iOS时间处理（NSDate、NSDateComponents、NSCalendar、NSDateFormatter、NSTimeZone）

1.NSDate存储的是世界标准时(UTC)，输出时需要根据时区转换为本地时间

2.NSTimeInterval： 时间戳，以double为单位

3.系统返回的时间都是格林尼治时间，要得到北京时间需要转化

 

---

 

NSDate类：

 

@interface NSDate (NSDateCreation)中方法：创建或初始化NSDate值

NSDate返回日期

 

@interface NSDate (NSExtendedDate)： NSDate的扩张方法

方法一：日前之间的前后比较

方法二：得到距离某一日起的时间间隔（时间戳）

方法三：得到在当前实例中保存的时间为基准， 过了sec的日期

方法四：将时间表示字符串：description  其实这个方法写不写一样 系统会自动的

 

参考：

冷雨之家博客对该类方法作了详尽的描述:http://hi.baidu.com/douxinchun/item/86c9732bc603349db73263ae

 

---

NSDateComponents类：()

 

NSDateComponents封装在一个可扩展的，面向对象的方式的日期组件。它是用来弥补时间的日期和时间组件提供一个指定日期：小时，分钟，秒，日，月，年，等等。它也可以用来指定的时间，例如，5小时16分钟。一个NSDateComponents对象不需要定义所有组件领域。当一个NSDateComponents的新实例被创建，日期组件被设置为NSUndefinedDateComponent。

一个NSDateComponents对象本身是毫无意义的;你需要知道它是针对什么日历解释，你需要知道它的值是否是正整数和值是多少。

NSDateComponents的实例不负责回答关于一个日期以外的信息，它是需要先初始化的。例如，如果你初始化一个对象为2004年5月6日，其星期几NSUndefinedDateComponent，不是星期四。要得到正确的星期几，你必须创建一个NSCalendar日历实例，创建一个NSDate对象并使用dateFromComponents：方法，然后使用components:fromDate:检索平周几

 

---

NSCalendar类：(日历)

 

用于处理时间相关问题。比如比较时间前后、计算日期所的周别等。

 

//在当前日期上加上设定的值得到的日期

NSDate *newdate = [calendar dateByAddingComponents:comps toDate:currentDate  options:0];

 

参考：

NSCalendar类方法的详细介绍：http://www.cnblogs.com/wujian1360/archive/2011/09/05/2168007.html

 

---

NSDateFormatter类：  设定时间的格式

 

用于格式化NSDate对象，支持本地化的信息。

setDateStyle和setTimeStyle可同时设置，但不能和setDateFormat共存，只可选其一

 

//设置为中国格式输出

dateFormater.locale = [[NSLocale alloc] initWithLocaleIdentifier:@"zh_CN"];

 

 

//设置日期、时间显示格式；

- (void)setDateStyle:(NSDateFormatterStyle)style;

- (void)setTimeStyle:(NSDateFormatterStyle)style;

 

NSDateFormatterStyle系统选项包含的Style:

{

    NSDateFormatterNoStyle,

    NSDateFormatterShortStyle,    // “11/23/37” or “3:30pm”.

    NSDateFormatterMediumStyle,     //“Nov 23, 1937”.or “3:30:32pm”.   

    NSDateFormatterLongStyle,     //“November 23, 1937” or “3:30:32pm”.  GMT+08:00

    NSDateFormatterFullStyle     //“Tuesday, April 12, 1952 AD” or “3:30:42pm PST”.

}

 

 

而经常使用的会是setDateFormat方法,可自定义输出格式

- (void)setDateFormat:(NSString *)string;

 

 

Symbol	Meaning	Example
G	era designator	G	AD
y	year	yy yyyy or y	96 1996
Y	year of "Week of Year"	Y	1997
u	extended year	u	4601
U	cyclic year name, as in Chinese lunar calendar	U	甲子
Q	quarter	Q or QQ QQQ QQQQ	02 Q2 2nd quarter
q	Stand Alone quarter	q or qq qqq qqqq	02 Q2 2nd quarter
M	month in year	M or MM MMM MMMM MMMMM	09 Sept September S
L	Stand Alone month in year	L or LL LLL LLLL LLLLL	09 Sept September S
w	week of year	w or ww	27
W	week of month	W	2
d	day in month	d dd	2 02
D	day of year	D	189
F	day of week in month		2 (2nd Wed in July)
g	modified julian day	g	2451334
E	day of week	E, EE, or EEE EEEE EEEEE	Tues Tuesday T
e	local day of week example: if Monday is 1st day, Tuesday is 2nd )	e or ee eee eeee eeeee	2 Tues Tuesday T
c	Stand Alone local day of week	e or ee eee eeee eeeee	2 Tues Tuesday T
a	am/pm marker	a	pm
h	hour in am/pm (1~12)	h hh	7 07
H	hour in day (0~23)	H HH	0 00
k	hour in day (1~24)	k kk	24 24
K	hour in am/pm (0~11)	K KK	0 00
m	minute in hour	m mm	4 04
s	second in minute	s ss	5 05
S	millisecond (maximum of 3 significant digits); for S or SS, truncates to the number of letters for SSSS or longer, fills additional places with 0	S SS SSS SSSS	2 23 235 2350
A	milliseconds in day	A	61201235
z	Time Zone: specific non-location	z, zz, or zzz zzzz	PDT Pacific Daylight Time
Z	Time Zone: RFC 822 Time Zone: localized GMT TIme Zone: ISO8601	Z, ZZ, or ZZZ ZZZZ ZZZZZ	-0800 GMT-08:00 -08:00
v	Time Zone: generic non-location	v vvvv	PT Pacific Time or United States (Los Angeles)
V	Time Zone: specific non-location, identical to z	V	PDT
VVVV	Time Zone: generic location	VVVV	United States (Los Angeles)
W	week in month		2
'	escape for text	'	(nothing)
' '	two single quotes produce one	' '	'

 

Format Pattern	Result
yyyy.MM.dd G 'at' HH:mm:ss zzz	1996.07.10 AD at 15:08:56 PDT
EEE, MMM d, ''yy	Wed, July 10, '96
h:mm a	12:08 PM
hh 'o''clock' a, zzzz	12 o'clock PM, Pacific Daylight Time
K:mm a, z	0:00 PM, PST
yyyyy.MMMM.dd GGG hh:mm aaa	01996.July.10 AD 12:08 PM

 

 

 

NSDateFormatter的格式串详解：

a: AM/PM (上午/下午)

A:0~86399999(一天的第A微秒)

c/cc:1~7(一周的第一天,周天为1)

ccc: Sun/Mon/Tue/Wed/Thu/Fri/Sat (星期几简写)

cccc: Sunday/Monday/Tuesday/Wednesday/Thursday/Friday/Saturday (星期几全拼)

d:1~31(月份的第几天,带0)

D:1~366(年份的第几天,带0)

e:1~7(一周的第几天,带0)

E~EEE: Sun/Mon/Tue/Wed/Thu/Fri/Sat (星期几简写)

EEEE: Sunday/Monday/Tuesday/Wednesday/Thursday/Friday/Saturday (星期几全拼)

F:1~5(每月的第几周,一周的第一天为周一)

g: Julian Day Number (number of days since4713BC January1)未知

G~GGG: BC/AD (Era Designator Abbreviated)未知

GGGG: Before Christ/Anno Domini未知

h:1~12(0padded Hour (12hr))带0的时,12小时制

H:0~23(0padded Hour (24hr)) 带0的时,24小时制

k:1~24(0padded Hour (24hr)带0的时,24小时制

K:0~11(0padded Hour (12hr))带0的时,12小时制

        

L/LL:1~12(0padded Month) 第几月

LLL: Jan/Feb/Mar/Apr/May/Jun/Jul/Aug/Sep/Oct/Nov/Dec月份简写

LLLL: January/February/March/April/May/June/July/August/September/October/November/December月份全称

        

m:0~59(0padded Minute)分钟

M/MM:1~12(0padded Month)第几月

MMM: Jan/Feb/Mar/Apr/May/Jun/Jul/Aug/Sep/Oct/Nov/Dec

MMMM: January/February/March/April/May/June/July/August/September/October/November/December

        

q/qq:1~4(0padded Quarter)第几季度

qqq: Q1/Q2/Q3/Q4季度简写

qqqq:1st quarter/2nd quarter/3rd quarter/4th quarter季度全拼

Q/QQ:1~4(0padded Quarter)同小写

QQQ: Q1/Q2/Q3/Q4同小写

QQQQ:1st quarter/2nd quarter/3rd quarter/4th quarter同小写

s:0~59(0padded Second)秒数

S: (rounded Sub-Second)未知

        

u: (0padded Year)未知

        

v~vvv: (General GMT Timezone Abbreviation)常规GMT时区的编写

vvvv: (General GMT Timezone Name)常规GMT时区的名称

        

w:1~53(0padded Week of Year,1st day of week = Sunday, NB:1st week of year starts from the last Sunday of last year)一年的第几周,一周的开始为周日,第一周从去年的最后一个周日起算

W:1~5(0padded Week of Month,1st day of week = Sunday)一个月的第几周

        

y/yyyy: (Full Year)完整的年份

yy/yyy: (2Digits Year) 2个数字的年份

Y/YYYY: (Full Year, starting from the Sunday of the1st week of year)这个年份未知干嘛用的

YY/YYY: (2Digits Year, starting from the Sunday of the1st week of year)这个年份未知干嘛用的

        

z~zzz: (Specific GMT Timezone Abbreviation)指定GMT时区的编写

zzzz: (Specific GMT Timezone Name) Z: +0000 (RFC 822 Timezone) 指定GMT时区的名称

 

eg.

NSString lastModifiedString = @"Mon, 06 Jun 2011 12:47:05 GMT";
 NSDateFormatter *df = [[NSDateFormatter alloc] init];  
 //df.dateFormat = @"EEE',' dd MMM yyyy HH':'mm':'ss 'GMT'";
 df.dateFormat = @"EEE, dd MMM yyyy HH:mm:ss z";
 df.locale = [[[NSLocale alloc] initWithLocaleIdentifier:@"en_US_POSIX"] autorelease];  
 df.timeZone = [NSTimeZone timeZoneWithAbbreviation:@"GMT"];  

NSDate date = [df dateFromString:lastModifiedString];  

　　

设置上下午显示格式：

NSDateFormatter* formatter = [[[NSDateFormatteralloc] init] autorelease];
 [formatter setDateFormat:dateFormatterString];
 [formatter setAMSymbol:@"am"];    //
 [formatter setPMSymbol:@"pm"];
return [formatter stringFromDate:self];

 

参考：

NSDateFormatter格式一览表：http://www.th7.cn/Program/IOS/201210/109696.shtml

开源项目库文档：http://userguide.icu-project.org/formatparse/datetime （我是没怎么看懂） 

NSDateFormatter的格式串详解：http://linuxp.blog.163.com/blog/static/17096277201221313933377/  

 

---

NSTimeZone：时区

    NSDate *date = [NSDate date];
    NSLog(@"date:%@",date);
    //系统时区
    NSTimeZone *zone = [NSTimeZone systemTimeZone];
    NSData *data = [zone data];
    NSLog(@"data:%@",data);
    //时间缩写
    NSString *abbStr = [zone abbreviation];
    NSLog(@"abbStr:%@",abbStr);
    //当地时区
    NSTimeZone *localTime = [NSTimeZonelocalTimeZone];
    NSLog(@"localTime:%@",localTime);
    //和格林尼治时间差
    NSInteger timeOff = [zone secondsFromGMT];
    //视察转化
    NSDate *timeOffDate = [date dateByAddingTimeInterval:timeOff];
    NSLog(@"timeOffDate:%@",timeOffDate);
    //所有地区名称
    NSArray *zoneArrs = [NSTimeZone knownTimeZoneNames];
    NSLog(@"zoneArrs:%@",zoneArrs);
    //遍历
    for (NSString *names in zoneArrs) {
        //时区
        NSTimeZone *timeZone = [[NSTimeZone alloc] initWithName:names];
        //设置格式
        NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
        [dateFormatter setDateStyle:kCFDateFormatterFullStyle];
        [dateFormatter setTimeStyle:kCFDateFormatterFullStyle];
        [dateFormatter setTimeZone:timeZone];
        NSString *string = [dateFormatter stringFromDate:date];
        NSLog(@"string:%@,[timeZone name]:%@",string,[timeZone name]);
        [dateFormatter release];
        [timeZone release];
    }

获取中国标准时间（没有看见有北京时区的，选了上海的）

    NSDate*date = [NSDate date];
    NSDateFormatter *dateFormatter = [[[NSDateFormatter alloc] init]autorelease];
    dateFormatter.dateFormat = @"yyyy-MM-dd HH:mm:ss EEEE";
    NSTimeZone *timeZone = [[NSTimeZone alloc] initWithName:@"Asia/Shanghai"];
    [dateFormatter setTimeZone:timeZone];
    NSLog(@"时间：%@",[dateFormatter stringFromDate:date]);

 

---

 

---

---

应用实例：

(1)获得某一日期是周几

NSDateComponents *comps = [[NSDateComponents alloc] init];
[comps setDay:11];
[comps setMonth:12];
[comps setYear:2012];
NSCalendar *gregorian = [[NSCalendar alloc]
    initWithCalendarIdentifier:NSGregorianCalendar];
NSDate *date = [gregorian dateFromComponents:comps];
[comps release];
NSDateComponents *weekdayComponents =
    [gregorian components:NSWeekdayCalendarUnit fromDate:date];
int weekday = [weekdayComponents weekday];
NSLog(@"%d",weekday);   //周二，值为3

//获得昨天的Date

NSDate*yesterday = [NSDatedateWithTimeIntervalSinceNow: -(24 * 60 * 60)];

NSLog(@"yesterday:%@",yesterday);

(2)获得当前时间并取出年/月/日等值

NSDateFormatter*formatter =[[[NSDateFormatteralloc] init] autorelease];
    NSDate *date = [NSDatedate];
    [formatter setTimeStyle:NSDateFormatterMediumStyle];
    NSCalendar *calendar = [[[NSCalendaralloc] initWithCalendarIdentifier:NSGregorianCalendar] autorelease];
    NSDateComponents *comps = [[[NSDateComponentsalloc] init] autorelease];
    NSInteger unitFlags = NSYearCalendarUnit |
    NSMonthCalendarUnit |
    NSDayCalendarUnit |
    NSWeekdayCalendarUnit |
    NSHourCalendarUnit |
    NSMinuteCalendarUnit |
    NSSecondCalendarUnit;
   
    comps = [calendar components:unitFlags fromDate:date];
    int week = [comps weekday];
    int year=[comps year];
    int month = [comps month];
    int day = [comps day];
    int hour = [comps hour];
    int min = [comps minute];
    int sec = [comps second];
   
    NSLog(@"week%d",week);
    NSLog(@"year%d",year);
    NSLog(@"month%d",month);
    NSLog(@"day%d",day);
    NSLog(@"hour%d",hour);
    NSLog(@"min%d",min);

    NSLog(@"sec%d",sec);

（3）//得到毫秒

//得到毫秒
   NSDateFormatter*dateFormatter = [[NSDateFormatteralloc] init];
    [dateFormatter setDateStyle:NSDateFormatterMediumStyle];
    [dateFormatter setTimeStyle:NSDateFormatterShortStyle];
    //[dateFormatter setDateFormat:@"hh:mm:ss"]
    [dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss.SSS"];
    NSLog(@"Date%@", [dateFormatter stringFromDate:[NSDatedate]]);
    [dateFormatter release];

（4）计算和所给时间和当天时间的差距

NSCalendar*calendar = [NSCalendarcurrentCalendar];//日历
NSDateComponents *components = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit fromDate:date toDate:[NSDate date] options:0];
int year = [components year];
int month = [components month];
int day = [components day];
//三天以内更改显示格式
if (year == 0 && month == 0 && day < 3) {
    if (day == 0) {
        title = NSLocalizedString(@"今天",nil);
    } elseif (day == 1) {
        title = NSLocalizedString(@"昨天",nil);
    } elseif (day == 2) {
        title = NSLocalizedString(@"前天",nil);
    }
}