原因：java.lang.IllegalArgumentException：不是托管類型：＆原因：org.hibernate.AnnotationException：未為實體指定標識符：

Question

我創建了兩個實體類。

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

現在，我有一個簡單的pojo，它將從這兩個實體中獲取數據，稍后將在服務中使用。

import java.util.Set;

public class UserRoleAssociationEntity {

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

現在，在運行項目時出現錯誤。

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

如果我使用@entity注釋UserRoleAssociationEntity類，則會出現以下錯誤：

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

我在這里面臨的問題是什么？

Answer 1

您需要在類中具有一個唯一字段，該字段充當此實體的標識符。 （帶有@Id注釋的字段）

Answer 2

無需創建新的POJO，而是在UserEntity類中添加多對多關系。

 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 ;