java - 序列化异常 GWT

Question

我在 GWT 应用程序中收到 SerializationException。我已经在 stackoverflow 上寻找它，但没有发现我的错误。我检查了我的类(class) this thread 中提到的所有要点- 我只是找不到我的错误。任何想法出了什么问题吗？

这是 Tomcat 错误日志:

Mär 13, 2014 2:40:07 PM org.apache.catalina.core.ApplicationContext log
SEVERE: Exception while dispatching incoming RPC call
com.google.gwt.user.client.rpc.SerializationException: Type 'test.shared.params.SelectParameter' was not included in the set of types which can be serialized by this SerializationPolicy or its Class object could not be loaded. For security purposes, this type will not be serialized.: instance = test.shared.params.SelectParameter@376b030f
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serialize(ServerSerializationStreamWriter.java:667)
    at com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamWriter.writeObject(AbstractSerializationStreamWriter.java:126)
    at com.google.gwt.user.client.rpc.core.java.util.Collection_CustomFieldSerializerBase.serialize(Collection_CustomFieldSerializerBase.java:44)
    at com.google.gwt.user.client.rpc.core.java.util.ArrayList_CustomFieldSerializer.serialize(ArrayList_CustomFieldSerializer.java:39)
    at com.google.gwt.user.client.rpc.core.java.util.ArrayList_CustomFieldSerializer.serializeInstance(ArrayList_CustomFieldSerializer.java:51)
    at com.google.gwt.user.client.rpc.core.java.util.ArrayList_CustomFieldSerializer.serializeInstance(ArrayList_CustomFieldSerializer.java:28)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serializeImpl(ServerSerializationStreamWriter.java:788)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serialize(ServerSerializationStreamWriter.java:669)
    at com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamWriter.writeObject(AbstractSerializationStreamWriter.java:126)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter$ValueWriter$8.write(ServerSerializationStreamWriter.java:153)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serializeValue(ServerSerializationStreamWriter.java:587)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serializeClass(ServerSerializationStreamWriter.java:757)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serializeImpl(ServerSerializationStreamWriter.java:796)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serialize(ServerSerializationStreamWriter.java:669)
    at com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamWriter.writeObject(AbstractSerializationStreamWriter.java:126)
    at com.google.gwt.user.client.rpc.core.java.util.Collection_CustomFieldSerializerBase.serialize(Collection_CustomFieldSerializerBase.java:44)
    at com.google.gwt.user.client.rpc.core.java.util.ArrayList_CustomFieldSerializer.serialize(ArrayList_CustomFieldSerializer.java:39)
    at com.google.gwt.user.client.rpc.core.java.util.ArrayList_CustomFieldSerializer.serializeInstance(ArrayList_CustomFieldSerializer.java:51)
    at com.google.gwt.user.client.rpc.core.java.util.ArrayList_CustomFieldSerializer.serializeInstance(ArrayList_CustomFieldSerializer.java:28)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serializeImpl(ServerSerializationStreamWriter.java:788)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serialize(ServerSerializationStreamWriter.java:669)
    at com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamWriter.writeObject(AbstractSerializationStreamWriter.java:126)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter$ValueWriter$8.write(ServerSerializationStreamWriter.java:153)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serializeValue(ServerSerializationStreamWriter.java:587)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serializeClass(ServerSerializationStreamWriter.java:757)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serializeImpl(ServerSerializationStreamWriter.java:796)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serialize(ServerSerializationStreamWriter.java:669)
    at com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamWriter.writeObject(AbstractSerializationStreamWriter.java:126)
    at com.google.gwt.user.client.rpc.core.java.util.Collection_CustomFieldSerializerBase.serialize(Collection_CustomFieldSerializerBase.java:44)
    at com.google.gwt.user.client.rpc.core.java.util.ArrayList_CustomFieldSerializer.serialize(ArrayList_CustomFieldSerializer.java:39)
    at com.google.gwt.user.client.rpc.core.java.util.ArrayList_CustomFieldSerializer.serializeInstance(ArrayList_CustomFieldSerializer.java:51)
    at com.google.gwt.user.client.rpc.core.java.util.ArrayList_CustomFieldSerializer.serializeInstance(ArrayList_CustomFieldSerializer.java:28)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serializeImpl(ServerSerializationStreamWriter.java:788)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serialize(ServerSerializationStreamWriter.java:669)
    at com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamWriter.writeObject(AbstractSerializationStreamWriter.java:126)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter$ValueWriter$8.write(ServerSerializationStreamWriter.java:153)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serializeValue(ServerSerializationStreamWriter.java:587)
    at com.google.gwt.user.server.rpc.RPC.encodeResponse(RPC.java:605)
    at com.google.gwt.user.server.rpc.RPC.encodeResponseForSuccess(RPC.java:471)
    at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:563)
    at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServiceServlet.java:208)
    at com.google.gwt.user.server.rpc.RemoteServiceServlet.processPost(RemoteServiceServlet.java:248)
    at com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet.doPost(AbstractRemoteServiceServlet.java:62)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:929)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1002)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:585)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)

这是我的抽象类:

public abstract class Parameter implements IsSerializable {

    private List<Condition> conditions;
    private boolean isMultipleParameter;
    private String predefinedTitle;
    private Map<String, String> helpText;
    private int typID;

    public Parameter() {
        super();
    }

    protected Parameter(List<Condition> conditions, boolean isMultipleParameter, String predefinedTitle, Map<String, String> helpText, int typID) {
        super();
        this.conditions = conditions;
        this.isMultipleParameter = isMultipleParameter;
        this.predefinedTitle = predefinedTitle;
        this.helpText = helpText;
        this.typID = typID;
    }
    // getter and setter
}

这是发生错误的类:

public class SelectParameter extends Parameter {

    private String defaultValue; // Default Value of this Parameter
    private List<String> valueList; // Value-Pool

    public SelectParameter() {
        super();
    }

    public SelectParameter(int typID, String defaultValue, List<Condition> conditionList, boolean isMultipleParameter, String predefinedTitle, Map<String, String> helpText) {
        super(conditionList, isMultipleParameter, predefinedTitle, helpText, typID);
        this.defaultValue = defaultValue;
        this.valueList = new ArrayList<>();
    }
    // getter and setter
}

web.xml 文件

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
              http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
         version="2.5"
         xmlns="http://java.sun.com/xml/ns/javaee">

  <!-- Servlets -->
  <servlet>
    <servlet-name>greetServlet</servlet-name>
    <servlet-class>test.server.GreetingServiceImpl</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>greetServlet</servlet-name>
    <url-pattern>/test/greet</url-pattern>
  </servlet-mapping>

  <!-- Default page to serve -->
  <welcome-file-list>
    <welcome-file>Test.html</welcome-file>
  </welcome-file-list>

</web-app>

编辑:

public class Condition implements IsSerializable{

    private String parameterTitle;
    private List<String> valueList;

    public Condition(String parameterTitle) {
        super();
        this.parameterTitle = parameterTitle;
        this.valueList = new ArrayList<String>();
    }

    public Condition(){
        super();
    }
    // getter and setter
}

Answer 1

你能改变this.valueList = new ArrayList<>();吗？在 SelectParameter 中说 this.valueList = new ArrayList<String>(); (将泛型类型添加到ArrayList)？

另外，请参阅“可序列化的用户定义类”部分:http://www.gwtproject.org/doc/latest/DevGuideServerCommunication.html#DevGuideSerializableTypes

3. As of GWT 1.5, it must have a default (zero argument) constructor (with any access modifier) or no constructor at all.

还要确保 #2 适用于您的 Condition类。

这个 Stackoverflow 答案也对此进行了总结:https://stackoverflow.com/a/5210713/1038832

您还可以通过在 RPC 方法中显式提及自定义类型将其列入白名单以进行序列化:https://stackoverflow.com/a/144894/1038832