1         NSString *string = @"2013-08-12 20:13:43";
2        
3          NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
4         //格式一定要一致，否则无法转换
5         formatter.dateFormat = @"yyyy-MM-dd HH:mm:ss";
6       
7         NSDate *date = [formatter dateFromString: string];
8         NSLog(@"\n%@", date);

1         NSDate *date = [NSDate date];
2         NSString *time;
3         NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
4         dateFormatter.dateFormat = @"yyyy-MM-dd HH:mm:ss";
5         time = [dateFormatter stringFromDate:date];
6         NSLog(@"\n%@", date);   

NSDate 与NSString的互相转换