如何通过套接字发送/更新对象？

Question

我在编程时遇到了相当烦人的问题。我是 Java 套接字的新手，并尽我所能学习，所以我提前道歉。无论如何，根据我当前程序的设置方式，我有一个在屏幕上移动的立方体，当你按下 Q 键时，它会将立方体的 x 和 y 坐标发送到服务器。第一次发送坐标时，它就像一个魅力；但是，第二次点击 Q 时，您会收到一条可爱的错误消息："java.io.StreamCorruptedException: invalid stream header: 71007E00"。

这是我的代码：

SnakeServer 类

public class SnakeServer {
    public static JFrame frame = new JFrame();
    public static ArrayList<Integer> alist = new ArrayList<Integer>();

    public static void main(String[] args) {
        runServer();
    }
    public static void runServer() {
        try {
            Connection connection = new Connection();
            connection.start();
        }
        catch (IOException e) {
            e.printStackTrace();
        }
    }
}

连接类

public class Connection extends Thread {

    private volatile BufferedReader br;
    private volatile PrintWriter pw;
    private volatile ObjectInputStream oos;
    private Socket s;
    private ServerSocket ss;

    Connection() throws IOException
    {
        ss = new ServerSocket(12355);
        s = ss.accept();
        //s.setKeepAlive(true);
        br = new BufferedReader(new InputStreamReader(s.getInputStream()));
        pw = new PrintWriter(s.getOutputStream(), true);
    }

    public void run()
    {
        try
        {
            while(true) {
                System.out.print("Server has connected!\n");
                oos = new ObjectInputStream(s.getInputStream());
                Object obj = oos.readObject();
                alist = (ArrayList<Integer>) obj;
                System.out.println(alist.get(1));
                System.out.println(alist.get(0));

            }
        }
        catch(IOException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException ex) {
            Logger.getLogger(Connection.class.getName()).log(Level.SEVERE, null, ex);
        }     
    }
}

SnakeGame 类

public class SnakeGame extends JPanel implements ActionListener  {
    public static Timer timer;
    public static int x = 100;
    public static int y = 100;
    public static boolean left,right,up,down;
    public static Socket skt;
    public static DataInputStream in;
    public static ObjectOutputStream out;
    public static ArrayList<Integer> set = new ArrayList<Integer>();

    public SnakeGame() {
        timer = new Timer(100, this);
        timer.start();
        right = true;
        setupConnection();
    }
    public void setupConnection() {
        try {
            skt = new Socket("localhost", 12355);
            out = new ObjectOutputStream(skt.getOutputStream());
            in = new DataInputStream(skt.getInputStream());
        }
        catch(IOException e) {
            e.printStackTrace();
        }
    }
    public void actionPerformed(ActionEvent e) {
        repaint();
        move();
        //connect();
    }
    public void move() {
        if(right) {
            x += 25;
        }
        if(left) {
            x -= 25;
        }
        if(up) {
            y -= 25;
        }
        if(down) {
            y += 25;
        }
        if(x > 400) {
            x = 0;
        }
        if(x < 0) {
            x = 400;
        }
        if(y > 400) {
            y = 0;
        }
        if(y < 0) {
            y = 400;
        }
    }
    public void paint(Graphics g) {
        super.paint(g);
        g.fillRect(x, y, 25, 25);
    }
    public static void connect() {
        set.add(0, x);
        set.add(1, y);
        try {
            //skt.setKeepAlive(true);
            out.writeObject(set);
            out.flush();
        }
        catch(Exception e) {
            e.printStackTrace();
        }
    }
}

Answer 1

摆脱 BufferedReader（未使用）、PrintWriter（未使用）和 DataInputStream（未使用）。如果您正在使用序列化，请在两个方向上将其用于所有内容。按此顺序构造一个 ObjectOutputStream 和一个 ObjectInputStream，并在套接字的整个生命周期中使用它们。由于对象流具有在构造时读取和写入的标头，因此如果不格外小心，每个套接字构造多个流就无法真正工作：而且没有必要。