iphone获得当前系统时间

 NSCalendar *calendar = [[NSCalendaralloc]initWithCalendarIdentifier:NSChineseCalendar];//NSGregorianCalendar

/*

NSGregorianCalendar 

NSChineseCalendar];

NSJapaneseCalendar

...

*/ 

NSDate *now;

   NSDateComponents *comps = [[NSDateComponentsalloc]init];

   NSInteger unitFlags =NSYearCalendarUnit |NSMonthCalendarUnit |NSDayCalendarUnit |NSWeekdayCalendarUnit | 

   NSHourCalendarUnit |NSMinuteCalendarUnit |NSSecondCalendarUnit;

    now=[NSDate date];

    comps = [calendarcomponents:unitFlagsfromDate:now];

    

    

    

   NSLog(@"currentDate is %@",now);

不过得到的系统时间不准确，比正确的系统时间多了四个小时－－－原因还要进一步研究中

补充：这个可以得到正确的时间

     NSDate *today = [[NSDate alloc]init];  

    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];  

    [dateFormatter setDateFormat:@"YYYY-MM-dd HH:mm:ss"];  

    NSString *currentTime = [dateFormatter stringFromDate:today];  

    

    [dateFormatter release];

    [today release];

    NSLog(@"date is %@",currentTime);