate = LocalDate.now();

转Instant

//Date转Instant
Instant dateInstant = date.toInstant();

//Timestamp转Instant
Instant timestampInstant = timestamp.toInstant();

//Calendar转Instant
Instant calendarInstant = calendar.toInstant();

//LocalDateTime转Instant
Instant localDateTimeInstant = localDateTime.atZone(ZoneId.systemDefault()).toInstant();

//ZonedDateTime转Instant
Instant zonedDateTimeInstant = zonedDateTime.toInstant();

//LocalDate转Instant
Instant localDateInstant = localDate.atStartOfDay(ZoneId.systemDefault()).toInstant();

转LocalDateTime

//Date转LocalDateTime
 LocalDateTime dateLocalDateTime =        LocalDateTime.ofInstant(date.toInstant(), ZoneId.systemDefault());

 //Timestamp转LocalDateTime
 LocalDateTime timestampLocalDateTime = timestamp.toLocalDateTime();

 //Calendar转LocalDateTime
 LocalDateTime calendarLocalDateTime = LocalDateTime.ofInstant(calendar.toInstant(), ZoneOffset.systemDefault());

 //Instant转LocalDateTime
 LocalDateTime instantLocalDateTime = LocalDateTime.ofInstant(instant, ZoneId.systemDefault());

 //ZonedDateTime转LocalDateTime
 LocalDateTime zonedDateTimeLocalDateTime = zonedDateTime.toLocalDateTime();

 //LocalDate转LocalDateTime
 LocalDateTime localDateLocalDateTime = localDate.atStartOfDay();

转ZonedDateTime

//Date转ZonedDateTime
 ZonedDateTime dateZonedDateTime = ZonedDateTime.ofInstant(date.toInstant(), ZoneId.systemDefault());

 //Timestamp转ZonedDateTime
 ZonedDateTime timestampZonedDateTime = ZonedDateTime.ofInstant(timestamp.toInstant(), ZoneId.systemDefault());

 //Calendar转ZonedDateTime
 ZonedDateTime calendarZonedDateTime = ZonedDateTime.ofInstant(calendar.toInstant(), ZoneId.systemDefault());

 //Instant转ZonedDateTime
 ZonedDateTime instantZonedDateTime = instant.atZone(ZoneId.systemDefault());

 //LocalDateTime转ZonedDateTime
 ZonedDateTime localDateTimeZonedDateTime = localDateTime.atZone(ZoneId.systemDefault());

 //LocalDate转ZonedDateTime
 ZonedDateTime localDateZonedDateTime = localDate.atStartOfDay(ZoneId.systemDefault());

转Date

//Timestamp转Date
Date timestampDate = new Date(timestamp.getTime());

//Calendar转Date
Date calendarDate = calendar.getTime();

//Instant转Date
Date instantDate = Date.from(instant);

//LocalDateTime转Date
Date localDateTimeDate = Date.from(localDateTime.atZone(ZoneId.systemDefault()).toInstant());

//ZonedDateTime转Date
Date zonedDateTimeDate = Date.from(zonedDateTime.toInstant());

//LocalDate转Date
Date localDateDate = Date.from(localDate.atStartOfDay(ZoneId.systemDefault()).toInstant());

转Timestamp

//Date转Timestamp
Timestamp dateTimestamp = new Timestamp(date.getTime());

//Calendar转Timestamp
Timestamp calendarTimestamp = new Timestamp(calendar.getTimeInMillis());

//Instant转Timestamp
Timestamp instantTimestamp = Timestamp.from(instant);

//LocalDateTime转Timestamp
Timestamp localDateTimeTimestamp = Timestamp.valueOf(localDateTime);

//ZonedDateTime转Timestamp
Timestamp zonedDateTimeTimestamp = Timestamp.from(zonedDateTime.toInstant());

//LocalDate转Timestamp
Timestamp localDateTimestamp = Timestamp.valueOf(localDate.atStartOfDay());

转Calendar

//Date转Calendar
Calendar dateCalendar = Calendar.getInstance();
dateCalendar.setTime(date);

//Timestamp转Calendar
Calendar timestampCalendar = Calendar.getInstance();
timestampCalendar.setTimeInMillis(timestamp.getTime());

//Instant转Calendar
Calendar instantCalendar = GregorianCalendar.from(ZonedDateTime.ofInstant(instant, ZoneId.systemDefault()));

//LocalDateTime转Calendar
Calendar localDateTimeCalendar = GregorianCalendar.from(ZonedDateTime.of(localDateTime, ZoneId.systemDefault()));

//ZonedDateTime转Calendar
Calendar zonedDateTimeInstantCalendar = GregorianCalendar.from(zonedDateTime);

//LocalDate转Calendar
Calendar localDateCalendar = GregorianCalendar.from(localDate.atStartOfDay(ZoneId.systemDefault()));

转LocalDate

//Date转LocalDate
LocalDate dateLocalDate = LocalDate.ofInstant(date.toInstant(), ZoneId.systemDefault());  //jdk11

LocalDate dateLocalDate = LocalDateTime.ofInstant(date.toInstant(), ZoneId.systemDefault()).toLocalDate();

//Timestamp转LocalDate
LocalDate timestampLocalDate = timestamp.toLocalDateTime().toLocalDate();

//Calendar转LocalDate
LocalDate calendarLocalDate = LocalDate.ofInstant(calendar.toInstant(), ZoneOffset.systemDefault());  //jdk11

LocalDate calendarLocalDate = LocalDateTime.ofInstant(calendar.toInstant(), ZoneOffset.systemDefault()).toLocalDate();

//Instant转LocalDate
LocalDate instantLocalDate = LocalDate.ofInstant(instant, ZoneId.systemDefault());  //jdk11

LocalDate instantLocalDate = LocalDateTime.ofInstant(instant, ZoneId.systemDefault()).toLocalDate();

//LocalDateTime转LocalDate
LocalDate localDateTimeLocalDate = localDateTime.toLocalDate();

//ZonedDateTime转LocalDate
LocalDate zonedDateTimeLocalDate = zonedDateTime.toLocalDate();