Hibernate:如何刷新子实体

Question

我有一个"登录"域对象:

public class Login extends AuditEntity {

private static final long serialVersionUID = -309839789761736747L;

private String userName;
private String password;
private Timestamp lastLogin;
private Set customers = new HashSet(0);
private Set addresses = new HashSet(0);

public Set getCustomers() {
    return this.customers;
}

public void setCustomers(Set customers) {
    this.customers = customers;
}

public Set getAddresses() {
    return this.addresses;
}

public void setAddresses(Set addresses) {
    this.addresses = addresses;
}
   //Other setter, getters

这是来自hibernate映射文件的片段:

        <set name="customers" fetch="select" lazy="false">
        <key>
            <column name="LoginID" />
        </key>
        <one-to-many class="com.domain.Customer" />
    </set>
    <set name="addresses" fetch="join" lazy="false">
        <key>
            <column name="LoginID" />
        </key>
        <one-to-many class="com.domain.Address" />
    </set>

登录参考的Address.hbm.xml映射如下所示:

    <many-to-one name="login" class="com.domain.Login"
        fetch="join" lazy="false">
        <column name="LoginID" />
    </many-to-one>

这是我的春季测试:

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = { "/applicationContext.xml" })
public class LoginDaoTest {

@Autowired
private BaseDao<Login, Integer> loginDao;

@Autowired
private BaseDao<Address, Integer> addressDao;

@Test
public void testLoginDao() {
    Login login = loginDao.load(1);
    Set<Address> addresses = login.getAddresses();

    System.out.println("size Before save..." + addresses.size());

    Address address = new Address();
    address.setCity("Kew gardens");
    address.setCreatedBy("user");
    address.setCreatedDate(new Timestamp(Calendar.getInstance().getTime().getTime()));
    address.setHouseNumber("1-2-3");
    address.setLogin(login);
    address.setLocality("Queens blvd");
    address.setState("NY");
    address.setStreetName("Some Street");
    address.setZipCode("11415");

    addressDao.save(address);

    System.out.println("size After save..." + addresses.size());

}

}

这是输出:

size Before save...14
size After save...14

问题/问题由于我没有懒惰加载,因此我希望在添加新地址后看到登录对象中设置的地址增加1.为什么我的套装不会增长？是因为我在同一个交易中运行查询吗？

谢谢.

Answer 1

您负责维护对象的内存状态.Hibernate不会自动将该地址粘贴到列表中.要编写严格正确的代码,您应该在创建时将新地址添加到列表中,以使您的内存状态与您想要持久保存的状态相匹配.

然后,您可以使用Transitive Persistence创建新地址,根本不需要在地址上调用"save".

从概念上讲,它与你期望的相反.框架的目的不是将数据库神奇地"绑定"到对象上.这是让你以与没有数据库时相同的方式使用普通对象(例如,将东西放入它们中的列表中),并且让你的对象状态的持久性神奇地发生.