使用Atomikos Transactions Essentials实现多数据源JTA分布式事务

9.17 update:使用NonXADataSourceBean. Mysql在5.0版本和Connecter/J5.0版本后提供了XADatasource支持，如果使用了支持XADatasouce版本，可以参考2楼补充.

最近做的project中遇到要将数据库中的表分布到两台不同的服务器上的Mysql5.0中，project主要使用spring+ibatis。因此需要JTA的支持，但是tomcat不支持，所以就搜索开源的JTA实现。
最开始使用的是JOTM，但是使用中不能自动rollback，无论什么情况都commit。然后看到infoq上一篇文章提到Atomikos Transactions Essentials，Atomikos Transactions Essentials 3.0是Atomikos 开发的核心事务引擎，支持JDBC 以及JMS 的JTA/XA 事务。易于部署，轻量级，同时支持JDBC 以及JMS 。
Atomikos Transactions Essentials现在的版本是3.1.7,可以在http://www.atomikos.com/Main/TransactionsEssentialsDownloadForm 下载，在发布包里的examples文件夹下面有些例子，非常实用，我在使用中参考里面的例子很容易配置成功。先将发布包里面dist目录下的atomikos-util.jar，transactions.jar，transactions-api.jar，transactions-jta.jar copy到项目lib里面， 如果使用hibernate则需要将另外两个hibernate相关的jar页copy到项目里面，spring配置文件如下:

xml 代码

<!-- 第一个数据库 -->
< bean   id = "dataSource"   class = "com.atomikos.jdbc.SimpleDataSourceBean"   init-method = "init"   destroy-method = "close" >
    < property   name = "uniqueResourceName" >
        < value > mysql/main </ value >
    </ property >
    < property   name = "xaDataSourceClassName" >
        <!-- 使用Mysql XADataSource(mysql>=5.0, Connector/J>=5.0才可以支持XADatasource)-->
        < value > com.mysql.jdbc.jdbc2.optional.MysqlXADataSource </ value >
    </ property >
    < property   name = "xaDataSourceProperties" >
        < value > URL =${jdbc.url}; user =${jdbc.username}; password =${jdbc.password} </ value >
    </ property >
    < property   name = "exclusiveConnectionMode" >
        < value > true </ value >
    </ property >
    < property   name = "connectionPoolSize" >
        < value > 3 </ value >
    </ property >
    < property   name = "validatingQuery" >
        < value > SELECT 1 </ value >
    </ property >
</ bean >
<!-- 第二个数据库 -->
< bean   id = "dataSourceB"   class = "com.atomikos.jdbc.SimpleDataSourceBean"   init-method = "init"   destroy-method = "close" >
    < property   name = "uniqueResourceName" >
        < value > mysql/news </ value >
    </ property >
    < property   name = "xaDataSourceClassName" >
        <!-- 使用Mysql XADataSource(mysql>=5.0, Connector/J>=5.0才可以支持XADatasource)-->
        < value > com.mysql.jdbc.jdbc2.optional.MysqlXADataSource </ value >
    </ property >
    < property   name = "xaDataSourceProperties" >
        < value > URL =${jdbc.url.b}; user =${jdbc.username.b}; password =${jdbc.password.b} </ value >
    </ property >
    < property   name = "exclusiveConnectionMode" >
        < value > true </ value >
    </ property >
    < property   name = "connectionPoolSize" >
        < value > 3 </ value >
    </ property >
    < property   name = "validatingQuery" >
        < value > SELECT 1 </ value >
    </ property >
</ bean >


< bean   id = "lobHandler"   class = "org.springframework.jdbc.support.lob.DefaultLobHandler"   />

<!-- 第一个数据库的sqlMapClient -->
< bean   id = "sqlMapClient"   class = "org.springframework.orm.ibatis.SqlMapClientFactoryBean" >
    < property   name = "configLocation" >
        <!-- 包含第一个数据库表的map -->
        < value > classpath:/sqlmap-config.xml </ value >
    </ property >
    < property   name = "dataSource"   ref = "dataSource"   />
    < property   name = "lobHandler"   ref = "lobHandler"   />
</ bean >
<!-- 第二个数据库的sqlMapClient -->
< bean   id = "sqlMapClientB"   class = "org.springframework.orm.ibatis.SqlMapClientFactoryBean" >
    < property   name = "configLocation" >
        <!-- 包含第一个数据库表的map -->
        < value > classpath:/sqlmap-configb.xml </ value >
    </ property >
    < property   name = "dataSource"   ref = "dataSourceB"   />
    < property   name = "lobHandler"   ref = "lobHandler"   />
</ bean >

<!-- Construct Atomikos UserTransactionManager, needed to configure Spring -->
< bean   id = "atomikosTransactionManager"   class = "com.atomikos.icatch.jta.UserTransactionManager"   init-method = "init"
    destroy-method = "close" >
    <!--  when close is called, should we force transactions to terminate or not? -->
    < property   name = "forceShutdown" >
        < value > true </ value >
    </ property >
</ bean >

<!-- Also use Atomikos UserTransactionImp, needed to configure Spring  -->
< bean   id = "atomikosUserTransaction"   class = "com.atomikos.icatch.jta.UserTransactionImp" >
    < property   name = "transactionTimeout"   value = "240"   />
</ bean >

<!-- Configure the Spring framework to use JTA transactions from Atomikos -->
< bean   id = "transactionManager"   class = "org.springframework.transaction.jta.JtaTransactionManager" >
    < property   name = "transactionManager" >
        < ref   bean = "atomikosTransactionManager"   />
    </ property >
    < property   name = "userTransaction" >
        < ref   bean = "atomikosUserTransaction"   />
    </ property >
</ bean >

事务的配置, 使用了spring2.0的语法，所以将namesapce也帖出来了.

xml 代码

<? 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: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-2.0.xsd
           http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.0.xsd
           http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.0.xsd"
       default-autowire = "byName"   default-lazy-init = "true" >
    <!-- 支持 @AspectJ 标记-->
    < aop:aspectj-autoproxy />

    < aop:config   proxy-target-class = "true" >
        < aop:advisor   pointcut = "execution(* *Facade.*(..))"   advice-ref = "txAdvice" />
        < aop:advisor   pointcut = "execution(* *Manager.*(..))"   advice-ref = "txAdvice" />
    </ aop:config >

    < tx:advice   id = "txAdvice" >
        < tx:attributes >
            < tx:method   name = "get*"   read-only = "true" />
            < tx:method   name = "find*"   read-only = "true" />
            < tx:method   name = "has*"   read-only = "true" />
            < tx:method   name = "locate*"   read-only = "true" />
            < tx:method   name = "*" />
        </ tx:attributes >
    </ tx:advice >
</ beans >

这样配置以后就可以使用分布式事务，测试中出现异常时事务也自动提交。和JOTM相比Atomikos Transactions Essentials更加稳定，它原来是商业项目，现在开源了。象mysql一样卖服务支持的。而且论坛页比较活跃，有问题很快可以解决。