public class FileChannelDemo {

    public static void main(String[] args) {
        fileChannelDemo();
    }

    private static void fileChannelDemo() {
        try {
            //處理中文亂碼
            Charset gbk = Charset.forName("GBK");
            CharsetDecoder dbkDecoder = gbk.newDecoder();

            //1- 定義一個緩衝區
            ByteBuffer buff = ByteBuffer.allocate(1024);

            CharBuffer charBuffer = CharBuffer.allocate(1024);

            //2- 通過檔案輸入流獲得檔案通道物件（讀取操作）
            FileInputStream fileInputStream = new FileInputStream("e://a.txt");
            FileChannel inChannel = fileInputStream.getChannel();

            //3- 通過檔案輸出流追加檔案內容
            FileOutputStream fileOutputStream = new FileOutputStream("e://b.txt",true);

            FileChannel outChannel = fileOutputStream.getChannel();

            //4- 讀取資料
            buff.clear();
            int len = inChannel.read(buff);
            System.out.println("len == " + len);
            buff.flip();
            dbkDecoder.decode(buff,charBuffer,false);
            String data = new String(charBuffer.array(),0,len);
            System.out.println(data);

            //5- 關閉輸入流
            inChannel.close();

            //6- 寫資料
            buff.flip();
            buff.clear();
            buff = ByteBuffer.wrap(data.getBytes("GBK"),0,data.length());
            outChannel.write(buff);

            //7- 關閉輸出流
            outChannel.close();
        } catch (Exception e) {

        }

    }

}