我想使用 JPA/Hibernate Criteria API 加載特定客戶的所有 CustomerRequests。
具體來說：我想加載所有 CustomerRequest，其中存在具有特定 customerId 的 CustomerRequest2Customer 條目。
@Entity
public class CustomerRequest {
@Id
private int id;
private int priority;
@OneToMany(mappedBy = "customerRequestId")
private List<CustomerRequest2Customer> listCustomerRequestToCustomer; // <- Query this field
}
@Entity
public class CustomerRequest2Customer {
@Id
private int id;
@ManyToOne
private Customer customer; // <- Query this field
@ManyToOne
private CustomerRequest customerRequest;
}
@Entity
public class Customer {
@Id
private int id; // <- Query this field
private String name;
}
我目前如何查詢其他欄位：
CriteriaBuilder cb = entityManager.getCriteriaBuilder();
CriteriaQuery<CustomerRequest> cq =
cb.createQuery(CustomerRequest.class);
Root<CustomerRequest> root = cq.from(CustomerRequest.class);
cq.where(cb.equal(root.get("priority"), 1));
return entityManager.createQuery(cq).getResultList();
uj5u.com熱心網友回復：
您必須像這樣加入物體：
CriteriaBuilder cb = entityManager.getCriteriaBuilder();
CriteriaQuery<CustomerRequest> cq = cb.createQuery(CustomerRequest.class);
Root<CustomerRequest> root = cq.from(CustomerRequest.class);
Join<CustomerRequest, CustomerRequest2Customer> customerRequest2Customer = root.join("listCustomerRequestToCustomer");
Join<CustomerRequest2Customer, Customer> customer = customerRequest2Customer .join("customer");
cq.where(cb.equal(customer .get("id"), 1));
return entityManager.createQuery(cq).getResultList();
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