Java GWT-RPC传输Hibernate对象问题

我在GWT中通过RPC调用传输一个对象时遇到问题。我在这个项目中使用SpringMVC和Hibernate

下面是实体类：

@Entity
public class Room implements Serializable{
    private static final long serialVersionUID = -5924198459524011627L;

    private Long id;
    private String name;
    private String description;

    private Set<Wall> walls = new HashSet<Wall>(0);

    public Room(){
    }

    public Room(String name, String description){
        this.name = name;
        this.description = description;
    }

    public Room(String name, String description, Set<Wall> walls){
        this.name = name;
        this.description = description;
        this.walls = walls;
    }

    @Id
    @Column(name = "ROOM_ID")
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getDescription() {
        return description;
    }
    public void setDescription(String description) {
        this.description = description;
    }

    @ManyToMany(cascade = CascadeType.ALL, fetch=FetchType.EAGER)
    @JoinTable(name = "ROOM_WALL", joinColumns = {@JoinColumn(name = "ROOM_ID")},
            inverseJoinColumns = {@JoinColumn(name = "WALL_ID")})
    public Set<Wall> getWalls(){
        return walls;
    }   

    public void setWalls(Set<Wall> walls){
        this.walls = walls;
    }
}

我想问一下，这个问题是否是由多个关系和用于映射实体之间关系的集合引起的。因为当我在使用Set的地方传输一个没有任何关系（ManyToMany或OneToMany等）的对象时，RPC调用可以正常工作

是否可以用列表替换集合？我知道这个列表对数据库无效，但我不想重建整个项目：D

我发现这些问题可以通过使用推土机来解决

---

非常感谢您的回答：）

这是一个已知的问题。请阅读本文中的“为什么Hibernate对象在进入浏览器世界时无法理解”一章。

感谢您的回答：）我已经检查了可能的解决方案。。。最后，我在服务器端调整了Hibernate对象，并将它们发送到客户端，而不包含不可序列化的对象。因此，我解决了无法在服务器端传输的逻辑：）

@Repository
public class RoomDAO {

    @Autowired
    private HibernateTemplate hibernate;

    public Room get(Long id){
        return hibernate.get(Room.class, id);
    }

    public void delete(Room entity){
        hibernate.delete(entity);
    }

    public void save(Room entity){
        hibernate.saveOrUpdate(entity);
    }

    private Session getCurrentSession(){
        return hibernate.getSessionFactory().getCurrentSession();
    }   

    @SuppressWarnings("unchecked")
    public List<Room> list(){
        String queryStr = "from "+Room.class.getSimpleName()+" fetch all properties";
        Query query = getCurrentSession().createQuery(queryStr);
        System.out.println("Room list succesfull");
        return (List<Room>)query.list();
    }

    @SuppressWarnings("unchecked")
    public List<Wall> getWalls(Long id){
        String queryStr = "from "+Wall.class.getSimpleName()+" wl join wl.walls ls where ls.id=:"+id;
        Query query = getCurrentSession().createQuery(queryStr);
        System.out.println("Walls list succesfull");
        return (List<Wall>)query.list();
    }
}

com.google.gwt.user.client.rpc.SerializationException: Type 'org.hibernate.collection.PersistentSet' 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 = []
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serialize(ServerSerializationStreamWriter.java:619)
    at com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamWriter.writeObject(AbstractSerializationStreamWriter.java:126)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter$ValueWriter$8.write(ServerSerializationStreamWriter.java:153)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serializeValue(ServerSerializationStreamWriter.java:539)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serializeClass(ServerSerializationStreamWriter.java:709)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serializeImpl(ServerSerializationStreamWriter.java:748)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serialize(ServerSerializationStreamWriter.java:621)
    at com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamWriter.writeObject(AbstractSerializationStreamWriter.java:126)
    at com.google.gwt.user.client.rpc.core.java.util.Collection_CustomFieldSerializerBase.serialize(Collection_CustomFieldSerializerBase.java:44)
    at com.google.gwt.user.client.rpc.core.java.util.ArrayList_CustomFieldSerializer.serialize(ArrayList_CustomFieldSerializer.java:39)
    at com.google.gwt.user.client.rpc.core.java.util.ArrayList_CustomFieldSerializer.serializeInstance(ArrayList_CustomFieldSerializer.java:51)
    at com.google.gwt.user.client.rpc.core.java.util.ArrayList_CustomFieldSerializer.serializeInstance(ArrayList_CustomFieldSerializer.java:28)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serializeImpl(ServerSerializationStreamWriter.java:740)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serialize(ServerSerializationStreamWriter.java:621)
    at com.google.gwt.user.client.rpc.impl.AbstractSerializationStreamWriter.writeObject(AbstractSerializationStreamWriter.java:126)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter$ValueWriter$8.write(ServerSerializationStreamWriter.java:153)
    at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamWriter.serializeValue(ServerSerializationStreamWriter.java:539)
    at com.google.gwt.user.server.rpc.RPC.encodeResponse(RPC.java:616)
    at com.google.gwt.user.server.rpc.RPC.encodeResponseForSuccess(RPC.java:474)
    at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:571)
    at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:551)
    at org.spring4gwt.server.SpringGwtRemoteServiceServlet.processCall(SpringGwtRemoteServiceServlet.java:37)
    at com.google.gwt.user.server.rpc.RemoteServiceServlet.processPost(RemoteServiceServlet.java:248)
    at com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet.doPost(AbstractRemoteServiceServlet.java:62)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:487)
    at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:362)
    at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
    at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
    at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:729)
    at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:405)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at org.mortbay.jetty.handler.RequestLogHandler.handle(RequestLogHandler.java:49)
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
    at org.mortbay.jetty.Server.handle(Server.java:324)
    at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:505)
    at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:843)
    at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:647)
    at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:211)
    at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:380)
    at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:395)
    at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:488)