Hibernate多态查询

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Hibernate多态查询5

我的代码有问题，直接查询子类可以，但是通过父类查询子类就不行无法正确执行查询，请教大家！
hbm.xml文件
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping
package="cn.edu.buaa.software.lee.hibernate.helloworld.domain">

<class name="BillingDetails" abstract="true">

<id name="id" column="BILLING_DETAILS_ID" type="long">
<generator class="native">
<param name="sequence">SEQ_BILLING_DETAILS</param>
<param name="parameters">INCREMENT BY 1 START WITH 1</param>
</generator>
</id>
<property name="owner" column="OWNER" type="string"/>

<union-subclass name="CreditCard" table="TB_CREDIT_CARD">
<property name="number" column="`NUMBER`" type="string" />
<property name="expMonth" column="`EXP_MONTH`" type="string"/>
<property name="expYear" column="`EXP_YEAR`" type="string" />
</union-subclass>

<union-subclass name="BankAccount" table="TB_BANK_ACCOUNT">
<property name="account" column="ACCOUNT" type="string"/>
<property name="bankName" column="BANK_NAME" type="string"/>
<property name="swift" column="SWIFT" type="string"/>
</union-subclass>
</class>
</hibernate-mapping>
Java代码：
public static void main(String[] args) {

Session session = HibernateUtil.getSession();
Transaction transaction = session.beginTransaction();

BankAccount bAccount = new BankAccount();
bAccount.setOwner("Owner Of BankAccount");
bAccount.setAccount("Account");
bAccount.setBankName("BankName");
bAccount.setSwift("Swift");
session.save(bAccount);

CreditCard cCard = new CreditCard();
cCard.setOwner("Owmer Of CreditCard");
cCard.setNumber("Number");
cCard.setExpYear("Year");
cCard.setExpMonth("Month");
session.save(cCard);

transaction.commit();
session.close();

Session newSession = HibernateUtil.getSession();
Transaction newTransaction = newSession.beginTransaction();

// Query query = newSession.createQuery("FROM CreditCard");
// List<BillingDetails> bDetails = query.list();
// System.out.println("Number of CreditCard: " + bDetails.size());

// Query query = newSession.createQuery("FROM BankAccount");
// List<BillingDetails> bDetails = query.list();
// System.out.println("Number of BankAccount: " + bDetails.size());

Query query = newSession.createQuery("from BillingDetails");
List<BillingDetails> bDetails = query.list();
System.out.println("Number of BillingDetails: " + bDetails.size());

newTransaction.commit();
newSession.close();

HibernateUtil.shutdown();
}

Hibernate

2009年7月23日 16:01

lishulonglee
15
0 0 0

1个答案按时间排序按投票排序

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如果不需要支持多态查询和多态关联，可以采用每个具体类对应一个表的映射方式，如果需要支持多态查询和多态关联，并且子类包含的属性不多，可以采用根类对应一个表的映射方式，如果需要支持多态查询和多态关联，并且子类包含的属性很多，可以采用每个类对应一个表的映射方式。如果继承关系树中包含接口，可以把它当做抽象类来处理。

所以：把两个子类映射到一张表上试试。

2009年7月24日 13:46

layer555
453
0 0 0