try {

            //创建输入通道

            FileInputStream fis = new FileInputStream("F:/iotest/readfile.txt");

            FileChannel readChannel = fis.getChannel();

            //创建缓冲区

            ByteBuffer buffer = ByteBuffer.allocate();

            //创建输出通道

            FileOutputStream fos = new FileOutputStream("F:/iotest/filewrite.txt");

            FileChannel writeChannel = fos.getChannel();

            while (true) {

                buffer.clear();

                //将文件内容读到缓冲区中

                int mark = readChannel.read(buffer);

                if (mark==-) {

                    break;

                }

                buffer.flip();

                writeChannel.write(buffer);

            }

        } catch (FileNotFoundException e) {

            e.printStackTrace();

        } catch (IOException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        }