Spring Framework最得以出名的是與Hibernate的無縫鏈接，基本上用Spring，就會用Hibernate。可惜的是Spring提供的HibernateTemplate功能顯得不夠，使用起來也不是很方便。我們編程序時，一般先寫BusinessService，由BusinessService調DAO來執行存儲，在這方面Spring沒有很好的例子，造成真正想用好它，并不容易。

我們的思路是先寫一個BaseDao，仿照HibernateTemplate，將基本功能全部實現：

public class BaseDao extends HibernateDaoSupport{

??? private Log log = LogFactory.getLog(getClass());

??? public Session openSession() {
??????? return SessionFactoryUtils.getSession(getSessionFactory(), false);
??? }

??? public Object get(Class entityClass, Serializable id) throws DataAccessException {
??????? Session session = openSession();
??????? try {
??????????? return session.get(entityClass, id);
??????? }
??????? catch (HibernateException ex) {
??????????? throw SessionFactoryUtils.convertHibernateAccessException(ex);
??????? }
??? }

??? public Serializable create(Object entity) throws DataAccessException {
??????? Session session = openSession();
??????? try {
??????????? return session.save(entity);
??????? }
??????? catch (HibernateException ex) {
??????????? throw SessionFactoryUtils.convertHibernateAccessException(ex);
??????? }
??? }

...

其它的DAO，從BaseDao繼承出來，這樣寫其他的DAO，代碼就會很少。

從BaseDao繼承出來EntityDao，專門負責一般實體的基本操作，會更方便。

public interface EntityDao {

??? public Object get(Class entityClass, Serializable id) throws DataAccessException;

??? public Object load(Class entityClass, Serializable id) throws DataAccessException;

??? public Serializable create(Object entity) throws DataAccessException;
...}

/**
?* Base class for Hibernate DAOs.? This class defines common CRUD methods for
?* child classes to inherit. User Sping AOP Inteceptor
?*/
public class EntityDaoImpl extends BaseDao implements EntityDao{

}

為了Transaction的控制，采用AOP的方式：

public interface EntityManager {

??? public Object get(Class entityClass, Serializable id);

??? public Object load(Class entityClass, Serializable id);

??? public Serializable create(Object entity);
...

}

/**
?* Base class for Entity Service. User Sping AOP Inteceptor
?*/
public class EntityManagerImpl implements EntityManager {

??? private EntityDao entityDao;

??? public void setEntityDao(EntityDao entityDao) {
??????? this.entityDao = entityDao;
??? }

??? public Object get(Class entityClass, Serializable id) {
??????? return entityDao.get(entityClass, id);
??? }

??? public Object load(Class entityClass, Serializable id) {
??????? return entityDao.load(entityClass, id);
??? }
...

}

這樣我們就有了一個通用的Hibernate實體引擎，可以對任何Hibernate實體實現基本的增加、修改、刪除、查詢等。

其它的BusinessService就可以繼承EntityManager，快速實現業務邏輯。

具體XML配置如下：

?<!-- Oracle JNDI DataSource for J2EE environments -->
?<bean id="dataSource" class="org.springframework.jndi.JndiObjectFactoryBean">
??<property name="jndiName"><value>java:comp/env/jdbc/testPool</value></property>
?</bean>

?<!-- Hibernate SessionFactory for Oracle -->
?<!-- Choose the dialect that matches your "dataSource" definition -->
?<bean id="sessionFactory" class="org.springframework.orm.hibernate.LocalSessionFactoryBean">
??<property name="dataSource"><ref local="dataSource"/></property>
??<property name="mappingResources">
???<value>user-hbm.xml</value>
??</property>
??<property name="hibernateProperties">
???<props>
????<prop key="hibernate.dialect">net.sf.hibernate.dialect.OracleDialect</prop>
????<prop key="hibernate.cache.provider_class">net.sf.ehcache.hibernate.Provider</prop>
????<prop key="hibernate.cache.use_query_cache">true</prop>
????????????????? <prop key="hibernate.show_sql">false</prop>
???</props>
??</property>
?</bean>

?<!-- AOP DAO Intecepter -->
??????? <bean id="hibernateInterceptor" class="org.springframework.orm.hibernate.HibernateInterceptor">
????????? <property name="sessionFactory">
??????????? <ref bean="sessionFactory"/>
????????? </property>
??????? </bean>

??????? <bean id="entityDaoTarget" class="com.gpower.services.entity.dao.EntityDaoImpl">
????????? <property name="sessionFactory">
??????????? <ref bean="sessionFactory"/>
????????? </property>
??????? </bean>

??????? <bean id="entityDao" class="org.springframework.aop.framework.ProxyFactoryBean">
????????? <property name="proxyInterfaces">
??????????? <value>com.gpower.services.entity.dao.EntityDao</value>
????????? </property>
????????? <property name="interceptorNames">
??????????? <list>
????????????? <value>hibernateInterceptor</value>
????????????? <value>entityDaoTarget</value>
??????????? </list>
????????? </property>
??????? </bean>

?<!-- Transaction manager for a single Hibernate SessionFactory (alternative to JTA) -->
?<bean id="transactionManager" class="org.springframework.orm.hibernate.HibernateTransactionManager">
??<property name="sessionFactory"><ref local="sessionFactory"/></property>
?</bean>

?<!-- Transaction manager that delegates to JTA (for a transactional JNDI DataSource) -->
?<!--
?<bean id="transactionManager" class="org.springframework.transaction.jta.JtaTransactionManager"/>
?-->

?<!-- Transactional proxy for the Application primary business object -->
??????? <bean id="entityManagerTarget" class="com.gpower.services.entity.EntityManagerImpl">
????????? <property name="entityDao">
??????????? <ref bean="entityDao"/>
????????? </property>
??????? </bean>

??????? <bean id="entityManager" class="org.springframework.transaction.interceptor.TransactionProxyFactoryBean">
????????? <property name="transactionManager">
??????????? <ref bean="transactionManager"/>
????????? </property>
????????? <property name="target">
??????????? <ref bean="entityManagerTarget"/>
????????? </property>
????????? <property name="transactionAttributes">
???? <props>
?????? <prop key="get*">PROPAGATION_SUPPORTS</prop>
?????? <prop key="*">PROPAGATION_REQUIRED</prop>
???? </props>
????????? </property>
??????? </bean>