使用非直接缓冲区与直接缓冲区进行文件的复制（基于Channel）

一、利用通道完成文件的复制(非直接缓冲区)

   

         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));//

二 、使用直接缓冲区完成文件的复制（内存映射）

         

         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));//