long start = System.currentTimeMillis();

         FileInputStream fis = new FileInputStream("g:/29.mp4");

         FileOutputStream fos = new FileOutputStream("g:/30.mp4");

         //获取通道

         FileChannel inChannel = fis.getChannel();

         FileChannel outChannel = fos.getChannel();

         //分配指定大小缓冲区

         ByteBuffer buf = ByteBuffer.allocate(1024);

         //将通道中的数据存入缓冲区

         while (inChannel.read(buf) != -1){

             buf.flip();

             //将缓冲区的数据写入到通道中

             outChannel.write(buf);

             buf.clear();//清空缓冲区

         }

         outChannel.close();

         inChannel.close();

         fis.close();

         fos.close();

         long end = System.currentTimeMillis();

         System.out.println("消耗的时间为：" + (end - start));//

         long start = System.currentTimeMillis();

         FileChannel inChannel = FileChannel.open(Paths.get("g:/29.mp4"), StandardOpenOption.READ);

         FileChannel outChannel = FileChannel.open(Paths.get("g:/30.mp4"), StandardOpenOption.WRITE,StandardOpenOption.READ, StandardOpenOption.CREATE);

         //内存映射文件

         MappedByteBuffer inMappedBuf = inChannel.map(FileChannel.MapMode.READ_ONLY,0,inChannel.size());

         MappedByteBuffer outMappedBuf = outChannel.map(FileChannel.MapMode.READ_WRITE,0,inChannel.size());

         //直接对缓冲区进行数据的读写操作

         byte[] dst = new byte[inMappedBuf.limit()];

         inMappedBuf.get(dst);

         outMappedBuf.put(dst);

         inChannel.close();

         outChannel.close();

         long  end = System.currentTimeMillis();

         System.out.println("消耗的时间为：" + (end - start));//