java - 为什么我不能通过 openjpa 持久化对象？ - 验证不正确

Question

在我的 Web 应用程序中，我在 Apache Tomcat (TomEE)/7.0.37 服务器上使用 OpenJPA。我使用 Netbeans 自动生成类(“来自数据库的实体类...”和“来自实体类的 session Bean...”)。

我的用户类:

@Entity
@Table(name = "USER")
@XmlRootElement
@NamedQueries({
@NamedQuery(name = "User.findAll", query = "SELECT u FROM User u"),
@NamedQuery(name = "User.findByIdUser", query = "SELECT u FROM User u WHERE u.idUser = :idUser"),
@NamedQuery(name = "User.findByLogin", query = "SELECT u FROM User u WHERE u.login = :login"),
@NamedQuery(name = "User.findByPassword", query = "SELECT u FROM User u WHERE u.password = :password")})
public class User implements Serializable {
 private static final long serialVersionUID = 1L;


 @Id
 @GeneratedValue(strategy = GenerationType.IDENTITY)
 @Basic(optional = false)
 @NotNull
 @Column(name = "id_user")
 private Short idUser;


 @Size(max = 8)
 @Column(name = "login")
 private String login;
 @Size(max = 64)
 @Column(name = "password")
 private String password;
 @JoinTable(name = "USER_has_ROLES", joinColumns = {
    @JoinColumn(name = "USER_id", referencedColumnName = "id_user")}, inverseJoinColumns = {
    @JoinColumn(name = "ROLES_id", referencedColumnName = "id_roles")})
 @ManyToMany
 private List<Roles> rolesList;
 @OneToMany(cascade = CascadeType.ALL, mappedBy = "user")
 private List<Lecturer> lecturerList;
 @OneToMany(cascade = CascadeType.ALL, mappedBy = "user")
 private List<Student> studentList;

//constructors, getters, setters
}

当我通过 ManagedBean 创建新用户时:

private void addUser() {
    User user = new User();    
    user.setLogin(registerLog);
    user.setPassword(registerPass);
    Roles r = new Roles();  
    r.setIdRoles(new Short("2"));
    List<Roles> roleList = new ArrayList<Roles>();
    roleList.add(r);        
    user.setRolesList(roleList);    


    userFacade.create(user);  //<------here i create by abstract facade by em.persist(user);

}

我得到异常:

javax.el.ELException: javax.ejb.EJBException: The bean encountered a non-application exception; nested exception is: javax.validation.ConstraintViolationException: A validation constraint failure occurred for class "model.entity.User".

viewId=/pages/register.xhtml
location=/home/jakub/Projekty/Collv2/build/web/pages/register.xhtml
phaseId=INVOKE_APPLICATION(5)

Caused by:
 javax.validation.ConstraintViolationException - A validation constraint failure occurred for class "model.entity.User".
at   org.apache.openjpa.persistence.validation.ValidatorImpl.validate(ValidatorImpl.java:282)

/pages/register.xhtml at line 26 and column 104 action="#{registerController.register}"

看来我的用户 ID 不正确。出了什么问题？

Answer 1

我认为你的问题是你的 id 生成类型 - GenerationType.IDENTITY。通常，当使用身份时，会使用特殊的数据库列来生成 id。直到将数据插入数据库后才会生成 id，并且在提交之后实体才可以使用 id 本身。但是，Bean 验证会使用实体的当前状态在预持久回调中进行。这将失败，因为 id 仍然为 null。

我可能只会更改生成类型。