分布式事务--XA 解决多个数据源操作

个人备忘

事务（官方解释）：是由一组sql语句组成的“逻辑处理单元”。

事务具有如下四个属性，通常称为事务的ACID属性 ：
1. 原子性（Atomicity）: 事务是一个原子操作单元，要么都执行，要么都不执行。
2. 一致性（Consistent）：在事务开始和完成时，数据都必须保持一致。
3. 隔离性（Isoation）: 数据库系统提供一定的隔离机制，保证事务在不受外部并发操作影响的“独立”环境执行。
4. 持久性（Durabe）: 事务完成之后，它对数据的修改是永久性的。

分布式事务 ： 分布式事务就是指事务的参与者，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。

本质上来说，分布式事务就是为了保证“不同数据库的数据一致性” 。

分布式事务产生场景 ：

分布式事务管理器 ：

XA 协议 是可以在数据库conmit 之后进行回滚的。

常见分布式事务解决方案 ：

通过日志来记录操作 ，从上到下任何一步有问题，就会rollback ， 如下图 ：

XA优缺点：

常见数据库都对XA 协议有支持，成本低。

XA相关框架：

Atomikos 代码实现：

基于ssm

//pom.xml<?xml version="1.0" encoding="UTF-8"?><project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">    <modelVersion>4.0.0</modelVersion>    <groupId>com.xy</groupId>    <artifactId>springmvc-mybatis</artifactId>    <version>1.0-SNAPSHOT</version>    <packaging>war</packaging>    <properties>        <spring.version>4.1.1.RELEASE</spring.version>    </properties>    <build>        <plugins>            <plugin>                <groupId>org.apache.maven.plugins</groupId>                <artifactId>maven-surefire-plugin</artifactId>                <version>2.15</version>                <configuration>                    <skip>true</skip>                </configuration>            </plugin>            <plugin>                <groupId>org.apache.maven.plugins</groupId>                <artifactId>maven-compiler-plugin</artifactId>                <version>3.1</version>                <configuration>                    <source>1.7</source>                    <target>1.7</target>                    <debug>true</debug>                </configuration>            </plugin>            <plugin>                <groupId>org.apache.maven.plugins</groupId>                <artifactId>maven-war-plugin</artifactId>                <!--<configuration>-->                <!--<packagingExcludes>**/*.properties</packagingExcludes>-->                <!--</configuration>-->            </plugin>            <plugin>                <groupId>org.mortbay.jetty</groupId>                <artifactId>maven-jetty-plugin</artifactId>                <version>6.1.26</version>                <configuration>                    <scanIntervalSeconds>10</scanIntervalSeconds>                    <webAppConfig>                        <contextPath>/maven-app</contextPath>                    </webAppConfig>                </configuration>            </plugin>        </plugins>    </build>    <dependencies>        <dependency>            <groupId>org.springframework</groupId>            <artifactId>spring-jdbc</artifactId>            <version>${spring.version}</version>        </dependency>        <dependency>            <groupId>org.springframework</groupId>            <artifactId>spring-context-support</artifactId>            <version>${spring.version}</version>        </dependency>        <dependency>            <groupId>org.springframework</groupId>            <artifactId>spring-context</artifactId>            <version>${spring.version}</version>        </dependency>        <dependency>            <groupId>com.fasterxml.jackson.core</groupId>            <artifactId>jackson-core</artifactId>            <version>2.3.0</version>        </dependency>        <dependency>            <groupId>com.fasterxml.jackson.core</groupId>            <artifactId>jackson-databind</artifactId>            <version>2.3.0</version>        </dependency>        <dependency>            <groupId>ch.qos.logback</groupId>            <artifactId>logback-classic</artifactId>            <version>1.0.11</version>        </dependency>        <dependency>            <groupId>ch.qos.logback</groupId>            <artifactId>logback-core</artifactId>            <version>1.0.11</version>        </dependency>        <dependency>            <groupId>org.slf4j</groupId>            <artifactId>slf4j-api</artifactId>            <version>1.7.6</version>        </dependency>        <dependency>            <groupId>org.springframework</groupId>            <artifactId>spring-webmvc</artifactId>            <version>${spring.version}</version>        </dependency>        <dependency>            <groupId>javax.servlet</groupId>            <artifactId>servlet-api</artifactId>            <version>2.5</version>            <scope>provided</scope>        </dependency>        <dependency>            <groupId>org.springframework</groupId>            <artifactId>spring-orm</artifactId>            <version>${spring.version}</version>        </dependency>        <dependency>            <groupId>org.springframework</groupId>            <artifactId>spring-tx</artifactId>            <version>${spring.version}</version>        </dependency>        <dependency>            <groupId>commons-dbcp</groupId>            <artifactId>commons-dbcp</artifactId>            <version>1.4</version>        </dependency>        <dependency>            <groupId>commons-fileupload</groupId>            <artifactId>commons-fileupload</artifactId>            <version>1.3.1</version>        </dependency>        <dependency>            <groupId>com.mchange</groupId>            <artifactId>c3p0</artifactId>            <version>0.9.2.1</version>        </dependency>        <dependency>            <groupId>javax.servlet</groupId>            <artifactId>javax.servlet-api</artifactId>            <version>3.1.0</version>        </dependency>        <dependency>            <groupId>org.mybatis</groupId>            <artifactId>mybatis</artifactId>            <version>3.2.7</version>        </dependency>        <dependency>            <groupId>mysql</groupId>            <artifactId>mysql-connector-java</artifactId>            <version>5.0.8</version>        </dependency>        <dependency>            <groupId>org.mybatis</groupId>            <artifactId>mybatis-spring</artifactId>            <version>1.2.2</version>        </dependency>        <dependency>            <groupId>com.atomikos</groupId>            <artifactId>atomikos-util</artifactId>            <version>3.7.0</version>        </dependency>        <dependency>            <groupId>com.atomikos</groupId>            <artifactId>transactions-jta</artifactId>            <version>3.7.0</version>        </dependency>        <dependency>            <groupId>com.atomikos</groupId>            <artifactId>transactions</artifactId>            <version>3.7.0</version>        </dependency>        <dependency>            <groupId>com.atomikos</groupId>            <artifactId>transactions-api</artifactId>            <version>3.7.0</version>        </dependency>        <dependency>            <groupId>com.atomikos</groupId>            <artifactId>transactions-jdbc</artifactId>            <version>3.7.0</version>        </dependency>        <dependency>            <groupId>org.codehaus.btm</groupId>            <artifactId>btm</artifactId>            <version>2.1.4</version>        </dependency>    </dependencies></project>

spring-mybatis.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"       xmlns:tx="http://www.springframework.org/schema/tx" xmlns:jdbc="http://www.springframework.org/schema/jdbc"       xmlns:rabbit="http://www.springframework.org/schema/rabbit"       xmlns:cache="http://www.springframework.org/schema/cache" xmlns:task="http://www.springframework.org/schema/task"       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc.xsd http://www.springframework.org/schema/rabbit http://www.springframework.org/schema/rabbit/spring-rabbit.xsd       http://www.springframework.org/schema/cache http://www.springframework.org/schema/cache/spring-cache.xsd http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task.xsd">    <context:component-scan base-package="com.xy">        <context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller"/>    </context:component-scan>    <context:property-placeholder location="classpath:context/database.properties"/>    <tx:annotation-driven/>    <bean id="abstractXADataSource" class="com.atomikos.jdbc.AtomikosDataSourceBean" init-method="init"          destroy-method="close" abstract="true">        <property name="xaDataSourceClassName" value="com.mysql.jdbc.jdbc2.optional.MysqlXADataSource"/>        <property name="poolSize" value="10" />        <property name="minPoolSize" value="10"/>        <property name="maxPoolSize" value="30"/>        <property name="borrowConnectionTimeout" value="60"/>        <property name="reapTimeout" value="20"/>        <!-- 最大空闲时间 -->        <property name="maxIdleTime" value="60"/>        <property name="maintenanceInterval" value="60"/>        <property name="loginTimeout" value="60"/>        <property name="testQuery">            <value>select 1</value>        </property>    </bean>    <bean id="qadataSource" parent="abstractXADataSource">        <!-- value只要两个数据源不同就行，随便取名 -->        <property name="uniqueResourceName" value="mysql/sitestone1" />        <property name="xaDataSourceClassName"                  value="com.mysql.jdbc.jdbc2.optional.MysqlXADataSource" />        <property name="xaProperties">            <props>                <prop key="URL">${qa.db.url}</prop>                <prop key="user">${qa.db.user}</prop>                <prop key="password">${qa.db.password}</prop>                <prop key="pinGlobalTxToPhysicalConnection">true</prop>            </props>        </property>    </bean>    <bean id="devdataSource" parent="abstractXADataSource">        <!-- value只要两个数据源不同就行，随便取名 -->        <property name="uniqueResourceName" value="mysql/sitestone" />        <property name="xaDataSourceClassName"                  value="com.mysql.jdbc.jdbc2.optional.MysqlXADataSource" />        <property name="xaProperties">            <props>                <prop key="URL">${dev.db.url}</prop>                <prop key="user">${dev.db.user}</prop>                <prop key="password">${dev.db.password}</prop>                <prop key="pinGlobalTxToPhysicalConnection">true</prop>            </props>        </property>    </bean>    <bean id="qasqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">        <property name="dataSource" ref="qadataSource" />        <property name="mapperLocations" value="classpath*:com/xy/dao/*.xml" />    </bean>    <bean id="devsqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">        <property name="dataSource" ref="devdataSource" />        <property name="mapperLocations" value="classpath*:com/xy/daodev/*.xml" />    </bean>    <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="300" />    </bean>    <bean id="transactionManager"          class="org.springframework.transaction.jta.JtaTransactionManager">        <property name="transactionManager">            <ref bean="atomikosTransactionManager"/>        </property>        <property name="userTransaction">            <ref bean="atomikosUserTransaction"/>        </property>        <!-- 必须设置，否则程序出现异常 JtaTransactionManager does not support custom isolation levels by default -->        <property name="allowCustomIsolationLevels" value="true"/>    </bean>    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">        <property name="basePackage" value="com.xy.dao"/>        <property name="sqlSessionFactoryBeanName" value="qasqlSessionFactory" />    </bean>    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">        <property name="basePackage" value="com.xy.daodev"/>        <property name="sqlSessionFactoryBeanName" value="devsqlSessionFactory" />    </bean></beans>

database.properties

qa.db.url=jdbc:mysql://localhost:3306/qa?useUnicode=true&characterEncoding=UTF-8qa.db.user=rootqa.db.password=123456dev.db.url=jdbc:mysql://localhost:3306/dev?useUnicode=true&characterEncoding=UTF-8dev.db.user=rootdev.db.password=123456

jta.properties

com.atomikos.icatch.service=com.atomikos.icatch.standalone.UserTransactionServiceFactorycom.atomikos.icatch.console_file_name = tm.outcom.atomikos.icatch.log_base_name = tmlogcom.atomikos.icatch.tm_unique_name = com.atomikos.spring.jdbc.tmcom.atomikos.icatch.console_log_level = INFOcom.atomikos.icatch.output_dir=/hello/atomikoscom.atomikos.icatch.log_base_dir=/hello/atomikoscom.atomikos.icatch.serial_jta_transactions=false

java代码 ：

service

package com.xy.service;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;import org.springframework.transaction.annotation.Transactional;import com.xy.dao.NameQaMapper;import com.xy.daodev.NameDevMapper;import com.xy.model.NameDev;import com.xy.model.NameQa;@Servicepublic class NameService {    @Autowired    NameQaMapper qaMapper;    @Autowired    NameDevMapper devMapper;    @Transactional(rollbackFor=Exception.class)    public void addQaAndDev(boolean hasException) throws Exception{        NameQa nameQa = new NameQa();        nameQa.setNameQa("hello qa");               qaMapper.insert(nameQa);        NameDev dev = new NameDev();        dev.setNameDev("hello dev");        devMapper.insert(dev);        if (hasException) {            throw new Exception();        }    }}

controller 代码

package com.xy.controller;import com.xy.service.NameService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Controller;import org.springframework.ui.ModelMap;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import org.springframework.web.bind.annotation.RequestParam;/** * Created by helloworld on 2014/11/22. */@Controllerpublic class mybatisController {    @Autowired    NameService nameService;    @RequestMapping(value = "/addName", method = RequestMethod.GET)    ModelMap addName(@RequestParam("hasException") boolean hasException) {        try {            nameService.addQaAndDev(hasException);        } catch (Exception e) {            e.printStackTrace();            return new ModelMap("false");        }        return new ModelMap("true");    }}

model 和 mapper 没什么可说的，这里就不粘贴了。