C#对文件操作（基本的读写以及压缩和解压）

主要是针对单个文件进行读写操作和压缩操作：用到的主要C#类有FileStream、FileInfo、StreamWrite、StreamRead、GZipStream。

字符数组和字节数组的转换：

 byte[] bytedata = new byte[200];
            char[] chardata = new char[200];
            try
            {
                FileStream fs = new FileStream("App.config", FileMode.Open);
                fs.Seek(0, SeekOrigin.Begin);
                fs.Read(bytedata, 0, 200);
            }
            catch (IOException io)
            {
                Console.WriteLine(io.ToString());
                Console.ReadKey();
                return;
            }
            Decoder dc = Encoding.UTF8.GetDecoder();//创建一个解码器用来对二进制数组解码成字符数组
            dc.GetChars(bytedata, 0, bytedata.Length, chardata, 0);
            Console.WriteLine(chardata);
            Console.ReadKey();
            byte[] byteData;
            char[] charData;
            try
            {
                FileStream fs = new FileStream("Log.txt", FileMode.Create);
                charData = "this is the user first log the software".ToCharArray();
                Encoder e = Encoding.UTF8.GetEncoder();
                byteData = new byte[charData.Length];
                e.GetBytes(charData, 0, charData.Length, byteData, 0, true);
                fs.Seek(0, SeekOrigin.End);
                fs.Write(byteData, 0, byteData.Length);
            }
            catch (IOException io)
            {
                Console.WriteLine(io.ToString());
                Console.ReadKey();
                return;
            }
            Console.ReadKey();

对文件进行压缩和解压（一单个文件为例）：

string fileName = "CompressedFile.txt";
            Console.WriteLine("Please input a word and it will repeate 100 times");
            string inputString = Console.ReadLine();
            StringBuilder sourceString = new StringBuilder(inputString.Length * 100);
            for (int i = 0; i < 100; i++) 
            {
                sourceString.AppendLine(inputString);
            }
            string sourceCompresses = sourceString.ToString();
            Console.WriteLine("source data's length is {0}", sourceCompresses.Length);
            try
            {
                CompressedFile(fileName, sourceCompresses);
                Console.WriteLine("Compressed successfully");
                FileInfo fileInfo = new FileInfo(fileName);
                Console.WriteLine("compressed file's length is{0}", fileInfo.Length);
                string loadCompressed = LoadCompressedFile(fileName);
                Console.WriteLine(loadCompressed);
            }
            catch (IOException io)
            {
                Console.WriteLine(io.ToString());
                Console.ReadKey();
                return;
            }
            Console.ReadKey();
        }

        private static void CompressedFile(string fileName, string sourceCompress) 
        {
            FileStream fs = new FileStream(fileName, FileMode.Create, FileAccess.Write);
            GZipStream gzCompressedFile = new GZipStream(fs, CompressionMode.Compress);
            StreamWriter sw = new StreamWriter(gzCompressedFile,Encoding.UTF8);
            sw.Write(sourceCompress);
            sw.Close();
        }

        private static string LoadCompressedFile(string fileName) 
        {
            FileStream fs = new FileStream(fileName, FileMode.Open, FileAccess.Read);
            GZipStream gzLoadCompressed = new GZipStream(fs, CompressionMode.Decompress);
            StreamReader sr = new StreamReader(gzLoadCompressed,Encoding.UTF8);
            StringBuilder strBuild = new StringBuilder();
            string strReadLine = sr.ReadLine();
            while (!string.IsNullOrEmpty(strReadLine)) 
            {
                strBuild.Append(strReadLine);
                strReadLine = sr.ReadLine();
            }
            return strBuild.ToString();
        }