iOS 时间转时间戳

1 +(NSString*)getTimeStamp:(NSDate*)dateNow
2 {
3
4     NSTimeInterval time = [dateNow timeIntervalSince1970]*1000;//NSTimeInterval本身是个秒级别的double类型数值，小数点后面即毫秒数,*1000.0f即可得到毫秒级别的时间差
5     long long dTime = [[NSNumber numberWithDouble:time] longLongValue]; // 将double转为long long型
6     NSString *timeSp = [NSString stringWithFormat:@"%llu",dTime]; // 输出long long型
7
8     return timeSp;
9 }