Java 试图序列化不存在的东西？

Question

我创建了一个类来保存组合框的内容并加载它们。我使用 ObjectOutput 并直接保存模型。问题是，我得到一个异常(exception):

java.io.WriteAbortedException: writing aborted; java.io.NotSerializableException: javax.swing.SpringLayout

我真的不明白为什么会这样，因为我没有在我的任何代码中的任何地方(据我所知)使用 SpringLayout。我什至在 stream.writeOutput(getModel()); 上设置了一个断点，getModel() 肯定会返回一个 DefaultComboboxModel，所以再一次没有提到 Spring Layout。

然后我编译我从 ( here ) 获得的示例代码，它工作正常。为什么会这样？

class MemComboBox extends JComboBox
{
    public static final int MAX_MEM_LEN = 30;

    public MemComboBox()
    {
        super();
        setEditable(true);
    }

    public void add(String item)
    {
        removeItem(item);
        insertItemAt(item, 0);
        setSelectedItem(item);
        if (getItemCount() > MAX_MEM_LEN)
            removeItemAt(getItemCount() - 1);
    }

    public void load(String fName)
    {
        try
        {
            if (getItemCount() > 0)
                removeAllItems();
            File f = new File(fName);
            if (!f.exists())
                return;
            FileInputStream fStream = new FileInputStream(f);
            ObjectInput stream = new ObjectInputStream(fStream);

            Object obj = stream.readObject();
            if (obj instanceof ComboBoxModel)
                setModel((ComboBoxModel) obj);

            stream.close();
            fStream.close();
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }

    public void save(String fName)
    {
        try
        {
            FileOutputStream fStream = new FileOutputStream(fName);
            ObjectOutput stream = new ObjectOutputStream(fStream);
            Object object = getModel();
            stream.writeObject(object);

            stream.flush();
            stream.close();
            fStream.close();
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }
}

我在这里创建实例:

    languageList = new MemComboBox();
    languageList.setBounds(146, 167, 166, 22);
    languageList.load(ClientInfo.GetAppData() + "/languages.xml");
    languageList.addActionListener(comboboxAdded);
    getContentPane().add(languageList);

这是堆栈跟踪:

java.io.NotSerializableException: javax.swing.SpringLayout
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.access$300(Unknown Source)
    at java.io.ObjectOutputStream$PutFieldImpl.writeFields(Unknown Source)
    at java.io.ObjectOutputStream.writeFields(Unknown Source)
    at java.awt.Container.writeObject(Unknown Source)
    at sun.reflect.GeneratedMethodAccessor14.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at java.io.ObjectStreamClass.invokeWriteObject(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.writeArray(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.access$300(Unknown Source)
    at java.io.ObjectOutputStream$PutFieldImpl.writeFields(Unknown Source)
    at java.io.ObjectOutputStream.writeFields(Unknown Source)
    at java.awt.Container.writeObject(Unknown Source)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at java.io.ObjectStreamClass.invokeWriteObject(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.writeArray(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.access$300(Unknown Source)
    at java.io.ObjectOutputStream$PutFieldImpl.writeFields(Unknown Source)
    at java.io.ObjectOutputStream.writeFields(Unknown Source)
    at java.awt.Container.writeObject(Unknown Source)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at java.io.ObjectStreamClass.invokeWriteObject(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.writeArray(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.access$300(Unknown Source)
    at java.io.ObjectOutputStream$PutFieldImpl.writeFields(Unknown Source)
    at java.io.ObjectOutputStream.writeFields(Unknown Source)
    at java.awt.Container.writeObject(Unknown Source)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at java.io.ObjectStreamClass.invokeWriteObject(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.writeArray(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.access$300(Unknown Source)
    at java.io.ObjectOutputStream$PutFieldImpl.writeFields(Unknown Source)
    at java.io.ObjectOutputStream.writeFields(Unknown Source)
    at java.awt.Container.writeObject(Unknown Source)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at java.io.ObjectStreamClass.invokeWriteObject(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.defaultWriteFields(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.writeObject(Unknown Source)
    at javax.swing.event.EventListenerList.writeObject(Unknown Source)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at java.io.ObjectStreamClass.invokeWriteObject(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.defaultWriteFields(Unknown Source)
    at java.io.ObjectOutputStream.writeSerialData(Unknown Source)
    at java.io.ObjectOutputStream.writeOrdinaryObject(Unknown Source)
    at java.io.ObjectOutputStream.writeObject0(Unknown Source)
    at java.io.ObjectOutputStream.writeObject(Unknown Source)
    at org.CCInc.Psyc.Windows.NewClient$MemComboBox.save(NewClient.java:688)
    at org.CCInc.Psyc.Windows.NewClient$7.windowClosing(NewClient.java:540)
    at java.awt.AWTEventMulticaster.windowClosing(Unknown Source)
    at java.awt.Window.processWindowEvent(Unknown Source)
    at javax.swing.JDialog.processWindowEvent(Unknown Source)
    at java.awt.Window.processEvent(Unknown Source)
    at java.awt.Component.dispatchEventImpl(Unknown Source)
    at java.awt.Container.dispatchEventImpl(Unknown Source)
    at java.awt.Window.dispatchEventImpl(Unknown Source)
    at java.awt.Component.dispatchEvent(Unknown Source)
    at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
    at java.awt.EventQueue.access$200(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.awt.EventQueue$4.run(Unknown Source)
    at java.awt.EventQueue$4.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.awt.EventQueue.dispatchEvent(Unknown Source)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.run(Unknown Source)

Answer 1

没有更多的代码我不能确定，但​​是......

堆栈跟踪中 at org.CCInc.Psyc.Windows.NewClient$MemComboBox.save(NewClient.java:688) 行表示 MemComboBox 类是NewClient 类的内部类。如果它不是静态内部类，那么序列化将尝试写出整个“NewClient”对象。这是因为在每个非静态内部类中都有对外部类的引用。