Java 返回空文件的ObjectOutputStream writeObject（）方法_Java

Java 返回空文件的ObjectOutputStream writeObject（）方法

java

Java 返回空文件的ObjectOutputStream writeObject（）方法,java,Java,我试图实现一个保存功能，将保存游戏的当前状态。这是我的密码： public class MyGame extends javax.swing.JFrame implements Serializable { private void saveGame(java.awt.event.ActionEvent evt) { JFileChooser fileChooser = n

我试图实现一个保存功能，将保存游戏的当前状态。这是我的密码：

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");}
        }

    }

结果保存的文件为0字节。我试图调试程序，但它在outputStream.writeObject（保存文件）行崩溃。我做错了什么

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)

您应该记录异常，而不是默默地忽略它们。我猜在

MyGame

中有一些字段不是

可序列化的

，或者它本身包含一些不完全可序列化的内容

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，因为序列化与Swing的未来版本不兼容。

为游戏创建一个GameState类（实现serializable）并将其保存。你尝试序列化JFrame时遇到了一个异常，从这个怪物的外表来看，你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");}
        }
    }
}

在关闭输出流之前尝试刷新它。将close（）方法移动到Try catch中的finally块。另外，将一些日志消息粘贴到现有的catch块中。您可能抛出了一个异常而没有报告它。@NathanD.Ryan：不必要。关闭outputstream总是首先刷新它。另外，保存整个GUI可能是保存游戏状态的愚蠢方法。将一个GameState类或实现可序列化的东西改为可序列化并保存。也不要忽略异常。重复出现的异常不是保存游戏造成的，而是完全无关的

JFrame

s应该是可序列化的，但您是对的，在这种情况下它可能没有用处。嗯，您是对的。这可以解释为什么它是NPE而不是IOE。更重要的是，

saveGame（）

方法不在stacktrace中。（NPE未被检查，因此仍有可能出现在那里）不知道。有人可能会说，无论OP有什么问题，你都没有真正解决。（在他给我们IOE的stacktrace之前这是不可能的。）我很确定这样做可以解决他的问题，如果是以迂回的方式。编辑答案中的例外是一个NPE没有被捕获，所以有效地记录了。这一点被忽略了，因此仅仅记录异常似乎不是处理异常的有效方法。-编辑：那里有一个IOException，其他地方也有NPE。@TomHawtin tackline-太糟糕了，OP没有发布IOException。发布的异常是否是问题的根源值得怀疑：堆栈跟踪没有显示OP代码的跟踪。这些NPE不可能来自执行发布代码的线程。它应该来自同一个线程。堆栈跟踪来自EDT线程，代码使用Swing。假设这是真的，NPE在

saveGame

退出后出现。@TomHawtin-tackline-哦，我刚刚注意到OP决定通过打印“IOException”一词来报告IOException。明亮的它看起来确实像是从

saveGame

返回后开始的堆栈跟踪。