0

我正在尝试实现一个保存功能，它将保存游戏的当前状态。这是我的代码：

public class MyGame extends javax.swing.JFrame implements Serializable {

     private void saveGame(java.awt.event.ActionEvent evt) {                                               

        JFileChooser fileChooser = new JFileChooser();
        int user_command = fileChooser.showSaveDialog(this);
        if (user_command == JFileChooser.APPROVE_OPTION) {
            try {
                File file = fileChooser.getSelectedFile();
                ObjectOutputStream outputStream = new ObjectOutputStream(new FileOutputStream(file));
                MyGame saveFile = this;

                outputStream.writeObject(saveFile);
                outputStream.close();

            } catch (FileNotFoundException e) {
            } catch (IOException e) {System.out.println("ioexception");}
        }

    }

生成的保存文件为 0 字节。我尝试调试程序，它在 outputStream.writeObject(saveFile) 行上崩溃。我究竟做错了什么？

编辑：它报告 IOException

ioexception
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at javax.swing.plaf.synth.SynthLookAndFeel.paintRegion(SynthLookAndFeel.java:386)
    at javax.swing.plaf.synth.SynthLookAndFeel.update(SynthLookAndFeel.java:350)
    at javax.swing.plaf.synth.SynthRootPaneUI.update(SynthRootPaneUI.java:77)
    at javax.swing.JComponent.paintComponent(JComponent.java:752)
    at javax.swing.JComponent.paintToOffscreen(JComponent.java:5128)
    at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1479)
    at javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1410)
    at javax.swing.RepaintManager.paint(RepaintManager.java:1224)
    at javax.swing.JComponent.paint(JComponent.java:1015)
    at java.awt.GraphicsCallback$PaintCallback.run(GraphicsCallback.java:21)
    at sun.awt.SunGraphicsCallback.runOneComponent(SunGraphicsCallback.java:60)
    at sun.awt.SunGraphicsCallback.runComponents(SunGraphicsCallback.java:97)
    at java.awt.Container.paint(Container.java:1780)
    at java.awt.Window.paint(Window.java:3375)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:796)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:713)
    at javax.swing.RepaintManager.seqPaintDirtyRegions(RepaintManager.java:693)
    at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:125)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:641)
    at java.awt.EventQueue.access$000(EventQueue.java:84)
    at java.awt.EventQueue$1.run(EventQueue.java:602)
    at java.awt.EventQueue$1.run(EventQueue.java:600)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:611)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at javax.swing.plaf.synth.SynthLookAndFeel.paintRegion(SynthLookAndFeel.java:386)
    at javax.swing.plaf.synth.SynthLookAndFeel.update(SynthLookAndFeel.java:350)
    at javax.swing.plaf.synth.SynthPanelUI.update(SynthPanelUI.java:94)
    at javax.swing.JComponent.paintComponent(JComponent.java:752)
    at javax.swing.JComponent.paint(JComponent.java:1029)
    at javax.swing.JComponent.paintToOffscreen(JComponent.java:5124)
    at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1479)
    at javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1410)
    at javax.swing.RepaintManager.paint(RepaintManager.java:1224)
    at javax.swing.JComponent._paintImmediately(JComponent.java:5072)
    at javax.swing.JComponent.paintImmediately(JComponent.java:4882)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:785)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:713)
    at javax.swing.RepaintManager.seqPaintDirtyRegions(RepaintManager.java:693)
    at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:125)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:641)
    at java.awt.EventQueue.access$000(EventQueue.java:84)
    at java.awt.EventQueue$1.run(EventQueue.java:602)
    at java.awt.EventQueue$1.run(EventQueue.java:600)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:611)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at javax.swing.plaf.synth.SynthLookAndFeel.paintRegion(SynthLookAndFeel.java:386)
    at javax.swing.plaf.synth.SynthLookAndFeel.update(SynthLookAndFeel.java:350)
    at javax.swing.plaf.synth.SynthPanelUI.update(SynthPanelUI.java:94)
    at javax.swing.JComponent.paintComponent(JComponent.java:752)
    at javax.swing.JComponent.paint(JComponent.java:1029)
    at javax.swing.JComponent.paintToOffscreen(JComponent.java:5124)
    at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1479)
    at javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1410)
    at javax.swing.RepaintManager.paint(RepaintManager.java:1224)
    at javax.swing.JComponent._paintImmediately(JComponent.java:5072)
    at javax.swing.JComponent.paintImmediately(JComponent.java:4882)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:785)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:713)
    at javax.swing.RepaintManager.seqPaintDirtyRegions(RepaintManager.java:693)
    at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:125)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:641)
    at java.awt.EventQueue.access$000(EventQueue.java:84)
    at java.awt.EventQueue$1.run(EventQueue.java:602)
    at java.awt.EventQueue$1.run(EventQueue.java:600)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:611)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at javax.swing.plaf.synth.SynthLookAndFeel.paintRegion(SynthLookAndFeel.java:386)
    at javax.swing.plaf.synth.SynthLookAndFeel.update(SynthLookAndFeel.java:350)
    at javax.swing.plaf.synth.SynthPanelUI.update(SynthPanelUI.java:94)
    at javax.swing.JComponent.paintComponent(JComponent.java:752)
    at javax.swing.JComponent.paint(JComponent.java:1029)
    at javax.swing.JComponent.paintToOffscreen(JComponent.java:5124)
    at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1479)
    at javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1410)
    at javax.swing.RepaintManager.paint(RepaintManager.java:1224)
    at javax.swing.JComponent._paintImmediately(JComponent.java:5072)
    at javax.swing.JComponent.paintImmediately(JComponent.java:4882)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:785)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:713)
    at javax.swing.RepaintManager.seqPaintDirtyRegions(RepaintManager.java:693)
    at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:125)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:641)
    at java.awt.EventQueue.access$000(EventQueue.java:84)
    at java.awt.EventQueue$1.run(EventQueue.java:602)
    at java.awt.EventQueue$1.run(EventQueue.java:600)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:611)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at javax.swing.plaf.synth.SynthLookAndFeel.paintRegion(SynthLookAndFeel.java:386)
    at javax.swing.plaf.synth.SynthLookAndFeel.update(SynthLookAndFeel.java:350)
    at javax.swing.plaf.synth.SynthPanelUI.update(SynthPanelUI.java:94)
    at javax.swing.JComponent.paintComponent(JComponent.java:752)
    at javax.swing.JComponent.paint(JComponent.java:1029)
    at javax.swing.JComponent.paintToOffscreen(JComponent.java:5124)
    at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1479)
    at javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1410)
    at javax.swing.RepaintManager.paint(RepaintManager.java:1224)
    at javax.swing.JComponent._paintImmediately(JComponent.java:5072)
    at javax.swing.JComponent.paintImmediately(JComponent.java:4882)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:785)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:713)
    at javax.swing.RepaintManager.seqPaintDirtyRegions(RepaintManager.java:693)
    at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:125)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:641)
    at java.awt.EventQueue.access$000(EventQueue.java:84)
    at java.awt.EventQueue$1.run(EventQueue.java:602)
    at java.awt.EventQueue$1.run(EventQueue.java:600)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:611)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at javax.swing.plaf.synth.SynthLookAndFeel.paintRegion(SynthLookAndFeel.java:386)
    at javax.swing.plaf.synth.SynthLookAndFeel.update(SynthLookAndFeel.java:350)
    at javax.swing.plaf.synth.SynthPanelUI.update(SynthPanelUI.java:94)
    at javax.swing.JComponent.paintComponent(JComponent.java:752)
    at javax.swing.JComponent.paint(JComponent.java:1029)
    at javax.swing.JComponent.paintToOffscreen(JComponent.java:5124)
    at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1479)
    at javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1410)
    at javax.swing.RepaintManager.paint(RepaintManager.java:1224)
    at javax.swing.JComponent._paintImmediately(JComponent.java:5072)
    at javax.swing.JComponent.paintImmediately(JComponent.java:4882)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:785)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:713)
    at javax.swing.RepaintManager.seqPaintDirtyRegions(RepaintManager.java:693)
    at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:125)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:641)
    at java.awt.EventQueue.access$000(EventQueue.java:84)
    at java.awt.EventQueue$1.run(EventQueue.java:602)
    at java.awt.EventQueue$1.run(EventQueue.java:600)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:611)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at javax.swing.plaf.synth.SynthLookAndFeel.paintRegion(SynthLookAndFeel.java:386)
    at javax.swing.plaf.synth.SynthLookAndFeel.update(SynthLookAndFeel.java:350)
    at javax.swing.plaf.synth.SynthPanelUI.update(SynthPanelUI.java:94)
    at javax.swing.JComponent.paintComponent(JComponent.java:752)
    at javax.swing.JComponent.paint(JComponent.java:1029)
    at javax.swing.JComponent.paintToOffscreen(JComponent.java:5124)
    at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1479)
    at javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1410)
    at javax.swing.RepaintManager.paint(RepaintManager.java:1224)
    at javax.swing.JComponent._paintImmediately(JComponent.java:5072)
    at javax.swing.JComponent.paintImmediately(JComponent.java:4882)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:785)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:713)
    at javax.swing.RepaintManager.seqPaintDirtyRegions(RepaintManager.java:693)
    at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:125)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:641)
    at java.awt.EventQueue.access$000(EventQueue.java:84)
    at java.awt.EventQueue$1.run(EventQueue.java:602)
    at java.awt.EventQueue$1.run(EventQueue.java:600)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:611)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at javax.swing.plaf.synth.SynthLookAndFeel.paintRegion(SynthLookAndFeel.java:386)
    at javax.swing.plaf.synth.SynthLookAndFeel.update(SynthLookAndFeel.java:350)
    at javax.swing.plaf.synth.SynthPanelUI.update(SynthPanelUI.java:94)
    at javax.swing.JComponent.paintComponent(JComponent.java:752)
    at javax.swing.JComponent.paint(JComponent.java:1029)
    at javax.swing.JComponent.paintToOffscreen(JComponent.java:5124)
    at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1479)
    at javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1410)
    at javax.swing.RepaintManager.paint(RepaintManager.java:1224)
    at javax.swing.JComponent._paintImmediately(JComponent.java:5072)
    at javax.swing.JComponent.paintImmediately(JComponent.java:4882)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:785)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:713)
    at javax.swing.RepaintManager.seqPaintDirtyRegions(RepaintManager.java:693)
    at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:125)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:641)
    at java.awt.EventQueue.access$000(EventQueue.java:84)
    at java.awt.EventQueue$1.run(EventQueue.java:602)
    at java.awt.EventQueue$1.run(EventQueue.java:600)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:611)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
4

2 回答 2

1

为您的游戏创建一个 GameState 类（实现可序列化）并保存它。您在尝试序列化 JFrame 时遇到了异常，并且从那个怪物的外观来看，您不会很快找到解决方法。

// GameState.java
class GameState implements Serializable
{
    public int score;
    public int numFoos;

    // etc etc
}

// MyGame.java
public class MyGame extends javax.swing.JFrame
{
    private GameState myState;

    private void saveGame(java.awt.event.ActionEvent evt)
    {
        JFileChooser fileChooser = new JFileChooser();
        int user_command = fileChooser.showSaveDialog(this);
        if (user_command == JFileChooser.APPROVE_OPTION) {
            try
            {
                File file = fileChooser.getSelectedFile();
                ObjectOutputStream outputStream = new ObjectOutputStream(new FileOutputStream(file));

                outputStream.writeObject(myState);
                outputStream.close();

            } 
            catch (FileNotFoundException e) {System.out.println("blaaagrgr");}
            catch (IOException e) {System.out.println("ioexception");}
        }
    }
}
于 2012-11-08T21:56:53.263 回答
0

您应该记录您的异常，而不是默默地忽略它们。我的猜测是你有一些字段MyGame不是Serializable或者它本身包含一些不能完全序列化的东西。

不过，您可能不应该序列化整个JFrame. 这不是保存游戏的好方法，因为序列化将与 Swing 的未来版本不兼容。

于 2012-11-08T21:47:21.277 回答