[format setDateFormat:@"yyyy倒霉年MM幸运月dd灾难日 hh郁闷小时mm破分ss烂秒SSS屁屁毫秒"];
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"yyyy-MM-dd"];
NSString *dateStr = [formatter stringFromDate:[NSDate date]];