NSDate *date = [NSDate dateWithTimeIntervalSinceNow:0];
NSTimeInterval a = [date timeIntervalSince1970];
NSString *timeStr = [NSString stringWithFormat:@"%f",a];
NSString *timeV = [NSString stringWithFormat:@"%d",[timeStr intValue]];
原文：http://blog.csdn.net/zh_2608/article/details/41806035