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2021
09-18

c# 用ICSharpCode组件压缩文件

一、单文件压缩

      场景,文件可能比较大,需要压缩传输,比如上传和下载

/// <summary>
        /// 单文件压缩
        /// </summary>
        /// <param name="sourceFile">源文件</param>
        /// <param name="zipedFile">zip压缩文件</param>
        /// <param name="blockSize">缓冲区大小</param>
        /// <param name="compressionLevel">压缩级别</param>
        public static void ZipFile(string sourceFile, string zipedFile, int blockSize = 1024, int compressionLevel = 6)
        {
            if (!File.Exists(sourceFile))
            {
                throw new System.IO.FileNotFoundException("The specified file " + sourceFile + " could not be found.");
            }
            var fileName = System.IO.Path.GetFileNameWithoutExtension(sourceFile);

            FileStream streamToZip = new FileStream(sourceFile, FileMode.Open, FileAccess.Read);
            FileStream zipFile = File.Create(zipedFile);
            ZipOutputStream zipStream = new ZipOutputStream(zipFile);

            ZipEntry zipEntry = new ZipEntry(fileName);
            zipStream.PutNextEntry(zipEntry);

            //存储、最快、较快、标准、较好、最好  0-9
            zipStream.SetLevel(compressionLevel);

            byte[] buffer = new byte[blockSize];

            int size = streamToZip.Read(buffer, 0, buffer.Length);
            zipStream.Write(buffer, 0, size);
            try
            {
                while (size < streamToZip.Length)
                {
                    int sizeRead = streamToZip.Read(buffer, 0, buffer.Length);
                    zipStream.Write(buffer, 0, sizeRead);
                    size += sizeRead;
                }
            }
            catch (Exception ex)
            {
                throw ex;
            }
            zipStream.Finish();
            zipStream.Close();
            streamToZip.Close();
        }

说明:26行,blocksize为缓存区大小,不能设置太大,如果太大也会报异常。26-38行,把文件通过FileStream流,读取到缓冲区中,再写入到ZipOutputStream流。你可以想象,两个管道,一个读,另一个写,中间是缓冲区,它们的工作方式是同步的方式。想一下,能不能以异步的方式工作,读的管道只管读,写的管道只管写?如果是这样一个场景,读的特别快,写的比较慢,比如,不是本地写,而是要经过网络传输,就可以考虑异步的方式。怎么做,读者可以自行改造。关键一点,流是有顺序的,所以要保证顺序的正确性即可。

二、多文件压缩

      这种场景也是比较多见,和单文件压缩类似,无非就是多循环几次。

/// <summary>
        /// 多文件压缩
        /// </summary>
        /// <param name="zipfile">zip压缩文件</param>
        /// <param name="filenames">源文件集合</param>
        /// <param name="password">压缩加密</param>
        public void ZipFiles(string zipfile, string[] filenames, string password = "")
        {
            ZipOutputStream s = new ZipOutputStream(System.IO.File.Create(zipfile));

            s.SetLevel(6);

            if (password != "")
                s.Password = Md5Help.Encrypt(password);

            foreach (string file in filenames)
            {
                //打开压缩文件
                FileStream fs = File.OpenRead(file);

                byte[] buffer = new byte[fs.Length];
                fs.Read(buffer, 0, buffer.Length);

                var name = Path.GetFileName(file);

                ZipEntry entry = new ZipEntry(name);
                entry.DateTime = DateTime.Now;
                entry.Size = fs.Length;
                fs.Close();
                s.PutNextEntry(entry);
                s.Write(buffer, 0, buffer.Length);
            }
            s.Finish();
            s.Close();
        }

说明:21行,缓冲区大小直接为文件大小,所以一次读完,没有循环读写。这种情况下,单个文件不能太大,比如超过1G。14行,可以为压缩包设置密码,MD5的生成方法如下:

public class Md5Help
    {
        /// <summary>
        ///32位 MD5加密
        /// </summary>
        /// <param name="str">加密字符</param>
        /// <returns></returns>
        public static string Encrypt(string str)
        {
            MD5 md5 = new MD5CryptoServiceProvider();

            byte[] encryptdata = md5.ComputeHash(Encoding.UTF8.GetBytes(str));

            return Convert.ToBase64String(encryptdata);
        }
    }

三、多文件异步压缩

      上面同步的压缩的前提是,假设文件不大,而且文件数不多,但是现实是,不光文件大,而且文件数比较多。这种情况,就要考虑异步方法了。否则会阻塞主线程,就是我们平常说的卡死。

/// <summary>
        /// 异步压缩文件为zip压缩包
        /// </summary>
        /// <param name="zipfile">压缩包存储路径</param>
        /// <param name="filenames">文件集合</param>
        public static async void ZipFilesAsync(string zipfile, string[] filenames)
        {
            await Task.Run(() =>
            {
                ZipOutputStream s = null;
                try
                {
                    s = new ZipOutputStream(System.IO.File.Create(zipfile));

                    s.SetLevel(6); // 0 - store only to 9 - means best compression 

                    foreach (string file in filenames)
                    {
                        //打开压缩文件 
                        FileStream fs = System.IO.File.OpenRead(file);

                        var name = Path.GetFileName(file);
                        ZipEntry entry = new ZipEntry(name);
                        entry.DateTime = DateTime.Now;
                        entry.Size = fs.Length;
                        s.PutNextEntry(entry);

                        //如果文件大于1G
                        long blockSize = 51200;

                        var size = (int)fs.Length;

                        var oneG = 1024 * 1024 * 1024;

                        if (size > oneG)
                        {
                            blockSize = oneG;
                        }
                        byte[] buffer = new byte[blockSize];

                        size = fs.Read(buffer, 0, buffer.Length);

                        s.Write(buffer, 0, size);

                        while (size < fs.Length)
                        {
                            int sizeRead = fs.Read(buffer, 0, buffer.Length);
                            s.Write(buffer, 0, sizeRead);
                            size += sizeRead;
                        }
                        s.Flush();
                        fs.Close();
                    }

                }
                catch (Exception ex)
                {
                    Console.WriteLine("异步压缩文件出错:" + ex.Message);
                }
                finally
                {
                    s?.Finish();
                    s?.Close();
                }
            });
        }

四、压缩文件夹

    实际的应用当中,是文件和文件夹一起压缩,所以这种情况,就干脆把要压缩的东西全部放到一个文件夹,然后进行压缩。

 主方法如下:

/// <summary>
        /// 异步压缩文件夹为zip压缩包
        /// </summary>
        /// <param name="zipfile">压缩包存储路径</param>
        /// <param name="sourceFolder">压缩包存储路径</param>
        /// <param name="filenames">文件集合</param>
        public static async void ZipFolderAsync(string zipfile, string sourceFolder, string[] filenames)
        {
            await Task.Run(() =>
            {
                ZipOutputStream s = null;
                try
                {
                    s = new ZipOutputStream(System.IO.File.Create(zipfile));

                    s.SetLevel(6); // 0 - store only to 9 - means best compression 

                    CompressFolder(sourceFolder, s, sourceFolder);
                }
                catch (Exception ex)
                {
                    Console.WriteLine("异步压缩文件出错:" + ex.Message);
                }
                finally
                {
                    s?.Finish();
                    s?.Close();
                }
            });
        }

压缩的核心方法:

/// <summary>
        /// 压缩文件夹
        /// </summary>
        /// <param name="source">源目录</param>
        /// <param name="s">ZipOutputStream对象</param>
        /// <param name="parentPath">和source相同</param>
        public static void CompressFolder(string source, ZipOutputStream s, string parentPath)
        {
            string[] filenames = Directory.GetFileSystemEntries(source);
            foreach (string file in filenames)
            {
                if (Directory.Exists(file))
                {
                    CompressFolder(file, s, parentPath);  //递归压缩子文件夹
                }
                else
                {
                    using (FileStream fs = System.IO.File.OpenRead(file))
                    {
                        var writeFilePath = file.Replace(parentPath, "");
                        ZipEntry entry = new ZipEntry(writeFilePath);
                        entry.DateTime = DateTime.Now;
                        entry.Size = fs.Length;

                        s.PutNextEntry(entry);

                        //如果文件大于1G
                        long blockSize = 51200;

                        var size = (int)fs.Length;

                        var oneG = 1024 * 1024 * 1024;

                        if (size > oneG)
                        {
                            blockSize = oneG;
                        }
                        byte[] buffer = new byte[blockSize];

                        size = fs.Read(buffer, 0, buffer.Length);

                        s.Write(buffer, 0, size);


                        while (size < fs.Length)
                        {
                            int sizeRead = fs.Read(buffer, 0, buffer.Length);
                            s.Write(buffer, 0, sizeRead);
                            size += sizeRead;
                        }

                        s.Flush();   //清除流的缓冲区,使得所有缓冲数据都写入到文件中
                        fs.Close();
                    }
                }
            }
        }

唯一需要注意的地方,可能解压出来的目录结构和压缩前的文件目录不同,这时候检查parentPath参数,它在ZipEntry实体new的时候用,替换绝对路径为当前的相对路径,也就是相对压缩文件夹的路径。

上面的方法比较复杂,还有一种相对简单的方式,直接调用api:

public static string ZipFolder(string sourceFolder, string zipFile)
        {
            string result = "";
            try
            {
                //创建压缩包
                if (!Directory.Exists(sourceFolder)) return result = "压缩文件夹不存在";

                DirectoryInfo d = new DirectoryInfo(sourceFolder);
                var files = d.GetFiles();
                if (files.Length == 0)
                {
                    //找子目录
                    var ds = d.GetDirectories();
                    if (ds.Length > 0)
                    {
                        files = ds[0].GetFiles();
                    }
                }
                if (files.Length == 0) return result = "待压缩文件为空";
                System.IO.Compression.ZipFile.CreateFromDirectory(sourceFolder, zipFile);
            }
            catch (Exception ex)
            {
                result += "压缩出错:" + ex.Message;
            }
            return result;
        }

以上就是c# 用ICSharpCode组件压缩文件的详细内容,更多关于c# 压缩文件的资料请关注自学编程网其它相关文章!

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