Java JPA：在三个实体之间使用多对多关系后的冗余sql插入

我拥有用户、角色和权限实体，并使用嵌入式数据库进行开发。用户和角色具有多对多关系，角色和权限也具有多对多关系： 1） 用户实体：

@Entity
@Table(name = "usr")
@JsonIgnoreProperties(ignoreUnknown = true)
public class User implements Serializable {

    private static final long serialVersionUID = 818129969599480161L;
    /**
     * Unique id for the User. "@Id" declare the parameter as the primary key
     * "@GeneratedValue" indicates JPA 2 (and behind Hibernate) which strategy
     * to use for creating a new value.
     * "GenerationType.AUTO" value allow JPA implementation to use the better way depending to the RDBMS used.
     */
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Integer id;
    /**
     * Login of the user. No annotation here, the parameter will be automatically mapped in the table.
     */
    private String login;
    /**
     * Password of the user. No annotation here, the parameter will be automatically mapped in the table.
     */
    private String password;

    @ManyToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL)
    @JoinTable(name = "USER_ROLES",
            joinColumns =
            @JoinColumn(name = "user_id"),
            inverseJoinColumns =
            @JoinColumn(name = "role_id"))
    private Set<Role> roles = new HashSet<>();
.....(getters and setters)

}

---

在日志中，我看到这一切都是创建的，但为什么我还不知道，请帮助日志位于此处：

您正在分别保存用户、角色和权限。这将导致多个记录。由于您已经给出了级联所有保存用户对象也将保存角色对象和权限对象

像这样试试

public void afterPropertiesSet() throws Exception {
_logger.debug("setting test uses data");

User user = new User();
user.setLogin("dmitro");
user.setPassword("2424");
user.setStatus(UserStatus.ACTIVE);
Set<Role> roles = new HashSet<Role>();
Role role = new Role();
role.setRoleName("ROLE_ADMIN");
Set<Permission> permissions = new HashSet<>();
Permission permission = new Permission();
permission.setPermissionName("PERM_SAVE_PRODUCT");
permissions.add(permission);
role.setPermissions(permissions);
roles.add(role);
user.setRoles(roles);
userRepository.save(user);

public void afterPropertieSet（）引发异常{
_调试（“设置测试使用数据”）；
用户=新用户（）；
user.setLogin（“dmitro”）；
user.setPassword（“2424”）；
user.setStatus（UserStatus.ACTIVE）；
Set roles=new HashSet（）；
角色=新角色（）；
role.setRoleName（“role_ADMIN”）；
Set permissions=new HashSet（）；
权限权限=新权限（）；
permission.setPermissionName（“PERM_SAVE_PRODUCT”）；
权限。添加（权限）；
角色。设置权限（权限）；
角色。添加（角色）；
user.setRoles（角色）；
userRepository.save（用户）；

}

---

关于cascade，请参见。希望能有所帮助

非常感谢！，您提供的文档和代码片段解决了我的问题

    @Entity
    public class Permission {
        @Id
        @GeneratedValue(strategy = GenerationType.AUTO)
        private int id;
        private String permissionName;

        @ManyToMany(mappedBy = "permissions", fetch=FetchType.EAGER, cascade = {})
        private Set<Role> roles = new HashSet<>();
    .....(getters and setters)

public void afterPropertiesSet() throws Exception {
    _logger.debug("setting test uses data");

    Permission permission = new Permission();
    permission.setPermissionName("PERM_SAVE_PRODUCT");

    permissionRepository.save(permission);

    Role role = new Role();
    role.setRoleName("ROLE_ADMIN");
    Set<Permission> permissions = new HashSet<>();
    permissions.add(permission);
    role.setPermissions(permissions);

    roleRepository.save(role);

    User user = new User();
    user.setLogin("dmitro");
    user.setPassword("2424");
    user.setStatus(UserStatus.ACTIVE);
    Set<Role> roles = new HashSet<Role>();
    roles.add(role);
    user.setRoles(roles);

    userRepository.save(user);
}

{
"links": [
],
"content": [
    {
        "links": [
            {
                "rel": "roles.Role.permissions",
                "href": "http://localhost:8080/admin/roles/1/permissions"
            },
            {
                "rel": "self",
                "href": "http://localhost:8080/admin/roles/1"
            },
            {
                "rel": "roles.Role.users",
                "href": "http://localhost:8080/admin/roles/1/users"
            }
        ],
        "roleName": "ROLE_ADMIN"
    },
    {
        "links": [
            {
                "rel": "roles.Role.permissions",
                "href": "http://localhost:8080/admin/roles/2/permissions"
            },
            {
                "rel": "self",
                "href": "http://localhost:8080/admin/roles/2"
            },
            {
                "rel": "roles.Role.users",
                "href": "http://localhost:8080/admin/roles/2/users"
            }
        ],
        "roleName": "ROLE_ADMIN"
    }
],
"page": {
    "size": 20,
    "totalElements": 2,
    "totalPages": 1,
    "number": 1
}

public void afterPropertiesSet() throws Exception {
_logger.debug("setting test uses data");

User user = new User();
user.setLogin("dmitro");
user.setPassword("2424");
user.setStatus(UserStatus.ACTIVE);
Set<Role> roles = new HashSet<Role>();
Role role = new Role();
role.setRoleName("ROLE_ADMIN");
Set<Permission> permissions = new HashSet<>();
Permission permission = new Permission();
permission.setPermissionName("PERM_SAVE_PRODUCT");
permissions.add(permission);
role.setPermissions(permissions);
roles.add(role);
user.setRoles(roles);
userRepository.save(user);