GWT +系列化

Question

我很难尝试序列化我的课程（从字面上看3-4小时才能找到解决方案）。我一个子类添加到现有的序列化和功能类，并比收到以下错误信息：

[ERROR] com.google.gwt.user.client.ui.DelegatingChangeListenerCollection is not default instantiable (it must have a zero-argument constructor or no constructors at all) and has no custom serializer. (reached via com.client.rpc.ItemRecRpc) 
       [ERROR] com.google.gwt.user.client.ui.DelegatingClickListenerCollection is not default instantiable (it must have a zero-argument constructor or no constructors at all) and has no custom serializer. (reached via com.client.rpc.ItemRecRpc) 
       [ERROR] com.google.gwt.user.client.ui.DelegatingFocusListenerCollection is not default instantiable (it must have a zero-argument constructor or no constructors at all) and has no custom serializer. (reached via com.client.rpc.ItemRecRpc) 
       [ERROR] com.google.gwt.user.client.ui.DelegatingKeyboardListenerCollection is not default instantiable (it must have a zero-argument constructor or no constructors at all) and has no custom serializer. (reached via com.client.rpc.ItemRecRpc) 
       [ERROR] com.google.gwt.view.client.ListDataProvider<T>.ListWrapper<> is not default instantiable (it must have a zero-argument constructor or no constructors at all) and has no custom serializer. (reached via com.client.rpc.ItemRecRpc) 
       [ERROR] com.client.rpc.ItemRecRpc.LogCollection is not default instantiable (it must have a zero-argument constructor or no constructors at all) and has no custom serializer. (reached via com.client.rpc.ItemRecRpc) 
       [ERROR] com.client.rpc.ItemRecRpc.LogCollection has no available instantiable subtypes. (reached via com.client.rpc.ItemRecRpc) 
       [ERROR] subtype com.client.rpc.ItemRecRpc.LogCollection is not default instantiable (it must have a zero-argument constructor or no constructors at all) and has no custom serializer. (reached via com.client.rpc.ItemRecRpc) 
       [ERROR] java.util.AbstractList.SubList<E> is not default instantiable (it must have a zero-argument constructor or no constructors at all) and has no custom serializer. (reached via com.client.rpc.ItemRecRpc) 
       [ERROR] java.util.Collections.UnmodifiableList<T> is not default instantiable (it must have a zero-argument constructor or no constructors at all) and has no custom serializer. (reached via com.client.rpc.ItemRecRpc) 
       [ERROR] java.util.Collections.UnmodifiableRandomAccessList<T> is not default instantiable (it must have a zero-argument 

我班的样子：

public class ItemRecRpc implements Serializable { 

    private static final long serialVersionUID = -5828108890651522661L; 
     . 
     . 

     private String rId; 
    private LogCollection logColl;//if i comment this, no error message... 

    public class LogCollection{ 

     public LogCollection(){ 

     } 
     //public long creationTime = System.currentTimeMillis(); 
     //public LongVector times = new LongVector(); 
     //public ArrayList<Object> messages = new ArrayList<Object>(); 
     //public int nSkipped = 0; 
     //public int nExceptions = 0; 
     //public Exception firstException = null; 
     //public long endGcTime=0; 
     public long endTime; 
    } 
. 
. 
. 
} 

当我评论了“私人LogCollection logColl”行之是好的，但是当我取消注释我再次得到错误消息。我试着用static关键字，当你看到我的评论每个子类中的变量，但不能帮助...反正如果我创建一个新类：

public class LogCollectionRpc implements Serializable { 

    public LogCollectionRpc() { 
     // 
    } 
    public long creationTime = System.currentTimeMillis(); 
    public LongVector times = new LongVector(); 
    public ArrayList<Object> messages = new ArrayList<Object>(); 
    public int nSkipped = 0; // due to reaching the limit 
    public int nExceptions = 0; // due to MyAppender-s 
    public Exception firstException = null; // due to MyAppender-s 
    public long endGcTime = 0; 
    public long endTime; 

} 

而不是试图用这个作为我的功能类，它是好吧......但这件事真的让我心烦......

有什么想法吗？ Gwt不支持子类序列化？或者我想念一些东西。赞扬任何答案。

最好的问候， 彼得

Answer 1

此错误：

subtype com.client.rpc.ItemRecRpc.LogCollection is not default instantiable

说，它不能创建和LogCollection实例默认。这是真的。由于要创建LogCollection的实例，您首先需要有一个ItemRecRpc的实例。声明LogCollection静态类应该有所帮助。

基本上，当你想通过gwt-rpc发送一些对象时，所有在这样的对象中用作字段的类都应该是默认实例化的。 （例如，没有特别的技巧来创建它，只是新的和空的构造函数）。您也可以为任何类定义一个自定义字段序列化程序，可以默认实例化。