spring mvc+mybatis+多数据源切换

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. <!-- Spring的log4j监听器 -->
6. <listener>
7. <listener-class>org.springframework.web.util.Log4jConfigListener</listener-class>
8. </listener>
9. <!-- 字符集 过滤器 -->
10. <filter>
11. <filter-name>CharacterEncodingFilter</filter-name>
12. <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
13. <init-param>
14. <param-name>encoding</param-name>
15. <param-value>utf8</param-value>
16. </init-param>
17. <init-param>
18. <param-name>forceEncoding</param-name>
19. <param-value>true</param-value>
20. </init-param>
21. </filter>
22. <filter-mapping>
23. <filter-name>CharacterEncodingFilter</filter-name>
24. <url-pattern>/*</url-pattern>
25. </filter-mapping>
26. <!-- Spring view分发器 -->
27. <servlet>
28. <servlet-name>dispatcher</servlet-name>
29. <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
30. <init-param>
31. <param-name>contextConfigLocation</param-name>
32. <param-value>/WEB-INF/dispatcher.xml</param-value>
33. </init-param>
34. <load-on-startup>1</load-on-startup>
35. </servlet>
36. <servlet-mapping>
37. <servlet-name>dispatcher</servlet-name>
38. <url-pattern>*.action</url-pattern>
39. </servlet-mapping>
40. <listener>
41. <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
42. </listener>

dispatcher.xml

Java代码  

1. <mvc:annotation-driven />
2. <context:component-scan base-package="com.trac" />
3. <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver" />
4. <!-- freemarker config -->
5. <bean id="freemarkerConfig" class="org.springframework.web.servlet.view.freemarker.FreeMarkerConfigurer">
6. <property name="templateLoaderPath" value="/WEB-INF/freemarker/" />
7. <property name="freemarkerVariables">
8. <map>
9. <entry key="xml_escape" value-ref="fmXmlEscape" />
10. </map>
11. </property>
12. <property name="freemarkerSettings">
13. <props>
14. <prop key="defaultEncoding">UTF-8</prop>
15. </props>
16. </property>
17. </bean>
18. <bean id="fmXmlEscape" class="freemarker.template.utility.XmlEscape" />
19. <!-- View resolvers can also be configured with ResourceBundles or XML files.
20. If you need different view resolving based on Locale, you have to use the
21. resource bundle resolver. -->
22. <bean id="viewResolver" class="org.springframework.web.servlet.view.freemarker.FreeMarkerViewResolver">
23. <property name="exposeRequestAttributes" value="true" />
24. <property name="exposeSessionAttributes" value="true" />
25. <property name="exposeSpringMacroHelpers" value="true" />
26. <property name="contentType" value="text/html;charset=UTF-8" />
27. <property name="cache" value="true" />
28. <property name="prefix" value="" />
29. <property name="suffix" value=".ftl" />
30. </bean>

applicationContext.xml

Java代码  

1. <bean id="parentDataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
2. </bean>
3. <bean id="mySqlDataSource" parent="parentDataSource">
4. <property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
5. <property name="url" value="jdbc:mysql://localhost:3306/test"></property>
6. <property name="username" value="root"></property>
7. <property name="password" value="root"></property>
8. </bean>
9. <bean id="oracleDataSource" parent="parentDataSource">
10. <property name="driverClassName" value="oracle.jdbc.driver.OracleDriver"></property>
11. <property name="url" value="jdbc:oracle:thin:@10.16.17.40:1531:addb"></property>
12. <property name="username" value="trac"></property>
13. <property name="password" value="trac"></property>
14. </bean>
15. <bean id="dataSource" class="com.trac.dao.datasource.DataSources">
16. <property name="targetDataSources">
17. <map key-type="java.lang.String">
18. <entry value-ref="mySqlDataSource" key="MYSQL"></entry>
19. <entry value-ref="oracleDataSource" key="ORACLE"></entry>
20. </map>
21. </property>
22. <property name="defaultTargetDataSource" ref="oracleDataSource"></property>
23. </bean>
24. <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
25. <property name="dataSource" ref="dataSource" />
26. </bean>
27. <!-- 创建SqlSessionFactory，同时指定数据源和mapper -->
28. <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
29. <property name="dataSource" ref="dataSource" />
30. <property name="mapperLocations" value="classpath*:com/trac/ibatis/dbcp/*.xml" />
31. </bean>
32. <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
33. <constructor-arg index="0" ref="sqlSessionFactory" />
34. </bean>
35. <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
36. <property name="basePackage" value="com.trac.dao" />
37. </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. 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. public static void setDataSourceType(String dataSourceType){
4. contextHolder.set(dataSourceType);
5. }
6. public static String getDataSourceType(){
7. return (String) contextHolder.get();
8. }
9. public static void clearDataSourceType(){
10. contextHolder.remove();
11. }
12. }

DataSources.java

Java代码  

1. import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource;
2. public class DataSources extends AbstractRoutingDataSource{
3. @Override
4. protected Object determineCurrentLookupKey() {
5. return DataSourceSwitch.getDataSourceType();
6. }
7. }
8. 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. @RequestMapping("/test.action")
7. public ModelAndView test(
8. HttpServletRequest request,
9. HttpServletResponse resp){
10. ModelAndView model = new ModelAndView("test");
11. model.addObject("test1", "这是一个测试,获取默认数据连接MYSQL:"+testMapper.test());
12. DataSourceSwitch.setDataSourceType(DataSourceInstances.ORACLE);
13. model.addObject("test2", "这是一个测试,获取数据连接ORACLE:"+testMapper.test());
14. DataSourceSwitch.setDataSourceType(DataSourceInstances.MYSQL);
15. model.addObject("test3", "这是一个测试,获取数据连接MYSQL:"+testMapper.test());
16. return model;
17. }
18. }

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springmvc + mybatis整合详细，及遇到的问题请参看以下资料：

参考资料：

http://www.springmvc,net/detail/6074493.html

http://my.spring.net/wangbiglei/blog/489583

http://my.springmvc.net/wangbiglei/blog/489604