During compilation of your client side GWT code a serialization policy file
is generated (thats the <HASH>.rpc file in your war/<appname> folder) which
contains information about all client side serializable types. This file
also includes java.util.List and all its implementation.
On your server you also have a List in your entities and you have chosen
ArrayList as implementation but Hibernate does enhance your entity classes
and replaces all Lists in your entities to PersistentList or PersistentBag
(depending on @IndexColumn) to support lazy loading and maybe other JPA
specific features. So at runtime its not an ArrayList anymore.
Well and as already mentioned, as PersistentBag is not in the serialization
policy file (GWT compiler does not know this class) the server refuses to
serialize your entity.
Solutions:
- use Gilead with hibernate (transforms hibernate lists back to
java.util.List and lazy properties will be null)
- use Data Transfer Objects (DTO): either write them by hand or use
something like Dozer
- use RequestFactory: similar to DTO as RequestFactory generates client
side beans for your server side entities. So you never send your server
side entities directly to the client.
- use pure JSON
-- J.
Am Dienstag, 1. Mai 2012 20:01:49 UTC+2 schrieb nofear:
>
> I have a problem with GW and Hibernate,
>
> in my database , I have Sinav(Exam) and Soru(Question) tables and a
> mid-table called sinav_soru(Exam_Question) , when i want to reach the
> exam list from the database using Hibernate the error occurs , please
> help.
>
> Thanks in advance.
>
> Here's the error detail ;
>
> [WARN] Exception while dispatching incoming RPC call
> com.google.gwt.user.client.rpc.SerializationException: Type
> 'org.hibernate.collection.PersistentBag' 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 =
> [tr.edu.gsu.yds.shared.domain.Soru@307262ee] 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.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: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)
>
> I really could'n fix the problem.
>
> here's my domain code ;
>
>
>
> Sinav.java (Exam)
>
> package tr.edu.gsu.yds.shared.domain;
>
> import java.io.Serializable;
> import java.util.ArrayList;
> import java.util.List;
>
> import javax.persistence.Column;
> import javax.persistence.Entity;
> import javax.persistence.FetchType;
> import javax.persistence.GeneratedValue;
> import javax.persistence.GenerationType;
> import javax.persistence.Id;
> import javax.persistence.JoinColumn;
> import javax.persistence.JoinTable;
> import javax.persistence.ManyToMany;
> import javax.persistence.ManyToOne;
> import javax.persistence.OneToMany;
> import javax.persistence.Table;
>
> import org.hibernate.annotations.Fetch;
> import org.hibernate.annotations.FetchMode;
>
> @Entity
> @Table(name = "sinav")
> public class Sinav implements Serializable
> {
> private static final long serialVersionUID = 1L;
>
> private Integer sinavId;
> private String sinavAd;
> private String eklenmeTarihi;
> private Ogretmen ogretmen;
> private List<Ogrenci> ogrenciler = new ArrayList<Ogrenci>();
> private List<Soru> sorular = new ArrayList<Soru>();
>
> @Id
> @GeneratedValue( strategy=GenerationType.IDENTITY )
> @Column(name = "sinavId", length=10)
> public Integer getSinavId() {
> return sinavId;
> }
>
> public void setSinavId(Integer sinavId) {
> this.sinavId = sinavId;
> }
>
> @Column(name = "sinavAd", nullable = false)
> public String getSinavAd() {
> return sinavAd;
> }
>
> public void setSinavAd(String sinavAd) {
> this.sinavAd = sinavAd;
> }
>
> @Column(name = "eklenmeTarihi", nullable = false)
> public String getEklenmeTarihi() {
> return eklenmeTarihi;
> }
>
>
> public void setEklenmeTarihi(String eklenmeTarihi) {
> this.eklenmeTarihi = eklenmeTarihi;
> }
>
>
>
> @ManyToOne(fetch = FetchType.EAGER)
> @JoinColumn(name = "ogretmenNo")
> public Ogretmen getOgretmen() {
> return this.ogretmen;
> }
>
> public void setOgretmen(Ogretmen ogretmen) {
> this.ogretmen = ogretmen;
> }
>
> @OneToMany(fetch = FetchType.LAZY, mappedBy = "sinav")
> public List<Ogrenci> getOgrenciler()
> {
> return ogrenciler;
> }
>
> public void setOgrenciler( List<Ogrenci> ogrenciler )
> {
> this.ogrenciler = ogrenciler;
> }
>
>
> @ManyToMany(fetch = FetchType.EAGER)
> @Fetch(value = FetchMode.SUBSELECT)
> @JoinTable(name = "sinav_soru",
> joinColumns = {
> @JoinColumn(name = "sinavId", nullable = false)
> },
> inverseJoinColumns = {
> @JoinColumn(name = "soruId", nullable = false)
> }
> )
> public List<Soru> getSorular() {
> return sorular;
> }
>
> public void setSorular(List<Soru> sorular) {
> this.sorular = sorular;
> }
>
>
> }
>
>
>
> Soru.java (Question)
>
> package tr.edu.gsu.yds.shared.domain;
>
> import java.io.Serializable;
> import java.util.ArrayList;
> import java.util.HashSet;
> import java.util.List;
> import java.util.Set;
>
> import javax.persistence.CascadeType;
> import javax.persistence.Column;
> import javax.persistence.Entity;
> import javax.persistence.FetchType;
> import javax.persistence.GeneratedValue;
> import javax.persistence.GenerationType;
> import javax.persistence.Id;
> import javax.persistence.ManyToMany;
> import javax.persistence.OneToMany;
> import javax.persistence.Table;
>
> @Entity
> @Table(name = "soru")
> public class Soru implements Serializable
> {
> private static final long serialVersionUID = 4L;
>
> private Integer soruId;
> private String soruTip;
> private String soruMetin;
> private String soruYardimci;
> private Integer soruPuan;
> private List<Cevap> cevaplar = new ArrayList<Cevap>();
> private List<Sinav> sinavlar = new ArrayList<Sinav>();
>
> @Id
> @GeneratedValue( strategy=GenerationType.IDENTITY )
> @Column(name = "soruId")
> public Integer getSoruId() {
> return soruId;
> }
>
> public void setSoruId(Integer soruId) {
> this.soruId = soruId;
> }
>
> @Column( name = "soruTip", nullable = false, length=20 )
> public String getSoruTip() {
> return soruTip;
> }
>
> public void setSoruTip( String soruTip ) {
> this.soruTip = soruTip;
> }
>
> @Column( name = "soruMetin", nullable = false, length = 65535,
> columnDefinition="Text" )
> public String getSoruMetin() {
> return soruMetin;
> }
>
> public void setSoruMetin( String soruMetin ) {
> this.soruMetin = soruMetin;
> }
>
> @Column( name = "soruYardimci", nullable = false, length=45 )
> public String getSoruYardimci() {
> return soruYardimci;
> }
>
> public void setSoruYardimci( String soruYardimci ) {
> this.soruYardimci = soruYardimci;
> }
>
> @Column( name = "soruPuan", nullable = false, length=3 )
> public Integer getSoruPuan() {
> return soruPuan;
> }
>
> public void setSoruPuan( Integer soruPuan ) {
> this.soruPuan = soruPuan;
> }
>
> @OneToMany( mappedBy = "soru", fetch = FetchType.EAGER,
> cascade=CascadeType.ALL )
> public List<Cevap> getCevaplar() {
> return cevaplar;
> }
>
> public void setCevaplar( List<Cevap> cevaplar ) {
> this.cevaplar = cevaplar;
> }
>
> @ManyToMany( mappedBy = "sorular", fetch = FetchType.LAZY )
> public List<Sinav> getSinavlar() {
> return sinavlar;
> }
>
> public void setSinavlar(List<Sinav> sinavlar) {
> this.sinavlar = sinavlar;
> }
>
> }
>
>
>
>
>
> Here's the code that i get the exam list ;
>
> package tr.edu.gsu.yds.client.controller.ogrenci;
>
> import java.util.List;
>
> import com.google.gwt.core.client.GWT;
> import com.google.gwt.event.dom.client.ClickEvent;
> import com.google.gwt.event.dom.client.ClickHandler;
> import com.google.gwt.user.client.Window;
> import com.google.gwt.user.client.rpc.AsyncCallback;
>
> import tr.edu.gsu.yds.client.remote.YdsRemoteService;
> import tr.edu.gsu.yds.client.remote.YdsRemoteServiceAsync;
> import
> tr.edu.gsu.yds.client.view.ogrenci.sinavislemleri.OgrenciWritingSoruSayfasi;
>
> import tr.edu.gsu.yds.shared.domain.Sinav;
> import tr.edu.gsu.yds.shared.domain.SinavTakvim;
> import tr.edu.gsu.yds.shared.domain.Soru;
>
> public class OgrenciWritingSoruSayfasiController
> {
>
> private YdsRemoteServiceAsync ydsRemoteServiceAsync =
> GWT.create( YdsRemoteService.class );
> private OgrenciWritingSoruSayfasi ogrenciWritingSoruSayfasi;
>
> public
> OgrenciWritingSoruSayfasiController( OgrenciWritingSoruSayfasi
> ogrenciWritingSoruSayfasi )
> {
> this.ogrenciWritingSoruSayfasi = ogrenciWritingSoruSayfasi;
>
> }
>
> public void send(){
>
> ydsRemoteServiceAsync.getSinavList( new
> AsyncCallback<List<Sinav>>()
> {
>
> @Override
> public void onSuccess( List<Sinav> result )
> {
> for ( Sinav sinav : result )
> {
> //Just to see , returning results.
> Window.alert( "sinav " + sinav.getSinavId() );
>
> }
> }
>
> @Override
> public void onFailure( Throwable caught )
> {
> Window.alert( "Failure" );
>
> }
> } );
>
> ogrenciWritingSoruSayfasi.getOgrenciWritingWidget().getOkayButton().addClickHandler(
>
> new
> ClickHandler()
> {
>
> @Override
> public void onClick( ClickEvent event )
> {
>
> ogrenciWritingSoruSayfasi.getOgrenciWritingWidget().getSoruMetniLabel().setText(
>
> "Basıldı" );
>
> }
> } );
>
>
> }
>
> }
--
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