ssh框架加入atomikos分布式事务管理

一、概念

 

 

 

分布式事务
分布式事务是指事务的参与者、支持事务的服务器、资源服务器以及事务管理器分别位于不同的分布式系统的不同节点之上。简言之，同时操作多个数据库保持事务的统一，达到跨库事务的效果。

 

 

 

JTA
JTA，即Java Transaction API，JTA允许应用程序执行分布式事务处理———在两个或多个网络计算机资源上访问并且更新数据。JDBC驱动程序的JTA支持极大地增强了数据访问能力。

 

 

 

JTA和JTS

 

Java事务API（JTA：Java Transaction API）和它的同胞Java事务服务（JTS：Java Transaction Service），为J2EE平台提供了分布式事务服务（distributed transaction）。
一个分布式事务（distributed transaction）包括一个事务管理器（transaction manager）和一个或多个资源管理器(resource manager）。
一个资源管理器（resource manager）是任意类型的持久化数据存储。
事务管理器（transaction manager）承担着所有事务参与单元者的相互通讯的责任。

 

 

 

JTA与JDBC

 

JTA事务比JDBC事务更强大。一个JTA事务可以有多个参与者，而一个JDBC事务则被限定在一个单一的数据库连接。下列任一个Java平台的组件都可以参与到一个JTA事务中：JDBC连接、JDO PersistenceManager 对象、JMS 队列、JMS 主题、企业JavaBeans（EJB）、一个用J2EE Connector Architecture 规范编译的资源分配器。

 

 

 

JOTM
JOTM (Java Open Transaction Manager)是一个开源独立的事务管理器，支持分布式事务，Spring3.X已经不再支持JOTM。

 

 

 

Atomikos
Atomikos TransactionsEssentials是一个为Java平台提供增值服务的并且开源类事务管理器，支持分布式事务，本文所采用的技术。

 

Atomikos是目前在分布式事务管理中做得相当不错的开源软件。有10年以上的经验，Atomikos保障您的关键事务和防止昂贵的数据丢失在发生系统故障或事故中．Atomikos支持XA(全局事务)和NON-XA(非全局事务)，NON-XA效率高于XA。本文主要是讲XA事件，因为要在不同的数据库中操作多张表。

 

接下来说一下Spring.x+Hibernate中集成Atomikos构建JTA的分布式事务

 

二、准备

 

 

Atomikos TransactionsEssentials 是一个为Java平台提供增值服务的并且开源类事务管理器，官方地址：http://www.atomikos.com/，使用最新版本3.9.3，下载以下jar包：

atomikos-util-3.9.3.jar

transactions-3.9.3.jar

transactions-api-3.9.3.jar

transactions-hibernate3-3.9.3.jar

transactions-jdbc-3.9.3.jar

transactions-jms-3.9.3.jar

transactions-jta-3.9.3.jar

官方地址经常打不开，需要国外vpn访问。可以通过maven地址进行下载。

 

       SSH框架版本为，struts2的版本为2.3.20，spring的版本为3.0.6，Hibernate的版本为 3.6.8.Final

 

三、配置

 

3.1 spring的配置如下：

 

<!-- mysql数据源 -->
	<bean id="mysqlDataSource" class="com.atomikos.jdbc.AtomikosDataSourceBean"
		init-method="init" destroy-method="close">
			<property name="uniqueResourceName" value="mysqlWebXADBMS" />
			<property name="xaDataSourceClassName"
				value="com.mysql.jdbc.jdbc2.optional.MysqlXADataSource" />
			<property name="xaProperties">
				<props>
					<prop key="user">${jdbc.username.mysql}</prop>
					<prop key="password">${jdbc.password.mysql}</prop>
					<prop key="URL">${jdbc.url.mysql}</prop>
					<prop key="pinGlobalTxToPhysicalConnection">true</prop>
					<prop key="autoReconnect">true</prop>
					
				</props>
			</property>
			<property name="poolSize" value="${pool.initialPoolSize}" />
			<property name="minPoolSize" value="${pool.minPoolSize}" />
			<property name="maxPoolSize" value="${pool.maxPoolSize}" />
			<property name="maxIdleTime" value="${pool.maxIdleTime}" />
			
			<property name="testQuery" value="select 1" />
	</bean>

<!-- oracle数据源 -->
	<bean id="oracleDataSource" class="com.atomikos.jdbc.AtomikosDataSourceBean"
		init-method="init" destroy-method="close">
			<property name="uniqueResourceName" value="oracleWebXADBMS" />
			<property name="xaDataSourceClassName" value="oracle.jdbc.xa.client.OracleXADataSource" />
			<property name="xaProperties">
				<props>
					<prop key="user">${jdbc.username}</prop>
					<prop key="password">${jdbc.password}</prop>
					<prop key="URL">${jdbc.url}</prop>
				</props>
			</property>
			<property name="poolSize" value="${pool.initialPoolSize}" />
			<property name="minPoolSize" value="${pool.minPoolSize}" />
			<property name="maxPoolSize" value="${pool.maxPoolSize}" />
			<property name="maxIdleTime" value="${pool.maxIdleTime}" />
			
			<property name="testQuery" value="select 1 from dual" />
	</bean>


<!-- 对应的oracleSessionFactory配置（Hibernate的）： -->
	<bean id="oracleSessionFactory"
		class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
		
		<!---采用注解扫描实体 -->
		<property name="packagesToScan" value="org.gjwu.web.entity" />
		<property name="dataSource" ref="oracleDataSource" />
		
		<property name="namingStrategy">
			<bean class="org.hibernate.cfg.ImprovedNamingStrategy" />
		</property>
		<property name="jtaTransactionManager" ref="atomikosTransactionManager" />

		<!--hibernate 配置属性，可以参考Hibernate帮助文档这里只罗列和jta相关的配置 -->
		<property name="hibernateProperties">
			<props>
				<prop key="hibernate.dialect">org.hibernate.dialect.Oracle10gDialect</prop>
				<prop key="hibernate.current_session_context_class">jta</prop>
				<prop key="hibernate.show_sql">true</prop>
				<prop key="hibernate.format_sql">false</prop>
				<prop key="hibernate.cache.use_query_cache">false</prop>
				<prop key="hibernate.cache.use_second_level_cache">false</prop>
				<prop key="hibernate.transaction.factory_class">
					com.atomikos.icatch.jta.hibernate3.AtomikosJTATransactionFactory
				</prop>
				<prop key="hibernate.transcation.manager_lookup_class">
					com.atomikos.icatch.jta.hibernate3.TransactionManagerLookup
				</prop>
<!-- 				<prop key="hibernate.connection.release_mode">after_statement</prop> -->

			</props>
		</property>
	</bean>
	
<!-- 对应的mysqlSessionFactory配置（Hibernate的）： -->
	<bean id="mysqlSessionFactory"
		class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
		<!---采用注解扫描实体 -->
		<property name="packagesToScan" value="org.gjwu.web.mysql.entity" />
		<property name="dataSource" ref="mysqlDataSource" />
		
		<property name="namingStrategy">
			<bean class="org.hibernate.cfg.ImprovedNamingStrategy" />
		</property>
		<property name="jtaTransactionManager" ref="atomikosTransactionManager" />

		<!--hibernate 配置属性，可以参考Hibernate帮助文档这里只罗列和jta相关的配置 -->
		<property name="hibernateProperties">
			<props>
				<prop key="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</prop>
				<prop key="hibernate.current_session_context_class">jta</prop>
				<prop key="hibernate.transaction.factory_class">
					com.atomikos.icatch.jta.hibernate3.AtomikosJTATransactionFactory
				</prop>
				<prop key="hibernate.transcation.manager_lookup_class">
					com.atomikos.icatch.jta.hibernate3.TransactionManagerLookup
				</prop>
<!-- 				<prop key="hibernate.connection.release_mode">after_statement</prop> -->

			</props>
		</property>
	</bean>
	
<!-- 定义 oracleHibernateTemplate 用于注入到对应dao -->
	<bean id="oracleHibernateTemplate"
        class="org.springframework.orm.hibernate3.HibernateTemplate">
        <property name="alwaysUseNewSession" value="false"></property>
        <property name="sessionFactory" ref="oracleSessionFactory"></property>
    </bean>

<!-- 定义 mysqlHibernateTemplate 用于注入到对应dao -->    
    <bean id="mysqlHibernateTemplate"
        class="org.springframework.orm.hibernate3.HibernateTemplate">
        <property name="alwaysUseNewSession" value="false"></property>
        <property name="sessionFactory" ref="mysqlSessionFactory"></property>
    </bean>
    
	
<!--进行jta的配置 -->
	<bean id="atomikosTransactionManager" class="com.atomikos.icatch.jta.UserTransactionManager"
		init-method="init" destroy-method="close">
		<property name="forceShutdown">
			<value>true</value>
		</property>
	</bean>

	<bean id="atomikosUserTransaction" class="com.atomikos.icatch.jta.UserTransactionImp">
		<property name="transactionTimeout" value="240" />
	</bean>

	<bean id="transactionManager"
		class="org.springframework.transaction.jta.JtaTransactionManager">
		<property name="transactionManager" ref="atomikosTransactionManager" />
		<property name="userTransaction" ref="atomikosUserTransaction" />
		<property name="allowCustomIsolationLevels" value="true" />
	</bean>
	
        
	<context:annotation-config />
	<tx:annotation-driven proxy-target-class="true" transaction-manager="transactionManager" />
    <context:component-scan base-package="org.gjwu.web" />

 

3.2 新增Atomikos配置文件：transactions.properties，放入到src目录下

# SAMPLE PROPERTIES FILE FOR THE TRANSACTION SERVICE

    # THIS FILE ILLUSTRATES THE DIFFERENT SETTINGS FOR THE TRANSACTION MANAGER

    # UNCOMMENT THE ASSIGNMENTS TO OVERRIDE DEFAULT VALUES;

    # Required: factory implementation class of the transaction core.

    # NOTE: there is no default for this, so it MUST be specified!

    #

    com.atomikos.icatch.service=com.atomikos.icatch.standalone.UserTransactionServiceFactory

    # Set base name of file where messages are output

    # \uFF08also known as the 'console file'\uFF09\u3002

    #

    # com.atomikos.icatch.console_file_name = tm.out

    # Size limit \uFF08in bytes\uFF09 for the console file;

    # negative means unlimited.

    #

    # com.atomikos.icatch.console_file_limit=-1

    # For size-limited console files, this option

    # specifies a number of rotating files to

    # maintain.

    #

    # com.atomikos.icatch.console_file_count=1

    # Set the number of log writes between checkpoints

    #

    # com.atomikos.icatch.checkpoint_interval=500

    # Set output directory where console file and other files are to be put

    # make sure this directory exists!

    #

    com.atomikos.icatch.output_dir = ${app.path.log}

    # Set directory of log files; make sure this directory exists!

    #

    com.atomikos.icatch.log_base_dir = ${app.path.log}

    # Set base name of log file

    # this name will be  used as the first part of

    # the system-generated log file name

    #

    #com.atomikos.icatch.log_base_name = tmlog

    # Set the max number of active local transactions

    # or -1 for unlimited.

    #

    # com.atomikos.icatch.max_actives = 50

    # Set the default timeout \uFF08in milliseconds\uFF09 for local transactions

    #

    # com.atomikos.icatch.default_jta_timeout = 10000

    # Set the max timeout \uFF08in milliseconds\uFF09 for local transactions

    #

    # com.atomikos.icatch.max_timeout = 300000

    # The globally unique name of this transaction manager process

    # override this value with a globally unique name

    #

    # com.atomikos.icatch.tm_unique_name = tm

    # Do we want to use parallel subtransactions? JTA's default

    # is NO for J2EE compatibility

    #

    # com.atomikos.icatch.serial_jta_transactions=true

    # If you want to do explicit resource registration then

    # you need to set this value to false.

    #

    # com.atomikos.icatch.automatic_resource_registration=true

    # Set this to WARN, INFO or DEBUG to control the granularity

    # of output to the console file.

    #

     com.atomikos.icatch.console_log_level=WARN

    # Do you want transaction logging to be enabled or not?

    # If set to false, then no logging overhead will be done

    # at the risk of losing data after restart or crash.

    #

    com.atomikos.icatch.enable_logging=false

    # Should two-phase commit be done in \uFF08multi-\uFF09threaded mode or not?

    # Set this to false if you want commits to be ordered according

    # to the order in which resources are added to the transaction.

    #

    # NOTE: threads are reused on JDK 1.5 or higher.

    # For JDK 1.4, thread reuse is enabled as soon as the

    # concurrent backport is in the classpath - see

    # http://mirrors.ibiblio.org/pub/mirrors/maven2/backport-util-concurrent/backport-util-concurrent/

    #

    # com.atomikos.icatch.threaded_2pc=false

    # Should shutdown of the VM trigger shutdown of the transaction core too?

    #

    # com.atomikos.icatch.force_shutdown_on_vm_exit=false

 

 

主要修改这四项：

com.atomikos.icatch.output_dir = ${app.path.log}
com.atomikos.icatch.log_base_dir = ${app.path.log}
com.atomikos.icatch.console_log_level=WARN
com.atomikos.icatch.enable_logging=false

 

3.3为dao层注入hibernateTemplate

即可使用

 

 

四、遇到的问题

4.1 启动的时候报没设置hibernateTemplate或者SessionFactory

原因：没有注入HibernateTemplate模板

 4.2 启动成功后经常有以下异常：
com.atomikos.datasource.ResourceException: XA resource 'mysqlMessage2XADBMS': resume for XID '3231382E36382E3235302E3132302E746D32313734343030323732:3231382E36382E3235302E3132302E746D3533383839' raised -5: invalid arguments were given for the XA operation

这个mysql的XA的bug，需要在数据源中设置

<prop key="pinGlobalTxToPhysicalConnection">true</prop>
<prop key="autoReconnect">true</prop>

 

4.3 同一台机子或代码启动多个应用程序失败

需要在Atomikos的配置文件中transactions.properties

com.atomikos.icatch.enable_logging=false

进行禁用