Question

我有一个Account抽象类，它由另外两个类继承： DoctorAccount，NurseAccount（为了保持简短的发布，我省略了getter和setter）。执行方法checkIfLoginAndPasswordIsCorrect后，我收到错误：

Caused by: org.hibernate.WrongClassException: Object [id=1] was not of the specified subclass [Model.Account] : Discriminator: 1。我发现query.getSingleResult();对此负有责任，但我不知道为什么会抛出这样的错误。使用多态性我可以将Account分配给Doctor / Nurse。你知道我做错了吗？

@Inheritance(strategy=InheritanceType.SINGLE_TABLE)
@Entity
@DiscriminatorColumn(name = "Type_of_account", discriminatorType = 
DiscriminatorType.STRING)
public abstract class Account {
     @Id
     @GeneratedValue(strategy=GenerationType.AUTO)
     @Column(name="Id")
     private int id;
     @Column(name="Login")
     private String login;
     @Column(name="Password")
     private String password;
}

@Entity
public class NurseAccount extends Account{
}

@Entity
public class DoctorAccount extends Account{
}

在logInDAO类中：

@Override
public boolean checkIfLoginAndPasswordIsCorrect(String login, String password) {
    Account account = null;
    EntityManagerFactory managerFacotry = Persistence.createEntityManagerFactory("manager");
    EntityManager manager = managerFacotry.createEntityManager();
    manager.getTransaction().begin();
    Query query =  manager.createQuery("SELECT a from Account a WHERE a.login = :login AND a.password = :password")
            .setParameter("login", login).setParameter("password", password);
    manager.getTransaction().commit();
    try {
         account = (Account) query.getSingleResult(); // HERE Occures error
    }
    catch(NoResultException lackOfResult){  
        return false;
    }
    if(account != null)
    {
        return true;
    }
    return false;
}

}

Answer 1

您需要添加您的帐户类<{p>}上的@org.hibernate.annotations.DiscriminatorOptions(force=true)

JPA WrongClassException - 继承

1 个答案: