ObjectInputStream 不多次读取

Posted 2023-03-30

【中文标题】ObjectInputStream 不多次读取

【英文标题】：ObjectInputStream Not Reading More Than Once

【发布时间】：2016-02-24 11:09:43

【问题描述】：

我一直在尝试制作一个两人多米诺骨牌游戏。现在，我希望玩家 1 的动作在玩家 2 的屏幕上被模仿，仅此而已。如果我启动播放器 1 的屏幕并移动一些多米诺骨牌，当我启动播放器 2 的屏幕时会出现更改。但从此以后的任何动作都没有改变。这里有什么问题？

public class Server 

    private static ObjectOutputStream output;
    private static ObjectInputStream input;
    private static ServerSocket server;
    private static Socket connection;
    private static Player1 p1Game;
    private static final int port = 12345;

    public static void main(String[] args)
        p1Game = new Player1();
        Thread p1GameThread = new Thread(p1Game);
        p1GameThread.run();
        startServer();
    

    private static void startServer() 
        p1Game.setStatusMessage("Starting server...");
        try 
            server = new ServerSocket(port, 100);
            p1Game.setStatusMessage("Awaiting connection from player 2...");
            connection = server.accept();
            output = new ObjectOutputStream(connection.getOutputStream());
            output.flush();
            p1Game.setStatusMessage("");
            while(true)
                ArrayList <CDomino> sendDominoes = p1Game.getP1Dominoes();
                System.out.println("N" + sendDominoes.get(0).getX());
                output.writeObject(sendDominoes);
                output.flush();
                Thread.sleep(1000);

                
         catch (Exception e) e.printStackTrace();
    


public class Client 

    private static ObjectOutputStream output;
    private static ObjectInputStream input;
    private static Socket client;
    private static Player2 p2Game;
    private static final String serverAddress = "127.0.0.1";
    private static final int serverPort = 12345;

    public static void main(String[] args)
        p2Game = new Player2();
        Thread p2GameThread = new Thread(p2Game);
        p2GameThread.run();
        connect();
    

    private static void connect() 
        p2Game.setStatusMessage("Attempting to connect to " + serverAddress + " on port " + serverPort + "...");
        try
            client = new Socket( InetAddress.getByName(serverAddress), serverPort);
            input = new ObjectInputStream(client.getInputStream());
            p2Game.setStatusMessage("");
            while (true)
                p2Game.setP1Dominoes((ArrayList<CDomino>) input.readObject());
         catch (Exception e) e.printStackTrace();
    


public class CDomino implements Serializable
    private static final long serialVersionUID = 345L;
    private int xC;
    private int yC;
    private int rotation;

    private Color playerColorDark;
    private Color playerColorLight;
    private int player;
    private int topSpots;
    private int bottomSpots;

    private final int[][] spotMatrix = 
               0, 0, 0, 0, 0, 0, 0, 0, 0 ,
               0, 0, 0, 0, 1, 0, 0, 0, 0 , 
               1, 0, 0, 0, 0, 0, 0, 0, 1 , 
               1, 0, 0, 0, 1, 0, 0, 0, 1 , 
               1, 0, 1, 0, 0, 0, 1, 0, 1 , 
               1, 0, 1, 0, 1, 0, 1, 0, 1 , 
               1, 0, 1, 1, 0, 1, 1, 0, 1 
              ;

    private final int[][] topGridMatrix = 
            -12, -30, -2, -30, 8, -30,
            -12, -20, -2, -20, 8, -20,
            -12, -10, -2, -10, 8, -10
    ;

    private final int[][] bottomGridMatrix = 
            -12, 5, -2, 5, 8, 5,
            -12, 15, -2, 15, 8, 15,
            -12, 25, -2, 25, 8, 25,
    ;

    public CDomino(int x, int y, int angle, int color)
        xC = x;
        yC = y;
        rotation = angle;
        topSpots = new Random().nextInt(7);
        bottomSpots = new Random().nextInt(7);

        if (color == 2)
            playerColorLight = new Color(60, 180, 60);
            playerColorDark = new Color(0, 100, 0);
        
        else
            playerColorLight = new Color(120, 120, 255);
            playerColorDark = new Color(0, 0, 200);
        
    

    public boolean isInside(int x, int y)
        if (rotation == 0 | rotation == 180) return (x > xC-15) && (x < xC+15) && (y > yC-30) && (y < yC+30);
        else return (x > xC-30) && (x < xC+30) && (y > yC-15) && (y < yC+15);
    

    public int getX()return xC;
    public int getY()return yC;
    public void setPosition(int x, int y)
        xC = x;
        yC = y;
    

    public void rotate()
        if (rotation == 270) rotation = 0;
        else rotation += 90;
    

    //dimensions are 36x71px
    public void draw(Graphics g, int viewingPlayer)

        g.setColor(Color.WHITE);
        if (rotation == 0 || rotation == 180)
            g.fillRect(xC-18, yC-36, 36, 71);
            g.setColor(playerColorDark);
            g.drawRoundRect(xC-18, yC-36, 36, 71, 5, 5);
            g.setColor(playerColorLight);
            g.drawRoundRect(xC-19, yC-37, 38, 73, 5, 5);
            g.setColor(Color.GRAY);
            g.drawLine(xC-13, yC, xC+14, yC);
        
        else 
            g.fillRect(xC-36, yC-18, 71, 36);
            g.setColor(playerColorDark);
            g.drawRoundRect(xC-36, yC-18, 71, 36, 5, 5);
            g.setColor(playerColorLight);
            g.drawRoundRect(xC-37, yC-19, 73, 38, 5, 5);
            g.setColor(Color.GRAY);
            g.drawLine(xC, yC-13, xC, yC+14);
        

        g.setColor(Color.RED);
        if (isInOpponentHomeArea(yC, viewingPlayer)) return;
        for (int i = 0; i < 9; i++)
            if (spotMatrix[topSpots][i] == 1)
                if (rotation == 0)
                    g.fillOval(xC+topGridMatrix[i][0]-1, yC+topGridMatrix[i][1]-1, 7, 7);
                else if (rotation == 90)
                    g.fillOval(xC-topGridMatrix[i][1]-7, yC+topGridMatrix[i][0]-1, 7, 7);
                else if (rotation == 180)
                    g.fillOval(xC-topGridMatrix[i][0]-6, yC-topGridMatrix[i][1]-6, 7, 7);
                else if (rotation == 270)
                    g.fillOval(xC+topGridMatrix[i][1]-1, yC-topGridMatrix[i][0]-7, 7, 7);
            
        

        for (int i = 0; i < 9; i++)
            if (spotMatrix[bottomSpots][i] == 1)
                if (rotation == 0)
                    g.fillOval(xC+bottomGridMatrix[i][0]-1, yC+bottomGridMatrix[i][1]-1, 7, 7);
                else if (rotation == 90)
                    g.fillOval(xC-bottomGridMatrix[i][1]-7, yC+bottomGridMatrix[i][0]-1, 7, 7);
                else if (rotation == 180)
                    g.fillOval(xC-bottomGridMatrix[i][0]-6, yC-bottomGridMatrix[i][1]-6, 7, 7);
                else if (rotation == 270)
                    g.fillOval(xC+bottomGridMatrix[i][1]-1, yC-bottomGridMatrix[i][0]-7, 7, 7);
            
        
    

    private boolean isInOpponentHomeArea(int y, int player)
        if (player == 1) return (y < 125);
        else return (y > 651);
    



public class Player1 extends JApplet implements KeyListener, MouseListener, MouseMotionListener, Runnable

    private ArrayList<CDomino> p1Dominoes;
    private ArrayList<CDomino> p2Dominoes;
    private CDomino activeDomino;
    private String statusMessage;

    public Player1()
    

    public void run()
        setFocusable(true);
        addKeyListener(this);
        addMouseListener(this);
        addMouseMotionListener(this);
        initialize();
        showWindow();
    

    public void initialize()
        statusMessage = "Initializing window...";
        p1Dominoes = new ArrayList<CDomino>();
        p2Dominoes = new ArrayList<CDomino>();
        for (int i = 0; i < 7; i++)
            p1Dominoes.add(new CDomino(85 + i*100, 715, 0, 1));
            p2Dominoes.add(new CDomino(85 + i*100, 60, 0, 2));
        
        activeDomino = null;
    

    public void paint(Graphics g)

        Image img = createImage(getSize().width, getSize().height);
        Graphics gimg = img.getGraphics();
        gimg.setColor(new Color(235, 235, 235));
        gimg.clearRect(0, 0, getSize().width, getSize().height);
        gimg.fillRect(0, 0, 800, 800);

        gimg.setColor(Color.MAGENTA);
        gimg.drawLine(0, 125, 800, 125);
        gimg.drawLine(0, 650, 800, 650);
        gimg.setColor(new Color(200, 255, 200));
        gimg.fillRect(0, 0, 800, 125);
        gimg.setColor(new Color(180, 230, 255));
        gimg.fillRect(0, 651, 800, 125);

        gimg.setColor(Color.RED);
        gimg.setFont(new Font("SansSerif", Font.BOLD, 18));
        gimg.drawString(statusMessage, 10, 630);

        for (CDomino domino : p1Dominoes) domino.draw(gimg, 1);
        for (CDomino domino : p2Dominoes) domino.draw(gimg, 1);


        g.drawImage(img, 0, 0, null);
    

    public void setStatusMessage(String message)
        statusMessage = message;
        repaint();
    

    public ArrayList<CDomino> getP1Dominoes()
        return p1Dominoes;
    

    public void mouseDragged(MouseEvent e) 
        if (e.isMetaDown()) return;
        for (CDomino domino : p1Dominoes)
            if ((domino.isInside(e.getX(), e.getY()) && activeDomino == null) || (activeDomino == domino))
                    activeDomino = domino;
                    domino.setPosition(e.getX(), e.getY());
                    repaint();
            
        
    

    public void mouseMoved(MouseEvent e) 
        // TODO Auto-generated method stub

    

    public void mouseClicked(MouseEvent e) 
        //if (!e.isMetaDown()) return;
        tryRotate(e);
    

    public void mouseEntered(MouseEvent e) 
        // TODO Auto-generated method stub

    

    public void mouseExited(MouseEvent e) 
        // TODO Auto-generated method stub

    

    public void mousePressed(MouseEvent e) 
        

    private void tryRotate(MouseEvent e) 
        if (!SwingUtilities.isRightMouseButton(e)) return;
        for (CDomino domino : p1Dominoes)
            if (domino.isInside(e.getX(), e.getY()))
                domino.rotate();
                repaint();
            
        
    

    public void mouseReleased(MouseEvent e) 
        activeDomino = null;
    

    public void keyPressed(KeyEvent e) 
    

    public void keyReleased(KeyEvent e) 

    

    public void keyTyped(KeyEvent e) 

    

    public void showWindow()
        JFrame application = new JFrame("Dominoes - Player 1 (Server)");
        application.add(this);
        application.setDefaultCloseOperation(3);
        application.setSize(800, 800);
        application.setLocationRelativeTo(null);
        application.setVisible(true);
        application.setResizable(false);
    

（Player2.java 非常相似，但有一个 setP1Dominoes() 确实调用了 repaint()。）

【参考方案1】：

您需要查找ObjectOutputStream.reset() 以及它的用途。在每个writeObject() 之后调用它。

【参考方案2】：

我看到的问题在这里：

public void paint(Graphics g)
    Image img = createImage(...);
    //...

因此，每次调用都会创建另一个图像。 - 将 Image img 的声明设为类变量并在别处初始化，以便绘制从获取 Graphics 对象开始。

有点奇怪 - 客户端的主要调用：

p1GameThread.run()

这不是启动线程的正确方式；这是通过调用 Thread.start() 来完成的。但是运行方法应该监听对方的套接字消息。

不要使用睡眠来确定另一次发送的时间。侦听器检测表上的操作何时完成：这是发送的时间。

不要使用两个不同的 Player 类 - 这会造成越来越多的陷阱。下棋（除了设置第一步）是对称的，所以一个 Player 类就足够了。 - 可能需要某种“裁判”来同步动作 - 因为一个玩家不能连续两次移动 - 将其添加到双方都存在的另一个类中。

【讨论】：

都是正确的，但这里没有解决实际问题。