spring 多数据源配置
spring 多数据源配置一般有两种方案：
1、在spring项目启动的时候直接配置两个不同的数据源，不同的sessionFactory。在dao 层根据不同业务自行选择使用哪个数据源的session来操作。
2、配置多个不同的数据源，使用一个sessionFactory,在业务逻辑使用的时候自动切换到不同的数据源，有一个种是在拦截器里面根据不同的业务现切换到不同的datasource;有的会在业务层根据业务来自动切换。但这种方案在多线程并发的时候会出现一些问题，需要使用threadlocal等技术来实现多线程竞争切换数据源的问题。
【本文暂时只讨论第一种方案】
spring多事务配置主要体现在db配置这块，配置不同的数据源和不同的session
1、一下贴出 spring-db.xml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:context="http://www.springframework.org/schema/context"
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/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.1.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd">
<bean id="test1DataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close" >
<property name="driverClassName" value="${database.test1.driverClassName}" />
<property name="url" value="${database.test1.url}" />
<property name="username" value="${database.test1.username}" />
<property name="password" value="${database.test1.password}" />
bean>
<bean id="test2DataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close" >
<property name="driverClassName" value="${database.test2.driverClassName}" />
<property name="url" value="${database.test2.url}" />
<property name="username" value="${database.test2.username}" />
<property name="password" value="${database.test2.password}" />
bean>
<bean id="test1SqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="test1DataSource" />
<property name="configLocation" value="classpath:mybatis/mybatis-config.xml">property>
<property name="mapperLocations" value="classpath*:mybatis/mapper/*.xml" />
bean>
<bean id="test2SqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="test2DataSource" />
<property name="configLocation" value="classpath:mybatis/mybatis-config.xml">property>
<property name="mapperLocations" value="classpath*:mybatis/mapper/*.xml" />
bean>
<bean id="test1TxManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="test1DataSource">property>
bean>
<bean id="test2TxManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="test2DataSource">property>
bean>
<tx:annotation-driven transaction-manager="test2TxManager" />
<tx:annotation-driven transaction-manager="test1TxManager" />
beans>
2、dao层做了一个小的封装，将不同的SqlSessionFactory 注入到 SessionFactory，通过BaseDao来做简单的封装，封装不同库的基本增删改。dao实现层都集成于Basedao 这样的话，实现可以根据自己需要来选择不同的库来操作不同的内容。
session工厂
package com.neo.dao;
import com.neo.entity.Entity;
public class BaseDao extends SessionFactory{
public void test1Update(Entity entity) {
this.getTest1Session().update(entity.getClass().getSimpleName()+".update", entity);
}
public void test2Update(Entity entity) {
this.getTest2Session().update(entity.getClass().getSimpleName()+".update", entity);
}
}
BaseDao
package com.neo.dao;
import com.neo.entity.Entity;
public class BaseDao extends SessionFactory{
public void test1Update(Entity entity) {
this.getTest1Session().update(entity.getClass().getSimpleName()+".update", entity);
}
public void test2Update(Entity entity) {
this.getTest2Session().update(entity.getClass().getSimpleName()+".update", entity);
}
}
以上的配置在多数据源连接，正常的增删改都是没有问题的，但是遇到分布式的事务是就出问题：
测试代码：
package com.neo.service.impl;
import javax.annotation.Resource;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import com.neo.dao.UserDao;
import com.neo.dao.UserInformationsDao;
import com.neo.entity.UserEntity;
import com.neo.entity.UserInformationsEntity;
import com.neo.service.UserService;
@Service
public class UserServiceImpl implements UserService {
@Resource UserDao userDao;
@Resource UserInformationsDao userInformationsDao;
@Override
@Transactional
public void updateUserinfo() {
UserEntity user=new UserEntity();
user.setId(1);
user.setUserName("李四4");
UserInformationsEntity userInfo=new UserInformationsEntity();
userInfo.setUserId(1);
userInfo.setAddress("陕西4");
userDao.updateUser(user);
userInformationsDao.updateUserInformations(userInfo);
if(true){
throw new RuntimeException("test tx ");
}
}
}
在service添加事务后，更新完毕抛出异常，test2更新进行了回滚，test1 数据更新没有回滚。
解决方案添加分布式的事务，Atomikos和spring结合来处理。
Atomikos多数据源的配置
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:context="http://www.springframework.org/schema/context"
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/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.1.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd">
<bean id="test1DataSource" class="com.atomikos.jdbc.AtomikosDataSourceBean" init-method="init" destroy-method="close">
<property name="uniqueResourceName" value="test1"/>
<property name="xaDataSourceClassName" value="com.mysql.jdbc.jdbc2.optional.MysqlXADataSource"/>
<property name="xaProperties">
<props>
<prop key="url">${database.test1.url}prop>
<prop key="user">${database.test1.username}prop>
<prop key="password">${database.test1.password}prop>
props>
property>
<property name="minPoolSize" value="10" />
<property name="maxPoolSize" value="100" />
<property name="borrowConnectionTimeout" value="30" />
<property name="testQuery" value="select 1" />
<property name="maintenanceInterval" value="60" />
bean>
<bean id="test2DataSource" class="com.atomikos.jdbc.AtomikosDataSourceBean" init-method="init" destroy-method="close">
<property name="uniqueResourceName" value="test2"/>
<property name="xaDataSourceClassName" value="com.mysql.jdbc.jdbc2.optional.MysqlXADataSource"/>
<property name="xaProperties">
<props>
<prop key="url">${database.test2.url}prop>
<prop key="user">${database.test2.username}prop>
<prop key="password">${database.test2.password}prop>
props>
property>
<property name="minPoolSize" value="10" />
<property name="maxPoolSize" value="100" />
<property name="borrowConnectionTimeout" value="30" />
<property name="testQuery" value="select 1" />
<property name="maintenanceInterval" value="60" />
bean>
<bean id="test1SqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="test1DataSource" />
<property name="configLocation" value="classpath:mybatis/mybatis-config.xml">property>
<property name="mapperLocations" value="classpath*:mybatis/mapper/*.xml" />
bean>
<bean id="test2SqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="test2DataSource" />
<property name="configLocation" value="classpath:mybatis/mybatis-config.xml">property>
<property name="mapperLocations" value="classpath*:mybatis/mapper/*.xml" />
bean>
<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>
<bean id="transactionManager" class="org.springframework.transaction.jta.JtaTransactionManager">
<property name="transactionManager" ref="atomikosTransactionManager"/>
<property name="userTransaction" ref="atomikosUserTransaction"/>
bean>
<tx:annotation-driven/>
beans>
所有代码请参考这里：
https://github.com/ityouknow/spring-examples