NSDateComponent小时不正确

是时区的问题：

用[components setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];

映射到你的时间设置：

int main(int argc, char *argv[]) {
@autoreleasepool {
    NSDate *today = [NSDate date];
    NSCalendar *calendar = [NSCalendar currentCalendar];
    NSDateComponents *components = [calendar components:  (NSYearCalendarUnit | NSMonthCalendarUnit |  NSDayCalendarUnit) fromDate:today];

    [components setMinute:50];
    [components setHour:7];
    [components setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];

    NSDate *myNewDate = [calendar dateFromComponents:components];
    NSLog(@"%@",myNewDate);
}
}