spring data jpa find all by example nested collection property

Question

I have two objects. The company that can have multiple nested addresses.

@Entity
@Data
@Table(name = "company")
public class Company {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id")
    private Long id;

    @Column(name = "name")
    private String name;

    @Column(name = "phone")
    private String phone;

    @OneToMany(mappedBy = "company", cascade = CascadeType.ALL, orphanRemoval = true, fetch = FetchType.LAZY)
    private List<Address> addresses;
}

Address class looks like this:

@Data
@Entity
@Table(name = "address")
@ToString(exclude = "company")
public class Address {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id")
    private Long id;

    @Column(name = "postal_code")
    private String postalCode;

    @Column(name = "city")
    private String city;

    @Column(name = "street")
    private String street;

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

I want somehow if it's possible, make a dynamic query that searches through the nested collection property. I made a search method which uses example matcher but the result is wrong. Every time I got everything from DB, not only company with address postal code that I'm looking for.

My search method looks like this:

@PostMapping("/search")
    public List<Company> search(@RequestBody final Company company){
        return companyRepository.findAll(Example.of(company,
                ExampleMatcher.matchingAny()
                        .withIgnoreNullValues()
                        .withIgnorePaths("id")
                        .withStringMatcher(ExampleMatcher.StringMatcher.STARTING)));
    }

In my database, I have two objects and this is the result of the search:

As you can see I received everything from DB instead of the only first company which address postal code starts with 1.

Answer 1

Hi you can use Specification<T>

https://spring.io/blog/2011/04/26/advanced-spring-data-jpa-specifications-and-querydsl/

For this you need to extend from interface JpaSpecificationExecutor:

public interface UserRepository extends JpaRepository<User> ,JpaSpecificationExecutor<User>{
}

And you also need to implement your custom Specification<T>

And then you can use repository.findAll(your impleneted Specification);

Spring docs :

https://docs.spring.io/spring-data/jpa/docs/current/api/org/springframework/data/jpa/repository/JpaSpecificationExecutor.html

I think this is helpful.