NSDate *date=[NSDate date];

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

formatter.dateFormat=@"yyy-MM-dd HH:mm:ss";

NSString *str=[formatter stringFromDate:date];

字符串转化时间

NSString *time=@“2011/02/10 18:34”;

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

formatter.dateFormat=@"yyy-MM-dd HH:mm:ss";

NSDate *date=[formatter dateFromString:date];