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/beans
http://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/beans
http://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。