假设您获取给定时区的本地日期，例如 2016-12-28，例如美国/New_York，并将该日期的开始转换为 UTC(在本例中为 2016-12-28T05：00：00Z)。

那么是否可以从 UTC 时间开始在不知道时区的情况下返回到原始本地日期？您所知道的是，UTC时间代表当地的午夜/一天的开始。

我想这在某些情况下是可能的，例如当偏移量相当小时，但我不确定当时区接近日期变更线时，即当两个时区具有相同的时间，但不同的日期/偏移量(-10 和 +14)时，不会有两个可能的答案。

(此问题最初是在数据库中遇到的，其中本地日期错误地以 UTC 格式存储，并且很难再次检索原始时区数据。

在某些约束下，可以识别时区偏移量(UTC-05:00)，但不能识别原始时区(America/New_York)。您只能列出偏移量当时可能属于的可能时区，正如霍华德在他的答案中所显示的那样。还有其他边缘情况使此问题变得困难：

你给出了一个非常清楚的例子，说明人们如何无法确定接近国际日期变更线的偏移日期。
- 例如，考虑2016-12-31T10:00:00Z. 这可能是2016-12-31T00:00:00-10:00(可能是Pacific/Honolulu)，也可能是2017-01-01T00:00:00+14:00(可能是Pacific/Tongatapu)。
- -10/+14和-11/+13配对都是可能的，但地球上没有有人居住的地方实际使用-12。因此，如果您的值正好在中午，则它们很可能+12，除非您在海上处理船只。
本地午夜值可能不存在于您期望的时区中。
- 例如，2016-10-16T03:00:00Z是America/Sao_Paulo和America/Bahia(均在巴西)的一天的开始。但是，America/Sao_Paulo的当地时间是01:00，而不是00:00。当天没有午夜，因为它们的夏令时春季向前过渡。
本地午夜值在预期的时区中可能存在两次。
- 例如，在America/Havana中，由于2016-11-06T04:00:00Z和2016-11-06T05:00:00Z的DST回退转换，它们的本地时间为00:00。

因此，在一般情况下，您可能能够将其中大部分解析回其原始偏移量，但对于具有-10、-11、+13或+14偏移的时区，以及具有午夜(春季)或凌晨 1：00(秋季)DST 转换的时区，您将存在歧义。 (请记住，北半球/南半球的春季/秋季不同。

使用这个免费的开源C++库，我可以计算出此问题的可能时区列表。

更新我重写了此代码的驱动程序，以真正探索一整天的结果，并将其与 Matt 出色答案中的特定示例进行了比较。

代码如下：

#include <iostream>
#include <vector>
template <class Duration>
std::vector<date::zoned_time<std::common_type_t<Duration, std::chrono::seconds>>>
find_by_offset(date::sys_time<Duration> tp, const std::chrono::seconds& offset)
{
using namespace std::chrono;
using namespace date;
std::vector<zoned_time<std::common_type_t<Duration, std::chrono::seconds>>> results;
auto& db = get_tzdb();
for (auto& z : db.zones)
{
if (z.get_info(tp).offset == offset)
results.push_back(make_zoned(&z, tp));
}
return results;
}
int
main()
{
using namespace date;
using namespace std::chrono;
for (auto offset = -15h; offset <= 13h; offset += 1h)
{
auto tp = sys_days{2016_y/12/28} + offset;
std::cout << "These are all the timezones it is midnight at " << format("%F %T %Zn", tp);
auto d0 = round<days>(tp);
auto dm1 = d0 - days{1};
auto dp1 = d0 + days{1};
auto v = find_by_offset(tp, dm1 - tp);
for (auto const& zt : v)
std::cout << format("%F %T %Z %z ", zt) << zt.get_time_zone()->name() << 'n';
v = find_by_offset(tp, d0 - tp);
for (auto const& zt : v)
std::cout << format("%F %T %Z %z ", zt) << zt.get_time_zone()->name() << 'n';
v = find_by_offset(tp, dp1 - tp);
for (auto const& zt : v)
std::cout << format("%F %T %Z %z ", zt) << zt.get_time_zone()->name() << 'n';
std::cout << 'n';
}
}

该代码创建一个 UTC 时间戳和偏移量对，并将其提供给遍历所有时区的find_by_offset，并查询每个时区在该 UTC 时间戳处的偏移量。如果时区的偏移量与所需的偏移量匹配，则会在结果中添加一个zoned_time(zoned_time是时区与时间戳的配对)。

以下是2016-12-28日期可能午夜的所有结果：

These are all the timezones it is midnight at 2016-12-27 09:00:00 UTC
2016-12-27 00:00:00 AKST -0900 America/Anchorage
2016-12-27 00:00:00 AKST -0900 America/Juneau
2016-12-27 00:00:00 AKST -0900 America/Metlakatla
2016-12-27 00:00:00 AKST -0900 America/Nome
2016-12-27 00:00:00 AKST -0900 America/Sitka
2016-12-27 00:00:00 AKST -0900 America/Yakutat
2016-12-27 00:00:00 -09 -0900 Etc/GMT+9
2016-12-27 00:00:00 GAMT -0900 Pacific/Gambier
These are all the timezones it is midnight at 2016-12-27 10:00:00 UTC
2016-12-27 00:00:00 HST -1000 America/Adak
2016-12-27 00:00:00 -10 -1000 Etc/GMT+10
2016-12-27 00:00:00 HST -1000 HST
2016-12-27 00:00:00 HST -1000 Pacific/Honolulu
2016-12-27 00:00:00 CKT -1000 Pacific/Rarotonga
2016-12-27 00:00:00 TAHT -1000 Pacific/Tahiti
2016-12-28 00:00:00 +14 +1400 Etc/GMT-14
2016-12-28 00:00:00 WSDT +1400 Pacific/Apia
2016-12-28 00:00:00 LINT +1400 Pacific/Kiritimati
2016-12-28 00:00:00 +14 +1400 Pacific/Tongatapu
These are all the timezones it is midnight at 2016-12-27 11:00:00 UTC
2016-12-27 00:00:00 -11 -1100 Etc/GMT+11
2016-12-27 00:00:00 NUT -1100 Pacific/Niue
2016-12-27 00:00:00 SST -1100 Pacific/Pago_Pago
2016-12-28 00:00:00 +13 +1300 Etc/GMT-13
2016-12-28 00:00:00 NZDT +1300 Pacific/Auckland
2016-12-28 00:00:00 PHOT +1300 Pacific/Enderbury
2016-12-28 00:00:00 TKT +1300 Pacific/Fakaofo
2016-12-28 00:00:00 FJST +1300 Pacific/Fiji
These are all the timezones it is midnight at 2016-12-27 12:00:00 UTC
2016-12-27 00:00:00 -12 -1200 Etc/GMT+12
2016-12-28 00:00:00 +12 +1200 Asia/Anadyr
2016-12-28 00:00:00 +12 +1200 Asia/Kamchatka
2016-12-28 00:00:00 +12 +1200 Etc/GMT-12
2016-12-28 00:00:00 TVT +1200 Pacific/Funafuti
2016-12-28 00:00:00 MHT +1200 Pacific/Kwajalein
2016-12-28 00:00:00 MHT +1200 Pacific/Majuro
2016-12-28 00:00:00 NRT +1200 Pacific/Nauru
2016-12-28 00:00:00 GILT +1200 Pacific/Tarawa
2016-12-28 00:00:00 WAKT +1200 Pacific/Wake
2016-12-28 00:00:00 WFT +1200 Pacific/Wallis
These are all the timezones it is midnight at 2016-12-27 13:00:00 UTC
2016-12-28 00:00:00 +11 +1100 Antarctica/Casey
2016-12-28 00:00:00 MIST +1100 Antarctica/Macquarie
2016-12-28 00:00:00 +11 +1100 Asia/Magadan
2016-12-28 00:00:00 +11 +1100 Asia/Sakhalin
2016-12-28 00:00:00 +11 +1100 Asia/Srednekolymsk
2016-12-28 00:00:00 AEDT +1100 Australia/Currie
2016-12-28 00:00:00 AEDT +1100 Australia/Hobart
2016-12-28 00:00:00 LHDT +1100 Australia/Lord_Howe
2016-12-28 00:00:00 AEDT +1100 Australia/Melbourne
2016-12-28 00:00:00 AEDT +1100 Australia/Sydney
2016-12-28 00:00:00 +11 +1100 Etc/GMT-11
2016-12-28 00:00:00 BST +1100 Pacific/Bougainville
2016-12-28 00:00:00 VUT +1100 Pacific/Efate
2016-12-28 00:00:00 SBT +1100 Pacific/Guadalcanal
2016-12-28 00:00:00 KOST +1100 Pacific/Kosrae
2016-12-28 00:00:00 NFT +1100 Pacific/Norfolk
2016-12-28 00:00:00 NCT +1100 Pacific/Noumea
2016-12-28 00:00:00 PONT +1100 Pacific/Pohnpei
These are all the timezones it is midnight at 2016-12-27 14:00:00 UTC
2016-12-28 00:00:00 +10 +1000 Antarctica/DumontDUrville
2016-12-28 00:00:00 +10 +1000 Asia/Ust-Nera
2016-12-28 00:00:00 +10 +1000 Asia/Vladivostok
2016-12-28 00:00:00 AEST +1000 Australia/Brisbane
2016-12-28 00:00:00 AEST +1000 Australia/Lindeman
2016-12-28 00:00:00 +10 +1000 Etc/GMT-10
2016-12-28 00:00:00 CHUT +1000 Pacific/Chuuk
2016-12-28 00:00:00 ChST +1000 Pacific/Guam
2016-12-28 00:00:00 PGT +1000 Pacific/Port_Moresby
These are all the timezones it is midnight at 2016-12-27 15:00:00 UTC
2016-12-28 00:00:00 +09 +0900 Asia/Chita
2016-12-28 00:00:00 TLT +0900 Asia/Dili
2016-12-28 00:00:00 WIT +0900 Asia/Jayapura
2016-12-28 00:00:00 +09 +0900 Asia/Khandyga
2016-12-28 00:00:00 KST +0900 Asia/Seoul
2016-12-28 00:00:00 JST +0900 Asia/Tokyo
2016-12-28 00:00:00 +09 +0900 Asia/Yakutsk
2016-12-28 00:00:00 +09 +0900 Etc/GMT-9
2016-12-28 00:00:00 PWT +0900 Pacific/Palau
These are all the timezones it is midnight at 2016-12-27 16:00:00 UTC
2016-12-28 00:00:00 BNT +0800 Asia/Brunei
2016-12-28 00:00:00 CHOT +0800 Asia/Choibalsan
2016-12-28 00:00:00 HKT +0800 Asia/Hong_Kong
2016-12-28 00:00:00 +08 +0800 Asia/Irkutsk
2016-12-28 00:00:00 MYT +0800 Asia/Kuala_Lumpur
2016-12-28 00:00:00 MYT +0800 Asia/Kuching
2016-12-28 00:00:00 CST +0800 Asia/Macau
2016-12-28 00:00:00 WITA +0800 Asia/Makassar
2016-12-28 00:00:00 PHT +0800 Asia/Manila
2016-12-28 00:00:00 CST +0800 Asia/Shanghai
2016-12-28 00:00:00 SGT +0800 Asia/Singapore
2016-12-28 00:00:00 CST +0800 Asia/Taipei
2016-12-28 00:00:00 ULAT +0800 Asia/Ulaanbaatar
2016-12-28 00:00:00 AWST +0800 Australia/Perth
2016-12-28 00:00:00 +08 +0800 Etc/GMT-8
These are all the timezones it is midnight at 2016-12-27 17:00:00 UTC
2016-12-28 00:00:00 +07 +0700 Antarctica/Davis
2016-12-28 00:00:00 ICT +0700 Asia/Bangkok
2016-12-28 00:00:00 +07 +0700 Asia/Barnaul
2016-12-28 00:00:00 ICT +0700 Asia/Ho_Chi_Minh
2016-12-28 00:00:00 HOVT +0700 Asia/Hovd
2016-12-28 00:00:00 WIB +0700 Asia/Jakarta
2016-12-28 00:00:00 +07 +0700 Asia/Krasnoyarsk
2016-12-28 00:00:00 +07 +0700 Asia/Novokuznetsk
2016-12-28 00:00:00 +07 +0700 Asia/Novosibirsk
2016-12-28 00:00:00 WIB +0700 Asia/Pontianak
2016-12-28 00:00:00 +07 +0700 Asia/Tomsk
2016-12-28 00:00:00 +07 +0700 Etc/GMT-7
2016-12-28 00:00:00 CXT +0700 Indian/Christmas
These are all the timezones it is midnight at 2016-12-27 18:00:00 UTC
2016-12-28 00:00:00 +06 +0600 Antarctica/Vostok
2016-12-28 00:00:00 +06 +0600 Asia/Almaty
2016-12-28 00:00:00 +06 +0600 Asia/Bishkek
2016-12-28 00:00:00 BDT +0600 Asia/Dhaka
2016-12-28 00:00:00 +06 +0600 Asia/Omsk
2016-12-28 00:00:00 +06 +0600 Asia/Qyzylorda
2016-12-28 00:00:00 BTT +0600 Asia/Thimphu
2016-12-28 00:00:00 XJT +0600 Asia/Urumqi
2016-12-28 00:00:00 +06 +0600 Etc/GMT-6
2016-12-28 00:00:00 IOT +0600 Indian/Chagos
These are all the timezones it is midnight at 2016-12-27 19:00:00 UTC
2016-12-28 00:00:00 +05 +0500 Antarctica/Mawson
2016-12-28 00:00:00 +05 +0500 Asia/Aqtau
2016-12-28 00:00:00 +05 +0500 Asia/Aqtobe
2016-12-28 00:00:00 +05 +0500 Asia/Ashgabat
2016-12-28 00:00:00 +05 +0500 Asia/Atyrau
2016-12-28 00:00:00 +05 +0500 Asia/Dushanbe
2016-12-28 00:00:00 PKT +0500 Asia/Karachi
2016-12-28 00:00:00 +05 +0500 Asia/Oral
2016-12-28 00:00:00 +05 +0500 Asia/Samarkand
2016-12-28 00:00:00 +05 +0500 Asia/Tashkent
2016-12-28 00:00:00 +05 +0500 Asia/Yekaterinburg
2016-12-28 00:00:00 +05 +0500 Etc/GMT-5
2016-12-28 00:00:00 +05 +0500 Indian/Kerguelen
2016-12-28 00:00:00 MVT +0500 Indian/Maldives
These are all the timezones it is midnight at 2016-12-27 20:00:00 UTC
2016-12-28 00:00:00 +04 +0400 Asia/Baku
2016-12-28 00:00:00 GST +0400 Asia/Dubai
2016-12-28 00:00:00 +04 +0400 Asia/Tbilisi
2016-12-28 00:00:00 +04 +0400 Asia/Yerevan
2016-12-28 00:00:00 +04 +0400 Etc/GMT-4
2016-12-28 00:00:00 +04 +0400 Europe/Astrakhan
2016-12-28 00:00:00 +04 +0400 Europe/Samara
2016-12-28 00:00:00 +04 +0400 Europe/Saratov
2016-12-28 00:00:00 +04 +0400 Europe/Ulyanovsk
2016-12-28 00:00:00 SCT +0400 Indian/Mahe
2016-12-28 00:00:00 MUT +0400 Indian/Mauritius
2016-12-28 00:00:00 RET +0400 Indian/Reunion
These are all the timezones it is midnight at 2016-12-27 21:00:00 UTC
2016-12-28 00:00:00 EAT +0300 Africa/Khartoum
2016-12-28 00:00:00 EAT +0300 Africa/Nairobi
2016-12-28 00:00:00 +03 +0300 Antarctica/Syowa
2016-12-28 00:00:00 AST +0300 Asia/Baghdad
2016-12-28 00:00:00 +03 +0300 Asia/Famagusta
2016-12-28 00:00:00 AST +0300 Asia/Qatar
2016-12-28 00:00:00 AST +0300 Asia/Riyadh
2016-12-28 00:00:00 +03 +0300 Etc/GMT-3
2016-12-28 00:00:00 +03 +0300 Europe/Istanbul
2016-12-28 00:00:00 +03 +0300 Europe/Kirov
2016-12-28 00:00:00 +03 +0300 Europe/Minsk
2016-12-28 00:00:00 MSK +0300 Europe/Moscow
2016-12-28 00:00:00 MSK +0300 Europe/Simferopol
2016-12-28 00:00:00 +03 +0300 Europe/Volgograd
These are all the timezones it is midnight at 2016-12-27 22:00:00 UTC
2016-12-28 00:00:00 EET +0200 Africa/Cairo
2016-12-28 00:00:00 SAST +0200 Africa/Johannesburg
2016-12-28 00:00:00 CAT +0200 Africa/Maputo
2016-12-28 00:00:00 EET +0200 Africa/Tripoli
2016-12-28 00:00:00 WAST +0200 Africa/Windhoek
2016-12-28 00:00:00 EET +0200 Asia/Amman
2016-12-28 00:00:00 EET +0200 Asia/Beirut
2016-12-28 00:00:00 EET +0200 Asia/Damascus
2016-12-28 00:00:00 EET +0200 Asia/Gaza
2016-12-28 00:00:00 EET +0200 Asia/Hebron
2016-12-28 00:00:00 IST +0200 Asia/Jerusalem
2016-12-28 00:00:00 EET +0200 Asia/Nicosia
2016-12-28 00:00:00 EET +0200 EET
2016-12-28 00:00:00 +02 +0200 Etc/GMT-2
2016-12-28 00:00:00 EET +0200 Europe/Athens
2016-12-28 00:00:00 EET +0200 Europe/Bucharest
2016-12-28 00:00:00 EET +0200 Europe/Chisinau
2016-12-28 00:00:00 EET +0200 Europe/Helsinki
2016-12-28 00:00:00 EET +0200 Europe/Kaliningrad
2016-12-28 00:00:00 EET +0200 Europe/Kiev
2016-12-28 00:00:00 EET +0200 Europe/Riga
2016-12-28 00:00:00 EET +0200 Europe/Sofia
2016-12-28 00:00:00 EET +0200 Europe/Tallinn
2016-12-28 00:00:00 EET +0200 Europe/Uzhgorod
2016-12-28 00:00:00 EET +0200 Europe/Vilnius
2016-12-28 00:00:00 EET +0200 Europe/Zaporozhye
These are all the timezones it is midnight at 2016-12-27 23:00:00 UTC
2016-12-28 00:00:00 CET +0100 Africa/Algiers
2016-12-28 00:00:00 CET +0100 Africa/Ceuta
2016-12-28 00:00:00 WAT +0100 Africa/Lagos
2016-12-28 00:00:00 WAT +0100 Africa/Ndjamena
2016-12-28 00:00:00 CET +0100 Africa/Tunis
2016-12-28 00:00:00 CET +0100 CET
2016-12-28 00:00:00 +01 +0100 Etc/GMT-1
2016-12-28 00:00:00 CET +0100 Europe/Amsterdam
2016-12-28 00:00:00 CET +0100 Europe/Andorra
2016-12-28 00:00:00 CET +0100 Europe/Belgrade
2016-12-28 00:00:00 CET +0100 Europe/Berlin
2016-12-28 00:00:00 CET +0100 Europe/Brussels
2016-12-28 00:00:00 CET +0100 Europe/Budapest
2016-12-28 00:00:00 CET +0100 Europe/Copenhagen
2016-12-28 00:00:00 CET +0100 Europe/Gibraltar
2016-12-28 00:00:00 CET +0100 Europe/Luxembourg
2016-12-28 00:00:00 CET +0100 Europe/Madrid
2016-12-28 00:00:00 CET +0100 Europe/Malta
2016-12-28 00:00:00 CET +0100 Europe/Monaco
2016-12-28 00:00:00 CET +0100 Europe/Oslo
2016-12-28 00:00:00 CET +0100 Europe/Paris
2016-12-28 00:00:00 CET +0100 Europe/Prague
2016-12-28 00:00:00 CET +0100 Europe/Rome
2016-12-28 00:00:00 CET +0100 Europe/Stockholm
2016-12-28 00:00:00 CET +0100 Europe/Tirane
2016-12-28 00:00:00 CET +0100 Europe/Vienna
2016-12-28 00:00:00 CET +0100 Europe/Warsaw
2016-12-28 00:00:00 CET +0100 Europe/Zurich
2016-12-28 00:00:00 MET +0100 MET
These are all the timezones it is midnight at 2016-12-28 00:00:00 UTC
2016-12-28 00:00:00 GMT +0000 Africa/Abidjan
2016-12-28 00:00:00 GMT +0000 Africa/Accra
2016-12-28 00:00:00 GMT +0000 Africa/Bissau
2016-12-28 00:00:00 WET +0000 Africa/Casablanca
2016-12-28 00:00:00 WET +0000 Africa/El_Aaiun
2016-12-28 00:00:00 GMT +0000 Africa/Monrovia
2016-12-28 00:00:00 GMT +0000 America/Danmarkshavn
2016-12-28 00:00:00 +00 +0000 Antarctica/Troll
2016-12-28 00:00:00 WET +0000 Atlantic/Canary
2016-12-28 00:00:00 WET +0000 Atlantic/Faroe
2016-12-28 00:00:00 WET +0000 Atlantic/Madeira
2016-12-28 00:00:00 GMT +0000 Atlantic/Reykjavik
2016-12-28 00:00:00 GMT +0000 Etc/GMT
2016-12-28 00:00:00 UCT +0000 Etc/UCT
2016-12-28 00:00:00 UTC +0000 Etc/UTC
2016-12-28 00:00:00 GMT +0000 Europe/Dublin
2016-12-28 00:00:00 WET +0000 Europe/Lisbon
2016-12-28 00:00:00 GMT +0000 Europe/London
2016-12-28 00:00:00 WET +0000 WET
These are all the timezones it is midnight at 2016-12-28 01:00:00 UTC
2016-12-28 00:00:00 EGT -0100 America/Scoresbysund
2016-12-28 00:00:00 AZOT -0100 Atlantic/Azores
2016-12-28 00:00:00 CVT -0100 Atlantic/Cape_Verde
2016-12-28 00:00:00 -01 -0100 Etc/GMT+1
These are all the timezones it is midnight at 2016-12-28 02:00:00 UTC
2016-12-28 00:00:00 FNT -0200 America/Noronha
2016-12-28 00:00:00 BRST -0200 America/Sao_Paulo
2016-12-28 00:00:00 GST -0200 Atlantic/South_Georgia
2016-12-28 00:00:00 -02 -0200 Etc/GMT+2
These are all the timezones it is midnight at 2016-12-28 03:00:00 UTC
2016-12-28 00:00:00 BRT -0300 America/Araguaina
2016-12-28 00:00:00 ART -0300 America/Argentina/Buenos_Aires
2016-12-28 00:00:00 ART -0300 America/Argentina/Catamarca
2016-12-28 00:00:00 ART -0300 America/Argentina/Cordoba
2016-12-28 00:00:00 ART -0300 America/Argentina/Jujuy
2016-12-28 00:00:00 ART -0300 America/Argentina/La_Rioja
2016-12-28 00:00:00 ART -0300 America/Argentina/Mendoza
2016-12-28 00:00:00 ART -0300 America/Argentina/Rio_Gallegos
2016-12-28 00:00:00 ART -0300 America/Argentina/Salta
2016-12-28 00:00:00 ART -0300 America/Argentina/San_Juan
2016-12-28 00:00:00 ART -0300 America/Argentina/San_Luis
2016-12-28 00:00:00 ART -0300 America/Argentina/Tucuman
2016-12-28 00:00:00 ART -0300 America/Argentina/Ushuaia
2016-12-28 00:00:00 PYST -0300 America/Asuncion
2016-12-28 00:00:00 BRT -0300 America/Bahia
2016-12-28 00:00:00 BRT -0300 America/Belem
2016-12-28 00:00:00 AMST -0300 America/Campo_Grande
2016-12-28 00:00:00 GFT -0300 America/Cayenne
2016-12-28 00:00:00 AMST -0300 America/Cuiaba
2016-12-28 00:00:00 BRT -0300 America/Fortaleza
2016-12-28 00:00:00 WGT -0300 America/Godthab
2016-12-28 00:00:00 BRT -0300 America/Maceio
2016-12-28 00:00:00 PMST -0300 America/Miquelon
2016-12-28 00:00:00 UYT -0300 America/Montevideo
2016-12-28 00:00:00 SRT -0300 America/Paramaribo
2016-12-28 00:00:00 BRT -0300 America/Recife
2016-12-28 00:00:00 BRT -0300 America/Santarem
2016-12-28 00:00:00 CLST -0300 America/Santiago
2016-12-28 00:00:00 CLST -0300 Antarctica/Palmer
2016-12-28 00:00:00 -03 -0300 Antarctica/Rothera
2016-12-28 00:00:00 FKST -0300 Atlantic/Stanley
2016-12-28 00:00:00 -03 -0300 Etc/GMT+3
These are all the timezones it is midnight at 2016-12-28 04:00:00 UTC
2016-12-28 00:00:00 AST -0400 America/Barbados
2016-12-28 00:00:00 AST -0400 America/Blanc-Sablon
2016-12-28 00:00:00 AMT -0400 America/Boa_Vista
2016-12-28 00:00:00 VET -0400 America/Caracas
2016-12-28 00:00:00 AST -0400 America/Curacao
2016-12-28 00:00:00 AST -0400 America/Glace_Bay
2016-12-28 00:00:00 AST -0400 America/Goose_Bay
2016-12-28 00:00:00 AST -0400 America/Grand_Turk
2016-12-28 00:00:00 GYT -0400 America/Guyana
2016-12-28 00:00:00 AST -0400 America/Halifax
2016-12-28 00:00:00 BOT -0400 America/La_Paz
2016-12-28 00:00:00 AMT -0400 America/Manaus
2016-12-28 00:00:00 AST -0400 America/Martinique
2016-12-28 00:00:00 AST -0400 America/Moncton
2016-12-28 00:00:00 AST -0400 America/Port_of_Spain
2016-12-28 00:00:00 AMT -0400 America/Porto_Velho
2016-12-28 00:00:00 AST -0400 America/Puerto_Rico
2016-12-28 00:00:00 AST -0400 America/Santo_Domingo
2016-12-28 00:00:00 AST -0400 America/Thule
2016-12-28 00:00:00 AST -0400 Atlantic/Bermuda
2016-12-28 00:00:00 -04 -0400 Etc/GMT+4
These are all the timezones it is midnight at 2016-12-28 05:00:00 UTC
2016-12-28 00:00:00 EST -0500 America/Atikokan
2016-12-28 00:00:00 COT -0500 America/Bogota
2016-12-28 00:00:00 EST -0500 America/Cancun
2016-12-28 00:00:00 EST -0500 America/Detroit
2016-12-28 00:00:00 ACT -0500 America/Eirunepe
2016-12-28 00:00:00 ECT -0500 America/Guayaquil
2016-12-28 00:00:00 CST -0500 America/Havana
2016-12-28 00:00:00 EST -0500 America/Indiana/Indianapolis
2016-12-28 00:00:00 EST -0500 America/Indiana/Marengo
2016-12-28 00:00:00 EST -0500 America/Indiana/Petersburg
2016-12-28 00:00:00 EST -0500 America/Indiana/Vevay
2016-12-28 00:00:00 EST -0500 America/Indiana/Vincennes
2016-12-28 00:00:00 EST -0500 America/Indiana/Winamac
2016-12-28 00:00:00 EST -0500 America/Iqaluit
2016-12-28 00:00:00 EST -0500 America/Jamaica
2016-12-28 00:00:00 EST -0500 America/Kentucky/Louisville
2016-12-28 00:00:00 EST -0500 America/Kentucky/Monticello
2016-12-28 00:00:00 PET -0500 America/Lima
2016-12-28 00:00:00 EST -0500 America/Nassau
2016-12-28 00:00:00 EST -0500 America/New_York
2016-12-28 00:00:00 EST -0500 America/Nipigon
2016-12-28 00:00:00 EST -0500 America/Panama
2016-12-28 00:00:00 EST -0500 America/Pangnirtung
2016-12-28 00:00:00 EST -0500 America/Port-au-Prince
2016-12-28 00:00:00 ACT -0500 America/Rio_Branco
2016-12-28 00:00:00 EST -0500 America/Thunder_Bay
2016-12-28 00:00:00 EST -0500 America/Toronto
2016-12-28 00:00:00 EST -0500 EST
2016-12-28 00:00:00 EST -0500 EST5EDT
2016-12-28 00:00:00 -05 -0500 Etc/GMT+5
2016-12-28 00:00:00 EASST -0500 Pacific/Easter
These are all the timezones it is midnight at 2016-12-28 06:00:00 UTC
2016-12-28 00:00:00 CST -0600 America/Bahia_Banderas
2016-12-28 00:00:00 CST -0600 America/Belize
2016-12-28 00:00:00 CST -0600 America/Chicago
2016-12-28 00:00:00 CST -0600 America/Costa_Rica
2016-12-28 00:00:00 CST -0600 America/El_Salvador
2016-12-28 00:00:00 CST -0600 America/Guatemala
2016-12-28 00:00:00 CST -0600 America/Indiana/Knox
2016-12-28 00:00:00 CST -0600 America/Indiana/Tell_City
2016-12-28 00:00:00 CST -0600 America/Managua
2016-12-28 00:00:00 CST -0600 America/Matamoros
2016-12-28 00:00:00 CST -0600 America/Menominee
2016-12-28 00:00:00 CST -0600 America/Merida
2016-12-28 00:00:00 CST -0600 America/Mexico_City
2016-12-28 00:00:00 CST -0600 America/Monterrey
2016-12-28 00:00:00 CST -0600 America/North_Dakota/Beulah
2016-12-28 00:00:00 CST -0600 America/North_Dakota/Center
2016-12-28 00:00:00 CST -0600 America/North_Dakota/New_Salem
2016-12-28 00:00:00 CST -0600 America/Rainy_River
2016-12-28 00:00:00 CST -0600 America/Rankin_Inlet
2016-12-28 00:00:00 CST -0600 America/Regina
2016-12-28 00:00:00 CST -0600 America/Resolute
2016-12-28 00:00:00 CST -0600 America/Swift_Current
2016-12-28 00:00:00 CST -0600 America/Tegucigalpa
2016-12-28 00:00:00 CST -0600 America/Winnipeg
2016-12-28 00:00:00 CST -0600 CST6CDT
2016-12-28 00:00:00 -06 -0600 Etc/GMT+6
2016-12-28 00:00:00 GALT -0600 Pacific/Galapagos
These are all the timezones it is midnight at 2016-12-28 07:00:00 UTC
2016-12-28 00:00:00 MST -0700 America/Boise
2016-12-28 00:00:00 MST -0700 America/Cambridge_Bay
2016-12-28 00:00:00 MST -0700 America/Chihuahua
2016-12-28 00:00:00 MST -0700 America/Creston
2016-12-28 00:00:00 MST -0700 America/Dawson_Creek
2016-12-28 00:00:00 MST -0700 America/Denver
2016-12-28 00:00:00 MST -0700 America/Edmonton
2016-12-28 00:00:00 MST -0700 America/Fort_Nelson
2016-12-28 00:00:00 MST -0700 America/Hermosillo
2016-12-28 00:00:00 MST -0700 America/Inuvik
2016-12-28 00:00:00 MST -0700 America/Mazatlan
2016-12-28 00:00:00 MST -0700 America/Ojinaga
2016-12-28 00:00:00 MST -0700 America/Phoenix
2016-12-28 00:00:00 MST -0700 America/Yellowknife
2016-12-28 00:00:00 -07 -0700 Etc/GMT+7
2016-12-28 00:00:00 MST -0700 MST
2016-12-28 00:00:00 MST -0700 MST7MDT
These are all the timezones it is midnight at 2016-12-28 08:00:00 UTC
2016-12-28 00:00:00 PST -0800 America/Dawson
2016-12-28 00:00:00 PST -0800 America/Los_Angeles
2016-12-28 00:00:00 PST -0800 America/Tijuana
2016-12-28 00:00:00 PST -0800 America/Vancouver
2016-12-28 00:00:00 PST -0800 America/Whitehorse
2016-12-28 00:00:00 -08 -0800 Etc/GMT+8
2016-12-28 00:00:00 PST -0800 PST8PDT
2016-12-28 00:00:00 PST -0800 Pacific/Pitcairn
These are all the timezones it is midnight at 2016-12-28 09:00:00 UTC
2016-12-28 00:00:00 AKST -0900 America/Anchorage
2016-12-28 00:00:00 AKST -0900 America/Juneau
2016-12-28 00:00:00 AKST -0900 America/Metlakatla
2016-12-28 00:00:00 AKST -0900 America/Nome
2016-12-28 00:00:00 AKST -0900 America/Sitka
2016-12-28 00:00:00 AKST -0900 America/Yakutat
2016-12-28 00:00:00 -09 -0900 Etc/GMT+9
2016-12-28 00:00:00 GAMT -0900 Pacific/Gambier
These are all the timezones it is midnight at 2016-12-28 10:00:00 UTC
2016-12-28 00:00:00 HST -1000 America/Adak
2016-12-28 00:00:00 -10 -1000 Etc/GMT+10
2016-12-28 00:00:00 HST -1000 HST
2016-12-28 00:00:00 HST -1000 Pacific/Honolulu
2016-12-28 00:00:00 CKT -1000 Pacific/Rarotonga
2016-12-28 00:00:00 TAHT -1000 Pacific/Tahiti
2016-12-29 00:00:00 +14 +1400 Etc/GMT-14
2016-12-29 00:00:00 WSDT +1400 Pacific/Apia
2016-12-29 00:00:00 LINT +1400 Pacific/Kiritimati
2016-12-29 00:00:00 +14 +1400 Pacific/Tongatapu
These are all the timezones it is midnight at 2016-12-28 11:00:00 UTC
2016-12-28 00:00:00 -11 -1100 Etc/GMT+11
2016-12-28 00:00:00 NUT -1100 Pacific/Niue
2016-12-28 00:00:00 SST -1100 Pacific/Pago_Pago
2016-12-29 00:00:00 +13 +1300 Etc/GMT-13
2016-12-29 00:00:00 NZDT +1300 Pacific/Auckland
2016-12-29 00:00:00 PHOT +1300 Pacific/Enderbury
2016-12-29 00:00:00 TKT +1300 Pacific/Fakaofo
2016-12-29 00:00:00 FJST +1300 Pacific/Fiji
These are all the timezones it is midnight at 2016-12-28 12:00:00 UTC
2016-12-28 00:00:00 -12 -1200 Etc/GMT+12
2016-12-29 00:00:00 +12 +1200 Asia/Anadyr
2016-12-29 00:00:00 +12 +1200 Asia/Kamchatka
2016-12-29 00:00:00 +12 +1200 Etc/GMT-12
2016-12-29 00:00:00 TVT +1200 Pacific/Funafuti
2016-12-29 00:00:00 MHT +1200 Pacific/Kwajalein
2016-12-29 00:00:00 MHT +1200 Pacific/Majuro
2016-12-29 00:00:00 NRT +1200 Pacific/Nauru
2016-12-29 00:00:00 GILT +1200 Pacific/Tarawa
2016-12-29 00:00:00 WAKT +1200 Pacific/Wake
2016-12-29 00:00:00 WFT +1200 Pacific/Wallis
These are all the timezones it is midnight at 2016-12-28 13:00:00 UTC
2016-12-29 00:00:00 +11 +1100 Antarctica/Casey
2016-12-29 00:00:00 MIST +1100 Antarctica/Macquarie
2016-12-29 00:00:00 +11 +1100 Asia/Magadan
2016-12-29 00:00:00 +11 +1100 Asia/Sakhalin
2016-12-29 00:00:00 +11 +1100 Asia/Srednekolymsk
2016-12-29 00:00:00 AEDT +1100 Australia/Currie
2016-12-29 00:00:00 AEDT +1100 Australia/Hobart
2016-12-29 00:00:00 LHDT +1100 Australia/Lord_Howe
2016-12-29 00:00:00 AEDT +1100 Australia/Melbourne
2016-12-29 00:00:00 AEDT +1100 Australia/Sydney
2016-12-29 00:00:00 +11 +1100 Etc/GMT-11
2016-12-29 00:00:00 BST +1100 Pacific/Bougainville
2016-12-29 00:00:00 VUT +1100 Pacific/Efate
2016-12-29 00:00:00 SBT +1100 Pacific/Guadalcanal
2016-12-29 00:00:00 KOST +1100 Pacific/Kosrae
2016-12-29 00:00:00 NFT +1100 Pacific/Norfolk
2016-12-29 00:00:00 NCT +1100 Pacific/Noumea
2016-12-29 00:00:00 PONT +1100 Pacific/Pohnpei

笔记：

2016-12-28 10：00：00 UTC在其结果中列出了太平洋/檀香山和太平洋/汤加塔布(以及其他几个
)。
这些结果列出了所有-10/+14和-11/+13配对，以及其他一些配对，但其他几个只涉及"航海"时区，如"Etc/GMT+12"。
如果您更改程序以探索 2016-10-16America/Sao_Paulo永远不会列出，尽管它被列为 2016-12-28，因为America/Sao_Paulo2016-10-16 没有午夜。但您确实发现America/Bahia列在 2016-10-16 03：00：00 UTC 下(偏移量 -0300)。
将程序更改为探索 2016-11-06 显示America/Havana在 2016-11-06 04：00：00 UTC 和 2016-11-06 05：00：00 UTC 下列出。
在这里突出显示的示例中，没有一个唯一的时区，即给定 UTC 时间点的午夜。对于 UTC 偏移量不是整数小时数的时区，可能存在这样的时间点。

啊，是的，这里有一些：

These are all the timezones it is midnight at 2016-12-27 09:30:00 UTC
2016-12-27 00:00:00 MART -0930 Pacific/Marquesas
These are all the timezones it is midnight at 2016-12-27 10:15:00 UTC
2016-12-28 00:00:00 CHADT +1345 Pacific/Chatham
These are all the timezones it is midnight at 2016-12-27 14:30:00 UTC
2016-12-28 00:00:00 ACST +0930 Australia/Darwin
These are all the timezones it is midnight at 2016-12-27 15:15:00 UTC
2016-12-28 00:00:00 ACWST +0845 Australia/Eucla
These are all the timezones it is midnight at 2016-12-27 15:30:00 UTC
2016-12-28 00:00:00 KST +0830 Asia/Pyongyang
These are all the timezones it is midnight at 2016-12-27 18:15:00 UTC
2016-12-28 00:00:00 NPT +0545 Asia/Kathmandu
These are all the timezones it is midnight at 2016-12-27 19:30:00 UTC
2016-12-28 00:00:00 AFT +0430 Asia/Kabul
These are all the timezones it is midnight at 2016-12-27 20:30:00 UTC
2016-12-28 00:00:00 IRST +0330 Asia/Tehran
These are all the timezones it is midnight at 2016-12-28 03:30:00 UTC
2016-12-28 00:00:00 NST -0330 America/St_Johns

Matt Johnson的回答是正确的。

如果您确定存储在数据库中的时刻代表某个时区某处一天中的第一个时刻，则可以获取日期。
您可以猜测时区，但无法确定当时多个区域共享 UTC 偏移量时的原始时区。

java.time

下面是一些使用现代java.time类的Java代码。

假设您在给定时区(例如美国/New_York)中获取本地日期，例如 2016-12-28，并将该日期的开始转换为 UTC(在本例中为 2016-12-28T05：00：00Z)。

请注意，我们让java.time通过LocalDate::atStartOfDay方法确定一天中的第一个时刻。不要假设一天从 00：00：00 开始。夏令时等异常情况意味着一天可能从另一个时间(如 01：00：00)开始。

LocalDate localDate = LocalDate.parse( "2016-12-28" ) ;
ZoneId zNewYork = ZoneId.of( "America/New_York" ) ;
ZonedDateTime zdtNewYork = localDate.atStartOfDay( zNewYork ) ;   // First moment of the day in that zone on that date.

通过提取Instant调整为 UTC 值。根据定义，Instant始终采用 UTC。

Instant instant = zdtNewYork.toInstant() ;

存储在数据库中类型类似于 SQL 标准TIMESTAMP WITH TIME ZONE的列中。

myPreparedStatement.setObject( … , instant ) ;

在不知道时区的情况下回到原来的本地日期？

取回。

Instant instant = myResultSet.getObject( … , Instant.class ) ;

现在尝试每个时区。仅供参考，请参阅维基百科上的区域名称列表，尽管该页面可能已过时。

对于每个区域，将我们的Instant(UTC时刻)调整到该区域以获得ZonedDateTime对象。某个时刻，时间轴上的同一点，但不同的挂钟时间。

对于每个ZonedDateTime，仅提取日期，不带时间，也不带时区。呈现LocalDate对象。要求LocalDate确定我们考虑的时区中一天中的第一个时刻(可能发生也可能不会发生在 00：00：00)。这将生成另一个ZonedDateTime对象。

从第二个ZonedDateTime，提取一个Instant以调整回 UTC。将这个新的Instant对象与我们的原始Instant进行比较。如果它们相同，我们就命中了。我们已经确定了存储在数据库中的一天开始的时区。因此，我们上面生成的LocalDate与最初存储在数据库中不恰当的日期相同。

List< ZoneId > hits = new ArrayList<>() ;
LocalDate originalLocalDate = null ;
Set< String > zoneIds = ZoneId.getAvailableZoneIds() ;  // Gets the set of available zone IDs.
for( String zoneId : zoneIds ) {
ZoneId z = ZoneId.of( zoneId ) ;                        // Get zone with that name.
ZonedDateTime zdt = instant.atZone( z ) ;
LocalDate ld = zdt.toLocalDate() ;                      // Extract the date-only value, dropping the time-of-day and dropping the time zone.
ZonedDateTime startOfDay = ld.atStartOfDay( z ) ;       // Determine first moment of the day on that date in that zone.
Instant instantOfStartOfDay = startOfDay.toInstant() ;  // Adjust back to UTC.
boolean hit = instant.equals( instantOfStartOfDay ) ;
if( hit ) {
originalLocalDate = ld ;
hits.add( z ) ;  // Collect this time zone as the zone possibly used originally.
}
}

查看此代码在 IdeOne.com 实时运行。

运行时，我们看到该日期America/New_York时区的偏移量比 UTC 晚 5 小时。您可以从此列表中看到，还有许多其他时区共享相同的-05:00偏移量。

原版本地日期至字符串()： 2016-12-28

hits.toString()： [美国/巴拿马，美国/印第安纳州/彼得堡，美国/艾鲁内佩，古巴，等等/格林威治标准时间+5，太平洋/复活节，美洲/Fort_Wayne，美洲/哈瓦那，美洲/Porto_Acre，美国/密歇根，美国/路易斯维尔，美国/瓜亚基尔，美国/印第安纳州/维瓦伊，美国/印第安纳州/文森斯，美国/印第安纳波利斯，美国/伊卡卢伊特，美国/肯塔基州/路易斯维尔， EST5EDT，美国/拿骚，美洲/牙买加，美洲/阿提科坎，美国/肯塔基州/蒙蒂塞洛，美国/Coral_Harbour，美国/开曼群岛，智利/复活节岛、美洲/印第安纳州/印第安纳波利斯、美洲/Thunder_Bay、美洲/印第安纳州/马伦戈、美洲/波哥大、SystemV/EST5、美国/东部、加拿大/东部、美洲/太子港、美洲/尼皮贡、巴西/英亩、美国/东印第安纳州、美洲/坎昆、美洲/利马、美洲/Rio_Branco、美洲/底特律、牙买加、美洲/庞尼通、美洲/蒙特利尔、美国/印第安纳州/Winamac、美洲/New_York、美国/多伦多、SystemV/EST5EDT]

请注意，生成的区域列表可能不明显。某些区域名称是别名，其中一个区域具有多个名称。例如，旧Asia/Calcutta现在Asia/Kolkata。

关于java.time

java.time框架内置于 Java 8 及更高版本中。这些类取代了麻烦的旧传统日期时间类，如java.util.Date、Calendar和SimpleDateFormat。

Joda-Time项目现在处于维护模式，建议迁移到 java.time 类。

要了解更多信息，请参阅Oracle 教程。并搜索堆栈溢出以获取许多示例和解释。规范为 JSR 310。

您可以直接与数据库交换java.time对象。使用符合 JDBC 4.2 或更高版本的 JDBC 驱动程序。不需要字符串，不需要java.sql.*类。

从哪里获得java.time类？

Java SE 8、Java SE

9、Java SE 10及更高版本
- 内置。
- 具有捆绑实现的标准 Java API 的一部分。
- Java 9添加了一些小功能和修复。
- java.time 功能在ThreeTen-Backport中向后移植到 Java 6 和 7。
- 更高版本的java.time类的 Android 捆绑实现。
- 对于早期的Android(<26)，ThreeTenABP项目适应了ThreeTen-Backport(如上所述)。请参阅如何使用ThreeTenABP...。

ThreeTen-Extra项目通过额外的类扩展了java.time。这个项目是未来可能添加到java.time的试验场。你可以在这里找到一些有用的类，如Interval、YearWeek、YearQuarter等。

是否可以从代表当地午夜的 UTC 时间计算本地日期

java.time

关于java.time

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