iOS -计算时间差

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

[date setDateFormat:@"yyyyMMddHH"];

[date setTimeZone:[NSTimeZone systemTimeZone]];

NSInteger timeSub = [[NSTimeZone systemTimeZone] secondsFromGMT];

NSDate *endD = [endTime dateByAddingTimeInterval:timeSub];

NSTimeInterval interval1 = [startD timeIntervalSince1970];

NSTimeInterval interval2 = [endD timeIntervalSince1970];

NSTimeInterval interval3 = interval2-interval1;