将多个文件写入一个文件中去并能分解

对于一个文件的读写，其实很简单，就是用FileStream进行Read或者Write就行了。但是如何把多个文件写入到同一个文件，之后要能把这个文件进行还原成多个文件。那么光靠FileStream的Read和Write方法是不够的，首先你需要自行建立文件索引，来标明每个文件在当前文件的位置。

　　那么最近作了一个简单的DEMO，其中类的部分代码如下：

以下是引用片段： //------------------------------- Compose Files ---------------------------------- //-------------------------------------------------------------------------------- //---File:clsComposeFiles.cs //---Description:This file is to show how-to compose multi-files into one file  //               and decompose one file to multi-files. //---Author:Knight //---Date:May.16, 2006 //-------------------------------------------------------------------------------- //------------------------------{ Compose Files }---------------------------------   namespace ComposeFiles {     using System;     using System.IO;     using System.Collections;     using System.Text;       /// <summary>     /// Summary description for clsComposeFiles.     /// </summary>     public class clsComposeFiles     {         private ArrayList arrFiles = new ArrayList();           public clsComposeFiles()         {             //             // TODO: Add constructor logic here             //         }           /// <summary>         /// Add a file to be composed         /// </summary>         /// <param name="sFileName"></param>         public void AddFile( string sFileName )         {             arrFiles.Add( sFileName );         }           /// <summary>         /// Compose files to the specific file         /// </summary>         /// <param name="sFileName"></param>         /// <returns></returns>         public bool ComposeFiles( string sFileName )         {             if( arrFiles.Count == 0 ) return false;                          FileInfo fi = new FileInfo( sFileName );             // Open file to write             FileStream fsWriter = null;             try             {                 if( !fi.Exists )                 {                     fsWriter = new FileStream(                          sFileName,                          FileMode.CreateNew,                          FileAccess.ReadWrite,                         FileShare.None );                 }                 else                     fsWriter = new FileStream(                          sFileName,                          FileMode.Truncate,                          FileAccess.ReadWrite,                         FileShare.None );             }             catch(Exception err)             {                 System.Diagnostics.Debug.WriteLine( err.Message );                 return false;             }                          byte[] bBuffer = null;             // Write files count             bBuffer = FileIndex.LongToBytes( arrFiles.Count );             fsWriter.Write( bBuffer, 0, 8 );               const long INDEX_START_POS = 8L;             // Init files index             FileIndex FI = new FileIndex();             for( int i = 0; i < arrFiles.Count; i++ )                 fsWriter.Write( FileIndex.ConvertToBytes( ref FI ), 0, 32 );               long FILE_START_POS = INDEX_START_POS + 32 * arrFiles.Count;             long lCurFileStartPos = FILE_START_POS;               // Write every file             for( int i = 0; i < arrFiles.Count; i++ )             {                 WriteFile( arrFiles.ToString(),                     ref lCurFileStartPos,                     INDEX_START_POS,                     fsWriter,                     i );             }               // Close stream             fsWriter.Close();             return true;         }           /// <summary>         /// Write file name and data into composed file         /// </summary>         /// <param name="sFileName"></param>         /// <param name="FileStartPos"></param>         /// <param name="IndexStartPos"></param>         /// <param name="fsWriter"></param>         /// <param name="Index"></param>         private void WriteFile(              string sFileName,              ref long FileStartPos,             long IndexStartPos,             FileStream fsWriter,             int Index )         {             FileInfo fi = new FileInfo( sFileName );             if( !fi.Exists ) return;               FileStream fsReader = null;             try             {                 fsReader = new FileStream(                      sFileName, FileMode.Open,                      FileAccess.Read );             }             catch{ return;}               // Get file name             byte[] bFileName = Encoding.Unicode.GetBytes( fi.Name );             // Write file name             fsWriter.Write( bFileName, 0, bFileName.Length );               const int BUFFER_LENGTH = 1024;             byte[] bBuffer = new byte[BUFFER_LENGTH];             int nRealRead = 0;             // Write data using             do             {                 // Read data from file                 nRealRead = fsReader.Read( bBuffer, 0,                      BUFFER_LENGTH );                 // Write data                  fsWriter.Write( bBuffer, 0, nRealRead );             }while( nRealRead > 0 );             // Close file reader             fsReader.Close();               FileIndex FINew = new FileIndex();             FINew.NameStartPos = FileStartPos;             FINew.NameLength = bFileName.Length;             FINew.FileStartPos = FileStartPos + bFileName.Length;             FINew.FileLength = fi.Length;               // Go back to file index position             fsWriter.Seek( IndexStartPos + Index * 32, SeekOrigin.Begin );               // Write file index info             fsWriter.Write( FileIndex.ConvertToBytes( ref FINew ), 0, 32 );               // Go back to file end             fsWriter.Seek( 0, SeekOrigin.End );               // Set file current position             FileStartPos += bFileName.Length + fi.Length;         }           /// <summary>         /// Decompose file to multi files into specific directory         /// </summary>         /// <param name="sFileName"></param>         /// <param name="sDestDir"></param>         /// <returns></returns>         public bool DecomposeFile( string sFileName, string sDestDir )         {             FileInfo fi = new FileInfo( sFileName );             if( !fi.Exists ) return false;               FileStream fsReader = null;             try             {                 fsReader = new FileStream(                      sFileName, FileMode.Open,                      FileAccess.Read );             }             catch{ return false;}                          // Read file count             byte[] bFileCount = new byte[8];             int nRealRead = 0;             nRealRead = fsReader.Read( bFileCount, 0, 8 );             if( nRealRead != 8 )             {                 fsReader.Close();                 return false;             }               long lFileCount = FileIndex.BytesToLong( bFileCount );             if( lFileCount > 0 )             {                 //Init file index array                 FileIndex[] fiArray = new FileIndex[lFileCount];                 byte[] bFileIndex = new byte[32];                 for( int i = 0; i < lFileCount; i++ )                 {                     fsReader.Read( bFileIndex, 0, 32 );                     fiArray = FileIndex.ConvertToFileIndex( bFileIndex );                 }                   if( sDestDir[ sDestDir.Length - 1] != ´\\´ )                     sDestDir += "\\";                 // Save every file into current directory                 for( int i = 0; i < fiArray.Length; i++ )                 {                     SaveFile( fsReader,                         ref fiArray,                         sDestDir );                 }             }               // Close file reader             fsReader.Close();             return true;         }           /// <summary>         /// Save every file into directory         /// </summary>         /// <param name="fsReader"></param>         /// <param name="FI"></param>         /// <param name="sDestDir"></param>         private void SaveFile(              FileStream fsReader,             ref FileIndex FI,             string sDestDir )         {             // Read file name             byte[] bFileName = new byte[ FI.NameLength ];             int nRealRead = fsReader.Read( bFileName, 0, bFileName.Length );             if( nRealRead != bFileName.Length ) return;             string sFileName = Encoding.Unicode.GetString( bFileName );             sFileName = sDestDir + sFileName;             FileInfo fi = new FileInfo( sFileName );             // Open file to write             FileStream fsWriter = null;             try             {                 if( !fi.Exists )                 {                     fsWriter = new FileStream(                          sFileName,                          FileMode.CreateNew,                          FileAccess.ReadWrite,                         FileShare.None );                 }                 else                     fsWriter = new FileStream(                          sFileName,                          FileMode.Truncate,                          FileAccess.ReadWrite,                         FileShare.None );             }             catch(Exception err){                 System.Diagnostics.Debug.WriteLine( err.Message );                 return;             }                      // Init buffer               const int BUFFER_LENGTH = 1024;             byte[] bBuffer = new byte[BUFFER_LENGTH];             long lLeft = FI.FileLength;               // Copy file              do             {                 if( lLeft > BUFFER_LENGTH )                 {                     fsReader.Read( bBuffer, 0, BUFFER_LENGTH );                     fsWriter.Write( bBuffer, 0, BUFFER_LENGTH );                       lLeft -= BUFFER_LENGTH;                 }                 else                 {                     nRealRead = fsReader.Read( bBuffer, 0, (int)lLeft );                     fsWriter.Write( bBuffer, 0, nRealRead );                       lLeft -= nRealRead;                 }             }             while( lLeft > 0 );               // close file writer             fsWriter.Close();         }     }       /// <summary>     /// File index data structure     /// </summary>     public struct FileIndex     {         public long NameStartPos;         public long NameLength;         public long FileStartPos;         public long FileLength;           public static byte[] ConvertToBytes( ref FileIndex FI  )         {             byte[] bData = new byte[32];               Array.Copy( LongToBytes( FI.NameStartPos ), 0, bData, 0, 8 );             Array.Copy( LongToBytes( FI.NameLength ), 0, bData, 8, 8 );             Array.Copy( LongToBytes( FI.FileStartPos ), 0, bData, 16, 8 );             Array.Copy( LongToBytes( FI.FileLength ), 0, bData, 24, 8 );               return bData;         }           public static byte[] LongToBytes( long lValue )         {             byte[] bData = new byte[8];                  bData[0] = (byte)( ( lValue >> 56 ) & 0xFF);             bData[1] = (byte)( ( lValue >> 48 ) & 0xFF);             bData[2] = (byte)( ( lValue >> 40 ) & 0xFF);             bData[3] = (byte)( ( lValue >> 32 ) & 0xFF);             bData[4] = (byte)( ( lValue >> 24 ) & 0xFF);             bData[5] = (byte)( ( lValue >> 16 ) & 0xFF);             bData[6] = (byte)( ( lValue >> 8 ) & 0xFF);             bData[7] = (byte)(lValue & 0xFF);             return bData;         }           public static FileIndex ConvertToFileIndex( byte[] bData )         {             if( bData == null || bData.Length != 32 )                  throw new Exception( "Invalid parameters!" );               FileIndex FI = new FileIndex();             byte[] bBuffer = new byte[8];             Array.Copy( bData, 0, bBuffer, 0, 8 );             FI.NameStartPos = BytesToLong( bBuffer );             Array.Copy( bData, 8, bBuffer, 0, 8 );             FI.NameLength = BytesToLong( bBuffer );             Array.Copy( bData, 16, bBuffer, 0, 8 );             FI.FileStartPos = BytesToLong( bBuffer );             Array.Copy( bData, 24, bBuffer, 0, 8 );             FI.FileLength = BytesToLong( bBuffer );             return FI;         }           public static long BytesToLong( byte[] bData )         {             if( bData == null || bData.Length != 8 )                 throw new Exception( "Invalid parameters!" );               long lngValue = 0;             lngValue += bData[0];             lngValue = ( lngValue << 8 );             lngValue += bData[1];             lngValue = ( lngValue << 8 );             lngValue += bData[2];             lngValue = ( lngValue << 8 );             lngValue += bData[3];             lngValue = ( lngValue << 8 );             lngValue += bData[4];             lngValue = ( lngValue << 8 );             lngValue += bData[5];             lngValue = ( lngValue << 8 );             lngValue += bData[6];             lngValue = ( lngValue << 8 );             lngValue += bData[7];             return lngValue;         }     } }

　　其中类的操作参看clsComposeFiles这个类，而文件索引结构参看FileIndex这个Structure。

　　之后的调用就很简单，例如：

　　合成文件：

以下是引用片段： 　　clsComposeFiles myComposeFiles = new clsComposeFiles(); 　　myComposeFiles.AddFile( @"D:\Ship.exe" ); 　　myComposeFiles.AddFile( @"D:\LoginPage.JPG" ); 　　myComposeFiles.ComposeFiles( @"D:\Ship.dat" );

　　分解文件：

以下是引用片段： 　　clsComposeFiles myComposeFiles = new clsComposeFiles(); 　　myComposeFiles.DecomposeFile( @"D:\Ship.dat", @"E:\" );

　　以上代码由于写得比较急，细节处理并不是很完善，因此使用的时候要加以细化，甚至可以在我的基础上进行扩充。