如何在Spring Boot中通过检查嵌套对象来获取对象？

Question

I am unable to to get what i intend using a JpaRepository. I'll try to explain what I want using the following code:

Repository

 @Repository
public interface CompanyRepository extends JpaRepository<Company, Long> {

    Optional<Company> findByIdAndBranches_parent_idIsNull(Long id);
}

Service

@Service
public class BillService {

@Autowired
private CompanyRepository companyRepository;

@Autowired
private BranchRepository branchRepository;

public Company getCompanyById(Long id)
{
    Optional<Company> company = companyRepository.findByIdAndBranches_parent_idIsNull(id);
    return company.get();
}

Company Entity class

public class Company 
{
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;

private String name;

private String address;

@OneToMany(mappedBy = "company")
private List<Branch> branches;

@OneToMany(mappedBy = "company")
private List<User> users;

}

Branch Entity class

@Entity
public class Branch 
{
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;

private String name;

private String address;

@JsonIgnore
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "company_id")
private Company company;

@JsonIgnore
@ManyToOne(cascade = CascadeType.ALL )
@JoinColumn(name = "parent_id")
@NotFound(action = NotFoundAction.IGNORE)
private Branch parent;

@OneToMany(mappedBy = "parent")
@NotFound(action = NotFoundAction.IGNORE)
private List<Branch> subBranches;

@OneToMany(mappedBy = "branch")
private List<User> users;

}

Now what i want to get is company with branches having parent id NULL but am getting all branches irrespective of parent id

This is what i want as result

{
"id": 1,
"name": "Lakshya",
"address": "Bahadurgarh",
"branches": [
    {
        "id": 1,
        "name": "Lakshya Branch1",
        "address": "Bahadurgarh1",
        "subBranches": [
            {
                "id": 3,
                "name": "Lakshya Branch1_3",
                "address": "Bahadurgarh1_3",
                "subBranches": [],
                "users": []
            }
        ],
        "users": [
            {
                "id": 3,
                "name": "User3_Company1_Branch1",
                "address": "Bgz"
            }
        ]
    }
],
"users": [
    {
        "id": 1,
        "name": "User_Company1",
        "address": "Bgz"
    },
    {
        "id": 2,
        "name": "User_Company1_Branch1",
        "address": "Bgz"
    },
    {
        "id": 3,
        "name": "User3_Company1_Branch1",
        "address": "Bgz"
    }
]
}

But this is what am getting

{
"id": 1,
"name": "Lakshya",
"address": "Bahadurgarh",
"branches": [
    {
        "id": 1,
        "name": "Lakshya Branch1",
        "address": "Bahadurgarh1",
        "subBranches": [
            {
                "id": 3,
                "name": "Lakshya Branch1_3",
                "address": "Bahadurgarh1_3",
                "subBranches": [],
                "users": []
            }
        ],
        "users": [
            {
                "id": 3,
                "name": "User3_Company1_Branch1",
                "address": "Bgz"
            }
        ]
    },
    {
        "id": 3,
        "name": "Lakshya Branch1_3",
        "address": "Bahadurgarh1_3",
        "subBranches": [],
        "users": []
    }
],
"users": [
    {
        "id": 1,
        "name": "User_Company1",
        "address": "Bgz"
    },
    {
        "id": 2,
        "name": "User_Company1_Branch1",
        "address": "Bgz"
    },
    {
        "id": 3,
        "name": "User3_Company1_Branch1",
        "address": "Bgz"
    }
]

}

Answer 1

If you need to filter out associated entities, you can use @Where . It's not a part of JPA specification, but JPA implementation by Hibernate provides this annotation. So you can specify any additional conditions:

public class Company 
{
    ...

    @OneToMany(mappedBy = "company")
    @Where(clause = "parent_id is null")
    private List<Branch> branches;

    @OneToMany(mappedBy = "company")
    private List<User> users;
}

Then you have to change the repository's method name, since you don't need extra condition anymore:

@Repository
public interface CompanyRepository extends JpaRepository<Company, Long> {
    Optional<Company> findById(Long id);
}

Using this approach you always get companies with only branches that don't have parent. If you need to get all branches of a company (whether they have parent or not) you can create and use repository for Branch entity class.