Spring JPA多对多关联被维护端如何获取维护端数据

使用Spring JPA多对多关联时被维护端如何获取维护端数据？

现在有User（维护端）、Role（被维护端）两个实体

请教一下如果我现在想单纯的获取Role对应的User列表该怎么样获取？

实体代码如下：

User实体

@DynamicInsert
@Entity
@Table(name = "axe_user")
public class User extends Base {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(name = "username", length = 20, nullable = false, unique = true)
    private String username;

    @ManyToMany
    @JoinTable(name = "axe_user_role"
            , joinColumns = @JoinColumn(name = "user_id")
            , inverseJoinColumns = @JoinColumn(name = "role_id"))
    private Set<Role> roles;

    ...

Role实体

@DynamicInsert
@Entity
@Table(name = "axe_role")
public class Role extends Base implements Serializable {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(name = "name", nullable = false, length = 16, unique = true)
    private String name;

    @Column(name = "description", nullable = false, length = 255)
    private String description;

    @ManyToMany(mappedBy = "roles")
    private Set<User> users;
}

实际应用测试发现User可以获取到roles，但是Roles的users属性为null。

建立双向关联
https://blog.csdn.net/csdndz/article/details/101542214