/*
 * 根據不同的事件做處理
 * */
protected void process(SelectionKey key) throws IOException{
    // 接收請求
    if (key.isAcceptable()) {
        ServerSocketChannel server = (ServerSocketChannel) key.channel();
        SocketChannel channel = server.accept();
        channel.configureBlocking(false);
        channel.register(selector, SelectionKey.OP_READ);
    }
    // 讀資訊
    else if (key.isReadable()) {
        SocketChannel channel = (SocketChannel) key.channel(); 
        int count = channel.read(buffer); 
        if (count > 0) { 
            buffer.flip(); 
            CharBuffer charBuffer = decoder.decode(buffer); 
            name = charBuffer.toString(); 
            SelectionKey sKey = channel.register(selector, SelectionKey.OP_WRITE); 
            sKey.attach(name); 
        } else { 
            channel.close(); 
        } 
        buffer.clear(); 
    }
    // 寫事件
    else if (key.isWritable()) {
        SocketChannel channel = (SocketChannel) key.channel(); 
        String name = (String) key.attachment(); 
        
        ByteBuffer block = encoder.encode(CharBuffer.wrap("Hello " + name)); 
        if(block != null)
        {
            channel.write(block);
        }
        else
        {
            channel.close();
        }

     }
}