Question

我有两张桌子，一张是用户，另一张是员工

用户：

public class User {

    private int id;

    private String userName;

    private String password;

    private Employee employee;

    // Getter and setter
}

User.hbm.xml：

<hibernate-mapping>
    <class name="com.site.dto.User" table="user">

        <id name="id" type="java.lang.Integer">
            <column name="id" />
            <generator class="identity" />
        </id>
        <property name="userName" type="string">
            <column name="user_name" length="50" not-null="true" unique="true" />
        </property>

        <property name="password" type="string">
            <column name="password" length="50" not-null="true" unique="true" />
        </property>

        <one-to-one name="employee" class="com.site.dto.Employee" fetch="join" cascade="all"/>
    </class>
</hibernate-mapping>

员工：

public class Employee implements Serializable{

    private static final long serialVersionUID = 1L;

    private int id;

    private String name;

    private User user;

    // Getter and setter

}

Employee.hbm.xml：

<hibernate-mapping>
    <class name="com.site.dto.Employee" table="employee">

        <id name="id" type="java.lang.Integer">
            <column name="id" />
            <generator class="identity" />
        </id>

        <property name="name" type="string">
            <column name="name" length="50" not-null="true" unique="true" />
        </property>

        // I'm enforcing the many-to-one to one-to-one by adding unique="true"
        <many-to-one name="user" column="user_id" class="com.site.dto.User" not-null="true" unique="true" fetch="join" cascade="all"/>      
    </class>
</hibernate-mapping>

登录后，我正在提取用户表

User user = userService.getCredentials(sessionDetails.getLoginUserName());
Employee employee = user.getEmployee();

DaoImpl代码：

@Transactional
public User getCredentials(String userName) {
    Criteria cr = getSession().createCriteria(User.class);
    cr.add(Restrictions.eq("userName", userName));
    return (User) cr.uniqueResult();
}

为了验证，我尝试了System.out.println(employee.getId());，但它返回了null。事实上，不是直接为null，因为空指针异常意味着它是空的。我尝试更改了获取类型，但我无法获得员工对象。为了进一步验证我至少获取用户对象，我在sysout user.getId();

时获得了预期的用户ID

昨天我在hibernate注释中使用了所有映射而不是hbm.xml。那时我已经为用户和员工提供了@ One-to-One注释，并且它正在成功运行。但今天我已将所有内容更改为hbm.xml，并且出现问题。

无法使用hbm.xml配置获取一对一的子节点

0 个答案: