文件大小

//单个文件的大小
- (long long) fileSizeAtPath:(NSString*) filePath{
    NSFileManager* manager = [NSFileManager defaultManager];
    if ([manager fileExistsAtPath:filePath]){
        return [[manager attributesOfItemAtPath:filePath error:nil] fileSize] / 1000.0;
    }
    return 0;
}