1. 獲取年月日時分秒
NSDate *date1 = [NSDate date];
NSDateFormatter *formatter1 = [[NSDateFormatter alloc] init];
[formatter1 setDateStyle:NSDateFormatterMediumStyle];
[formatter1 setTimeStyle:NSDateFormatterShortStyle];
[formatter1 setDateFormat:@"YYYY-MM-dd hh:mm:ss"];
NSString *DateTime1 = [formatter1 stringFromDate:date1];
str就是我們需要的時間，代碼中("YYYY-MM-dd HH:mm:ss")這個時間的樣式是可以根據(jù)我們的需求進(jìn)行修改的，比如： 20170901112253 ==> ("YYYYMMddHHmmss")
如果只想獲取年月，代碼如下：
NSDate *date1 = [NSDate date];
NSDateFormatter *formatter1 = [[NSDateFormatter alloc] init];
[formatter1 setDateStyle:NSDateFormatterMediumStyle];
[formatter1 setTimeStyle:NSDateFormatterShortStyle];
[formatter1 setDateFormat:@"YYYY-MM"];
NSString *DateTime1 = [formatter1 stringFromDate:date1];
2. 區(qū)分系統(tǒng)時間是24小時制還是12小時制
//獲取系統(tǒng)是24小時制或者12小時制
NSString *formatStringForHours = [NSDateFormatter dateFormatFromTemplate:@"j" options:0 locale:[NSLocale currentLocale]];
NSRange contains = [formatStringForHours rangeOfString:@"a"];
BOOL thisAMPM = contains.location != NSNotFound;
thisAMPM == true //表示12小時制 否則為24小時制
3. 字符串轉(zhuǎn)時間戳
//字符串轉(zhuǎn)時間戳
//datenow為當(dāng)前時間
NSString *timeSp = [NSString stringWithFormat:@"%d", (long)[datenow timeIntervalSince1970]];
//時間戳的值
NSLog(@"timeSp:%@",timeSp);
4.時間戳轉(zhuǎn)字符串
//時間戳轉(zhuǎn)字符串
NSString *timeStr = "1506064573";
NSTimeInterval interval=[timeStr doubleValue] / 1000.0;
NSDate *date = [NSDate dateWithTimeIntervalSince1970:interval];
//實例化一個NSDateFormatter對象
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc]init];
//設(shè)定時間格式,這里可以設(shè)置成自己需要的格式
[dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
NSString *currentDateStr = [dateFormatter stringFromDate:date];
