NSDate NSString时间字符串 NSTimeInterval 的转换

//时间格式

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

[formatter setDateFormat:@"MMM dd,yyyy HH:mm tt"];

//时间字符串NSDate

NSDate *date = [formatter dateFromString:string];

//NSDate转时间字符串

NSString *dateString = [formatter stringFromDate:date];

//时间转时间戳

NSTimeInterval interval = [date timeIntervalSince1970];

//时间戳转时间

date = [NSDate dateWithTimeIntervalSince1970:interval];