Spring Data JPA/Hibernate 处理关联

Question

我需要基于参数检索或不是来自实体的一些关联。在下面的示例中，仅当参数通过我的 api 传递时，我才需要获取记录列表。你能推荐一种使用休眠/弹簧数据实现这一目标的方法吗？我正在寻找最干净和类似弹簧数据的方法。

public class Customer {
  private UUID id;

  @OneToMany(mappedBy = "customer")

  private List<Record> records = new ArrayList<>();
}

public class Record {
    private UUID id;

    @Column(name = "customer_id", length = 36, columnDefinition = "varchar(36)", nullable = false)
    private UUID customerId;
    
    @JoinColumn(name = "customer_id", insertable = false, updatable = false)
    private Customer customer;
}

我的仓库是空的：

public interface CustomerRepository extends JpaRepository<Customer, UUID> {

}

在我的服务中，我正在做类似的事情：

Customer customer = customerRepository.findById(customerId).orElseThrow(() -> new CustomerNotFoundException("customerId", customerId));

但我想做的是：

if (showRecords) {
    Customer customer = customerRepository.findById(customerId).orElseThrow(() -> new CustomerNotFoundException("customerId", customerId));
} else {
    Customer customer = customerRepository.findByIdWithoutAssociations(customerId).orElseThrow(() -> new CustomerNotFoundException("customerId", customerId));
}

Answer 1

如何使用基础findById 仅返回客户对象并使用另一个方法findWithRecordsById 使用@EntityGraph 返回客户+记录？

public interface CustomerRepository extends JpaRepository<Customer, UUID>{

    @EntityGraph(attributePaths = {"records"})
    Customer findWithRecordsById(UUID id);
...
}