Spring Framework之最佳实践二

转载地址：http://www.gpowersoft.com/tech/Spring/46.htm

 

Spring Framework最得以出名的是与Hibernate的无缝链接，基本上用Spring，就会用Hibernate。可惜的是Spring提供的HibernateTemplate功能显得不够，使用起来也不是很方便。我们编程序时，一般先写BusinessService，由BusinessService调DAO来执行存储，在这方面Spring没有很好的例子，造成真正想用好它，并不容易。

 

 

我们的思路是先写一个BaseDao，仿照HibernateTemplate，将基本功能全部实现：

 

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，从BaseDao继承出来，这样写其他的DAO，代码就会很少。

从BaseDao继承出来EntityDao，专门负责一般实体的基本操作，会更方便。

 

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{

}

 

 

为了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);
    }
...

}

 

 

这样我们就有了一个通用的Hibernate实体引擎，可以对任何Hibernate实体实现基本的增加、修改、删除、查询等。

其它的BusinessService就可以继承EntityManager，快速实现业务逻辑。

 

具体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>