Copy this link when reproducing:
http://www.casperlee.com/en/y/blog/183
According to its official document (https://docs.spring.io/spring/docs/2.5.x/javadoc-api/org/springframework/orm/hibernate3/HibernateTemplate.html), HibernateTemplate is a helper class that simplifies Hibernate data access code. Let's find out how it simplifies the code and how to let it works.
With the help of the class "org.hibernate.SessionFactory", we can access the database and perform the actions like Add, Update, or Delete, for instance:
public void add(Day aDay) {
Session session = this.sessionFactory.openSession();
Transaction trans = session.beginTransaction();
try {
session.persist(aDay);
trans.commit();
}
catch (Exception ex) {
// dealing with the exceptions
trans.rollback();
}
}
public void update(Day aDay) {
Session session = this.sessionFactory.openSession();
Transaction trans = session.beginTransaction();
try {
session.update(aDay);
trans.commit();
}
catch (Exception ex) {
// dealing with the exceptions
trans.rollback();
}
}
public void del(Day aDay) {
Session session = this.sessionFactory.openSession();
Transaction trans = session.beginTransaction();
try {
session.delete(aDay);
trans.commit();
}
catch (Exception ex) {
// dealing with the exceptions
trans.rollback();
}
}Clearly, this is very frustrating. Each method is very long and contains similar code to deal with transactions and exceptions. With the help of HibernateTemplate, we can make the method a lot shorter, and we only need to write the core code, and HibernateTemplate will take care of transactions and exceptions for us:
public void add(Day aDay) {
template.save(aDay);
}
public void update(Day aDay) {
template.update(aDay);
}
public void delete(Day aDay) {
template.delete(aDay);
}Now, let's see how to use Hibernate template in my application.
1. Open the configuration file "WebContent\WEB-INF\config\springmvc-config.xml".
I. Add a definition for HibernateTemplate:
<bean id="hibernateTemplate" class="org.springframework.orm.hibernate5.HibernateTemplate">
<property name="sessionFactory" ref="hibernateAnnotatedSessionFactory"></property>
</bean>II. Add a definition for HibernateTransactionManager:
<bean id="transactionManager" class="org.springframework.orm.hibernate5.HibernateTransactionManager">
<property name="sessionFactory" ref="hibernateAnnotatedSessionFactory"></property>
</bean>III. In case you forgot, I've defined the hibernateAnnotatedSessionFactory:
<bean id="hibernateAnnotatedSessionFactory"
class="org.springframework.orm.hibernate5.LocalSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="annotatedClasses">
<list>
<value>com.casperlee.today.domain.Day</value>
<value>com.casperlee.today.domain.DayEvent</value>
<value>com.casperlee.today.domain.DayBirth</value>
<value>com.casperlee.today.domain.DayDeath</value>
<value>com.casperlee.today.domain.DayFestival</value>
</list>
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
<!--
<prop key="hibernate.current_session_context_class">thread</prop>
-->
<prop key="hibernate.show_sql">false</prop>
</props>
</property>
</bean>IV. Remove or comment the line of "<prop key="hibernate.current_session_context_class">thread</prop>".
V. Enable the transaction manager we have just defined:
<tx:annotation-driven transaction-manager="transactionManager" />VI. To use the "tx" prefix, we need to include the following lines in the header:
<beans xmlns="http://www.springframework.org/schema/beans"
...
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:aop="http://www.springframework.org/schema/aop"
...
xsi:schemaLocation="
...
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop.xsd
...>2. Use the template in the data access class:
@Service
@Transactional
public class DayServiceImpl implements DayService {
@Autowired
private HibernateTemplate template;
@Override
public Day getByKey(String aKey) {
Session session = template.getSessionFactory().openSession();
Query<Day> query = session.createQuery("from Day where key = :keyName", Day.class);
query.setParameter("keyName", aKey);
return query.uniqueResult();
}
@Override
public void add(Day aDay) {
template.save(aDay);
}
@Override
public void update(Day aDay) {
template.update(aDay);
}
@Override
public void delete(Day aDay) {
template.delete(aDay);
}
}3. Done!