自動切換數據源

背景： spring+mybatis項目

數據源：

<?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"
       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-3.0.xsd">
    <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="location" value="classpath:jdbc.properties"/>
    </bean>
    <bean id="sqlServerDataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
        <property name="driverClassName" value="${jdbc.sqlserver.driver}"/>
        <property name="url" value="${jdbc.sqlserver.url}"/>
        <property name="username" value="${jdbc.sqlserver.username}"/>
        <property name="password" value="${jdbc.sqlserver.password}"/>
        <property name="initialSize" value="${jdbc.initialSize}"/>
        <property name="minIdle" value="${jdbc.minIdle}"/>
        <property name="maxIdle" value="${jdbc.maxIdle}"/>
        <property name="maxActive" value="${jdbc.maxActive}"/>
        <property name="maxWait" value="${jdbc.maxWait}"/>
        <property name="defaultAutoCommit" value="${jdbc.defaultAutoCommit}"/>
        <property name="removeAbandoned" value="${jdbc.removeAbandoned}"/>
        <property name="removeAbandonedTimeout" value="${jdbc.removeAbandonedTimeout}"/>
        <property name="testWhileIdle" value="${jdbc.testWhileIdle}"/>
        <property name="timeBetweenEvictionRunsMillis" value="${jdbc.timeBetweenEvictionRunsMillis}"/>
        <property name="numTestsPerEvictionRun" value="${jdbc.numTestsPerEvictionRun}"/>
        <property name="minEvictableIdleTimeMillis" value="${jdbc.minEvictableIdleTimeMillis}"/>
    </bean>
    <bean id="mySqlDataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
        <property name="driverClassName" value="${jdbc.mysql.driver}"/>
        <property name="url" value="${jdbc.mysql.url}"/>
        <property name="username" value="${jdbc.mysql.username}"/>
        <property name="password" value="${jdbc.mysql.password}"/>
        <property name="initialSize" value="${jdbc.initialSize}"/>
        <property name="minIdle" value="${jdbc.minIdle}"/>
        <property name="maxIdle" value="${jdbc.maxIdle}"/>
        <property name="maxActive" value="${jdbc.maxActive}"/>
        <property name="maxWait" value="${jdbc.maxWait}"/>
        <property name="defaultAutoCommit" value="${jdbc.defaultAutoCommit}"/>
        <property name="removeAbandoned" value="${jdbc.removeAbandoned}"/>
        <property name="removeAbandonedTimeout" value="${jdbc.removeAbandonedTimeout}"/>
        <property name="testWhileIdle" value="${jdbc.testWhileIdle}"/>
        <property name="timeBetweenEvictionRunsMillis" value="${jdbc.timeBetweenEvictionRunsMillis}"/>
        <property name="numTestsPerEvictionRun" value="${jdbc.numTestsPerEvictionRun}"/>
        <property name="minEvictableIdleTimeMillis" value="${jdbc.minEvictableIdleTimeMillis}"/>
    </bean>
    <bean id="multipleDataSource" class="com.cnblogs.lzrabbit.MultipleDataSource">
        <property name="defaultTargetDataSource" ref="mySqlDataSource"/>
        <property name="targetDataSources">
            <map>
                <entry key="mySqlDataSource" value-ref="mySqlDataSource"/>
                <entry key="sqlServerDataSource" value-ref="sqlServerDataSource"/>
            </map>
        </property>
    </bean>
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="multipleDataSource"/>
    </bean>

    <!-- mybatis.spring自動映射 -->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.cnblogs.lzrabbit"/>
    </bean>

    <!-- 自動掃描，多個包以 逗號分隔 -->
    <context:component-scan base-package="com.cnblogs.lzrabbit"/>
    <aop:aspectj-autoproxy/>
</beans>

applicationContext.xml

  MultipleDataSource實現：

package com.cnblogs.lzrabbit;

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


public class MultipleDataSource extends AbstractRoutingDataSource {
    private static final ThreadLocal<String> dataSourceKey = new InheritableThreadLocal<String>();

    public static void setDataSourceKey(String dataSource) {
        dataSourceKey.set(dataSource);
    }

    @Override
    protected Object determineCurrentLookupKey() {
        return dataSourceKey.get();
    }
}

使用SpringAOP方式實現自動切換：

package com.cnblogs.lzrabbit;

import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.stereotype.Component;

@Component
@Aspect
public class MultipleDataSourceAspectAdvice {

    @Around("execution(* com.cnblogs.lzrabbit.*.*(..))")
    public Object doAround(ProceedingJoinPoint jp) throws Throwable {
        if (jp.getTarget() instanceof MySqlMapper) {
            MultipleDataSource.setDataSourceKey("mySqlDataSource");
        } else if (jp.getTarget() instanceof SqlServerMapper) {
            MultipleDataSource.setDataSourceKey("sqlServerDataSource");
        }
        return jp.proceed();
    }
}