.NET 压缩与解压

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using ICSharpCode.SharpZipLib.Zip;
using ICSharpCode.SharpZipLib.Checksums;
using System.Security.Cryptography;

namespace zip压缩与解压
{
    public class ZipHelper
    {
        /// <summary>
        /// 压缩单个文件
        /// </summary>
        /// <param name="fileToZip">需压缩的文件名</param>
        /// <param name="zipFile">压缩后的文件名（文件名都是绝对路径）</param>
        /// <param name="level">压缩等级（0-9）</param>
        /// <param name="password">压缩密码（解压是需要的密码）</param>
        public static void ZipFile(string fileToZip, string zipFile, int level = 5, string password = "123")
        {
            if (!File.Exists(fileToZip))
                throw new FileNotFoundException("压缩文件" + fileToZip + "不存在");

            using (FileStream fs = File.OpenRead(fileToZip))
            {
                fs.Position = 0;//设置流的起始位置
                byte[] buffer = new byte[(int)fs.Length];
                fs.Read(buffer, 0, buffer.Length);//读取的时候设置Position，写入的时候不需要设置
                fs.Close();
                using (FileStream zfstram = File.Create(zipFile))
                {
                    using (ZipOutputStream zipstream = new ZipOutputStream(zfstram))
                    {
                        zipstream.Password = md5(password);//设置属性的时候在PutNextEntry函数之前
                        zipstream.SetLevel(level);
                        string fileName = fileToZip.Substring(fileToZip.LastIndexOf('\\') + 1);
                        ZipEntry entry = new ZipEntry(fileName);
                        zipstream.PutNextEntry(entry);
                        zipstream.Write(buffer, 0, buffer.Length);
                    }
                }

            }
        }

        /// <summary>
        /// 压缩多个文件目录
        /// </summary>
        /// <param name="dirname">需要压缩的目录</param>
        /// <param name="zipFile">压缩后的文件名</param>
        /// <param name="level">压缩等级</param>
        /// <param name="password">密码</param>
        public static void ZipDir(string dirname, string zipFile, int level = 5, string password = "123")
        {
            ZipOutputStream zos = new ZipOutputStream(File.Create(zipFile));
            zos.Password = md5(password);
            zos.SetLevel(level);
            addZipEntry(dirname, zos, dirname);
            zos.Finish();
            zos.Close();

        }
        /// <summary>
        /// 往压缩文件里面添加Entry
        /// </summary>
        /// <param name="PathStr">文件路径</param>
        /// <param name="zos">ZipOutputStream</param>
        /// <param name="BaseDirName">基础目录</param>
        private static void addZipEntry(string PathStr, ZipOutputStream zos, string BaseDirName)
        {
            DirectoryInfo dir = new DirectoryInfo(PathStr);
            foreach (FileSystemInfo item in dir.GetFileSystemInfos())
            {
                if ((item.Attributes & FileAttributes.Directory) == FileAttributes.Directory)//如果是文件夹继续递归
                {
                    addZipEntry(item.FullName, zos, BaseDirName);
                }
                else
                {
                    FileInfo f_item = (FileInfo)item;
                    using (FileStream fs = f_item.OpenRead())
                    {
                        byte[] buffer = new byte[(int)fs.Length];
                        fs.Position = 0;
                        fs.Read(buffer, 0, buffer.Length);
                        fs.Close();
                        ZipEntry z_entry = new ZipEntry(item.FullName.Replace(BaseDirName, ""));
                        zos.PutNextEntry(z_entry);
                        zos.Write(buffer, 0, buffer.Length);
                    }
                }
            }


        }

        /// <summary>
        /// 解压多个文件目录
        /// </summary>
        /// <param name="zfile">压缩文件绝对路径</param>
        /// <param name="dirname">解压文件目录</param>
        /// <param name="password">密码</param>
        public static void UnZip(string zfile, string dirname, string password)
        {
            if (!Directory.Exists(dirname)) Directory.CreateDirectory(dirname);

            using (ZipInputStream zis = new ZipInputStream(File.OpenRead(zfile)))
            {
                zis.Password = md5(password);
                ZipEntry entry;
                while ((entry = zis.GetNextEntry()) != null)
                {
                    var strArr = entry.Name.Split('\\');//这边判断压缩文件里面是否存在目录，存在的话先创建目录后继续解压
                    if (strArr.Length > 2)        
                        Directory.CreateDirectory(dirname + @"\" + strArr[1]);
                    
                    using (FileStream dir_fs = File.Create(dirname + entry.Name))
                    {
                        int size = 1024 * 2;
                        byte[] buffer = new byte[size];
                        while (true)
                        {
                            size = zis.Read(buffer, 0, buffer.Length);
                            if (size > 0)
                                dir_fs.Write(buffer, 0, size);
                            else
                                break;
                        }
                    }
                }
            }
        }

        private static string md5(string pwd)
        {
            var res = "";
            MD5 md = MD5.Create();
            byte[] s = md.ComputeHash(Encoding.Default.GetBytes(pwd));
            for (int i = 0; i < s.Length; i++)
                res = res + s[i].ToString("X");

            return res;
        }
    }
}