JPA-獨立實體通過以保持多對多

Question

我有一個問題，因為我使用一個中間表來保存其他2個表（播放列表和Midia for MidiaPlaylist）的ID。 對於多對一/一對多的關系。

當我使用帶有額外列的MapID時，我創建了兩個多對一關系。 我使用@EmbeddedId表示法創建ID的關系。 映射類型無法解析為“ MERGE”類型。

表Midia

id_midia
--------

桌子MidiaPlaylist

id_playlist
id_midia
nr_order

表格播放清單

id_playlist
-------

我的播放列表控制器

instance.setDtCriacao(new Date(System.currentTimeMillis()));
instance.setQtMidiaTransmissao(dualListMidias.getTarget().size());
instance = playlistBean.salvarPlaylist(referenceValue);

int i = 1;
for(Midia midias : dualListMidias.getTarget()){             
    MidiaPlaylist midiaPlaylist = new MidiaPlaylist();
    MidiaPlaylistPK midiaPlaylistPK = new MidiaPlaylistPK();

    midiaPlaylistPK.setIdMidia(midias.getIdMidia());
    midiaPlaylistPK.setIdPlaylist(instance.getIdPlaylist());                
    midiaPlaylist.setPk(midiaPlaylistPK);           

    midiaPlaylist.setNrOrdem(i++);
    midiaPlaylist.setMidia(midias); 
    midiaPlaylist.setPlaylist(instance);

    //playlistBean.salvar(midiaPlaylist);
    **midiaPlaylistBean.salvar(midiaPlaylist);** -> error
}   

將ID保存在“播放列表”表中。 我將Midia的ID保存在MidiaPlaylist中。

我的MidiaPlaylistBean

@TransactionAttribute(TransactionAttributeType.REQUIRED)
public MidiaPlaylist salvar(MidiaPlaylist entity){
    try{
        entity = super.save(entity);
    }catch(Exception e){
        e.printStackTrace();
    }
    return entity;
}

我的Midia播放清單

@EmbeddedId 
private MidiaPlaylistPK pk = new MidiaPlaylistPK();

public MidiaPlaylist(){
}

@MapsId("idMidia")
@ManyToOne
@JoinColumn(name="id_midia", referencedColumnName="id_midia")
private Midia midia;

@MapsId("idPlaylist")
@ManyToOne
@JoinColumn(name="id_playlist", referencedColumnName="id_playlist")
private Playlist playlist;  

@Column(name="nr_ordem", nullable=false)
private int nrOrdem;


public Midia getMidia() {
    return midia;
}

public void setMidia(Midia midia) {
    this.midia = midia;
}

public Playlist getPlaylist() {
    return playlist;
}

public void setPlaylist(Playlist playlist) {
    this.playlist = playlist;
}

public void setPk(MidiaPlaylistPK id) {
    this.pk = id;
}

public MidiaPlaylistPK getPk() {
    return this.pk;
}

public void setNrOrdem(int nrOrdem){
    this.nrOrdem = nrOrdem;
}

public int getNrOrdem(){
    return this.nrOrdem;
}

我的播放清單

@Id
@GeneratedValue
@Column(name="id_playlist")
private Long idPlaylist;

@OneToMany(mappedBy = "playlist", cascade=CascadeType.MERGE)
private List<MidiaPlaylist> midiaPlaylist;
--get et setter

控制台錯誤 ：

傳遞給持久對象的獨立實體：com.bcm.midia.database.entity.Midia

我認為錯誤出在哪里 ：在Midia映射中

@Id
@GeneratedValue
@Column(name="id_midia")
private Long idMidia; 

@OneToMany(mappedBy = "midia", fetch = FetchType.LAZY, cascade=CascadeType.MERGE)   
private List<MidiaPlaylist> midiaPlaylist;
--get et setter 

您能幫助我了解如何在此映射中保存多對多嗎？ 重做這種關系最好嗎？ 我不知道該怎么辦了。

Answer 1

經過多方犧牲，我得到了解決方案，它是這樣的：

midia播放列表

public class MidiaPlaylist implements Serializable {

@EmbeddedId 
private MidiaPlaylistPK pk;

@ManyToOne
@JoinColumn(name="id_midia", updatable = false, insertable = false)
private Midia midia;

@ManyToOne
@JoinColumn(name="id_playlist", updatable = false, insertable = false)
private Playlist playlist;  

@Column(name="nr_ordem", nullable=false)
private int nrOrdem;
--GET AND SET
}

MidiaPlaylistPK

@Column(name = "id_midia")
private Long idMidia;

@Column(name = "id_playlist")
private Long idPlaylist;

public MidiaPlaylistPK(){
}

播放清單

//mapping
@Transient
private List<PlaylistProgramacao> listTerminal;

米迪亞

@Transient
private List<MidiaPlaylist> midiaPlaylist = new ArrayList<MidiaPlaylist>();

播放列表控制器

        try{                
            instance = playlistBean.salvarPlaylist(referenceValue);
        }catch(Exception e){
            e.printStackTrace();
        }

        int i = 1;
        for(Midia midias : dualListMidias.getTarget()){ 
            MidiaPlaylist midiaPlaylist1 = new MidiaPlaylist(midias, instance, i++);                
            midiaPlaylistBean.salvar(midiaPlaylist1);
        }           

這解決了我的問題，即使用hibernate和JPA與帶有多列的多對多映射的EJB持久存在。