在Spring-Mybatis-Restful中配置多数据源的properties文件

在Spring的配置文件中，如下：

<?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:aop="http://www.springframework.org/schema/aop"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="
            http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
            http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-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/jee http://www.springframework.org/schema/jee/spring-jee-3.0.xsd
            http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd"
            default-autowire="byName" default-lazy-init="false">
  <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="locations">
            <list>
                <value>/WEB-INF/database.properties</value>
            </list>
        </property>
    </bean>

  <bean id="ds1" class="org.apache.commons.dbcp.BasicDataSource">
     <property name="driverClassName" value="${cc.driver}"/>
     <property name="url" value="${cc.url}"/>
     <property name="username" value="${cc.username}"/>
     <property name="password" value="${cc.password}"/>
  </bean>
  <bean id="ds2" class="org.apache.commons.dbcp.BasicDataSource">
     <property name="driverClassName" value="${tt.driver}"/>
     <property name="url" value="${tt.url}"/>
     <property name="username" value="${tt.username}"/>
     <property name="password" value="${tt.password}"/>
  </bean>
  <bean id="dataSource" class="cn.ac.iscas.pebble.ufe.ds.DynamicDataSource">
    <property name="targetDataSources">
        <map key-type="java.lang.String">
            <entry value-ref="ds1" key="ds1"></entry>
            <entry value-ref="ds2" key="ds2"></entry>
        </map>
    </property>
    <property name="defaultTargetDataSource" ref="ds1"></property>      <!-- 默认使用ds1的数据源 -->
    </bean>  

    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource" />
    </bean>

    <bean id="ysSqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <property name="mapperLocations" value="classpath*:cn/ac/iscas/pebble/ufe/mapper/*Mapper.xml"/>
    </bean>

    <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
        <constructor-arg index="0" ref="ysSqlSessionFactory" />
    </bean> 

    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
      <property name="sqlSessionFactoryBeanName" value="ysSqlSessionFactory"/>
    <property name="basePackage" value="cn.ac.iscas.pebble.ufe.inter"/>
  </bean>
</beans> 

注意上述黄色背景的部分，注意事项：

1. 其中必须是  sqlSessionFactoryBeanName 而不能是 sqlSessionFactoryBean

2. 如果是sqlSessionFactoryBeanName 则其后应该用value，而不是ref（ref对应于sqlSessionFactoryBean）

3.  org.mybatis.spring.SqlSessionFactoryBean 的id 不能是 SqlSessionFactory，也不能类似SqlSessionFactory2，sqlSessionFactory或者MySqlSessionFactory，可以是ySqlSessionFactory等。

主要原因是mybatis的问题，在有mybatis的时候，Spring会先加载MapperScannerConfigurer，而使用sqlSessionFactoryBean就会报错找不到DatabaseID，因为此时还没有读取database.properties文件，sqlSessionFactoryBean在实例化的时候报错，可以使用sqlSessionFactoryBeanName，此参数不会实例化，只是声明。