条件继承：按子字段加入和搜索

Question

我有根实体：

@Data
@NoArgsConstructor
@AllArgsConstructor
@Entity(name = "applications")
public class Application {

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

    @OneToOne(cascade = CascadeType.REFRESH)
    private Customer customer;
}

与父抽象实体有关系：

@Data
@NoArgsConstructor
@AllArgsConstructor
@Entity(name = "customers")
public abstract class Customer {

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

    private String name;
}

还有子实体：

@Data
@NoArgsConstructor
@AllArgsConstructor
@Entity
public class SpecificCustomer extends Customer {
    private String title;
}

我尝试搜索字段：

@Service
@RequiredArgsConstructor
public class UserSearchRepository {

    private final EntityManager entityManager;
    private final PredicateUtils predicate;

    public void search() {
        CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
        CriteriaQuery<Application> criteriaQuery = criteriaBuilder.createQuery(Application.class);
        Root<Application> root = criteriaQuery.from(Application.class);
        Join<Application, Customer> applicationCustomerJoin = root.join(Application_.CUSTOMER, JoinType.LEFT);
        Predicate[] predicates = {
                predicate.like(applicationCustomerJoin.get(Customer_.NAME), "some name") // it works
                // predicate.like(applicationCustomerJoin.get(SpecificCustomer_.TITLE), "some title") // it doesn't work
                
        };
        criteriaQuery.select(root).where(predicates);
        TypedQuery<Application> query = entityManager.createQuery(criteriaQuery);
        List<Application> result = query.getResultList();

        System.out.println("test:");
        System.out.println(result);
    }

    @PostConstruct
    void init() {
        this.search();
    }
}

当我按父项中存在的字段进行搜索时，它起作用了：

predicate.like(applicationCustomerJoin.get(Customer_.NAME), "some name")

但是当我从 child 按字段搜索时它不起作用:

predicate.like(applicationCustomerJoin.get(SpecificCustomer_.TITLE), "some title")

异常：

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userSearchRepository': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Unable to locate Attribute  with the the given name [title] on this ManagedType [my.Customer]
...
Caused by: java.lang.IllegalArgumentException: Unable to locate Attribute  with the the given name [title] on this ManagedType [my.Customer]
    at my.UserSearchRepository.search(UserSearchRepository.java:32) ~[classes/:na]

我无法更改模型的设计。

Answer 1

我发现我可以在第一个连接上使用方法 treat 并创建具有特定类型的第二个连接：

Join<Application, Customer> applicationCustomerJoin = root.join(Application_.CUSTOMER, JoinType.LEFT);
Join<Application, SpecificCustomer> applicationSpecificCustomerJoin = criteriaBuilder.treat(applicationCustomerJoin, SpecificCustomer.class);
Predicate[] predicates = {
        predicate.like(applicationSpecificCustomerJoin.get(SpecificCustomer_.TITLE), "some title")
};

条件继承：按子字段加入和搜索

Criteria inheritance: join and search by child field

java

hibernate

jpa

criteria