C# 压缩和解压缩（Gzip和Zip的方式）

使用ICSharpCode.SharpZipLib.dll来压缩/解压（压缩效率比GZip要高一点）

public static class ZipUtil
    {
        /// <summary>
        /// 压缩
        /// </summary>
        /// <param name="param"></param>
        /// <returns></returns>
        public static string Compress(string param)
        {
            byte[] data = System.Text.Encoding.UTF8.GetBytes(param);
            //byte[] data = Convert.FromBase64String(param);
            MemoryStream ms = new MemoryStream();
            Stream stream = new ICSharpCode.SharpZipLib.BZip2.BZip2OutputStream(ms);
            try
            {
                stream.Write(data, 0, data.Length);
            }
            finally
            {
                stream.Close();
                ms.Close();
            }
            return Convert.ToBase64String(ms.ToArray());
        }


        /// <summary>
        /// 解压
        /// </summary>
        /// <param name="param"></param>
        /// <returns></returns>
        public static string Decompress(string param)
        {
            string commonString = "";
            byte[] buffer = Convert.FromBase64String(param);
            MemoryStream ms = new MemoryStream(buffer);
            Stream sm = new ICSharpCode.SharpZipLib.BZip2.BZip2InputStream(ms);
            //这里要指明要读入的格式，要不就有乱码
            StreamReader reader = new StreamReader(sm, System.Text.Encoding.UTF8);
            try
            {
                commonString = reader.ReadToEnd();
            }
            finally
            {
                sm.Close();
                ms.Close();
            }
            return commonString;
        }
    }
           

使用GZip来压缩/解压缩（字符串）

public static class GZipUtil
    {
        public static string Zip(string value)
        {
            //Transform string into byte[]    
            byte[] byteArray = new byte[value.Length];
            int indexBA = 0;
            foreach (char item in value.ToCharArray())
            {
                byteArray[indexBA++] = (byte)item;
            }


            //Prepare for compress  
            System.IO.MemoryStream ms = new System.IO.MemoryStream();
            System.IO.Compression.GZipStream sw = new System.IO.Compression.GZipStream(ms,
                System.IO.Compression.CompressionMode.Compress);


            //Compress  
            sw.Write(byteArray, 0, byteArray.Length);
            //Close, DO NOT FLUSH cause bytes will go missing...  
            sw.Close();


            //Transform byte[] zip data to string  
            byteArray = ms.ToArray();
            System.Text.StringBuilder sB = new System.Text.StringBuilder(byteArray.Length);
            foreach (byte item in byteArray)
            {
                sB.Append((char)item);
            }
            ms.Close();
            sw.Dispose();
            ms.Dispose();
            return sB.ToString();
        }


        public static string UnZip(string value)
        {
            //Transform string into byte[]  
            byte[] byteArray = new byte[value.Length];
            int indexBA = 0;
            foreach (char item in value.ToCharArray())
            {
                byteArray[indexBA++] = (byte)item;
            }


            //Prepare for decompress  
            System.IO.MemoryStream ms = new System.IO.MemoryStream(byteArray);
            System.IO.Compression.GZipStream sr = new System.IO.Compression.GZipStream(ms,
                System.IO.Compression.CompressionMode.Decompress);


            //Reset variable to collect uncompressed result  
            byteArray = new byte[byteArray.Length];


            //Decompress  
            int rByte = sr.Read(byteArray, 0, byteArray.Length);


            //Transform byte[] unzip data to string  
            System.Text.StringBuilder sB = new System.Text.StringBuilder(rByte);
            //Read the number of bytes GZipStream red and do not a for each bytes in  
            //resultByteArray;  
            for (int i = 0; i < rByte; i++)
            {
                sB.Append((char)byteArray[i]);
            }
            sr.Close();
            ms.Close();
            sr.Dispose();
            ms.Dispose();
            return sB.ToString();
        }
    }