Question

我遇到了@ManyToMany集合未在数据加载时填充的问题。我尝试了FetchType.LAZY和FetchType.EAGER，但结果没有变化。

当我打印用户对象时，角色的集合对象为空。

用户[userId = 2，firstName = Ajay，lastName = C，email = admin.demo @ gmail.com，密码= 12345，roles = []]

也尝试通过添加引用的列。但是没用。

请协助解决此问题。

用户和角色实体如下。

@Entity
@Table(name = "\"ROLE\"",schema="\"PLATFORM_PROD_IOT\"")
public class Role {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name="\"ROLE_ID\"")
    private Long roleId;

    @Column(name="\"ROLE_NAME\"")
    private RoleName name;
//Getters and Setters
}

@Entity
@Table(name = "\"USER\"", schema = "\"PLATFORM_PROD_IOT\"", uniqueConstraints = {
     @UniqueConstraint(columnNames = { "\"EMAIL_ID\"" }) })
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Size(min = 1, max = 50)
    @Column(name = "\"USER_ID\"")
    private Long userId;

    @NotBlank
    @Size(min = 3, max = 50)
    @Column(name = "\"FIRST_NAME\"")
    private String firstName;

    @NotBlank
    @Size(min = 3, max = 50)
    @Column(name = "\"LAST_NAME\"")
    private String lastName;

    @NaturalId
    @NotBlank
    @Size(max = 50)
    @Email
    @Column(name = "\"EMAIL_ID\"")
    private String email;

    @NotBlank
    @Size(min = 3, max = 100)
    @Column(name = "\"PASSWORD\"")
    private String password;


    @ManyToMany(fetch = FetchType.LAZY)
    @JoinTable(name = "\"USER_ROLE_MAPPING\"", schema = "\"\PLATFORM_PROD_IOT\"", joinColumns = @JoinColumn(name = "\"USER_ID\""), inverseJoinColumns = @JoinColumn(name = "\"ROLE_ID\""))
    private Set<Role> roles = new HashSet<>();

//Getters and Setters

}
@Entity
@Table(name = "\"ROLE\"",schema="\"PLATFORM_PROD_IOT\"")
public class Role {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name="\"ROLE_ID\"")
    private Long roleId;

    @Column(name="\"ROLE_NAME\"")
    private RoleName name;
//Getters and Setters
}

Answer 1

在Role类中尝试。

  @ManyToMany(fetch = FetchType.EAGER)
    @JoinTable(name = "USER_ROLE_MAPPING",joinColumns = @JoinColumn(name = "ROLE_ID"), inverseJoinColumns = @JoinColumn(name = "USER_ID""))
    private Set<Role> roles = new HashSet<>();

然后在用户类中将fetchType更改为EAGER。如果不起作用，请尝试将表更改为其他名称。示例：用户，角色。某些东西不起作用，因为它在SQL DATABASE中名称相同。

@ManyToMany集合未填充spring-boot-starter-data-jpa

1 个答案: