Postgresql 分布式事务JTA实现Atomikos与Spring集成实践_整合atomikos postgresql

作者：你好赵伟 | 2024-04-01 01:51:54

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整合atomikos postgresql

理解分布式事务JTA原理参见: http://www.ibm.com/developerworks/cn/java/j-lo-jta/

JTA实现产品介绍: http://blog.chinaunix.net/uid-122937-id-3793220.html

Atomikos官网无法访问，不过Maven中央库中具atomikos包。Atomikos集成Spring，Hibernate，Mybatis网上文章比较多，本文是通过JavaSE的方式借用Spring配置来测试Atomikos对JTA的实现。

下面做一件事，就是两（+）个数据库，在一个事务里对其分别对数据库操作验证操作的原子性，即要么两个数据库的操作都成功，要么都失败。

1.准备工作

1.1 Maven pom.xml中添加依赖包

atomikos:（目前最新版）

<dependency>
			<groupId>com.atomikos</groupId>
			<artifactId>transactions-jdbc</artifactId>
			<version>3.9.3</version>
		</dependency>

jar依赖图：

Postgresql数据库驱动:

<dependency>
			<groupId>org.postgresql</groupId>
			<artifactId>postgresql</artifactId>
			<version>9.2-1004-jdbc4</version>
		</dependency>

Spring,Junit依赖这里省略。

1.2 创建数据库以及表

数据库分别是:javaee,tomdb

2.在项目中添加配置文件

spring-jta.xml 和transaction.properties文件，spring-jta.xml在src/main/resources/integration下，transaction.properties在src/main/resources/下。

2.1在spring-jta.xml中配置两个XADataSource:

<!-- 使用分布式事务时设置Postgresql的max_prepared_transactions为大于0的值,该值默认是0 -->
	<!-- 数据库A -->
	<bean id="a" class="com.atomikos.jdbc.AtomikosDataSourceBean"
		init-method="init" destroy-method="close">
		<property name="uniqueResourceName" value="pg/a" />
		<property name="xaDataSourceClassName" value="org.postgresql.xa.PGXADataSource" />
		<property name="xaProperties">
			<props>
				<prop key="user">postgres</prop>
				<prop key="password">postgres</prop>
				<prop key="serverName">localhost</prop>
				<prop key="portNumber">5432</prop>
				<prop key="databaseName">tomdb</prop>
			</props>
		</property>
		<property name="poolSize" value="10" />
		<property name="reapTimeout" value="20000" />
	</bean>
	<bean id="b" class="com.atomikos.jdbc.AtomikosDataSourceBean"
		init-method="init" destroy-method="close">
		<property name="uniqueResourceName" value="pg/b" />
		<property name="xaDataSourceClassName" value="org.postgresql.xa.PGXADataSource" />
		<property name="xaProperties">
			<props>
				<prop key="user">postgres</prop>
				<prop key="password">postgres</prop>
				<prop key="serverName">localhost</prop>
				<prop key="portNumber">5432</prop>
				<prop key="databaseName">javaee</prop>
			</props>
		</property>
		<property name="poolSize" value="10" />
		<property name="reapTimeout" value="20000" />
	</bean>

说明:

Postgresql的max_prepared_transactions参数值默认是0，要开启分布式事务需要设置为大于0的值，该参数在PostgreSQL\9.3\data\postgresql.conf文件中。

PGXADataSource的父类BaseDataSource没有url属性，可需要分别设置serverName,portNumber,databaseName等属性。不同的数据库驱动有不同的实现方法。

2.2 配置事务管理对象和UserTransaction接口实现

<!-- atomikos事务管理 -->
	<bean id="atomikosUserTransactionManager" class="com.atomikos.icatch.jta.UserTransactionManager">
		<description>UserTransactionManager</description>
		<property name="forceShutdown" value="true" />
	</bean>

	<bean id="atomikosUserTransaction" class="com.atomikos.icatch.jta.UserTransactionImp">
		<property name="transactionTimeout" value="300" />
	</bean>

	<bean id="transactionManager"
		class="org.springframework.transaction.jta.JtaTransactionManager">
		<property name="transactionManager" ref="atomikosUserTransactionManager"></property>
	</bean>

上面三个Bean可以独立使用来进行事务控制，具体看下面3。

3. 编写测试

3.1 使用atomikosUserTransactionManager对象测试（TestAtomikos1.java）


package secondriver.springsubway.example.jta;
 
import java.sql.Connection;
import java.sql.SQLException;
 
import javax.transaction.HeuristicMixedException;
import javax.transaction.HeuristicRollbackException;
import javax.transaction.NotSupportedException;
import javax.transaction.RollbackException;
import javax.transaction.SystemException;
 
import org.junit.BeforeClass;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
 
import com.atomikos.icatch.jta.UserTransactionManager;
import com.atomikos.jdbc.AtomikosDataSourceBean;
 
public class TestAtomikos1 {
 
	public static ApplicationContext ctx;
 
	@BeforeClass
	public static void beforeClass() {
		ctx = new ClassPathXmlApplicationContext(
				"classpath:integration/spring-jta.xml");
	}
 
	public static void afterClass() {
		ctx = null;
	}
 
	@Test
	public void test1() {
		exe("abc", "abc");
	}
 
	@Test
	public void test2() {
		exe("123=", "123");
	}
 
	public void exe(String av, String bv) {
 
		AtomikosDataSourceBean adsA = (AtomikosDataSourceBean) ctx.getBean("a");
		AtomikosDataSourceBean adsB = (AtomikosDataSourceBean) ctx.getBean("b");
		Connection connA;
		Connection connB;
		UserTransactionManager utm = (UserTransactionManager) ctx
				.getBean("atomikosUserTransactionManager");
		try {
			utm.begin();
			connA = adsA.getConnection();
			connB = adsB.getConnection();
			connA.prepareStatement(
					"insert into jta_temp (value) values('" + av + "')")
					.execute();
			connB.prepareStatement(
					"insert into jta_temp (value) values('" + bv + "')")
					.execute();
			utm.commit();
		} catch (SQLException | NotSupportedException | SystemException
				| SecurityException | IllegalStateException | RollbackException
				| HeuristicMixedException | HeuristicRollbackException e) {
			e.printStackTrace();
		}
	}
}

3.2使用Spring的JtaUserTransactionManager对象测试（TestAtomikos2.java 修改TestAtomikos1.java中的exe方法即可）


@Test
	public void test1() {
		exe("abc", "abc");
	}
 
	@Test
	public void test2() {
		exe("123=", "123");
	}

public void exe(String av, String bv) {
		TransactionFactory txm = (TransactionFactory) ctx
				.getBean("transactionManager");

		JdbcTemplate a = (JdbcTemplate) ctx.getBean("jdbcTemplateA");
		JdbcTemplate b = (JdbcTemplate) ctx.getBean("jdbcTemplateB");
		try {
			Transaction tx = txm.createTransaction("tx-name-define", 10000);
			a.update("insert into jta_temp (value) values('" + av + "')");
			b.update("insert into jta_temp (value) values('" + bv + "')");
			tx.commit();
		} catch (NotSupportedException | SystemException | SecurityException
				| RollbackException | HeuristicMixedException
				| HeuristicRollbackException e) {
			e.printStackTrace();
		}
	}

3.3使用atomikosUserTransaction Bean对象进行测试（TestAtomikos3.java 修改TestAtomikos1.java中的exe方法即可）


@Test
	public void test1() {
		exe("abc", "abc");
	}
 
	@Test
	public void test2() {
		exe("123", "123=");
	}

public void exe(String av, String bv) {

		AtomikosDataSourceBean adsA = (AtomikosDataSourceBean) ctx.getBean("a");
		AtomikosDataSourceBean adsB = (AtomikosDataSourceBean) ctx.getBean("b");
		Connection connA;
		Connection connB;
		UserTransaction utx = (UserTransaction) ctx
				.getBean("atomikosUserTransaction");
		try {
			utx.begin();
			connA = adsA.getConnection();
			connB = adsB.getConnection();
			connA.prepareStatement(
					"insert into jta_temp (value) values('" + av + "')")
					.execute();
			connB.prepareStatement(
					"insert into jta_temp (value) values('" + bv + "')")
					.execute();
			utx.commit();
		} catch (SQLException | NotSupportedException | SystemException
				| SecurityException | IllegalStateException | RollbackException
				| HeuristicMixedException | HeuristicRollbackException e) {
			e.printStackTrace();
		}
	}

使用上述三种UserTransaction进行测试，其中test1方法是成功执行，test2方法是执行失败的（因为插入的值长度超过的字段长度限制）。通过分析之后，如果分布式事物控制正确，那么数据库中写入的值对于两张不同的表而言，是没有数字值被写入的。如图所示：

在测试过程中，经过对比确实达到了分布式事务控制的效果。

关于JTA原理文章开始提到的那篇文章，写的很详细和清晰，可以细细阅读和理解。


<?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"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:jdbc="http://www.springframework.org/schema/jdbc"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
       http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
       http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc.xsd
       http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">
	<aop:aspectj-autoproxy />
	
	
		
	<!-- 采用注释的方式配置bean -->
	<context:annotation-config />
	<bean id="springContextHolder"
		class="com.hihsoft.framework.core.utils.SpringContextHolder"
		lazy-init="false" />
	<bean id="propertyConfigurerForProject_framework"
		class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
		<property name="order" value="1" />
		<property name="ignoreUnresolvablePlaceholders" value="true" />
		<property name="location">
			<value>classpath:jdbc.properties</value>
		</property>
	</bean>
	<bean id="db1_dataSource" class="com.atomikos.jdbc.AtomikosDataSourceBean"
		init-method="init" destroy-method="close">
		<property name="uniqueResourceName" value="db1_dataSource" />
		<property name="xaDataSourceClassName"
			value="com.mysql.jdbc.jdbc2.optional.MysqlXADataSource" />
 
		<property name="xaProperties">
			<props>
				<prop key="user">${jdbc.username}</prop>
				<prop key="password">${jdbc.password}</prop>
				<prop key="URL">${jdbc.url}</prop>
			</props>
		</property>
		<!-- 连接池里面连接的个数? -->
		<property name="poolSize" value="3" />
	</bean>
 
	<bean id="db2_dataSource" class="com.atomikos.jdbc.AtomikosDataSourceBean"
		init-method="init" destroy-method="close">
		<property name="uniqueResourceName" value="db2_dataSource" />
		<property name="xaDataSourceClassName"
			value="com.mysql.jdbc.jdbc2.optional.MysqlXADataSource" />
		<property name="xaProperties">
			<props>
				<prop key="user">${jdbc.username.hihsoft}</prop>
				<prop key="password">${jdbc.password.hihsoft}</prop>
				<prop key="URL">${jdbc.url.hihsoft}</prop>
			</props>
		</property>
		<!-- 连接池里面连接的个数? -->
		<property name="poolSize" value="3" />
	</bean>
	<!-- enable transaction demarcation with annotations -->
	<tx:annotation-driven transaction-manager="jtaTransactionManager"
		proxy-target-class="false" />
 
	<!-- atomikos事务管理器 -->
	<bean id="atomikosTransactionManager" class="com.atomikos.icatch.jta.UserTransactionManager"
		init-method="init" destroy-method="close">
		<property name="forceShutdown" value="true" />
	</bean>
 
	<bean id="atomikosUserTransaction" class="com.atomikos.icatch.jta.UserTransactionImp">
		<property name="transactionTimeout" value="300" />
	</bean>
 
	<!-- spring 事务管理器 -->
	<bean id="jtaTransactionManager"
		class="org.springframework.transaction.jta.JtaTransactionManager">
		<property name="transactionManager" ref="atomikosTransactionManager" />
		<property name="userTransaction" ref="atomikosUserTransaction" />
		<property name="allowCustomIsolationLevels" value="true" />
	</bean>
	<bean id="db1_sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
		<property name="dataSource" ref="db1_dataSource" />
		<property name="mapperLocations"
			value="classpath*:com/hihsoft/db1/persistence/**/*.xml" />
	</bean>
 
	<bean id="db1MapperScannerConfigurer" class="org.mybatis.spring.mapper.MapperScannerConfigurer">
		<property name="basePackage" value="com.hihsoft.db1.persistence" />
		<property name="sqlSessionFactoryBeanName" value="db1_sqlSessionFactory" />
	</bean>
	<bean id="db2_sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
		<property name="dataSource" ref="db2_dataSource" />
		<property name="mapperLocations"
			value="classpath*:com/hihsoft/db2/persistence/**/*.xml" />
	</bean>
 
	<bean id="db2MapperScannerConfigurer" class="org.mybatis.spring.mapper.MapperScannerConfigurer">
		<property name="basePackage" value="com.hihsoft.db2.persistence" />
		<property name="sqlSessionFactoryBeanName" value="db2_sqlSessionFactory" />
	</bean>
	<!-- mybatis日志打印 -->
	<bean class="org.apache.ibatis.logging.LogFactory" init-method="useStdOutLogging"></bean>
	<!-- spring jdbc ibatis mybatis初始化数据导入 -->
	<jdbc:initialize-database data-source="db1_dataSource"
		enabled="false" ignore-failures="ALL">
		<jdbc:script location="classpath:/resources/dbcfg/initframework_db1.sql"
			encoding="UTF-8" />
	</jdbc:initialize-database>
	<jdbc:initialize-database data-source="db2_dataSource"
		enabled="false" ignore-failures="ALL">
		<jdbc:script location="classpath:/resources/dbcfg/initframework_db2.sql"
			encoding="UTF-8" />
	</jdbc:initialize-database>
	<!-- 扫描范围 -->
	<context:component-scan base-package="com.hihsoft">
		<context:exclude-filter type="annotation"
			expression="org.springframework.stereotype.Controller" />
	</context:component-scan>
	
 
 
	<!-- 获取bean工具注入 -->
</beans>

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