NSDateFormatter
格式化日期字符串苹祟，copy一份常用參數(shù)：
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, 周天為1)
ccc: Sun/Mon/Tue/Wed/Thu/Fri/Sat (星期幾簡(jiǎn)寫)
cccc: Sunday/Monday/Tuesday/Wednesday/Thursday/Friday/Saturday (星期幾全拼)
d: 1~31 (月份的第幾天, 帶0)
D: 1~366 (年份的第幾天,帶0)
e: 1~7 (一周的第幾天, 帶0)
E~EEE: Sun/Mon/Tue/Wed/Thu/Fri/Sat (星期幾簡(jiǎn)寫)
EEEE: Sunday/Monday/Tuesday/Wednesday/Thursday/Friday/Saturday (星期幾全拼)
F: 1~5 (每月的第幾周, 一周的第一天為周一)
g: Julian Day Number (number of days since 4713 BC January 1) 未知
G~GGG: BC/AD (Era Designator Abbreviated) 未知
GGGG: Before Christ/Anno Domini 未知
h: 1~12 (0 padded Hour (12hr)) 帶0的時(shí), 12小時(shí)制
H: 0~23 (0 padded Hour (24hr)) ?帶0的時(shí), 24小時(shí)制
k: 1~24 (0 padded Hour (24hr) 帶0的時(shí), 24小時(shí)制
K: 0~11 (0 padded Hour (12hr)) 帶0的時(shí), 12小時(shí)制
L/LL: 1~12 (0 padded Month) ?第幾月
LLL: Jan/Feb/Mar/Apr/May/Jun/Jul/Aug/Sep/Oct/Nov/Dec 月份簡(jiǎn)寫
LLLL: January/February/March/April/May/June/July/August/September/October/November/December 月份全稱
m: 0~59 (0 padded Minute) 分鐘
M/MM: 1~12 (0 padded Month) 第幾月
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 (0 padded Quarter) 第幾季度
qqq: Q1/Q2/Q3/Q4 季度簡(jiǎn)寫
qqqq: 1st quarter/2nd quarter/3rd quarter/4th quarter 季度全拼
Q/QQ: 1~4 (0 padded Quarter) 同小寫
QQQ: Q1/Q2/Q3/Q4 同小寫
QQQQ: 1st quarter/2nd quarter/3rd quarter/4th quarter 同小寫
s: 0~59 (0 padded Second) 秒數(shù)
S: (rounded Sub-Second) 未知
u: (0 padded Year) 未知
v~vvv: (General GMT Timezone Abbreviation) 常規(guī)GMT時(shí)區(qū)的編寫
vvvv: (General GMT Timezone Name) 常規(guī)GMT時(shí)區(qū)的名稱
w: 1~53 (0 padded Week of Year, 1st day of week = Sunday, NB: 1st week of year starts from the last Sunday of last year) 一年的第幾周, 一周的開始為周日,第一周從去年的最后一個(gè)周日起算
W: 1~5 (0 padded Week of Month, 1st day of week = Sunday) 一個(gè)月的第幾周
y/yyyy: (Full Year) 完整的年份
yy/yyy: (2 Digits Year) ?2個(gè)數(shù)字的年份
Y/YYYY: (Full Year, starting from the Sunday of the 1st week of year) 這個(gè)年份未知干嘛用的
YY/YYY: (2 Digits Year, starting from the Sunday of the 1st week of year) 這個(gè)年份未知干嘛用的
z~zzz: (Specific GMT Timezone Abbreviation) 指定GMT時(shí)區(qū)的編寫
zzzz: (Specific GMT Timezone Name) Z: +0000 (RFC 822 Timezone) 指定GMT時(shí)區(qū)的名稱
實(shí)例：
http://blog.sina.com.cn/s/blog_60b45f230100i0r9.html
NSDateFormatter * dateFormatter = [[[NSDateFormatter alloc] init]autorelease];
[dateFormatter setAMSymbol:@"AM"];
[dateFormatter setPMSymbol:@"PM"];
[dateFormatter setDateFormat:@"dd/MM/yyyy hh:mmaaa"];
NSDate *date = [NSDate date];
NSString * s = [dateFormatter stringFromDate:date];
顯示效果為：10/05/2010 03:49PM
下面附上幾個(gè)格式：這個(gè)是從Cocoachina上來的矮固。呵呵。
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, '99
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
下面是得到當(dāng)前的年氯质，月募舟，日，時(shí)闻察，分拱礁，秒。
NSCalendar *cal = [NSCalendar currentCalendar];
unsigned int unitFlags = NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit;
NSDateComponents *dd = [cal components:unitFlags fromDate:date];
int y = [dd year];
int m = [dd month];
int d = [dd day];
int h = [dd hour];
int m = [dd minute];
int s = [dd second];
