Springmvc+mybatis多数据源切换

源码地址获取：http://blog.sina.com.cn/s/blog_150df94af0102vngn.html

spring mvc+mybatis+多数据源切换 选取oracle,mysql作为例子切换数据源。oracle为默认数据源，在测试的action中，进行mysql和oracle的动态切换。 

web.xml 

Java代码  

1. <context-param>  

2.         <param-name>webAppRootKey</param-name>  

3.         <param-value>trac</param-value>  

4.     </context-param>  

5.   

6.     <!-- Spring的log4j监听器 -->  

7.     <listener>  

8.         <listener-class>org.springframework.web.util.Log4jConfigListener</listener-class>  

9.     </listener>  

10.   

11.     <!-- 字符集 过滤器 -->  

12.     <filter>  

13.         <filter-name>CharacterEncodingFilter</filter-name>  

14.         <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>  

15.         <init-param>  

16.             <param-name>encoding</param-name>  

17.             <param-value>utf8</param-value>  

18.         </init-param>  

19.         <init-param>  

20.             <param-name>forceEncoding</param-name>  

21.             <param-value>true</param-value>  

22.         </init-param>  

23.     </filter>  

24.     <filter-mapping>  

25.         <filter-name>CharacterEncodingFilter</filter-name>  

26.         <url-pattern>/*</url-pattern>  

27.     </filter-mapping>  

28.   

29.     <!-- Spring view分发器 -->  

30.     <servlet>  

31.         <servlet-name>dispatcher</servlet-name>  

32.         <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>  

33.         <init-param>  

34.             <param-name>contextConfigLocation</param-name>  

35.             <param-value>/WEB-INF/dispatcher.xml</param-value>  

36.         </init-param>  

37.         <load-on-startup>1</load-on-startup>  

38.     </servlet>  

39.     <servlet-mapping>  

40.         <servlet-name>dispatcher</servlet-name>  

41.         <url-pattern>*.action</url-pattern>  

42.     </servlet-mapping>  

43.       

44.     <listener>  

45.         <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>  

46.     </listener>  

dispatcher.xml 

Java代码  

1. <mvc:annotation-driven />  

2.     <context:component-scan base-package="com.trac" />  

3.   

4.     <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver" />  

5.   

6.     <!-- freemarker config -->  

7.     <bean id="freemarkerConfig" class="org.springframework.web.servlet.view.freemarker.FreeMarkerConfigurer">  

8.         <property name="templateLoaderPath" value="/WEB-INF/freemarker/" />  

9.         <property name="freemarkerVariables">  

10.             <map>  

11.                 <entry key="xml_escape" value-ref="fmXmlEscape" />  

12.             </map>  

13.         </property>  

14.         <property name="freemarkerSettings">  

15.             <props>  

16.                 <prop key="defaultEncoding">UTF-8</prop>  

17.             </props>  

18.         </property>  

19.     </bean>  

20.   

21.     <bean id="fmXmlEscape" class="freemarker.template.utility.XmlEscape" />  

22.   

23.     <!-- View resolvers can also be configured with ResourceBundles or XML files.   

24.         If you need different view resolving based on Locale, you have to use the   

25.         resource bundle resolver. -->  

26.     <bean id="viewResolver" class="org.springframework.web.servlet.view.freemarker.FreeMarkerViewResolver">  

27.         <property name="exposeRequestAttributes" value="true" />  

28.         <property name="exposeSessionAttributes" value="true" />  

29.         <property name="exposeSpringMacroHelpers" value="true" />  

30.         <property name="contentType" value="text/html;charset=UTF-8" />  

31.         <property name="cache" value="true" />  

32.         <property name="prefix" value="" />  

33.         <property name="suffix" value=".ftl" />  

34.     </bean>  

applicationContext.xml 

Java代码  

1. <bean id="parentDataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">  

2.     </bean>  

3.       

4.     <bean id="mySqlDataSource" parent="parentDataSource">  

5.         <property name="driverClassName" value="com.mysql.jdbc.Driver"></property>  

6.         <property name="url" value="jdbc:mysql://localhost:3306/test"></property>  

7.         <property name="username" value="root"></property>  

8.         <property name="password" value="root"></property>  

9.     </bean>  

10.       

11.     <bean id="oracleDataSource" parent="parentDataSource">  

12.         <property name="driverClassName" value="oracle.jdbc.driver.OracleDriver"></property>  

13.         <property name="url" value="jdbc:oracle:thin:@10.16.17.40:1531:addb"></property>  

14.         <property name="username" value="trac"></property>  

15.         <property name="password" value="trac"></property>  

16.     </bean>  

17.       

18.     <bean id="dataSource" class="com.trac.dao.datasource.DataSources">  

19.         <property name="targetDataSources">  

20.             <map key-type="java.lang.String">  

21.                 <entry value-ref="mySqlDataSource" key="MYSQL"></entry>  

22.                 <entry value-ref="oracleDataSource" key="ORACLE"></entry>  

23.             </map>  

24.         </property>  

25.         <property name="defaultTargetDataSource" ref="oracleDataSource"></property>  

26.     </bean>  

27.   

28.     <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">  

29.         <property name="dataSource" ref="dataSource" />  

30.     </bean>  

31.   

32.     <!-- 创建SqlSessionFactory，同时指定数据源和mapper -->  

33.     <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">  

34.         <property name="dataSource" ref="dataSource" />  

35.         <property name="mapperLocations" value="classpath*:com/trac/ibatis/dbcp/*.xml" />  

36.     </bean>  

37.   

38.     <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">  

39.         <constructor-arg index="0" ref="sqlSessionFactory" />  

40.     </bean>  

41.   

42.     <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">  

43.         <property name="basePackage" value="com.trac.dao" />  

44.     </bean>  

配 置 parentDataSource 的父bean.再配置多个数据源继承这个父bean,对driverClass,url,username,password,等数据源连接参数进行各自 的重写。例如 mySqlDataSource ，在 DataSources bean中注入所有要切换的数据源，并且设置默认的数据源。 

DataSourceInstances.java 

Java代码  

1. public class DataSourceInstances{  

2.     public static final String MYSQL="MYSQL";  

3.     public static final String ORACLE="ORACLE";  

4. }     

5.   

6. 定义数据源的标识, 和applicationContext.xml中 DataSources 的 targetDataSources 的key对应  

DataSourceSwitch.java 

Java代码  

1. public class DataSourceSwitch{  

2.     private static final ThreadLocal contextHolder=new ThreadLocal();  

3.       

4.     public static void setDataSourceType(String dataSourceType){  

5.         contextHolder.set(dataSourceType);  

6.     }  

7.       

8.     public static String getDataSourceType(){  

9.         return (String) contextHolder.get();  

10.     }  

11.       

12.     public static void clearDataSourceType(){  

13.         contextHolder.remove();  

14.     }  

15. }  

DataSources.java 

Java代码  

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

2.   

3. public class DataSources extends AbstractRoutingDataSource{  

4.   

5.     @Override  

6.     protected Object determineCurrentLookupKey() {  

7.         return DataSourceSwitch.getDataSourceType();  

8.     }  

9.   

10. }  

11.   

12. 配置于applicationContext 中，线程局部变量 ThreadLocal contextHolder 保存当前需要的数据源类型， 当 DataSourceSwitch.setDataSourceType(DataSourceInstances.XXX) 保存当前需要的数据源 类型的时候，DataSources 会从当前线程中查找线程变量的数据源类型，从而决定使用何种数据源  

TestAction.java 

Java代码  

1. @Controller   

2. @SuppressWarnings("unused")  

3. public class TestAction {  

4. @Autowired  

5.     TestMapper testMapper;  

6.   

7.    @RequestMapping("/test.action")  

8.     public ModelAndView test(  

9.             HttpServletRequest request,  

10.             HttpServletResponse resp){  

11.         ModelAndView model = new ModelAndView("test");  

12.         model.addObject("test1", "这是一个测试,获取默认数据连接MYSQL:"+testMapper.test());  

13.         DataSourceSwitch.setDataSourceType(DataSourceInstances.ORACLE);  

14.         model.addObject("test2", "这是一个测试,获取数据连接ORACLE:"+testMapper.test());  

15.         DataSourceSwitch.setDataSourceType(DataSourceInstances.MYSQL);  

16.         model.addObject("test3", "这是一个测试,获取数据连接MYSQL:"+testMapper.test());  

17.         return model;  

18.     }  

19. }