spring+atomikos+mybatis 多數據源事務（動態切換）

注：自動切換，是爲不一樣的數據源，卻要對應相同的dao層；

1.與無事務版的同樣，建立DynamicDataSource類，繼承AbstractRoutingDataSource

package com.test.main.dataSource;

import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;

public class DynamicDataSource extends AbstractRoutingDataSource {

    @Override
    protected Object determineCurrentLookupKey() {
        return DynamicDataSourceHolder.getDataSource();
    }

}
建立輔助類DynamicDataSourceHolder，主要用於保存當前線程所需的datasource的key值

package com.test.main.dataSource;

public class DynamicDataSourceHolder {
    private static final ThreadLocal<String> THREAD_DATA_SOURCE = new ThreadLocal<String>();

    public static String getDataSource() {
        return THREAD_DATA_SOURCE.get();
    }

    public static void setDataSource(String dataSource) {
        THREAD_DATA_SOURCE.set(dataSource);
    }

    public static void clearDataSource() {
        THREAD_DATA_SOURCE.remove();
    }
}

建立dao層切面，註解選擇數據源DataSourceAspect類：

package com.test.main.dataSource;

import java.lang.annotation.Annotation;
import java.lang.reflect.Method;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.stereotype.Component;

import com.test.main.annotations.DataSource;

@Component
@Aspect
public class DataSourceAspect {
    @Before("execution(* com.test.model.dao.*.*.*(..))")
    public void intercept(JoinPoint point) throws Exception {
        Class<?> target = point.getTarget().getClass();
        MethodSignature signature = (MethodSignature) point.getSignature();
        for (Class<?> clazz : target.getInterfaces()) {
            resolveDataSource(clazz, signature.getMethod());
        }
        resolveDataSource(target, signature.getMethod());

    }
    private void resolveDataSource(Class<?> clazz, Method method) {
        String sourceName = null;
        try {
            Class<?>[] types = method.getParameterTypes();
            if (clazz.isAnnotationPresent((Class<? extends Annotation>) DataSource.class)) {
                DataSource source = clazz.getAnnotation(DataSource.class);
                sourceName = source.value();
                DynamicDataSourceHolder.setDataSource(sourceName);
            }
            Method m = clazz.getMethod(method.getName(), types);
            if (m != null && m.isAnnotationPresent(DataSource.class)) {
                DataSource source = m.getAnnotation(DataSource.class);
                sourceName = source.value();
                DynamicDataSourceHolder.setDataSource(sourceName);
            }
        } catch (Exception e) {
            System.out.println(clazz + ":" + e.getMessage());
        }
    }

}
2.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:util="http://www.springframework.org/schema/util"
    xmlns:tx="http://www.springframework.org/schema/tx" xmlns:aop="http://www.springframework.org/schema/aop"
    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-4.2.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.2.xsd
        http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.2.xsd">

    <util:properties id="jdbc"
        location="classpath:etc/mybatis/db.properties" />

    <!-- 鏈接池配置開始 -->
    <bean id="chicken" class="com.atomikos.jdbc.AtomikosDataSourceBean"
        init-method="init" destroy-method="close">
        <property name="xaDataSourceClassName"
            value="com.mysql.jdbc.jdbc2.optional.MysqlXADataSource" />
        <property name="uniqueResourceName" value="mysql/chicken" />
        <property name="xaProperties">
            <props>
                <prop key="user">#{jdbc.username}</prop>
                <prop key="password">#{jdbc.password}</prop>
                <prop key="url">#{jdbc.chicken}</prop>
            </props>
        </property>
        <property name="minPoolSize" value="5" />
        <property name="maxPoolSize" value="20" />
        <property name="maxIdleTime" value="60" />
        <property name="reapTimeout" value="20000" />
    </bean>
    <bean id="test_chicken" class="com.atomikos.jdbc.AtomikosDataSourceBean"
        init-method="init" destroy-method="close">
        <property name="xaDataSourceClassName"
            value="com.mysql.jdbc.jdbc2.optional.MysqlXADataSource" />
        <property name="uniqueResourceName" value="mysql/test_chicken" />
        <property name="xaProperties">
            <props>
                <prop key="user">#{jdbc.username}</prop>
                <prop key="password">#{jdbc.password}</prop>
                <prop key="url">#{jdbc.c_test}</prop>
            </props>
        </property>
        <property name="minPoolSize" value="5" />
        <property name="maxPoolSize" value="20" />
        <property name="maxIdleTime" value="60" />
        <property name="reapTimeout" value="20000" />
    </bean>

    <bean id="fariyking" class="com.atomikos.jdbc.AtomikosDataSourceBean"
        init-method="init" destroy-method="close">
        <property name="xaDataSourceClassName"
            value="com.mysql.jdbc.jdbc2.optional.MysqlXADataSource" />
        <property name="uniqueResourceName" value="mysql/fariyking" />
        <property name="xaProperties">
            <props>
                <prop key="user">#{jdbc.username}</prop>
                <prop key="password">#{jdbc.password}</prop>
                <prop key="url">#{jdbc.fariyking}</prop>
            </props>
        </property>
        <property name="minPoolSize" value="5" />
        <property name="maxPoolSize" value="20" />
        <property name="maxIdleTime" value="60" />
        <property name="reapTimeout" value="20000" />
    </bean>
    <bean id="test_fariyking" class="com.atomikos.jdbc.AtomikosDataSourceBean"
        init-method="init" destroy-method="close">
        <property name="xaDataSourceClassName"
            value="com.mysql.jdbc.jdbc2.optional.MysqlXADataSource" />
        <property name="uniqueResourceName" value="mysql/test_fariyking" />
        <property name="xaProperties">
            <props>
                <prop key="user">#{jdbc.username}</prop>
                <prop key="password">#{jdbc.password}</prop>
                <prop key="url">#{jdbc.f_test}</prop>
            </props>
        </property>
        <property name="minPoolSize" value="5" />
        <property name="maxPoolSize" value="20" />
        <property name="maxIdleTime" value="60" />
        <property name="reapTimeout" value="20000" />
    </bean>


    <!-- 鏈接池配置結束 -->

    <!-- MyBatis整合開始 -->

    <bean id="c_dynamicDataSource" class="com.test.main.dataSource.DynamicDataSource">
        <property name="targetDataSources">
            <map key-type="java.lang.String">
                <entry key="chicken" value-ref="chicken"></entry>
                <entry key="test_chicken" value-ref="test_chicken"></entry>
            </map>
        </property>
    </bean>
    <bean id="cFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="c_dynamicDataSource" />
        <property name="configLocation" value="classpath:etc/mybatis/mybatis-config.xml" />
        <property name="mapperLocations" value="classpath:com/test/**/*.xml" />
    </bean>    
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.test.model.dao.c" />
        <property name="annotationClass" value="com.test.main.annotations.MyBatisRepository" />
        <property name="sqlSessionFactory" ref="cFactory"></property>
        <property name="sqlSessionFactoryBeanName" value="cFactory"></property>
    </bean>
    
    <bean id="f_dynamicDataSource" class="com.test.main.dataSource.DynamicDataSource">
        <property name="targetDataSources">
            <map key-type="java.lang.String">
                <entry key="fariyking" value-ref="fariyking"></entry>
                <entry key="test_fariyking" value-ref="test_fariyking"></entry>
            </map>
        </property>
    </bean>
    <bean id="fFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="f_dynamicDataSource" />
        <property name="configLocation" value="classpath:etc/mybatis/mybatis-config.xml" />
        <property name="mapperLocations" value="classpath:com/test/**/*.xml" />
    </bean>
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.test.model.dao.f" />
        <property name="annotationClass" value="com.test.main.annotations.MyBatisRepository" />
        <property name="sqlSessionFactory" ref="fFactory"></property>
        <property name="sqlSessionFactoryBeanName" value="fFactory"></property>
    </bean>
    <!-- MyBatis整合結束 -->


    <!-- 配置數據庫事務開始 -->
    <!-- atomikos事務管理器 -->
    <bean id="atomikosTransactionManager" class="com.atomikos.icatch.jta.UserTransactionManager"
        init-method="init" destroy-method="close">
        <description>UserTransactionManager</description>
        <property name="forceShutdown">
            <value>true</value>
        </property>
    </bean>
    <bean id="atomikosUserTransaction" class="com.atomikos.icatch.jta.UserTransactionImp">
        <property name="transactionTimeout" value="3000" />
    </bean>
    <bean id="springTransactionManager"
        class="org.springframework.transaction.jta.JtaTransactionManager">
        <property name="transactionManager">
            <ref bean="atomikosTransactionManager" />
        </property>
        <property name="userTransaction">
            <ref bean="atomikosUserTransaction" />
        </property>
        <property name="allowCustomIsolationLevels" value="true" />
    </bean>

    <tx:annotation-driven transaction-manager="springTransactionManager" />
    <!-- 配置數據庫事務結束 -->

</beans>

2.1在同一個事務中，不一樣的數據源須要不一樣 SqlSessionFactoryBean，注意配置時，須要配置 MapperScannerConfigurer的：


<property name="sqlSessionFactoryBeanName" value="cFactory"></property>

value值爲：SqlSessionFactoryBean 的 bean id；

2.2同一事務中的SqlSessionFactoryBean，對應MapperScannerConfigurer 中的 basePackage 不能範圍重合，否則在同一事務時，spring不會切換數據源，而是取先前與之重合的SqlSessionFactoryBean的數據源