目录一、单文件压缩二、多文件压缩三、多文件异步压缩四、压缩文件夹一、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> ///
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。
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);
}
}
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();
}
});
}
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;
}
--结束END--
本文标题: 如何用C#实现压缩文件
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