iOS - NSDateFormatter 日期 和 字符串

NSDateFormatter * dateFormatter = [NSDateFormatter new];dateFormatter.dateFormat = @"yyyy-MM-dd";// 获取指定格式的日期字符串NSString * dateStr = [dateFormatter stringFromDate:date];// 获取字符串指定的日期NSDate *date2 = [dateFormatter dateFromString:@"2011-11-12"];

NSDateFormatter中时间格式串的含义

        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)        dd: 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 since 4713 BC January 1) 未知            G~GGG: BC/AD (Era Designator Abbreviated) 未知        GGGG: Before Christ/Anno Domini 未知        hh: 1~12 (0 padded Hour (12hr)) 带0的时, 12小时制        HH: 0~23 (0 padded Hour (24hr))  带0的时, 24小时制        k: 1~24 (0 padded Hour (24hr) 带0的时, 24小时制         K: 0~11 (0 padded Hour (12hr)) 带0的时, 12小时制         L/LL: 1~12 (0 padded 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 (0 padded Minute) 分钟         M/MM: 1~12 (0 padded 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 (0 padded 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 (0 padded Quarter) 同小写         QQQ: Q1/Q2/Q3/Q4 同小写         QQQQ: 1st quarter/2nd quarter/3rd quarter/4th quarter 同小写         ss: 0~59 (0 padded Second) 秒数         S: (rounded Sub-Second) 未知         u: (0 padded 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 (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 (0 padded 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: (2 Digits Year)  2个数字的年份         Y/YYYY: (Full Year, starting from the Sunday of the 1st week of year) 这个年份未知干嘛用的         YY/YYY: (2 Digits Year, starting from the Sunday of the 1st 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