自己动手写代码，整合Spring和Hibernate（三）之DAOSupport和DAOTemplate

在《自己动手写代码，整合Spring和Hibernate》系列博文的前两篇中，我们需要为每个DAO类定义一个SessionFactory，需要在DAO的每个方法中获取Session、关闭Session。我们可以写一个公用的DAO类，然后让其他DAO类继承它，实现代码复用。

公用DAO类（抽象类）：

package com.zzj.dao;import java.io.Serializable;import org.hibernate.Session;import org.hibernate.SessionFactory;public abstract class DAOSupport {private SessionFactory sessionFactory;public void setSessionFactory(SessionFactory sessionFactory) {this.sessionFactory = sessionFactory;} /** * 保存 * @param t * @return */protected Serializable save(Object t){Session session = sessionFactory.openSession();session.beginTransaction();Serializable id = session.save(t);session.getTransaction().commit();session.close();return id;}protected Object findByID(Class<?> clazz, Serializable id){Session session = sessionFactory.openSession();Object t = session.get(clazz, id);session.close();return t;}}

CustomerDAO类：

package com.zzj.dao;import com.zzj.entity.Customer;public class CustomerDAO extends DAOSupport{/** * 查询 * @param ID * @return */public Customer findByID(String ID){return (Customer) findByID(Customer.class, ID);}/** * 保存 * @param customer * @return */public String save(Customer customer){return (String) super.save(customer);}}

spring配置文件：

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsd"><!-- 配置数据源 --><!-- <bean name="dataSource" class="com.zzj.base.MyDataSource"><property name="url"><value>jdbc:oracle:thin:@localhost:1521:orcl</value>                </property><property name="username"><value>system</value></property><property name="password"><value>1223</value></property><property name="driveClass"><value>oracle.jdbc.driver.OracleDriver</value></property></bean> --><bean name="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"><property name="JdbcUrl"><value>jdbc:oracle:thin:@localhost:1521:orcl</value>                </property><property name="User"><value>system</value></property><property name="Password"><value>1223</value></property><property name="DriverClass"><value>oracle.jdbc.driver.OracleDriver</value></property></bean>    <!-- 配置sessionFactory对象 -->      <bean name="sessionFactory" class="com.zzj.base.MySessionFactory">           <property name="dataSource" ref="dataSource"/>         <property name="dialect"><value>org.hibernate.dialect.Oracle9Dialect</value> </property>         <property name="mappings">         <list>         <value>com/zzj/entity/Customer.hbm.xml</value>         </list>         </property>    </bean>       <!-- 配置DAO -->    <bean id="customerDAO" class="com.zzj.dao.CustomerDAO"><property name="sessionFactory" ref="sessionFactory"></property>    </bean></beans>

以上是使用继承达到了代码的复用，下面使用组合模式达到相同的目的。

公用DAO类（为了区别继承，另外命名，非抽象类）：

package com.zzj.dao;import java.io.Serializable;import org.hibernate.Session;import org.hibernate.SessionFactory;public class DAOTemplate {private SessionFactory sessionFactory;public void setSessionFactory(SessionFactory sessionFactory) {this.sessionFactory = sessionFactory;} /** * 保存 * @param t * @return */protected Serializable save(Object t){Session session = sessionFactory.openSession();session.beginTransaction();Serializable id = session.save(t);session.getTransaction().commit();session.close();return id;}protected Object findByID(Class<?> clazz, Serializable id){Session session = sessionFactory.openSession();Object t = session.get(clazz, id);session.close();return t;}}

CustomerDAO类：

package com.zzj.dao;import com.zzj.entity.Customer;public class CustomerDAO{private DAOTemplate daoTemplate;public void setDaoTemplate(DAOTemplate daoTemplate) {this.daoTemplate = daoTemplate;}/** * 查询 * @param ID * @return */public Customer findByID(String ID){return (Customer) daoTemplate.findByID(Customer.class, ID);}/** * 保存 * @param customer * @return */public String save(Customer customer){return (String) daoTemplate.save(customer);}}

Spring配置文件：

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans.xsd"><!-- 配置数据源 --><!-- <bean name="dataSource" class="com.zzj.base.MyDataSource"><property name="url"><value>jdbc:oracle:thin:@localhost:1521:orcl</value>                </property><property name="username"><value>system</value></property><property name="password"><value>1223</value></property><property name="driveClass"><value>oracle.jdbc.driver.OracleDriver</value></property></bean> --><bean name="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"><property name="JdbcUrl"><value>jdbc:oracle:thin:@localhost:1521:orcl</value>                </property><property name="User"><value>system</value></property><property name="Password"><value>1223</value></property><property name="DriverClass"><value>oracle.jdbc.driver.OracleDriver</value></property></bean>    <!-- 配置sessionFactory对象 -->      <bean name="sessionFactory" class="com.zzj.base.MySessionFactory">           <property name="dataSource" ref="dataSource"/>         <property name="dialect"><value>org.hibernate.dialect.Oracle9Dialect</value> </property>         <property name="mappings">         <list>         <value>com/zzj/entity/Customer.hbm.xml</value>         </list>         </property>    </bean>       <!-- 配置DAOTemplate -->    <bean name="daoTemplate" class="com.zzj.dao.DAOTemplate">    <property name="sessionFactory" ref="sessionFactory"></property>    </bean>    <!-- 配置DAO -->    <bean id="customerDAO" class="com.zzj.dao.CustomerDAO">      <property name="daoTemplate" ref="daoTemplate"></property>    </bean></beans>

上面两种方法中，推荐使用组合。 当然了，具体使用哪种方式，就看个人喜好了。

注：每一个具体的DAO类，最终都需要注入一个sessionFactory。