我很难尝试连载我的类(class)(实际上需要 3-4 小时才能找到解决方案)。我将一个子类添加到现有的可序列化和功能类中，然后收到以下错误消息:
[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
我的类(class)看起来像:
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;
}
.
.
.
}
当我注释“private LogCollection logColl”行时它没问题，但是当我取消注释时我再次收到错误消息。我尝试使用 static 关键字，如您所见，我注释了每个子类变量，但无能为力......无论如何，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;
}
然后尝试将其用作我的功能类，没关系......但这件事真的让我很烦恼......
有什么想法吗？ Gwt 不支持子类序列化？或者我错过了什么。感谢您的回答。
最好的问候， 彼得
最佳答案
这个错误:
子类型 com.client.rpc.ItemRecRpc.LogCollection 不是默认可实例化的
表示默认情况下它无法创建 LogCollection 的实例。这是真的。因为要创建 LogCollection 实例，首先需要有一个 ItemRecRpc 实例。将 LogCollection 声明为静态类应该有所帮助。
基本上，当您想通过 gwt-rpc 发送一些对象时，所有用作此类对象中字段的类默认情况下都应该是可实例化的。 (例如，没有特殊的技巧来创建它，只是新的和空的构造函数)。您还可以为任何类定义一个自定义字段序列化器，它可以默认实例化。
关于GWT + 序列化，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/9211246/