Spring 对事务管理的支持

2023-08-11 14:24:52

1、Spring对事务管理的支持

Spring为事务管理提供了一致的编程模板，在高层次建立了统一的事务抽象。也就是说，不管选择Spring JDBC、Hibernate 、JPA 还是iBatis，Spring都让我们可以用统一的编程模型进行事务管理。

在Spring事务管理SPI（Service Provider Interface）的抽象层主要包括3个接口，分别是PlatformTransactionManager、TransactionDefinition和TransactionStatus。TransactionDefinition用于描述事务的隔离级别、超时时间、是否为只读事务和事务传播规则等控制事务具体行为的事务属性，这些事务属性可以通过XML配置或注解描述提供，也可以通过手工编程的方式设置。PlatformTransactionManager根据TransactionDefinition提供的事务属性配置信息，创建事务，并用TransactionStatus描述这个激活事务的状态。

1）Spring JDBC 和iBatis

基于数据源的数据管理器

<context:property-placeholder location="classpath:jdbc.properties"/>

    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"

          destroy-method="close"

          p:driverClassName="${jdbc.driverClassName}"

          p:url="${jdbc.url}"

          p:username="${jdbc.username}"

          p:password="${jdbc.password}"/>

     <bean id="transactionManager"

      class="org.springframework.jdbc.datasource.DataSourceTransactionManager"

      p:dataSource-ref="dataSource"/>

2）JPA

JAP事务管理器配置

<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"

          p:dataSource-ref="dataSource"/>

    ...

<bean id="transactionManger" class="org.springframework.orm.jpa.JpaTransactionManager"

          p:entityManagerFacotry-ref="entityManagerFactory"/>

3）Hibernate

Hibernate3.0事务管理器配置

<bean id="sessionFactory"

     class="org.springframework.orm.hibernate3.LocalSessionFactoryBean"

     p:dataSource-ref="dataSource"

     p:mappingResources="classpath:bbtForum.hbm.xml">

   <property name="hibernateProperties">

     <props>

       <prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>

       <prop key="hibernate.show_sql">true</prop>

       <prop key="hibernate.generate_statistics">true</prop>

     </props>

   </property>

</bean>

4）JTA

JTA事务管理器

<jee:jndi-lookup id="accountDs" jndi-name="java:comp/env/jdbc/account"/>

<jee:jndi-lookup id="orderDs" jndi-name="java:comp/env/jdbc/account"/>

<bean id="transactionManager"

     class="org.springframework.transaction.jta.JtaTransactionManager"/>

2、编程式事务管理

Spring事务管理提供了模板类org.springframework.transaction.support.TransactionTemplate，以满足一些特殊场合的需要。

package com.baobaotao.service;

import org.springframework.transaction.TransactionStatus;

import org.springframework.transaction.support.TransactionCallbackWithoutResult;

import org.springframework.transaction.support.TransactionTemplate;

import com.baobaotao.dao.ForumDao;

import com.baobaotao.domain.Forum;

public class ForumService1 {

    private ForumDao forumDao;

    //通过IoC注入

    private TransactionTemplate template;

    public void addForum(final Forum forum) {

        template.execute(new TransactionCallbackWithoutResult() {

            protected void doInTransactionWithoutResult(TransactionStatus status) {

                //需要在事务环境中执行的代码

                forumDao.addForum(forum);

            }

        });

    }

    public void setForumDao(ForumDao forumDao) {

        this.forumDao = forumDao;

    }

    public void setTemplate(TransactionTemplate template) {

        this.template = template;

    }

}

3、使用XML配置声明式事务

Spring的声明式事务管理是通过Spring AOP实现的，通过事务的声明性信息，Spring负责将事务管理增强逻辑动态织入到业务方法相应连接点中。这些逻辑包括获取线程绑定资源、开始事务、提交/回滚事务、进行异常转换和处理等工作。

BbtForum接口：

package com.yyq.service;

import com.yyq.domain.Forum;

import com.yyq.domain.Topic;

public interface BbtForum {

    void addTopic(Topic topic) throws Exception;

    void updateForum(Forum forum);

    Forum getForum(int forumId);

    int getForumNum();

}

BbtForumImpl实现类：

package com.yyq.service.impl;

import com.yyq.dao.ForumDao;

import com.yyq.dao.PostDao;

import com.yyq.dao.TopicDao;

import com.yyq.domain.Forum;

import com.yyq.domain.Topic;

import com.yyq.service.BbtForum;

public class BbtForumImpl implements BbtForum {

    private ForumDao forumDao;

    private TopicDao topicDao;

    private PostDao postDao;

    public void addTopic(Topic topic) throws Exception {

        topicDao.addTopic(topic);

//        if(true) throw new PessimisticLockingFailureException("fail");

        postDao.addPost(topic.getPost());

    }

    public Forum getForum(int forumId) {

        return forumDao.getForum(forumId);

    }

    public void updateForum(Forum forum) {

        forumDao.updateForum(forum);

    }

    public int getForumNum() {

        return forumDao.getForumNum();

    }

    public void setForumDao(ForumDao forumDao) {

        this.forumDao = forumDao;

    }

    public void setPostDao(PostDao postDao) {

        this.postDao = postDao;

    }

    public void setTopicDao(TopicDao topicDao) {

        this.topicDao = topicDao;

    }

}

Dao和Datasource配置文件applicationContext-dao.xml：

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

       xmlns:p="http://www.springframework.org/schema/p"

       xmlns:context="http://www.springframework.org/schema/context"

       xsi:schemaLocation="http://www.springframework.org/schema/beans

       http://www.springframework.org/schema/beans/spring-beans-3.0.xsd

       http://www.springframework.org/schema/context

       http://www.springframework.org/schema/context/spring-context-3.0.xsd">

    <context:property-placeholder location="classpath:jdbc.properties"/>

    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"

          destroy-method="close"

          p:driverClassName="${jdbc.driverClassName}"

          p:url="${jdbc.url}"

          p:username="${jdbc.username}"

          p:password="${jdbc.password}"/>

    <bean id="jdbcTemplate"

            class="org.springframework.jdbc.core.JdbcTemplate"

            p:dataSource-ref="dataSource"/>

    <bean id="abstracDao" abstract="true" p:jdbcTemplate-ref="jdbcTemplate"/>

    <bean id="forumDao" parent="abstracDao" class="com.yyq.dao.jdbc.ForumDaoImpl" />

    <bean id="postDao" parent="abstracDao" class="com.yyq.dao.jdbc.PostDaoImpl"/>

    <bean id="topicDao" parent="abstracDao" class="com.yyq.dao.jdbc.TopicDaoImpl"/>

</beans>

1）使用原始的TransactionProxyFactoryBean进行声明式事务配置：

<?xml version="1.0" encoding="UTF-8" ?>

<beans xmlns="http://www.springframework.org/schema/beans"

       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

       xmlns:p="http://www.springframework.org/schema/p"

       xsi:schemaLocation="http://www.springframework.org/schema/beans

         http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

    <!--导入Dao和DataSource的配置文件-->

    <import resource="applicationContext-dao.xml"/>

    <bean id="txManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">

        <property name="dataSource" ref="dataSource"/>

    </bean>

    <!--需要实施事务增强的目标业务Bean-->

    <bean id="bbtForumTarget" class="com.yyq.service.impl.BbtForumImpl"

          p:forumDao-ref="forumDao"

          p:topicDao-ref="topicDao"

          p:postDao-ref="postDao"/>

    <!--使用事务代理工程类为目标业务Bean提供事务增强-->

    <bean id="bbtForum" class="org.springframework.transaction.interceptor.TransactionProxyFactoryBean"

          p:transactionManager-ref="txManager"

          p:target-ref="bbtForumTarget">

        <property name="transactionAttributes">

            <props>

                <prop key="get*">PROPAGATION_REQUIRED,readOnly</prop>

                <prop key="*">PROPAGATION_REQUIRED</prop>

            </props>

        </property>

    </bean>

</beans>

测试方法：

import com.yyq.domain.Post;

import com.yyq.domain.Topic;

import com.yyq.service.BbtForum;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class TestBbtForumPfb {

    public static void main(String[] args) throws Throwable{

        String configPath = "classpath:applicationContext-pfb.xml";

        ApplicationContext ctx = new ClassPathXmlApplicationContext(configPath);

        BbtForum bbtForum = ctx.getBean("bbtForum",BbtForum.class);

        System.out.println("begin........");

        Topic topic = new Topic();

        topic.setTopicTitle("Title -pfb");

        Post post = new Post();

        post.setPostText("post content -pfb");

        topic.setPost(post);

        bbtForum.addTopic(topic);

        System.out.println("end........");

    }

}

2）基于tx/aop命名空间的配置：

<?xml version="1.0" encoding="UTF-8" ?>

<beans xmlns="http://www.springframework.org/schema/beans"

       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

       xmlns:p="http://www.springframework.org/schema/p"

       xmlns:aop="http://www.springframework.org/schema/aop"

       xmlns:tx="http://www.springframework.org/schema/tx"

       xsi:schemaLocation="

    http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd

    http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd

    http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd">

    <!--导入Dao和DataSource的配置文件-->

    <import resource="classpath:applicationContext-dao.xml"/>

    <!--声明事务管理器-->

    <bean id="txManager"

          class="org.springframework.jdbc.datasource.DataSourceTransactionManager"

          p:dataSource-ref="dataSource"/>

    <!--不再需要为了事务AOP增强的实施而改名换姓-->

    <bean id="bbtForum"

          class="com.yyq.service.impl.BbtForumImpl"

          p:forumDao-ref="forumDao"

          p:topicDao-ref="topicDao"

          p:postDao-ref="postDao"/>

    <!--使用强大的切点表达式语言轻松定义目标方法-->

    <aop:config>

        <!--通过aop定义事务增强切面-->

        <aop:pointcut id="serviceMethod" expression="execution(* com.yyq.service.*Forum.*(..))"/>

        <!--引用事务增强-->

        <aop:advisor pointcut-ref="serviceMethod" advice-ref="txAdvice"/>

    </aop:config>

    <!--事务增强-->

    <tx:advice id="txAdvice" transaction-manager="txManager">

        <tx:attributes>

            <!--事务属性定义-->

            <tx:method name="get*" read-only="false"/>

            <tx:method name="add*" rollback-for="PessimisticLockingFailureException"/>

            <tx:method name="update*"/>

        </tx:attributes>

    </tx:advice>

</beans>

测试方法：

import com.yyq.domain.Post;

import com.yyq.domain.Topic;

import com.yyq.service.BbtForum;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class TestBbtForumTx {

    public static void main(String[] args) throws Throwable{

        String configPath = "classpath:applicationContext-tx.xml";

        ApplicationContext ctx = new ClassPathXmlApplicationContext(configPath);

        BbtForum bbtForum = ctx.getBean(BbtForum.class);

        System.out.println("begin........");

        Topic topic = new Topic();

        topic.setTopicTitle("Title Tx-");

        Post post = new Post();

        post.setPostText("post content -Tx");

        topic.setPost(post);

        bbtForum.addTopic(topic);

        System.out.println("end........");

    }

}

4、使用注解配置声明式事务

使用@Transaction注解声明事务，可以应用于接口定义和接口方法、类定义和类的public方法上。

使用@Transaction注解的业务类：

@Transactional

public class BbtForumImpl implements BbtForum {

    private ForumDao forumDao;

    private TopicDao topicDao;

    private PostDao postDao;

    public void addTopic(Topic topic) throws Exception {

        topicDao.addTopic(topic);

        //if(true) throw new PessimisticLockingFailureException("fail");

        postDao.addPost(topic.getPost());

    }

    public Forum getForum(int forumId) {

        return forumDao.getForum(forumId);

    }

    public void updateForum(Forum forum) {

        forumDao.updateForum(forum);

    }

   ....

applicationContext-anno.xml：使事务注解生效

<?xml version="1.0" encoding="UTF-8" ?>

<beans xmlns="http://www.springframework.org/schema/beans"

       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

       xmlns:p="http://www.springframework.org/schema/p"

       xmlns:tx="http://www.springframework.org/schema/tx"

       xsi:schemaLocation="http://www.springframework.org/schema/beans

        http://www.springframework.org/schema/beans/spring-beans-3.0.xsd

        http://www.springframework.org/schema/tx

        http://www.springframework.org/schema/tx/spring-tx-3.0.xsd">

    <import resource="classpath:applicationContext-dao.xml"/>

    <!--由于该Bean实现类标注了@Transaction，所以将会被注解驱动自动织入事务-->

    <bean id="bbtForum"

          class="com.yyq.service.impl.BbtForumImpl"

          p:forumDao-ref="forumDao"

          p:topicDao-ref="topicDao"

          p:postDao-ref="postDao"/>

    <bean id="txManager"

          class="org.springframework.jdbc.datasource.DataSourceTransactionManager"

          p:dataSource-ref="dataSource"/>

    <!--对标注@Transaction注解的Bean进行加工处理，以织入事务管理切面-->

    <tx:annotation-driven transaction-manager="txManager" proxy-target-class="true"/>

</beans>

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