NSDate和NSString的相互转换

//输入的日期字符串形如：@"1992-05-21 13:08:08"- (NSDate *)dateFromString:(NSString *)dateString{NSDateFormatter *dateFormatter = [[NSDateFormatteralloc] init];[dateFormatter setDateFormat: @"yyyy-MM-dd HH:mm:ss"]; NSDate *destDate= [dateFormatter dateFromString:dateString];return destDate;}- (NSString *)stringFromDate:(NSDate *)date{NSDateFormatter *dateFormatter = [[NSDateFormatteralloc] init]; //zzz表示时区，zzz可以删除，这样返回的日期字符将不包含时区信息。[dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss zzz"];NSString *destDateString = [dateFormatter stringFromDate:date];[dateFormatter release];return destDateString;}