java - 如何将对象的 ArrayList(ArrayLists) 转换为字节数组？

Question

我目前有一个 java 程序，需要在客户端和服务器之间进行快速通信。在尝试了 TCP 和 RMI 之后，我决定使用 UDP，这对我的目的来说都太慢了。

我有多个ArrayList，存储在一个ArrayList中，然后发送到服务器。这种方法在TCP和RMI中运行良好，但在UDP中需要改为字节。

ArrayList<Object> array = new ArrayList<Object>();
array.add(arrayList1);
array.add(arrayList2);
array.add(arrayList3);
array.add(arrayList4);
array.add(arrayList5);
array.add(arrayList6);

// Convert the ArrayList to bytes, then send to client

添加到正在发送给客户端的 ArrayList 的每个 ArrayList 都包含对象，并且每个 ArrayList 包含不同类型的对象。大多数 ArrayList 包含由我创建的类生成的对象，但我认为没有必要显示它们。

我在互联网上搜索了将 ArrayList 的 ArrayList 转换为字节的答案，但是 .getBytes() 方法对 ArrayList 或其中的对象不起作用。

如果您需要我正在使用的代码的更多示例，请随时询问。上面的代码不是我的真实代码(因为编号 ArrayLists 会非常困惑)，但它是我想要实现的目标的准确表示。

谢谢。

Answer 1

要在 UDP 中执行，它将是这样的:

查看服务器:

public static byte[] serialize(Object obj) throws IOException {
    ByteArrayOutputStream out = new ByteArrayOutputStream();
    ObjectOutputStream os = new ObjectOutputStream(out);
    os.writeObject(obj);
    return out.toByteArray();
}
    public static Object deserialize(byte[] data) throws IOException,   ClassNotFoundException {
    ByteArrayInputStream in = new ByteArrayInputStream(data);
    ObjectInputStream is = new ObjectInputStream(in);
    return is.readObject();
}
public static void main(String[] args) {
    new Server();
    byte[] receiveData = new byte[65536];
    byte[] sendData = new byte[65536];
    try (DatagramSocket datagramSocket = new DatagramSocket(3333);) {
        Board.start = true;
        while (true) {
            try {
                DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
                datagramSocket.receive(receivePacket);
                ArrayList<Object> object1 = (ArrayList)deserialize(receivePacket.getData());
                InetAddress address = receivePacket.getAddress();
                int port = receivePacket.getPort();
                ArrayList<Object> array = new ArrayList<Object>();
                array.add(arrayList1);
                array.add(arrayList2);
                array.add(arrayList3);
                array.add(arrayList4);
                array.add(arrayList5);
                array.add(arrayList6);
                sendData = serialize(array);
                DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, address, port);
                datagramSocket.send(sendPacket);
            } catch (ClassNotFoundException e) {
                e.printStackTrace();
            }



        }

    } catch (IOException e) {
        e.printStackTrace();
    }
}

在客户看来:

public static byte[] serialize(Object obj) throws IOException {
    ByteArrayOutputStream out = new ByteArrayOutputStream();
    ObjectOutputStream os = new ObjectOutputStream(out);
    os.writeObject(obj);
    return out.toByteArray();
}
public static Object deserialize(byte[] data) throws IOException, ClassNotFoundException {
    ByteArrayInputStream in = new ByteArrayInputStream(data);
    ObjectInputStream is = new ObjectInputStream(in);
    return is.readObject();
}
public static void main(String[] args) {
    new Client();
    try {
        DatagramSocket clientSocket = new DatagramSocket();
        byte[] sendData = new byte[65536];
        byte[] receiveData = new byte[65536];

        while (true) {
            try {
                ArrayList<Object> fromUser = new ArrayList<Object>();
                fromUser.add(arrayList1);
                fromUser.add(arrayList2);
                sendData = serialize(fromUser);
                InetAddress address = InetAddress.getByName("localhost");
                DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, address, 3333);
                clientSocket.send(sendPacket);

                DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
                clientSocket.receive(receivePacket);
                ArrayList<Object> object = (ArrayList)deserialize(receivePacket.getData());
                arrayList1 = (ArrayList<Object>)object.get(0);
            } catch (ClassNotFoundException e) {
                e.printStackTrace();
            }   
        }
    } catch (UnknownHostException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    } catch (IOException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    }
}