xml压缩与解压缩

using System;

using System.Text;

using System.IO;

using System.IO.Compression;



namespace 努力偷懒.Commonds

{

    /// <summary>

    /// 使用系统默认压缩流的方法进行压缩并保存成文件，

    /// 约定1：文件前面8个字节保存的是long类型，存储的是字符串压缩前的字节长度。

    /// </summary>

    public class ZipFileHelper

    {

        public static long WriteString(string fileName, string data)

        {

            long lResult = 0;

            byte[] bs = Encoding.UTF8.GetBytes(data);

            MemoryStream ms = new MemoryStream();

            //创建文件流

            FileStream fs = new FileStream(fileName, FileMode.Create);

            try

            {

                DeflateStream compressedzipStream = null;

                try

                {

                    compressedzipStream = new DeflateStream(ms, CompressionMode.Compress, true);

                    compressedzipStream.Write(bs, 0, bs.Length);//把bs中的数据进行二进制压缩后写入到ms中。

                    lResult = ms.Length;

                }

                finally

                {

                    if (null != compressedzipStream)

                        compressedzipStream.Close();

                }

                byte[] bl = BitConverter.GetBytes((long)bs.Length);//把没有压缩的数据长度保存下来，以在还原时使用。

                fs.Write(bl, 0, bl.Length);

                ms.WriteTo(fs);

                fs.Flush();

            }

            finally

            {

                fs.Close();

                ms.Close();

            }

            return lResult;

        }

        /// <summary>

        /// 解压，返回byte数组

        /// </summary>

        /// <param name="fileName"></param>

        /// <returns></returns>

        public static byte[] LoadBytes(string fileName)

        {

            //源数据长度的byte数据

            byte[] bs;

            long nSize;//bs转换后的实际值

            //结果

            byte[] decompressBuffer;

            FileStream fs = new FileStream(fileName, FileMode.Open);

            try

            {

                //读入源数据的字节长度

                byte[] bl = new byte[8];

                fs.Read(bl, 0, 8);

                nSize = BitConverter.ToInt64(bl, 0);

                //把文件流中字符的二进制数据写入到bs数组中

                bs = new byte[fs.Length - 8];

                fs.Read(bs, 0, (int)fs.Length - 8);

            }

            finally

            {

                fs.Close();

            }



            //bs数据写入到ms流中

            MemoryStream ms = new MemoryStream();

            DeflateStream DecompressedzipStream=null;

            try

            {

                ms.Write(bs, 0, bs.Length);

                ms.Position = 0;

                //解压

                DecompressedzipStream = new DeflateStream(ms, CompressionMode.Decompress);

                DecompressedzipStream.Flush();

                //解压后的数据

                decompressBuffer = new byte[nSize];

                DecompressedzipStream.Read(decompressBuffer, 0, decompressBuffer.Length);

            }

            finally

            {

                if (null != DecompressedzipStream)

                    DecompressedzipStream.Close();

                if (null!=ms )

                    ms.Close();

            }

            return decompressBuffer;

        }

    }

} 

 

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