java - Hibernate在对象关系中全部抛出空指针异常

Question

我有 2 个类，即与 Address 类具有多对一关系的 Person 类。当我试图获取人员时，地址对象内部有空元素，为什么会发生这种情况？惰性配置不起作用？我可以级联保存一个包含地址的 Person 对象。

这是我的代码:

人员类别:

public class Person  implements java.io.Serializable {

    private int idPerson;
    private String name;
    private String surname;
    private String dni;
    private Date dateBirth;
    private String cellPhone;
    private String landPhone;
    private String email;
    private String discr;
    private Address address ;
   
    public Person() {
    }
    // getters and setters
}

我的地址类:

public class Address  implements java.io.Serializable {

    private int idAddress;
    private City city;
    private String street;
    private String number;
    private Integer apartament;
    private int level;

    public Address() {
    }
    //getters an setters
}

我的两个映射文件:

<hibernate-mapping>
    <class name="com.efix.model.enterprise.Address" table="address" schema="public">
        <id name="idAddress" type="int">
            <column name="id_address" />
            <generator class="assigned" />
        </id>
        <many-to-one name="city" class="com.efix.model.enterprise.City" cascade="all" lazy="false">
            <column name="id_city" not-null="true" />
        </many-to-one>
        <property name="street" type="string">
            <column name="street" length="60" not-null="true" />
        </property>
        <property name="number" type="string">
            <column name="number" length="6" />
        </property>
        <property name="apartament" type="java.lang.Integer">
            <column name="apartament" />
        </property>
        <property name="level" type="int">
            <column name="level" not-null="true" />
        </property>
    </class>
</hibernate-mapping>

上面是地址映射，这是我的人员映射:

<hibernate-mapping>
    <class name="com.efix.model.enterprise.Person" table="person" schema="public">
        <id name="idPerson" type="int">
            <column name="id_person" />
            <generator class="identity" />
        </id>
        <discriminator column="discr" type="string"/>
        <property name="name" type="string">
            <column name="name" length="40" not-null="true" />
        </property>
        <property name="surname" type="string">
            <column name="surname" length="40" not-null="true" />
        </property>
        <property name="dni" type="string">
            <column name="dni" length="40" />
        </property>
        <property name="dateBirth" type="date">
            <column name="date_birth" length="13" />
        </property>
        <property name="cellPhone" type="string">
            <column name="cell_phone" length="20"/>
        </property>
        <property name="landPhone" type="string">
            <column name="land_phone" length="20"/>
        </property>
        <property name="email" type="string">
            <column name="email" length="25" />
        </property>
        <many-to-one class="com.efix.model.enterprise.Address" name="address">
            <column name="id_address" not-null="true"/>
        </many-to-one>
        <!-- Subclase Empleado -->
        <subclass name="com.efix.model.enterprise.Employee" discriminator-value="Employee">
            <property name="admissionDate" type="date">
                <column name="admission_date" length="13" />
            </property>
            <property name="outDate" type="date">
                <column name="out_date" length="13" />
            </property>
            <property name="position" type="string">
                <column name="position" length="40" />
            </property>
        </subclass>

        <!-- Sublcase cliente -->
        <subclass name="com.efix.model.enterprise.Client" discriminator-value="Client">
            <property name="notes" type="string">
                <column name="notes" />
            </property>
        </subclass>

    </class>
</hibernate-mapping>

我的 NullPointerException 在这段代码中抛出:

ClientServiceImpl serviceImpl = new ClientServiceImpl();
for (Client cli : serviceImpl.findAll()) {
    System.out.println(cli.getAddress().getNumber());

Answer 1

谢谢您的回复!!我的错误出在 .我引用了一个不存在的属性(property)!!