Spring整合多数据源实现动态切换的实例讲解

在实际项目中时常需要连接多个数据库，而且不同的业务需求在实现过程当中往往需要访问不同的数据库。

jdbc.properties配置文件,配置多个dataSource

##########################MySQL#####################################

hibernate.dialect=org.hibernate.dialect.MySQLInnoDBDialect

connection.driver_class=com.mysql.jdbc.Driver

connection.url=jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8

connection.username=yahu

connection.password=123456

##########################Oracle#####################################

connection1.driver_class=oracle.jdbc.driver.OracleDriver

connection1.url=jdbc\\:oracle\\:thin\\:@localhost\\:1521/MEDB

connection1.username=yahu

connection1.password=123456

##########################Sql Server2008#####################################

connection2.driver_class=net.sourceforge.jtds.jdbc.Driver

connection2.url=jdbc:jtds:sqlserver://localhost:1433;DatabaseName=test

connection2.username=yahu

connection2.password=123456

spring-config.xml配置文件如下,将DynamicDataSource Bean加入到Spring的上下文xml配置文件中去，同时配置DynamicDataSource的targetDataSources(多数据源目标)属性的Map映射,使用动态数据源DynamicDataSource是继承与AbstractRoutingDataSource，而AbstractRoutingDataSource又是继承于org.springframework.jdbc.datasource.AbstractDataSource，AbstractDataSource实现了统一的DataSource接口，所以DynamicDataSource同样可以当一个DataSource使用:

<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">

<property name="driverClassName" value="${connection.driver_class}" />

<property name="url" value="${connection.url}" />

<property name="username" value="${connection.username}" />

<property name="password" value="${connection.password}" />

<property name="initialSize" value="5" />

<property name="minIdle" value="1" />

<property name="maxActive" value="200" />

<property name="maxWait" value="30000" />

<property name="timeBetweenEvictionRunsMillis" value="60000" />

<property name="minEvictableIdleTimeMillis" value="300000" />

</bean>

<bean id="dataSource1" class="org.apache.commons.dbcp.BasicDataSource">

<property name="driverClassName" value="${connection1.driver_class}" />

<property name="url" value="${connection1.url}" />

<property name="username" value="${connection1.username}" />

<property name="password" value="${connection1.password}" />

</bean>

<bean id="dataSource2" class="org.apache.commons.dbcp.BasicDataSource">

<property name="driverClassName" value="${connection2.driver_class}" />

<property name="url" value="${connection2.url}" />

<property name="username" value="${connection2.username}" />

<property name="password" value="${connection2.password}" />

</bean>

<bean id="dynamicDataSource" class="com.yahu.core.dao.DynamicDataSource">

<property name="targetDataSources">

<map>

<entry value-ref="dataSource" key="datasource" />

<entry value-ref="dataSource1" key="datasource1" />

<entry value-ref="dataSource2" key="datasource2" />

</map>

</property>

<property name="defaultTargetDataSource" ref="dataSource" />

</bean>

DynamicDataSource动态数据源类,扩展Spring的AbstractRoutingDataSource抽象类，实现动态数据源,AbstractRoutingDataSource中的抽象方法determineCurrentLookupKey是实现数据源的route的核心.这里对该方法进行Override: