具有@OneToMany关系的Java Spring Data @Query不返回任何结果

Question

我有以下实体:

@Entity
public class Customer extends BaseEntity {

    private String firstname;
    private String lastname;
    @OneToMany(mappedBy = "customer", cascade = CascadeType.ALL)
    private Set<Address> addresses;

    ...

@Entity
public class Address extends BaseEntity {

    private String street;
    private String houseNumber;
    private String zipCode;
    private String city;
    @ManyToOne
    private Customer customer;

    ...

以及以下存储库接口(interface)类:

@Repository
public interface CustomerRepository extends CrudRepository<Customer, Long> {

    @Query("select c from Customer c join c.addresses a where (a.city = :cityName)")
    List<Customer> findByCity(@Param("cityName")String city);

}

现在，我正在尝试运行以下集成测试，但它失败了，我完全不知道为什么。不幸的是，我是 Spring 的初学者，我正在努力学习它 ;-)

@Test
public void testFindCustomerByCity() {
    Customer customer = new Customer("Max", "Tester");
    Address address = new Address("Street", "1", "12345", "City");
    HashSet<Address> addresses = new HashSet<Address>();
    addresses.add(address);
    customer.setAddresses(addresses);
    Customer savedCustomer = customerRepository.save(customer);
    Assert.assertTrue(savedCustomer.getId() > 0);

    List<Customer> customerList = customerRepository.findByCity("City");
    Assert.assertThat(customerList.size(), is(1));
}

错误信息是:

java.lang.AssertionError: Expected: is <1> but: was <0>

为什么结果是空的。我的测试设置错了吗？实体关系？没关系，如果你能帮助我。

Answer 1

您可以使用这样的查询方法。使用下划线 (_) 获取子属性。

@Repository
public interface CustomerRepository extends JpaRepository<Customer, Long> {
    List<Customer> findByAddresses_City(String city);
}