持久性三重關聯JPA/EclipseLink

Question

我目前使用Java EE/EclipseLink和postgreSQL開發Web應用程序。 關於我的實體，我特別管理「項目」，「用戶」和「正確」（訪問權限如讀取，寫入，刪除...）。這些實體之間的關係是：一個項目可以擁有多個對該項目擁有不同權限的用戶。因此，我得到了三重關聯：項目+用戶+權利。

我在這個關聯的持久化過程中遇到了一個煩人的問題。當我堅持一個項目的信息時，一切都很好（它在數據庫中，我可以在我的應用程序中使用它），我也堅持權利和用戶。然後，我想他們之間，所以我創建了一個名爲ProjectUserRight關聯實體添加關聯，我設置項目，用戶從現有實體的權利，但我堅持它，我得到下面的異常：

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is javax.persistence.RollbackException: Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.3.2.v20111125-r10461): org.eclipse.persistence.exceptions.DatabaseException 
Internal Exception: org.postgresql.util.PSQLException: ERREUR: une valeur NULL viole la contrainte NOT NULL de la colonne « id_project » 
Error Code: 0 
Call: INSERT INTO project_user_right (id_right, id_project, id_user) VALUES (?, ?, ?) 
bind => [3 parameters bound] 
Query: InsertObjectQuery(ProjectUserRight@192db555) 

這裏是類項目：

@Entity 
@Table(name="project") 
public class Project implements Serializable { 
private static final long serialVersionUID = 1L; 

@Id 
@GeneratedValue(strategy=GenerationType.IDENTITY) 
@Column(name="id_project", unique=true, nullable=false) 
private Integer idProject; 


    //bi-directional many-to-one association to ProjectUserRight 
@OneToMany(mappedBy="project", cascade={CascadeType.ALL}) 
private Set<ProjectUserRight> projetUtilDroits; 


    ... 

類用戶：

@Entity 
@Table(name="user") 
public class User implements Serializable { 
private static final long serialVersionUID = 1L; 

@Id 
@GeneratedValue(strategy=GenerationType.IDENTITY) 
@Column(name="id_user", unique=true, nullable=false) 
private Integer idUser; 


@Column(name="nom_utilisateur", nullable=false, length=50) 
private String userName; 

    //bi-directional many-to-one association to ProjectUserRight 
@OneToMany(mappedBy="user") 
private Set<ProjectUserRight> projetUtilDroits; 

    ... 

類右：

@Entity 
    @Table(name="right") 
    public class Right implements Serializable { 
private static final long serialVersionUID = 1L; 

@Id 
@GeneratedValue(strategy=GenerationType.IDENTITY) 
@Column(name="id_right", unique=true, nullable=false) 
private Integer idRight; 

@Column(name="type_right", nullable=false, length=10) 
private String typeRight; 

//bi-directional many-to-one association to ProjectUserRight 
@OneToMany(mappedBy="right") 
private Set<ProjectUserRight> projetUtilDroits; 

    ... 

和關聯類：

@Entity 
@Table(name="project_user_right") 
public class ProjectUserRight implements Serializable { 
private static final long serialVersionUID = 1L; 

@EmbeddedId 
private ProjectUserRightPK id; 

//bi-directional many-to-one association to Right 
    @ManyToOne(cascade={CascadeType.MERGE, CascadeType.REFRESH}) 
@JoinColumn(name="id_right", insertable=false, updatable=false) 
private Right right; 

//bi-directional many-to-one association to Project 
@ManyToOne(cascade={CascadeType.MERGE, CascadeType.REFRESH}) 
@JoinColumn(name="id_project", insertable=false, updatable=false) 
private Project project; 

//bi-directional many-to-one association to User 
@ManyToOne(cascade={CascadeType.MERGE, CascadeType.REFRESH}) 
@JoinColumn(name="id_user", insertable=false, updatable=false) 
private User user; 

而且ProjectUserRightPK（評論後可進行編輯）：

@Embeddable 
public class ProjectUserRightPK implements Serializable { 
//default serial version id, required for serializable classes. 
private static final long serialVersionUID = 1L; 

@Column(name="id_project", unique=true, nullable=false) 
private Integer idProject; 

@Column(name="id_right", unique=true, nullable=false) 
private Integer idRight; 
    ...//getters and setters 
@Column(name="id_user", unique=true, nullable=false) 
private Integer idUser; 

我寫了下面的代碼來持久協會：

Project project = getService(Projet.class).getFromID(projectId);//retrieve the existing project from database with id 

User user = getService(Utilisateur.class).getFromID(userId);//retrieve the existing user from database with id 

Right right = getService(Right.class).getFromID(rightId);//retrieve the existing right from database with id 
if(project !=null && user!=null && right!=null){ 
    ProjectUserRight pud = new ProjectUserRight(); 
    pud.setRight(right); 
    pud.setProject(project); 
    pud.setUser(user); 
    project.getProjectUserRights().add(pud); 
    right.getProjectUserRights().add(pud); 
    user.getProjectUserRights().add(pud); 
    service(ProjetUtilDroit.class).persist(pud);//call the persist function on this entity (works fine with all other entities) 
    } 

我也嘗試合併該項目，而不是堅持協會，但我是t同樣的錯誤...（我也檢查了id項目，它設置正確）我想知道是否這是關聯錯誤地註釋，但我找不到改變它的正確方法。

所以，我真的需要你的幫助！ :-)

在此先感謝您的建議！

Answer 1

您無緣@MapsId註釋：

表示一個多對一或OneToOne關係屬性表示 提供了一種用於EmbeddedId主鍵的映射關係，屬性 一個EmbeddedId主鍵內，或的一個簡單的主鍵 父實體。值元素指定關係屬性所對應的組合關鍵字 內的屬性。

@MapsId("idRight") 
@ManyToOne(cascade={CascadeType.MERGE, CascadeType.REFRESH}) 
@JoinColumn(name="id_right") 
private Right right; 

@MapsId("idProject") 
@ManyToOne(cascade={CascadeType.MERGE, CascadeType.REFRESH}) 
@JoinColumn(name="id_project") 
private Project project; 

@MapsId("idUser") 
@ManyToOne(cascade={CascadeType.MERGE, CascadeType.REFRESH}) 
@JoinColumn(name="id_user") 
private User user;