[英]Using Hibernate to persist a one-to-many list with a superclass type
有人在Hibernate論壇上問了這個問題,我在這里鏈接到它,因為我有同樣的問題。 似乎沒有人在那里提供任何幫助,所以我希望這可能更有用。
這里是:
謝謝。
有趣。 這就是我所做的
package br.com.ar.model.domain.Parent;
@Entity
public class Parent implements Serializable {
private Integer id;
private AbstractChild[] childArray;
@Id
@GeneratedValue
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
@OneToMany
@IndexColumn(name="CHILD_INDEX", nullable=false)
@JoinColumn(name="PARENT_ID", nullable=false)
@Cascade(CascadeType.SAVE_UPDATE)
public AbstractChild[] getChildArray() {
return childArray;
}
public void setChildArray(AbstractChild[] childArray) {
this.childArray = childArray;
}
}
現在我們的AbstractChild數組( 你確定你已經定義了你的AbstractChild(這里,它扮演Book類的角色)作為抽象 ??? )
package br.com.ar.model.domain;
@Entity
/**
* I am using InheritanceType.SINGLE_TABLE instead of TABLE_PER_CLASS
* Because MySQL (DB used) DOES NOT SUPPORT identity generation strategy
* Otherwise, i will get some Exception
*/
@Inheritance(strategy=InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(
name="BILLING_DETAILS_TYPE",
discriminatorType=DiscriminatorType.STRING
)
/**
* ARE YOU SURE your Book class HAS BEEN MARKED AS abstract
*/
public abstract class AbstractChild implements Serializable {
private Integer id;
@Id
@GeneratedValue(strategy=GenerationType.AUTO)
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
}
mapping.hbm.xml(類路徑的根)
<hibernate-mapping>
<class name="br.com.ar.model.domain.AbstractChild" abstract="true">
<id column="id" name="id" type="integer">
<generator class="native"/>
</id>
<discriminator column="BILLING_DETAILS_TYPE" type="string"/>
<subclass name="br.com.ar.model.domain.Child" discriminator-value="CC">
<property name="someProperty" type="string"/>
</subclass>
<!--I CAN NOT USE union-subclass because MySQL does not support DB identity generation strategy-->
<!--union-subclass name="br.com.ar.model.domain.Child">
<property name="someProperty" type="string"/>
</union-subclass-->
</class>
<class name="br.com.ar.model.domain.Parent">
<id column="id" name="id" type="integer">
<generator class="native"/>
</id>
<array name="childArray" cascade="all">
<key column="PARENT_ID"/>
<index column="SORT_ORDER"/>
<one-to-many class="br.com.ar.model.domain.AbstractChild"/>
</array>
</class>
</hibernate-mapping>
現在讓我們來測試吧
同
@Test
public void doWithAnnotations() {
AnnotationConfiguration configuration = new AnnotationConfiguration();
SessionFactory sessionFactory = configuration
.addAnnotatedClass(Parent.class)
.addAnnotatedClass(Child.class)
.addAnnotatedClass(AbstractChild.class)
.setProperty(Environment.DRIVER, "com.mysql.jdbc.Driver")
.setProperty(Environment.URL, "jdbc:mysql://127.0.0.1:3306/ar")
.setProperty(Environment.USER, "root")
.setProperty(Environment.PASS, "root")
.setProperty(Environment.SHOW_SQL, "true")
.setProperty(Environment.FORMAT_SQL, "true")
.setProperty(Environment.DIALECT, "org.hibernate.dialect.MySQLDialect")
.setProperty(Environment.HBM2DDL_AUTO, "create-drop").buildSessionFactory();
Session session = sessionFactory.openSession();
session.beginTransaction();
Parent parent = new Parent();
parent.setChildArray(new AbstractChild[] {new Child("AAA"), new Child("BBB")});
session.save(parent);
session.getTransaction().commit();
session.close();
}
沒有
@Test
public void doWithoutAnnotations() {
Configuration configuration = new Configuration().configure();
SessionFactory sessionFactory = configuration.buildSessionFactory();
Session session = sessionFactory.openSession();
session.beginTransaction();
Parent parent = new Parent();
parent.setChildArray(new AbstractChild[] {new Child("AAA"), new Child("BBB")});
session.save(parent);
session.getTransaction().commit();
session.close();
}
兩者都很好!
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.