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ObjectOutputStream writeObject()方法返回空文件
EN

Stack Overflow用户
提问于 2012-11-09 05:40:24
回答 2查看 1.3K关注 0票数 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。下面是我的代码:

代码语言:javascript
复制
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");}
        }

    }             

结果保存的文件是0字节。我尝试调试该程序,但它在outputStream.writeObject(saveFile)行崩溃。我做错了什么?

编辑:其对IOException的报道

代码语言:javascript
复制
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)     
EN

回答 2

Stack Overflow用户

发布于 2012-11-09 05:56:53

为游戏创建一个GameState类(实现serializable)并保存它。在尝试序列化JFrame时,您会得到一个异常,从这个怪物的外观来看,您不会很快找到解决办法的。

代码语言:javascript
复制
// 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");}
        }
    }
}
票数 1
EN

Stack Overflow用户

发布于 2012-11-09 05:47:21

你应该记录你的异常,而不是默默地忽略它们。我的猜测是,您在MyGame中有一些不是Serializable的字段,或者它本身包含一些不能完全序列化的内容。

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。

票数 0
EN
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接:

https://stackoverflow.com/questions/13298297

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