Hibernate多对一映射中的EntityNotFoundException但是数据存在 [英] EntityNotFoundException in Hibernate Many To One mapping however data exist

问题描述

当我尝试通过 Invoice 对象获取 User 时出现 javax.persistence.EntityNotFoundException 错误

I am getting javax.persistence.EntityNotFoundException error when I am trying to get User through Invoice object

invoice.getUser().getId()

invoice.getUser().getId()

javax.persistence.EntityNotFoundException: Unable to find com.indianretailshop.domain.User with id 5
    at org.hibernate.ejb.Ejb3Configuration$Ejb3EntityNotFoundDelegate.handleEntityNotFound(Ejb3Configuration.java:137)
    at org.hibernate.proxy.AbstractLazyInitializer.checkTargetState(AbstractLazyInitializer.java:189)
    at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:178)
    at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:215)

实体类如下(不包括getter和setter)

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

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    @Column(unique=true, nullable=false)
    private int id;

    .
        .
        .

    //bi-directional many-to-one association to Invoice
    @OneToMany(mappedBy="user")
    private List<Invoice> invoices;
}

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

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    @Column(unique=true, nullable=false)
    private int id;
        .
        .
        .

    //bi-directional many-to-one association to User
    @ManyToOne(fetch=FetchType.LAZY)
    @JoinColumn(name="Users_id")
    private User user;
}

推荐答案

问题可能是直接实体不存在，也可能是来自该实体的引用实体，通常用于 EAGER 获取类型，或可选=假.

The problem could be that the direct entity does not exist, but also it could be that the referenced entity from that entity, normally for a EAGER fetch type, or optional=false.

试试这个:

     //bi-directional many-to-one association to User
     @ManyToOne(fetch=FetchType.LAZY)
     @JoinColumn(name="Users_id")
     private User user = new User();

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