实体不是已知的实体类型

Question

我尝试使用 JSF 和 Java EE 在 java 中制作一个简单的 Java EE 应用程序。

我无法部署以下客户实体：

package ch.uufstellend.onlineshop.model;

import java.io.Serializable;
import javax.ejb.Stateful;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.NamedQuery;
import javax.persistence.Table;
import lombok.Data;

@Entity
@Data
@Table(name = "CUSTOMER")
@NamedQuery(
        name = "Customer.findAll",
        query = "SELECT c FROM Customer c")
public class Customer implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue
    private Long id;

    private String email;

    private String password;

    public Customer() {
    }

    @Override
    public String toString() {
        return id + "-" + email + "-" + password;
    }
}

因为：

Severe: Exception while deploying the app [uuf-onlineshop-ear] : Invalid ejb jar [uuf-onlineshop-ejb-1.0-SNAPSHOT.jar]: it contains zero ejb. Note:

A valid ejb jar requires at least one session, entity (1.x/2.x style), or message-driven bean.

EJB3+ entity beans (@Entity) are POJOs and please package them as library jar.

If the jar file contains valid EJBs which are annotated with EJB component level annotations (@Stateless, @Stateful, @MessageDriven, @Singleton), please check server.log to see whether the annotations were processed properly.

如果我向实体添加 @Stateful 注释，我就可以部署该应用程序。但是，当我随后访问 RegisterController 时，在保留 Customer 时抛出以下异常：

exception:> javax.servlet.ServletException: java.lang.IllegalArgumentException: Object: ch.uufstellend.onlineshop.model.__EJB31_Generated__Customer__Intf___302872188 is not a known entity type. root cause

javax.faces.el.EvaluationException: java.lang.IllegalArgumentException: Object: ch.uufstellend.onlineshop.model.__EJB31_Generated__Customer__Intf___302872188 is not a known entity type.

控制器：

package ch.uufstellend.onlineshop;

import ch.uufstellend.onlineshop.model.Customer;
import java.io.Serializable;

import javax.annotation.Resource;
import javax.enterprise.context.RequestScoped;
import javax.faces.application.FacesMessage;
import javax.faces.context.FacesContext;
import javax.inject.Inject;
import javax.inject.Named;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.PersistenceUnit;
import javax.transaction.HeuristicMixedException;
import javax.transaction.HeuristicRollbackException;
import javax.transaction.NotSupportedException;
import javax.transaction.RollbackException;
import javax.transaction.SystemException;
import javax.transaction.UserTransaction;
import lombok.Getter;
import lombok.Setter;

@Named
@RequestScoped
public class RegisterController implements Serializable {

    private static final long serialVersionUID = 1L;

    @PersistenceUnit
    private EntityManagerFactory emf;

    @Resource
    private UserTransaction ut;

    @Inject
    @Getter
    @Setter
    private Customer customer;


    public String persist() {
        try {
            ut.begin();
            EntityManager entityManager = emf.createEntityManager();
            entityManager.persist(customer); // HERE the error is thrown
            ut.commit();
            FacesMessage m = new FacesMessage("Succesfully registered!", "Your email was saved under id " + customer.getId());
            FacesContext.getCurrentInstance().addMessage("registerForm", m);
        } catch (NotSupportedException | SystemException | RollbackException | HeuristicMixedException | HeuristicRollbackException | SecurityException | IllegalStateException e) {
            e.printStackTrace();
            FacesMessage m = new FacesMessage(FacesMessage.SEVERITY_WARN, e.getMessage(), e.getCause().getMessage());
            FacesContext.getCurrentInstance().addMessage("registerForm", m);
        }
        return "/register.jsf";
    }
}

知道问题出在哪里吗？

Answer 1

您的 @Entity 实体 bean 一切正常。不要修改它。使其成为 EJB 确实会导致所描述的异常，因为 EJB 容器围绕 class 创建了一个代理，而后者又不被识别为 JPA 实体。

您的 @Named 托管 bean 有误。它与 EJB 职责（持久性和事务管理）紧密结合。将 EJB 职责拆分为一个真正的 @Stateless 会话 bean，并让托管 bean 调用它。

@Stateless
public class RegisterService {

    @PersistenceContext
    private EntityManager entityManager;

    public void persist(Customer customer) {
        entityManager.persist(customer);
    }

}

@Named
@RequestScoped
public class RegisterController {

    @Inject
    private Customer customer;

    @EJB
    private RegisterService registerService;

    public String submit() {
        FacesMessage m;

        try {
            registerService.persist(customer);
            m = new FacesMessage("Succesfully registered!", "Your email was saved under id " + customer.getId());
        } catch (Exception e) {
            m = new FacesMessage(FacesMessage.SEVERITY_WARN, e.getMessage(), e.getCause().getMessage());
        }

        FacesContext.getCurrentInstance().addMessage("registerForm", m);
        return "/register.jsf";
    }

    // ...
}

请注意，您不需要手动 fiddle 处理真实 EJB 中的用户事务。只有 Customer 上的 @Inject 有点奇怪。我不确定 @Data 的作用，但如果它与 CDI 的 @Model 注释具有相同的效果，那么就可以了。否则请前往下面的第二个 link 以获取具体示例和更多 links.

另请参阅：

When is it necessary or convenient to use Spring or EJB3 or all of them together?

实体不是已知的实体类型

Entity is not a known entity type

jsf

ejb

另请参阅：