NSDate简单介绍

NSDate简单介绍

一:NSDate是一个日期\时间方面的类,主要用来创建\获取时间

1.NSDate对象的创建:

date 创建一个当前系统日期和时间的对象

dateWithTimeIntervalSinceNow: 创建距离当前时间戳的对象

dateWithTimeInterval:sinceDate: 创建距离日期和时间对象的时间戳的对象

dateWithTimeIntervalSince1970: 创建距离1970年的时间戳对象

这里简单阐述下时间戳:时间戳的字面意思就是唯一的标识某一刻的时间,比如:2016年4月27日17点54分30秒,这就是我写这句话的时间戳

简单来说:就是从指定时间开始的那一秒数(楼主自己的理解)

2.类方法:

distantFuture 获取很久以后的日期对象

distantPast 获取很久以前的日期对象

3.日期时间比较:

isEqualToDate: 比较日期时间是否相等

earlierDate: 较早的那个日期时间

laterDate: 较晚的那个日期时间

compare: 时间先后

4.获取时间戳

timeIntervalSinceDate: 获取到指定日期时间的时间戳

timeIntervalSinceNow: 获取到现在的时间戳

timeIntervalSince1970: 获取从1970年到指定日期的时间戳

5.在日期时间对象上增加时间戳:

dateByAddingTimeInterval:返回新NSDate对象

二.代码

1.创建日期:

 //创建一个日期时间对象
         NSDate *nowDate = [NSDate date];
         //                     时区
         //2015-07-20 08:08:40 +0000
         //          + 8
         NSLog(@"date = %@",nowDate);
         //2)日期时间的格式化显示
         // NSDateFormatter 类完成
         NSDateFormatter *formatter = [NSDateFormatter new];
         // 指定了显示的格式
         // formatter.dateFormat 可以赋值一个字符串，字符串就是我们要显示的格
         formatter.dateFormat = @"yyyy年MM月dd日 HH时mm分ss秒";
         /*

          y 表示年
          yyyy  表示显示4位的年  2015
          MM    表示月份(两位M表示不足两位补0)
          dd    表示天数

          HH    以24小时制显示 小时
          hh 以12小时制小时
          mm    显示分钟
          ss    显示秒数
          */
         //用指定的格式对我们的 nowDate进行格式化
         // 把date 转换为字符串
         // 按照我们指定的格式进行转换
         NSString *dateStr = [formatter stringFromDate:nowDate];
         NSLog(@"dataStr = %@",dateStr);

         //计算日期
         // 当前日期
         NSDate *date = [NSDate date];
         NSTimeInterval time = **;  //24小时的秒数
         //明天的此刻
         NSDate *mt = [date dateByAddingTimeInterval:time];
         NSDateFormatter *formatter0 = [NSDateFormatter new];
         // 指定了显示的格式
         // formatter.dateFormat 可以赋值一个字符串，字符串就是我们要显示的格式
         formatter0.dateFormat = @"yyyy年MM月dd日 HH时mm分ss秒";
         NSString *timeStr = [formatter stringFromDate:mt];
         NSLog(@"timeStr = %@",timeStr);
         NSTimeInterval time1 = **;  //24小时的秒数
         //昨天的现在
         NSDate *date1 = [NSDate dateWithTimeIntervalSinceNow:time1];
         NSDateFormatter *formatter1 = [NSDateFormatter new];
         // 指定了显示的格式
         // formatter.dateFormat 可以赋值一个字符串，字符串就是我们要显示的格式
         formatter1.dateFormat = @"yyyy年MM月dd日 HH时mm分ss秒";
         NSString *timeStr1 = [formatter stringFromDate:date1];
         NSLog(@"timeStr = %@",timeStr1);

 //        例：
         //刚才返回的 2015年07月19日 16时29分16秒  字符串？
         //假设 我要去获取日期的 年份  月份  天数
         //NSCalendar 可以帮我们分解日期的每一部分
         //创建日期时间对象
         NSCalendar *cal = [NSCalendar currentCalendar];

         //获取当前日期的每一部分                  要获取的部分                                从哪个日期对象
         NSDateComponents *coms = [cal components:NSCalendarUnitYear|NSCalendarUnitMonth|NSCalendarUnitDay fromDate:[NSDate date]];

         NSLog(@"------%ld,-----%ld,----%ld",coms.year,coms.month,coms.day);

2.打印结果:

 -- ::08.182 NADate[:] date = -- :: +
 -- ::08.183 NADate[:] dataStr = 2016年04月27日 18时16分08秒
 -- ::08.183 NADate[:] timeStr = 2016年04月28日 18时16分08秒
 -- ::08.183 NADate[:] timeStr = 2016年04月28日 18时16分08秒
 -- ::08.184 NADate[:] ------,-----,----
 Program ended with exit code: 

3.日期格式化:

 //
 //  main.m
 //  NADate
 //
 //  Created by admin on 16/4/27.
 //  Copyright © 2016年 admin. All rights reserved.
 //

 #import <Foundation/Foundation.h>

 int main(int argc, const char * argv[]) {
     @autoreleasepool {
         //创建日期时间格式化对象
         NSDateFormatter *df = [[NSDateFormatter alloc] init];

         //        查看时区
         NSArray *arr = [NSTimeZone knownTimeZoneNames];
         NSLog(@"%@",arr);

         df.timeZone = [NSTimeZone timeZoneWithName:@"Asia/Chongqing"];

         //设置格式化内容
         df.dateFormat = @"yyyy-MM-dd HH:mm:ss";

         //        把字符串转换成日期对象
         NSDate *date = [df dateFromString:@"2005-08-30 08:00:00"];
         NSLog(@"%@",date);
         //        把日期对象转换成字符串
         NSDate *nowDate = [NSDate date];
         NSString *string= [df stringFromDate:nowDate];
         NSLog(@"%@",string);

         //创建日历对象
 //                NSCalendar *calendar1 = [NSCalendar currentCalendar];
 //                NSCalendar *calendar2 = [NSCalendar calendarWithIdentifier:NSCalendarIdentifierChinese];
 //                NSLog(@"%@",calendar1.calendarIdentifier);
 //                NSLog(@"%@",calendar2.calendarIdentifier);

         //地区标识
 //                NSArray *arr1 = [NSLocale availableLocaleIdentifiers];
 //                NSLog(@"%@",arr1);

         //
         NSCalendar *cl = [NSCalendar calendarWithIdentifier:NSCalendarIdentifierChinese];
         //设置地区
         cl.locale = [NSLocale localeWithLocaleIdentifier:@"zh_CN"];
         //设置时区
         cl.timeZone = [NSTimeZone timeZoneWithName:@"Asia/Chongqing"];
         //设置每周起始
         cl.firstWeekday = ;
         //获取年月日
         NSDate *now = [NSDate date];
         NSInteger month,day;
         //获取年月日的方法(NSCalendar的对象方法)
         [cl getEra:nil year:nil month:&month day:&day fromDate:now];
         NSLog(@"%ld月%ld日\n",month,day);

4.打印结果:

 -- ::03.929 NADate[:] (
     "Africa/Abidjan",
     "Africa/Accra",
     "Africa/Addis_Ababa",
     "Africa/Algiers",
     "Africa/Asmara",
     "Africa/Bamako",
     "Africa/Bangui",
     "Africa/Banjul",
     "Africa/Bissau",
     "Africa/Blantyre",
     "Africa/Brazzaville",
     "Africa/Bujumbura",
     "Africa/Cairo",
     "Africa/Casablanca",
     "Africa/Ceuta",
     "Africa/Conakry",
     "Africa/Dakar",
     "Africa/Dar_es_Salaam",
     "Africa/Djibouti",
     "Africa/Douala",
     "Africa/El_Aaiun",
     "Africa/Freetown",
     "Africa/Gaborone",
     "Africa/Harare",
     "Africa/Johannesburg",
     "Africa/Juba",
     "Africa/Kampala",
     "Africa/Khartoum",
     "Africa/Kigali",
     "Africa/Kinshasa",
     "Africa/Lagos",
     "Africa/Libreville",
     "Africa/Lome",
     "Africa/Luanda",
     "Africa/Lubumbashi",
     "Africa/Lusaka",
     "Africa/Malabo",
     "Africa/Maputo",
     "Africa/Maseru",
     "Africa/Mbabane",
     "Africa/Mogadishu",
     "Africa/Monrovia",
     "Africa/Nairobi",
     "Africa/Ndjamena",
     "Africa/Niamey",
     "Africa/Nouakchott",
     "Africa/Ouagadougou",
     "Africa/Porto-Novo",
     "Africa/Sao_Tome",
     "Africa/Tripoli",
     "Africa/Tunis",
     "Africa/Windhoek",
     "America/Adak",
     "America/Anchorage",
     "America/Anguilla",
     "America/Antigua",
     "America/Araguaina",
     "America/Argentina/Buenos_Aires",
     "America/Argentina/Catamarca",
     "America/Argentina/Cordoba",
     "America/Argentina/Jujuy",
     "America/Argentina/La_Rioja",
     "America/Argentina/Mendoza",
     "America/Argentina/Rio_Gallegos",
     "America/Argentina/Salta",
     "America/Argentina/San_Juan",
     "America/Argentina/San_Luis",
     "America/Argentina/Tucuman",
     "America/Argentina/Ushuaia",
     "America/Aruba",
     "America/Asuncion",
     "America/Atikokan",
     "America/Bahia",
     "America/Bahia_Banderas",
     "America/Barbados",
     "America/Belem",
     "America/Belize",
     "America/Blanc-Sablon",
     "America/Boa_Vista",
     "America/Bogota",
     "America/Boise",
     "America/Cambridge_Bay",
     "America/Campo_Grande",
     "America/Cancun",
     "America/Caracas",
     "America/Cayenne",
     "America/Cayman",
     "America/Chicago",
     "America/Chihuahua",
     "America/Costa_Rica",
     "America/Creston",
     "America/Cuiaba",
     "America/Curacao",
     "America/Danmarkshavn",
     "America/Dawson",
     "America/Dawson_Creek",
     "America/Denver",
     "America/Detroit",
     "America/Dominica",
     "America/Edmonton",
     "America/Eirunepe",
     "America/El_Salvador",
     "America/Fort_Nelson",
     "America/Fortaleza",
     "America/Glace_Bay",
     "America/Godthab",
     "America/Goose_Bay",
     "America/Grand_Turk",
     "America/Grenada",
     "America/Guadeloupe",
     "America/Guatemala",
     "America/Guayaquil",
     "America/Guyana",
     "America/Halifax",
     "America/Havana",
     "America/Hermosillo",
     "America/Indiana/Indianapolis",
     "America/Indiana/Knox",
     "America/Indiana/Marengo",
     "America/Indiana/Petersburg",
     "America/Indiana/Tell_City",
     "America/Indiana/Vevay",
     "America/Indiana/Vincennes",
     "America/Indiana/Winamac",
     "America/Inuvik",
     "America/Iqaluit",
     "America/Jamaica",
     "America/Juneau",
     "America/Kentucky/Louisville",
     "America/Kentucky/Monticello",
     "America/Kralendijk",
     "America/La_Paz",
     "America/Lima",
     "America/Los_Angeles",
     "America/Lower_Princes",
     "America/Maceio",
     "America/Managua",
     "America/Manaus",
     "America/Marigot",
     "America/Martinique",
     "America/Matamoros",
     "America/Mazatlan",
     "America/Menominee",
     "America/Merida",
     "America/Metlakatla",
     "America/Mexico_City",
     "America/Miquelon",
     "America/Moncton",
     "America/Monterrey",
     "America/Montevideo",
     "America/Montreal",
     "America/Montserrat",
     "America/Nassau",
     "America/New_York",
     "America/Nipigon",
     "America/Nome",
     "America/Noronha",
     "America/North_Dakota/Beulah",
     "America/North_Dakota/Center",
     "America/North_Dakota/New_Salem",
     "America/Ojinaga",
     "America/Panama",
     "America/Pangnirtung",
     "America/Paramaribo",
     "America/Phoenix",
     "America/Port-au-Prince",
     "America/Port_of_Spain",
     "America/Porto_Velho",
     "America/Puerto_Rico",
     "America/Rainy_River",
     "America/Rankin_Inlet",
     "America/Recife",
     "America/Regina",
     "America/Resolute",
     "America/Rio_Branco",
     "America/Santa_Isabel",
     "America/Santarem",
     "America/Santiago",
     "America/Santo_Domingo",
     "America/Sao_Paulo",
     "America/Scoresbysund",
     "America/Shiprock",
     "America/Sitka",
     "America/St_Barthelemy",
     "America/St_Johns",
     "America/St_Kitts",
     "America/St_Lucia",
     "America/St_Thomas",
     "America/St_Vincent",
     "America/Swift_Current",
     "America/Tegucigalpa",
     "America/Thule",
     "America/Thunder_Bay",
     "America/Tijuana",
     "America/Toronto",
     "America/Tortola",
     "America/Vancouver",
     "America/Whitehorse",
     "America/Winnipeg",
     "America/Yakutat",
     "America/Yellowknife",
     "Antarctica/Casey",
     "Antarctica/Davis",
     "Antarctica/DumontDUrville",
     "Antarctica/Macquarie",
     "Antarctica/Mawson",
     "Antarctica/McMurdo",
     "Antarctica/Palmer",
     "Antarctica/Rothera",
     "Antarctica/South_Pole",
     "Antarctica/Syowa",
     "Antarctica/Troll",
     "Antarctica/Vostok",
     "Arctic/Longyearbyen",
     "Asia/Aden",
     "Asia/Almaty",
     "Asia/Amman",
     "Asia/Anadyr",
     "Asia/Aqtau",
     "Asia/Aqtobe",
     "Asia/Ashgabat",
     "Asia/Baghdad",
     "Asia/Bahrain",
     "Asia/Baku",
     "Asia/Bangkok",
     "Asia/Beirut",
     "Asia/Bishkek",
     "Asia/Brunei",
     "Asia/Chita",
     "Asia/Choibalsan",
     "Asia/Chongqing",
     "Asia/Colombo",
     "Asia/Damascus",
     "Asia/Dhaka",
     "Asia/Dili",
     "Asia/Dubai",
     "Asia/Dushanbe",
     "Asia/Gaza",
     "Asia/Harbin",
     "Asia/Hebron",
     "Asia/Ho_Chi_Minh",
     "Asia/Hong_Kong",
     "Asia/Hovd",
     "Asia/Irkutsk",
     "Asia/Jakarta",
     "Asia/Jayapura",
     "Asia/Jerusalem",
     "Asia/Kabul",
     "Asia/Kamchatka",
     "Asia/Karachi",
     "Asia/Kashgar",
     "Asia/Kathmandu",
     "Asia/Katmandu",
     "Asia/Khandyga",
     "Asia/Kolkata",
     "Asia/Krasnoyarsk",
     "Asia/Kuala_Lumpur",
     "Asia/Kuching",
     "Asia/Kuwait",
     "Asia/Macau",
     "Asia/Magadan",
     "Asia/Makassar",
     "Asia/Manila",
     "Asia/Muscat",
     "Asia/Nicosia",
     "Asia/Novokuznetsk",
     "Asia/Novosibirsk",
     "Asia/Omsk",
     "Asia/Oral",
     "Asia/Phnom_Penh",
     "Asia/Pontianak",
     "Asia/Pyongyang",
     "Asia/Qatar",
     "Asia/Qyzylorda",
     "Asia/Rangoon",
     "Asia/Riyadh",
     "Asia/Sakhalin",
     "Asia/Samarkand",
     "Asia/Seoul",
     "Asia/Shanghai",
     "Asia/Singapore",
     "Asia/Srednekolymsk",
     "Asia/Taipei",
     "Asia/Tashkent",
     "Asia/Tbilisi",
     "Asia/Tehran",
     "Asia/Thimphu",
     "Asia/Tokyo",
     "Asia/Ulaanbaatar",
     "Asia/Urumqi",
     "Asia/Ust-Nera",
     "Asia/Vientiane",
     "Asia/Vladivostok",
     "Asia/Yakutsk",
     "Asia/Yekaterinburg",
     "Asia/Yerevan",
     "Atlantic/Azores",
     "Atlantic/Bermuda",
     "Atlantic/Canary",
     "Atlantic/Cape_Verde",
     "Atlantic/Faroe",
     "Atlantic/Madeira",
     "Atlantic/Reykjavik",
     "Atlantic/South_Georgia",
     "Atlantic/St_Helena",
     "Atlantic/Stanley",
     "Australia/Adelaide",
     "Australia/Brisbane",
     "Australia/Broken_Hill",
     "Australia/Currie",
     "Australia/Darwin",
     "Australia/Eucla",
     "Australia/Hobart",
     "Australia/Lindeman",
     "Australia/Lord_Howe",
     "Australia/Melbourne",
     "Australia/Perth",
     "Australia/Sydney",
     "Europe/Amsterdam",
     "Europe/Andorra",
     "Europe/Athens",
     "Europe/Belgrade",
     "Europe/Berlin",
     "Europe/Bratislava",
     "Europe/Brussels",
     "Europe/Bucharest",
     "Europe/Budapest",
     "Europe/Busingen",
     "Europe/Chisinau",
     "Europe/Copenhagen",
     "Europe/Dublin",
     "Europe/Gibraltar",
     "Europe/Guernsey",
     "Europe/Helsinki",
     "Europe/Isle_of_Man",
     "Europe/Istanbul",
     "Europe/Jersey",
     "Europe/Kaliningrad",
     "Europe/Kiev",
     "Europe/Lisbon",
     "Europe/Ljubljana",
     "Europe/London",
     "Europe/Luxembourg",
     "Europe/Madrid",
     "Europe/Malta",
     "Europe/Mariehamn",
     "Europe/Minsk",
     "Europe/Monaco",
     "Europe/Moscow",
     "Europe/Oslo",
     "Europe/Paris",
     "Europe/Podgorica",
     "Europe/Prague",
     "Europe/Riga",
     "Europe/Rome",
     "Europe/Samara",
     "Europe/San_Marino",
     "Europe/Sarajevo",
     "Europe/Simferopol",
     "Europe/Skopje",
     "Europe/Sofia",
     "Europe/Stockholm",
     "Europe/Tallinn",
     "Europe/Tirane",
     "Europe/Uzhgorod",
     "Europe/Vaduz",
     "Europe/Vatican",
     "Europe/Vienna",
     "Europe/Vilnius",
     "Europe/Volgograd",
     "Europe/Warsaw",
     "Europe/Zagreb",
     "Europe/Zaporozhye",
     "Europe/Zurich",
     GMT,
     "Indian/Antananarivo",
     "Indian/Chagos",
     "Indian/Christmas",
     "Indian/Cocos",
     "Indian/Comoro",
     "Indian/Kerguelen",
     "Indian/Mahe",
     "Indian/Maldives",
     "Indian/Mauritius",
     "Indian/Mayotte",
     "Indian/Reunion",
     "Pacific/Apia",
     "Pacific/Auckland",
     "Pacific/Bougainville",
     "Pacific/Chatham",
     "Pacific/Chuuk",
     "Pacific/Easter",
     "Pacific/Efate",
     "Pacific/Enderbury",
     "Pacific/Fakaofo",
     "Pacific/Fiji",
     "Pacific/Funafuti",
     "Pacific/Galapagos",
     "Pacific/Gambier",
     "Pacific/Guadalcanal",
     "Pacific/Guam",
     "Pacific/Honolulu",
     "Pacific/Johnston",
     "Pacific/Kiritimati",
     "Pacific/Kosrae",
     "Pacific/Kwajalein",
     "Pacific/Majuro",
     "Pacific/Marquesas",
     "Pacific/Midway",
     "Pacific/Nauru",
     "Pacific/Niue",
     "Pacific/Norfolk",
     "Pacific/Noumea",
     "Pacific/Pago_Pago",
     "Pacific/Palau",
     "Pacific/Pitcairn",
     "Pacific/Pohnpei",
     "Pacific/Ponape",
     "Pacific/Port_Moresby",
     "Pacific/Rarotonga",
     "Pacific/Saipan",
     "Pacific/Tahiti",
     "Pacific/Tarawa",
     "Pacific/Tongatapu",
     "Pacific/Truk",
     "Pacific/Wake",
     "Pacific/Wallis"
 )
 -- ::04.393 NADate[:] -- :: +
 -- ::04.393 NADate[:] -- ::
 -- ::04.394 NADate[:] 3月21日
 Program ended with exit code: 

打印结果中的数组,是时区代码

从430行开始是日期打印结果

三.注意

NSDate比较简单,大致分为两个步骤:1.创建日期  2.日期格式化(显示成什么格式)

还有一个需要注意的地方:

如果在打印的过程中,发现获取的时间与当前时间相差8个小时,不要担心,那是正常的,因为程序默认时间是美国时间.加上8个小时就好了.

希望能帮到需要的人,如果有什么不对的,请直接告诉我,我会用最短的时间改正.谢谢~