TimeZone

八、java.util.TimeZone

Java中的java.util.TimeZone类用于表达时区，当你进行跨时区的java.util.Calendar的计算时，可以尝试使用java.util.TimeZone来连接不同时区的calendar。

注意：在Java 8中日期时间功能中，时区使用的是java.time.ZoneId类，但你只需要在你使用Java 8的日期时间类（像ZonedDateTime类）的时候，才需要用到ZoneId。如果你只是使用一个Calendar类，那你不妨继续使用java.util.TimeZone。

获取一个Calendar的时区

//获取时区： Calendar calendar = new GregorianCalendar(); TimeZone timeZone = calendar.getTimeZone(); //设置时区： calendar.setTimeZone(timeZone);

创建一个TimeZone的实例对象 
有两种方式获得TimeZone实例：

TimeZone timeZone1 = TimeZone.getDefault();
TimeZone timeZone2 = TimeZone.getTimeZone("Europe/Copenhagen");

第一种方法返回默认的时区，即系统当前时区。 
第二种方法返回指定的地区ID（在这个例子里是Europe/Copenhagen）的时区，在本篇的末尾将附上一个可用地区ID表。

时区的名字、ID和时差(Offset) 
你也可以展示指定TimeZone对象的时区名字、ID和时差：

timeZone.getDisplayName();
timeZone.getID();
timeZone.getOffset( System.currentTimeMillis() );

getOffset(time)方法返回的是以毫秒为单位的，与世界标准时间UTC为time的时差（如此段代码若在上海时区运行，将返回28800,000，即正好8个小时，符合预期中国UTC+8的时区）

不同时区之间的转换 
你可以对一个Calendar进行转时区操作，举例如下：

TimeZone timeZone1 = TimeZone.getTimeZone("America/Los_Angeles"); TimeZone timeZone2 = TimeZone.getTimeZone("Europe/Copenhagen"); Calendar calendar = new GregorianCalendar(); long timeCPH = calendar.getTimeInMillis(); System.out.println("timeCPH = " + timeCPH); System.out.println("hour = " + calendar.get(Calendar.HOUR_OF_DAY)); calendar.setTimeZone(timeZone1); long timeLA = calendar.getTimeInMillis(); System.out.println("timeLA = " + timeLA); System.out.println("hour = " + calendar.get(Calendar.HOUR_OF_DAY));

原作者的代码运行于”Europe/Copenhagen”时区，输出结果如下：

timeHere = 1264881305341 hour = 20 timeLA = 1264881305341 hour = 11

注意虽然当天的时间不同了（从20点到了11点），但表达的时间（自1970年初到当前时间的毫秒数）是完全相同的。可见Calendar类可正确完成更改时区这个操作。

附录：可用时区 
以下将列出TimeZone中所有可用的时区ID，你也可以通过TimeZone.getAvailableIDs()获得这个列表.

Etc/GMT+12 Etc/GMT+11 MIT Pacific/Apia Pacific/Midway Pacific/Niue Pacific/Pago_Pago Pacific/Samoa US/Samoa America/Adak America/Atka Etc/GMT+10 HST Pacific/Fakaofo Pacific/Honolulu Pacific/Johnston Pacific/Rarotonga Pacific/Tahiti SystemV/HST10 US/Aleutian US/Hawaii Pacific/Marquesas AST America/Anchorage America/Juneau America/Nome America/Yakutat Etc/GMT+9 Pacific/Gambier SystemV/YST9 SystemV/YST9YDT US/Alaska America/Dawson America/Ensenada America/Los_Angeles America/Tijuana America/Vancouver America/Whitehorse Canada/Pacific Canada/Yukon Etc/GMT+8 Mexico/BajaNorte PST PST8PDT Pacific/Pitcairn SystemV/PST8 SystemV/PST8PDT US/Pacific US/Pacific-New America/Boise America/Cambridge_Bay America/Chihuahua America/Dawson_Creek America/Denver America/Edmonton America/Hermosillo America/Inuvik America/Mazatlan America/Phoenix America/Shiprock America/Yellowknife Canada/Mountain Etc/GMT+7 MST MST7MDT Mexico/BajaSur Navajo PNT SystemV/MST7 SystemV/MST7MDT US/Arizona US/Mountain America/Belize America/Cancun America/Chicago America/Costa_Rica America/El_Salvador America/Guatemala America/Managua America/Menominee America/Merida America/Mexico_City America/Monterrey America/North_Dakota/Center America/Rainy_River America/Rankin_Inlet America/Regina America/Swift_Current America/Tegucigalpa America/Winnipeg CST CST6CDT Canada/Central Canada/East-Saskatchewan Canada/Saskatchewan Chile/EasterIsland Etc/GMT+6 Mexico/General Pacific/Easter Pacific/Galapagos SystemV/CST6 SystemV/CST6CDT US/Central America/Bogota America/Cayman America/Detroit America/Eirunepe America/Fort_Wayne America/Grand_Turk America/Guayaquil America/Havana America/Indiana/Indianapolis America/Indiana/Knox America/Indiana/Marengo America/Indiana/Vevay America/Indianapolis America/Iqaluit America/Jamaica America/Kentucky/Louisville America/Kentucky/Monticello America/Knox_IN America/Lima America/Louisville America/Montreal America/Nassau America/New_York America/Nipigon America/Panama America/Pangnirtung America/Port-au-Prince America/Porto_Acre America/Rio_Branco America/Thunder_Bay America/Toronto Brazil/Acre Canada/Eastern Cuba EST EST5EDT Etc/GMT+5 IET Jamaica SystemV/EST5 SystemV/EST5EDT US/East-Indiana US/Eastern US/Indiana-Starke US/Michigan America/Anguilla America/Antigua America/Aruba America/Asuncion America/Barbados America/Boa_Vista America/Campo_Grande America/Caracas America/Cuiaba America/Curacao America/Dominica America/Glace_Bay America/Goose_Bay America/Grenada America/Guadeloupe America/Guyana America/Halifax America/La_Paz America/Manaus America/Martinique America/Montserrat America/Port_of_Spain America/Porto_Velho America/Puerto_Rico America/Santiago America/Santo_Domingo America/St_Kitts America/St_Lucia America/St_Thomas America/St_Vincent America/Thule America/Tortola America/Virgin Antarctica/Palmer Atlantic/Bermuda Atlantic/Stanley Brazil/West Canada/Atlantic Chile/Continental Etc/GMT+4 PRT SystemV/AST4 SystemV/AST4ADT America/St_Johns CNT Canada/Newfoundland AGT America/Araguaina America/Bahia America/Belem America/Buenos_Aires America/Catamarca America/Cayenne America/Cordoba America/Fortaleza America/Godthab America/Jujuy America/Maceio America/Mendoza America/Miquelon America/Montevideo America/Paramaribo America/Recife America/Rosario America/Sao_Paulo Antarctica/Rothera BET Brazil/East Etc/GMT+3 America/Noronha Atlantic/South_Georgia Brazil/DeNoronha Etc/GMT+2 America/Scoresbysund Atlantic/Azores Atlantic/Cape_Verde Etc/GMT+1 Africa/Abidjan Africa/Accra Africa/Bamako Africa/Banjul Africa/Bissau Africa/Casablanca Africa/Conakry Africa/Dakar Africa/El_Aaiun Africa/Freetown Africa/Lome Africa/Monrovia Africa/Nouakchott Africa/Ouagadougou Africa/Sao_Tome Africa/Timbuktu America/Danmarkshavn Atlantic/Canary Atlantic/Faeroe Atlantic/Madeira Atlantic/Reykjavik Atlantic/St_Helena Eire Etc/GMT Etc/GMT+0 Etc/GMT-0 Etc/GMT0 Etc/Greenwich Etc/UCT Etc/UTC Etc/Universal Etc/Zulu Europe/Belfast Europe/Dublin Europe/Lisbon Europe/London GB GB-Eire GMT GMT0 Greenwich Iceland Portugal UCT UTC Universal WET Zulu Africa/Algiers Africa/Bangui Africa/Brazzaville Africa/Ceuta Africa/Douala Africa/Kinshasa Africa/Lagos Africa/Libreville Africa/Luanda Africa/Malabo Africa/Ndjamena Africa/Niamey Africa/Porto-Novo Africa/Tunis Africa/Windhoek Arctic/Longyearbyen Atlantic/Jan_Mayen CET ECT Etc/GMT-1 Europe/Amsterdam Europe/Andorra Europe/Belgrade Europe/Berlin Europe/Bratislava Europe/Brussels Europe/Budapest Europe/Copenhagen Europe/Gibraltar Europe/Ljubljana Europe/Luxembourg Europe/Madrid Europe/Malta Europe/Monaco Europe/Oslo Europe/Paris Europe/Prague Europe/Rome Europe/San_Marino Europe/Sarajevo Europe/Skopje Europe/Stockholm Europe/Tirane Europe/Vaduz Europe/Vatican Europe/Vienna Europe/Warsaw Europe/Zagreb Europe/Zurich MET Poland ART Africa/Blantyre Africa/Bujumbura Africa/Cairo Africa/Gaborone Africa/Harare Africa/Johannesburg Africa/Kigali Africa/Lubumbashi Africa/Lusaka Africa/Maputo Africa/Maseru Africa/Mbabane Africa/Tripoli Asia/Amman Asia/Beirut Asia/Damascus Asia/Gaza Asia/Istanbul Asia/Jerusalem Asia/Nicosia Asia/Tel_Aviv CAT EET Egypt Etc/GMT-2 Europe/Athens Europe/Bucharest Europe/Chisinau Europe/Helsinki Europe/Istanbul Europe/Kaliningrad Europe/Kiev Europe/Minsk Europe/Nicosia Europe/Riga Europe/Simferopol Europe/Sofia Europe/Tallinn Europe/Tiraspol Europe/Uzhgorod Europe/Vilnius Europe/Zaporozhye Israel Libya Turkey Africa/Addis_Ababa Africa/Asmera Africa/Dar_es_Salaam Africa/Djibouti Africa/Kampala Africa/Khartoum Africa/Mogadishu Africa/Nairobi Antarctica/Syowa Asia/Aden Asia/Baghdad Asia/Bahrain Asia/Kuwait Asia/Qatar Asia/Riyadh EAT Etc/GMT-3 Europe/Moscow Indian/Antananarivo Indian/Comoro Indian/Mayotte W-SU Asia/Riyadh87 Asia/Riyadh88 Asia/Riyadh89 Mideast/Riyadh87 Mideast/Riyadh88 Mideast/Riyadh89 Asia/Tehran Iran Asia/Aqtau Asia/Baku Asia/Dubai Asia/Muscat Asia/Oral Asia/Tbilisi Asia/Yerevan Etc/GMT-4 Europe/Samara Indian/Mahe Indian/Mauritius Indian/Reunion NET Asia/Kabul Asia/Aqtobe Asia/Ashgabat Asia/Ashkhabad Asia/Bishkek Asia/Dushanbe Asia/Karachi Asia/Samarkand Asia/Tashkent Asia/Yekaterinburg Etc/GMT-5 Indian/Kerguelen Indian/Maldives PLT Asia/Calcutta IST Asia/Katmandu Antarctica/Mawson Antarctica/Vostok Asia/Almaty Asia/Colombo Asia/Dacca Asia/Dhaka Asia/Novosibirsk Asia/Omsk Asia/Qyzylorda Asia/Thimbu Asia/Thimphu BST Etc/GMT-6 Indian/Chagos Asia/Rangoon Indian/Cocos Antarctica/Davis Asia/Bangkok Asia/Hovd Asia/Jakarta Asia/Krasnoyarsk Asia/Phnom_Penh Asia/Pontianak Asia/Saigon Asia/Vientiane Etc/GMT-7 Indian/Christmas VST Antarctica/Casey Asia/Brunei Asia/Chongqing Asia/Chungking Asia/Harbin Asia/Hong_Kong Asia/Irkutsk Asia/Kashgar Asia/Kuala_Lumpur Asia/Kuching Asia/Macao Asia/Macau Asia/Makassar Asia/Manila Asia/Shanghai Asia/Singapore Asia/Taipei Asia/Ujung_Pandang Asia/Ulaanbaatar Asia/Ulan_Bator Asia/Urumqi Australia/Perth Australia/West CTT Etc/GMT-8 Hongkong PRC Singapore Asia/Choibalsan Asia/Dili Asia/Jayapura Asia/Pyongyang Asia/Seoul Asia/Tokyo Asia/Yakutsk Etc/GMT-9 JST Japan Pacific/Palau ROK ACT Australia/Adelaide Australia/Broken_Hill Australia/Darwin Australia/North Australia/South Australia/Yancowinna AET Antarctica/DumontDUrville Asia/Sakhalin Asia/Vladivostok Australia/ACT Australia/Brisbane Australia/Canberra Australia/Hobart Australia/Lindeman Australia/Melbourne Australia/NSW Australia/Queensland Australia/Sydney Australia/Tasmania Australia/Victoria Etc/GMT-10 Pacific/Guam Pacific/Port_Moresby Pacific/Saipan Pacific/Truk Pacific/Yap Australia/LHI Australia/Lord_Howe Asia/Magadan Etc/GMT-11 Pacific/Efate Pacific/Guadalcanal Pacific/Kosrae Pacific/Noumea Pacific/Ponape SST Pacific/Norfolk Antarctica/McMurdo Antarctica/South_Pole Asia/Anadyr Asia/Kamchatka Etc/GMT-12 Kwajalein NST NZ Pacific/Auckland Pacific/Fiji Pacific/Funafuti Pacific/Kwajalein Pacific/Majuro Pacific/Nauru Pacific/Tarawa Pacific/Wake Pacific/Wallis NZ-CHAT Pacific/Chatham Etc/GMT-13 Pacific/Enderbury Pacific/Tongatapu Etc/GMT-14 Pacific/Kiritimati