java - 应用程序序列化错误，java.io.NotSerializedException :

Question

我正在尝试使用 Google Cloud Platform(Eclipse 中的插件)在 Google Cloud Platform 中运行 Vaadin 项目。运行后我得到这个异常:

WARNING: Error in serialization of the application: Class 
rand.TestProject.AutoCrudView$1 must implement serialization.
2019-03-02 15:54:06.159:WARN:oejs.session:qtp1757676444-19: 
java.io.NotSerializableException: java.lang.ref.WeakReference
at java.io.ObjectOutputStream.writeObject0(Unknown Source)
at java.io.ObjectOutputStream.writeObject(Unknown Source)
at java.util.LinkedList.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)

这是 AutoCrudView 类:

    @SuppressWarnings("serial")
    public class AutoCrudView  extends Window implements Serializable{
    private static final long serialVersionUID = 1L;

    public AutoCrudView(String PERSISTENCE_UNIT) {
        final HorizontalSplitPanel horizontalSplitPanel = new HorizontalSplitPanel();
        Tree navTree = new Tree();
        navTree.addListener(new Property.ValueChangeListener() {
            /**
             * 
             */
            private static final long serialVersionUID = 1L;

            @Override
            public void valueChange(ValueChangeEvent event) {
                @SuppressWarnings("rawtypes")
                BasicCrudView cv = (BasicCrudView) event.getProperty()
                        .getValue();
                cv.refreshContainer();
                horizontalSplitPanel.setSecondComponent(cv);
            }
        });
        navTree.setSelectable(true);
        navTree.setNullSelectionAllowed(false);
        navTree.setImmediate(true);

        horizontalSplitPanel.setSplitPosition(200,
                HorizontalSplitPanel.UNITS_PIXELS);
        horizontalSplitPanel.addComponent(navTree);
        setContent(horizontalSplitPanel);

        // add a basic crud view for all entities known by the JPA
        // implementation, most often this is not desired and developers
        // should just list those entities they want to have editors for
        Metamodel metamodel = JPAContainerFactory
                .createEntityManagerForPersistenceUnit(PERSISTENCE_UNIT)
                .getEntityManagerFactory().getMetamodel();
        Set<EntityType<?>> entities = metamodel.getEntities();
        for (EntityType<?> entityType : entities) {
            Class<?> javaType = entityType.getJavaType();
            @SuppressWarnings({ "rawtypes", "unchecked" })
            BasicCrudView view = new BasicCrudView(javaType,
                    PERSISTENCE_UNIT);
            navTree.addItem(view);
            navTree.setItemCaption(view, view.getCaption());
            navTree.setChildrenAllowed(view, false);
            if(javaType == Person.class) {
                view.setVisibleTableProperties("firstName","lastName", "boss");
                view.setVisibleFormProperties("firstName","lastName", "phoneNumber", "street", "city", "zipCode", "boss");
            }

        }

        // select first entity view
        navTree.setValue(navTree.getItemIds().iterator().next());
    }

    }

正如你所看到的，我已经实现了可序列化，但没有成功。这是我从 App Engine 窗口获得的图像: here

Answer 1

您会收到有关匿名内部类(类名末尾的 $1)而不是实际类本身的警告。

所以:去寻找你(不小心)创建了一个内部类实例并尝试保留该实例的地方。

也许是这样

new(...) {

将更改监听器添加到树对象的位置。如果是这样，问题是监听器是否应该是一个应该实现该接口(interface)的不同类。或者，如果您只是通过尝试保留具有此类监听器的内容而犯了错误(不是该框架的专家，我发现保留包括监听器实例在内的 ui 元素很可疑)。