Spring之ORM模块

ORM模块对Hibernate、JDO、TopLinkiBatis等ORM框架提供支持

ORM模块依赖于dom4j.jar、antlr.jar等包

在Spring里，Hibernate的资源要交给Spring管理，Hibernate以及其SessionFactory等知识Spring一个特殊的Bean，有Spring负责实例化与销毁。因此DAO层只需要继承HibernateDaoSupport，而不需要与Hibernate的API打交道，不需要开启、关闭Hibernate的Session、Transaction，Spring会自动维护这些对象

[java]  view plain copy print ?

1. public interface ICatDao{  
2.       public void createCat(Cat cat);  
3.       public List<Cat> listCats();  
4.       public int getCatsCount();  
5.       public Cat findCatByName(String name);  
6. }  

 

[java]  view plain copy print ?

1. import org.springframework.orm.hibernate3.support.HibernateDaoSupport;  
2. public class CatDaoImpl extends HibernateDaoSupportimplements ICatDao{  
3.       public void createCat(Cat cat){  
4.              this.getHibernateTemplate().persist(cat);  
5.       }  
6.       public List<Cat> listCats(){  
7.              return this. getHibernateTemplate().find("select cfrom Cat c");  
8.       }  
9.       public int getCatsCount(){  
10.              Number n = (Number)this.getSession(true).createQuery("selectcount(c) from Cat c").uniqueResult();  
11.              return n.intValue();  
12.       }  
13.       public Cat findCatByName(String name){  
14.              List<Cat> catList =this.getHibernateTemplate().find("select c from Cat where c.name = ?",name);  
15.              if(catList.size()>0)  
16.                     return catList.get(0);  
17.              return null;  
18.       }  
19.    
20. }  

 

[html]  view plain copy print ?

1. <bean id="sessionFactory" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean" destroy-method="destroy">  
2. <property name="dataSource" ref="dataSource" />  
3. <!--  该Package下的所有类都会被当做实体类加载-->  
4. <property name="annotatedPackages" value="classpath:/com/clf/orm" />  
5. <property name="anotatedClasses">  
6.       <list>  
7.              <value>com.clf.spring.orm.Cat</value>  
8.              <value>com.clf.spring.orm.Dog</value>  
9.       </list>  
10. <property name="hibernateProperties">  
11.       <props>  
12.              <prop key="hiberante.dialect">org.hibernate.dialect.MySQLDialect</prop>  
13.              <prop key="hibernate.show_sql">true</prop>  
14.              <prop key=" hibernate.format_sql">true</prop>  
15.              <prop key=" hibernate.hbm2ddl.auto">create</prop>  
16.       </props>  
17. </property>  
18.    
19. <bean id="catDao" class="com.clf.spring.orm.CatDaoImpl">  
20.       <property name="sessionFactory" ref=" sessionFactory"/>  
21. </bean>  

 

如果使用XML配置的实体类，则改为

[html]  view plain copy print ?

1. <bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean" destroy-method="destroy">  
2. <property name="mappingResources">  
3.       <list>  
4.              <value>classpath:/com/clf/orm/Cat.hbm.xml</value>  
5.       </list>  
6. </property>  
7. ……  
8. </bean>  

 

Spring默认在DAO层添加事务，DAO层的每个方法为一个事务。Spring+Hibernate编程中，习惯的做法实在DAO层上再添加一个Service层，然后把事务配置在Service层

[java]  view plain copy print ?

1. public interface ICatService{  
2.       public void createCat(Cat cat);  
3.       public List<Cat> listCats();   
4.       public int getCatsCount();  
5. }  

分层的做法是，程序调用Service层，Service层调用DAO层，DAO层调用Hibernate实现数据访问，原则上不允许跨曾访问。分层使业务层次更加清晰

 

[java]  view plain copy print ?

1. public class CatServiceImpl implements ICatService{  
2.       private IDao catDao;  
3.       public IDao getCatDao(){  
4.              return catDao;  
5.       }  
6.    
7.       public void setCatDao(IDao dao){  
8.              this.catDao = dao;  
9.       }  
10.        
11.       public void createCat(Cat cat){  
12.              catDao.createCat(cat);  
13.       }  
14.       public List<Cat> listCats(){  
15.              return catDao.listCats();  
16.       }  
17.       public int getCatsCount(){  
18.              return catDao.getCatsCount();  
19.       }  
20.    
21. }  

 

然后再Service层配置事务管理

[html]  view plain copy print ?

1. <!--  事务管理器-->  
2. <bean id="hibernateTransactionManager" class=" org.springframework.orm.hibernate3.HibernateTransactionManager  
3. ">  
4.       <property name="sessionFactory" ref="sessionFactory"/>  
5. </bean>  
6.    
7. <!--  事务管理规则-->  
8. <bean id="hibernateTransactionAttributeSource" class=" org.springframework.transaction.interceptor.NameMatchTransactionAttributeSource">  
9.       <property name="properties">  
10.              <props><!--  为所有方法加上事务-->  
11.                     <propkeypropkey="*">PROPGATION_REQUIRED</prop>  
12.       </property>  
13. </bean>  
14.    
15. <!--  事务工厂代理类，将Service实现类、事务管理器、事务管理规则组装在一起-->  
16. <bean id="catService" class="org.springframework.transaction.interceptor.TransactionProxyFactoryBean">  
17.       <property name="transactionManager" ref=" hibernateTransactionManager">  
18.       <property name="target">  
19.              <bean class="com.clf.spring.orm.CatServiceImpl" >  
20.                     <property name="catDao" ref="catDao"/>  
21.              </bean>  
22.       </property>  
23.       <property name="transactionAttributeSource" ref=" hibernateTransactionAttributeSource" />  
24. </bean>