Java读取(复制)文件

import   java.io.File; import   java.io.FileInputStream; import   java.io.FileOutputStream; import   java.io.FileNotFoundException; import   java.io.IOException; import   java.nio.channels.FileChannel; public   class   FileCopy   {     public   static   void   main(String[]   args)   {     String   fileDirectory= "D:/jdk/src/java/io/copy.txt ";             File   fromFile   =   new   File(fileDirectory);         if(!fromFile.exists())   {             System.out.printf( "File   to   copy,   %s,   does   not   exist. ",fromFile.getAbsolutePath());         }           File   toFile   =   createBackupFile(fromFile);         FileInputStream   inFile   =   null;         FileOutputStream   outFile   =   null;         try   {             inFile   =   new   FileInputStream(fromFile);               outFile   =   new   FileOutputStream(toFile);         }   catch(FileNotFoundException   e)   {             e.printStackTrace(System.err);             assert   false;         }         FileChannel   inChannel   =   inFile.getChannel();                 FileChannel   outChannel   =   outFile.getChannel();           try   {             int   bytesWritten   =   0;             long   byteCount   =   inChannel.size();             while(bytesWritten