C# 壓縮和解壓縮（Gzip和Zip的方式）

使用ICSharpCode.SharpZipLib.dll來壓縮/解壓（壓縮效率比GZip要高一點）

    public static class ZipUtil

        {

            /// <summary>

            /// 壓縮

            /// </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>  
        /// 解壓  
        /// </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);  
            //這里要指明要讀入的格式，要不就有亂碼  
            StreamReader reader = new StreamReader(sm, System.Text.Encoding.UTF8);  
            try  
            {  
                commonString = reader.ReadToEnd();  
            }  
            finally  
            {  
                sm.Close();  
                ms.Close();  
            }  
            return commonString;  
        }  
    }  </pre> 


 使用GZip來壓縮/解壓縮（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();  
        }  
    }  </pre>