我对文件对比这一块还是比较感兴趣的，也想知道哪种方式性价比最高，效率最好，所以，根据这篇文章，我自己也自测一下，顺便留出自己对比的结果，供大佬们参考一二。

大致对比方案

我这边根据文章里的主要三个方案

MD5
缓存长度读取比较
缓存长度读取(Span)比较
Hash256
CRC(最后补的)

新增了Hash256模式，原因是因为GitHub就是用Hash256来确定文件的唯一性的，所以，也想测试下它的性能到底如何。

又新增了CRC模式，后来才想起来的。

代码大致如下

挺简单的一个抽象工具类，方便增加相关的相同测试。
我也搜了OpenAi的建议和NewBing的建议，大致都是一样的建议。

根据建议和参考文章

抽象工具

public abstract class AFileCompare
{public AFileCompare(string name){this.Name = name;}public string Name { get; set; }public bool Compare(string file1, string file2){var result = false;Stopwatch stopwatch = Stopwatch.StartNew();if (Check(file1, file2)){result = CompareCore(file1, file2);}stopwatch.Stop();TimeSpan = stopwatch.Elapsed;return result;}public abstract bool CompareCore(string file1, string file2);public TimeSpan TimeSpan { get; set; }public bool Check(string file1, string file2){if (file1 == file2){return true;}if (new FileInfo(file1).Length == new FileInfo(file2).Length){return true;}return false;}public override string ToString(){return $"{Name}耗时:{TimeSpan.TotalSeconds}秒";}
}

MD5工具

public class MD5Compare : AFileCompare
{public MD5Compare() : base("MD5 "){}public override bool CompareCore(string file1, string file2){using (var md5 = MD5.Create()){byte[] one, two;using (var fs1 = File.Open(file1, FileMode.Open)){// 以FileStream读取文件内容,计算HASH值one = md5.ComputeHash(fs1);}using (var fs2 = File.Open(file2, FileMode.Open)){// 以FileStream读取文件内容,计算HASH值two = md5.ComputeHash(fs2);}for (int i = 0; i < one.Length; i++){if (one[i] != two[i]){return false;}}return true;}}
}

Hash256

public class HashCompare : AFileCompare
{public HashCompare() : base("Hash256"){}public override bool CompareCore(string file1, string file2){byte[] one, two;using (SHA1 mySHA1 = SHA1.Create()){using (FileStream stream = File.OpenRead(file1)){one = mySHA1.ComputeHash(stream);}}using (SHA1 mySHA1 = SHA1.Create()){using (FileStream stream = File.OpenRead(file2)){two = mySHA1.ComputeHash(stream);}}for (int i = 0; i < one.Length; i++){if (one[i] != two[i]){return false;}}return true;}
}

缓存长度读取比较

public class FileSizeCompare : AFileCompare
{public FileSizeCompare() : base("FileSize_4096"){}public override bool CompareCore(string file1, string file2){using (FileStream fs1 = new FileStream(file1, FileMode.Open))using (FileStream fs2 = new FileStream(file2, FileMode.Open)){byte[] buffer1 = new byte[4096];byte[] buffer2 = new byte[4096];int bytesRead1;int bytesRead2;do{bytesRead1 = fs1.Read(buffer1, 0, buffer1.Length);bytesRead2 = fs2.Read(buffer2, 0, buffer2.Length);if (bytesRead1 != bytesRead2){return false;}for (int i = 0; i < bytesRead1; i++){if (buffer1[i] != buffer2[i]){return false;}}} while (bytesRead1 > 0);return true;}}
}

缓存长度读取(Span)比较

public class FileSizeCompare2 : AFileCompare
{public FileSizeCompare2() : base("FileSize_4096_Span"){}public override bool CompareCore(string file1, string file2){using (FileStream fs1 = new FileStream(file1, FileMode.Open))using (FileStream fs2 = new FileStream(file2, FileMode.Open)){byte[] buffer1 = new byte[4096];byte[] buffer2 = new byte[4096];int bytesRead1;int bytesRead2;do{bytesRead1 = fs1.Read(buffer1, 0, buffer1.Length);bytesRead2 = fs2.Read(buffer2, 0, buffer2.Length);if (bytesRead1 != bytesRead2){return false;}if (!((ReadOnlySpan<byte>)buffer1).SequenceEqual((ReadOnlySpan<byte>)buffer2)){return false;}} while (bytesRead1 > 0);return true;}}
}

CRC(补充)

public class CRCCompare : AFileCompare
{public CRCCompare() : base("CRC"){}public override bool CompareCore(string file1, string file2){Crc32Algorithm crc32 = new Crc32Algorithm();byte[] one, two;using (var fs1 = File.Open(file1, FileMode.Open)){one = crc32.ComputeHash(fs1);}using (var fs2 = File.Open(file2, FileMode.Open)){two = crc32.ComputeHash(fs2);}for (int i = 0; i < one.Length; i++){if (one[i] != two[i]){return false;}}return true;}
}

main 入口

static void Main(string[] args)
{var files = new List<(string name, string source, string target)>(){("ubuntu_4.58 GB",@"E:\重装系统\ubuntu-22.04.2-desktop-amd64.iso",@"E:\重装系统\ubuntu-22.04.2-desktop-amd64 - 副本.iso"),("Docker_523 MB",@"E:\重装系统\Docker Desktop Installer(1).exe",@"E:\重装系统\Docker Desktop Installer(1) - 副本.exe"),("Postman_116 MB",@"E:\重装系统\Postman-win64-8.5.0-Setup.exe",@"E:\重装系统\Postman-win64-8.5.0-Setup - 副本.exe")};var list = new List<AFileCompare>();list.Add(new MD5Compare());list.Add(new HashCompare());list.Add(new FileSizeCompare());list.Add(new FileSizeCompare2());foreach ((string name, string source, string target) in files){foreach (var item in list){var result = item.Compare(source, target);Console.WriteLine($"{name} - {item.Name} 结果:{result} {item}");}Console.WriteLine();}Console.WriteLine("测试完毕");Console.ReadLine();
}