hibernate - Hibernate、テーブル結合の問題（おそらく）

Question

GWとHibernateに問題があります。

私のデータベースにはSinav(Exam)、Soru(Question)テーブルとと呼ばれるミッドテーブルがありますsinav_soru(Exam_Question)。Hibernateを使用してデータベースから試験リストにアクセスしたい場合、エラーが発生します。

エラーの詳細は次のとおりです

   [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)

本当に問題を解決できませんでした。

これが私のドメインコードです：

Sinav.java（試験）

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（質問）

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;
    }

}

これが私が試験リストを取得するコードです;

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" );

            }
        } );


    }

}

Answer 1

よくわかりませんが、他の質問の回答から読んだところによると、デフォルト（ゼロ）の引数コンストラクターを追加するのを忘れています。これを追加してからやり直してください。

Answer 2

これらを交換します：

  private List<Ogrenci> ogrenciler = new ArrayList<Ogrenci>();
private List<Soru> sorular = new ArrayList<Soru>();

と：

  private Set<Ogrenci> ogrenciler = new HashSet<Ogrenci>();
private Set<Soru> sorular = new HashSet<Soru>();

同様に、他の Entity クラスのリスト。

このリンクを確認してください: GWT RPC のシリアライズ可能な Hibernate データ オブジェクト

Answer 3

これらの変数とそれぞれのメソッドを省略すると、GWT では機能しません。

private List<Ogrenci> ogrenciler = new ArrayList<Ogrenci>();
private List<Soru> sorular = new ArrayList<Soru>();

ない

private Set<Ogrenci> ogrenciler = new HashSet<Ogrenci>();
private Set<Soru> sorular = new HashSet<Soru>();

dozer、Gilead など、さまざまなソリューションが利用可能です。また、単純化のためにこれらの結果を取得するために getbyids メソッドを使用することもできます。