Spring中编程式事务处理(使用TransactionTemplate)

Spring的编程式事务处理，需要使用Hibernate事务回调接口，事务回调接口可以管理Hibernate的事务：

TransactionCallbackWithoutResult —— 执行事务没有返回值，例如save、update、delete等等；

TransactionCallback —— 执行事务处理后有返回值，如find要返回结果集(List)；

使用Spring的IoC容器来管理bean，具体注入的过程为：

装配DataSource —— 将DataSource注入到SessionFactory Bean中 —— 将SessionFactory Bean注入到HibernateTransactionManager中 —— 将SessionFactory Bean与HibernateTransactionManager Bean一起都注入到DAO中

对应的Spring的配置文件applicationContext.xml的配置如下所示：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">

<beans>

<bean id="threeDataSource"
??
??? value="com.microsoft.jdbc.sqlserver.SQLServerDriver">
?? </property>
?? <property name="url"
??? value="jdbc:microsoft:sqlserver://localhost:1433;databasename=hibernate">
?? </property>
?? <property name="username" value="sa"></property>
?? <property name="password" value="111111"></property>
</bean>

<bean id="threeSessionFactory"
?? />
?? </property>
?? <property name="mappingResources">
??? <list>
???? <value>org/shirdrn/entity/Person.hbm.xml</value>
??? </list>
?? </property>
?? <property name="hibernateProperties">
??? <props>
???? <prop key="hibernate.dialect">
????? org.hibernate.dialect.SQLServerDialect
???? </prop>
???? <prop key="hibernate.show_sql">
??????????????????? true
??????????????? </prop>
??? </props>
?? </property>
</bean>

<bean id="hTransactionManager"
??
?? abstract="false" singleton="true" lazy-init="default"
?? autowire="default" dependency-check="default">
?? <property name="sessionFactory">
??? <ref bean="threeSessionFactory" />
?? </property>
</bean>

<bean id="threePersonDao"
?? abstract="false" singleton="true" lazy-init="default"
?? autowire="default" dependency-check="default">
?? <property name="transactionManager">
??? <ref bean="hTransactionManager"/>
?? </property>
?? <property name="sessionFactory">
??? <ref bean="threeSessionFactory" />
?? </property>
</bean>

</beans>

实体类Person对应DAO的服务接口为IPerson，如下所示：

package org.shirdrn.no.three.interf;

import java.util.List;

import org.shirdrn.entity.Person;

public interface IPersonDao {
public void createPerson(Person person);
public void updatePerson(Person person);
public void deletePerson(Person person);
public List queryPerson(String hql);
public Person queryOnePerson(String hql);
}

PersonDao实现了服务接口IPerson，同时必须集成HibernateDaoSupport，因为在HibernateDaoSupport中实现了DataSource、SessionFactory的setter方法，继承HibernateDaoSupport从而将SessionFactory注入到DAO中可以简化编程。

PersonDao的实现如下所示：

package org.shirdrn.no.three.dao;

import java.util.List;

import org.shirdrn.entity.Person;
import org.shirdrn.no.three.interf.IPersonDao;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.TransactionDefinition;
import org.springframework.transaction.TransactionStatus;
import org.springframework.transaction.support.TransactionCallback;
import org.springframework.transaction.support.TransactionCallbackWithoutResult;
import org.springframework.transaction.support.TransactionTemplate;

public class PersonDao extends HibernateDaoSupport implements IPersonDao{

private TransactionTemplate transactionTemplate;

public void setTransactionManager(PlatformTransactionManager transactionManager){???? // 注入TransactionManager
?? this.transactionTemplate = new TransactionTemplate(transactionManager);???? //?? 以注入的TransactionManager作为参数，获取一个TransactionTemplate实例，该实例封装了Hibernate的行为

}

public void createPerson(final Person person) {
?? transactionTemplate.setPropagationBehavior(TransactionDefinition.PROPAGATION_REQUIRED);
?? transactionTemplate.execute(new TransactionCallbackWithoutResult(){??? // 使用无返回值的事务回调接口
??? @Override
??? protected void doInTransactionWithoutResult(TransactionStatus arg0) {
???? getHibernateTemplate().save(person);???
??? }??
?? });
}

public void deletePerson(final Person person) {
?? transactionTemplate.setPropagationBehavior(TransactionDefinition.PROPAGATION_REQUIRED);
?? transactionTemplate.execute(new TransactionCallbackWithoutResult(){???? // 使用无返回值的事务回调接口
??? @Override
??? protected void doInTransactionWithoutResult(TransactionStatus arg0) {
???? getHibernateTemplate().delete(person);???
??? }??
?? });
}

public void updatePerson(final Person person) {
?? transactionTemplate.setPropagationBehavior(TransactionDefinition.PROPAGATION_REQUIRED);
?? transactionTemplate.execute(new TransactionCallbackWithoutResult(){???? // 使用无返回值的事务回调接口
??? @Override
??? protected void doInTransactionWithoutResult(TransactionStatus arg0) {
???? getHibernateTemplate().update(person);???
??? }??
?? });
}

public List queryPerson(final String hql) {
?? transactionTemplate.setPropagationBehavior(TransactionDefinition.PROPAGATION_REQUIRED);
?? List list = (List)transactionTemplate.execute(new TransactionCallback(){?? // 使用带返回值的事务回调接口

??? public Object doInTransaction(TransactionStatus arg0) {
???? System.out.println(hql);
???? return getHibernateTemplate().find(hql);
??? }??
?? });
?? return list;
}

public Person queryOnePerson(final String hql) {
?? transactionTemplate.setPropagationBehavior(TransactionDefinition.PROPAGATION_REQUIRED);
?? return (Person)transactionTemplate.execute(new TransactionCallback(){???? // 使用带返回值的事务回调接口

??? public Object doInTransaction(TransactionStatus arg0) {
???? return getHibernateTemplate().find(hql).get(0);
??? }??
?? });
}
}

编写测试函数，如下所示：

package org.shirdrn.no.three.test;

import org.shirdrn.entity.Person;
import org.shirdrn.no.three.interf.IPersonDao;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class SpringTest {
public static void main(String[] args) {
?? ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
?? IPersonDao personDao = (IPersonDao)ctx.getBean("threePersonDao");
?? /**
?? * 测试save
?? */
?? /*Person p = new Person();
?? p.setId("200804150016");
?? p.setName("Sujnn");
?? p.setAddr("Shanghai");
?? p.setAge(new Integer(22));
?? p.setGender("male");
?? personDao.createPerson(p);*/
?? /**
?? * 测试update
?? */
?? /*Person p = new Person();
?? p.setId("200804150016");
?? p.setName("SujnnXXX");
?? p.setAddr("Hongkong");
?? p.setAge(new Integer(22));
?? p.setGender("male");
?? personDao.updatePerson(p);*/
?? /**
?? * 测试delete
?? */
?? /*Person p = new Person();
?? p.setId("200804150016");
?? personDao.deletePerson(p);*/
?? /**
?? * 测试find(HQL)
?? */
?? /*List list = personDao.queryPerson("from Person");
?? for(Object o : list.toArray()){
??? Person p = (Person)o;
??? System.out.println("Id?? = "+p.getId());
??? System.out.println("Name = "+p.getName());
??? System.out.println("Addr = "+p.getAddr());
??? System.out.println("******************************");
?? }*/
?? /**
?? * 测试find(Person)
?? */
?? Person p = personDao.queryOnePerson("from Person p where p.id='200804150015'");
?? System.out.println("Id??? = "+p.getId());
?? System.out.println("Name = "+p.getName());
?? System.out.println("Addr = "+p.getAddr());
?? System.out.println("Gender= "+p.getGender());
?? System.out.println("Age = "+p.getAge());
}
}

以上主函数中的五个测试均成功。