Question

我创建了两个实体类。

RoleEntity：

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table (name ="roles")
public class RoleEntity {

@Id
@Column(name = "role_id")
private Integer roleId;
@Column(name = "role_name")
private String roleName;
//Getters
//Setters

UserEntity：

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name="user_master")
public class UserEntity {

@Id
private Integer id;
@Column(name = "user_name")
private String username;
@Column(name = "user_password")
private String password;
//getters
//setters

现在我有一个简单的pojo，它将从这两个实体中获取数据，稍后将在服务中使用。

import java.util.Set;

public class UserRoleAssociationEntity {

UserEntity user;
Set<RoleEntity> roles;
//getters
//setters

现在我在运行项目时遇到错误。

Caused by: java.lang.IllegalArgumentException: Not a managed type: class com.dataGuru.BusDirV3.Entities.UserRoleAssociationEntity

如果我使用@entity注释UserRoleAssociationEntity类，则会出现以下错误：

Caused by: org.hibernate.AnnotationException: No identifier specified for entity: com.dataGuru.BusDirV3.Entities.UserRoleAssociationEntity

我在这里面临的问题是什么？该问题的解决方案。

Answer 1

您需要在类中具有一个唯一字段，该字段充当此实体的标识符。（带有if(index == 0)批注的字段））

Answer 2

不是创建新的POJO，而是在UserEntity类中添加了多对多关系。

 import javax.persistence.Column;
 import javax.persistence.Entity;
 import javax.persistence.Id;
 import javax.persistence.Table;

 @Entity
 @Table(name="user_master")
 public class UserEntity 
{
 @Id
 private Integer id;
 @Column(name = "user_name")
 private String username;
 @Column(name = "user_password")
 private String password;
 @Column(name = "user_password")
 private String password;

 @ManyToMany(cascade=CascadeType.MERGE, fetch = FetchType.EAGER) //
 @JoinTable(
        name="USERROLE_ASSOCIATION",
        joinColumns={@JoinColumn(name="USER_ID", referencedColumnName="ID")},
        inverseJoinColumns={@JoinColumn(name="ROLE_ID", referencedColumnName="ID")})
private Set<RoleEntity> UserRoleAssociationEntity ;

原因：java.lang.IllegalArgumentException：不是托管类型：＆原因：org.hibernate.AnnotationException：未为实体指定标识符：

2 个答案: