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
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5"> <context-param> <param-name>webAppRootKey</param-name> <param-value>trac</param-value> </context-param> <!-- Spring的log4j监听器 --> <listener> <listener-class>org.springframework.web.util.Log4jConfigListener</listener-class> </listener> <!-- 字符集 过滤器 --> <filter> <filter-name>CharacterEncodingFilter</filter-name> <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class> <init-param> <param-name>encoding</param-name> <param-value>utf8</param-value> </init-param> <init-param> <param-name>forceEncoding</param-name> <param-value>true</param-value> </init-param> </filter> <filter-mapping> <filter-name>CharacterEncodingFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <!-- Spring view分发器 --> <servlet> <servlet-name>dispatcher</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value>/WEB-INF/dispatcher.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>dispatcher</servlet-name> <url-pattern>*.action</url-pattern> </servlet-mapping> <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> </web-app>
dispatcher.xml
<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" xmlns:p="http://www.springframework.org/schema/p" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:jdbc="http://www.springframework.org/schema/jdbc" xmlns:util="http://www.springframework.org/schema/util" xmlns:mvc="http://www.springframework.org/schema/mvc" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd "> <mvc:annotation-driven /> <context:component-scan base-package="com.trac" /> <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver" /> <!-- freemarker config --> <bean id="freemarkerConfig" class="org.springframework.web.servlet.view.freemarker.FreeMarkerConfigurer"> <property name="templateLoaderPath" value="/WEB-INF/freemarker/" /> <property name="freemarkerVariables"> <map> <entry key="xml_escape" value-ref="fmXmlEscape" /> </map> </property> <property name="freemarkerSettings"> <props> <prop key="defaultEncoding">UTF-8</prop> </props> </property> </bean> <bean id="fmXmlEscape" class="freemarker.template.utility.XmlEscape" /> <!-- View resolvers can also be configured with ResourceBundles or XML files. If you need different view resolving based on Locale, you have to use the resource bundle resolver. --> <bean id="viewResolver" class="org.springframework.web.servlet.view.freemarker.FreeMarkerViewResolver"> <property name="exposeRequestAttributes" value="true" /> <property name="exposeSessionAttributes" value="true" /> <property name="exposeSpringMacroHelpers" value="true" /> <property name="contentType" value="text/html;charset=UTF-8" /> <property name="cache" value="true" /> <property name="prefix" value="" /> <property name="suffix" value=".ftl" /> </bean> </beans>
applicationContext.xml
<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" xmlns:p="http://www.springframework.org/schema/p" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:jdbc="http://www.springframework.org/schema/jdbc" xmlns:util="http://www.springframework.org/schema/util" xmlns:mvc="http://www.springframework.org/schema/mvc" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd "> <bean id="parentDataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"> </bean> <bean id="mySqlDataSource" parent="parentDataSource"> <property name="driverClassName" value="com.mysql.jdbc.Driver"></property> <property name="url" value="jdbc:mysql://localhost:3306/test"></property> <property name="username" value="root"></property> <property name="password" value="root"></property> </bean> <bean id="oracleDataSource" parent="parentDataSource"> <property name="driverClassName" value="oracle.jdbc.driver.OracleDriver"></property> <property name="url" value="jdbc:oracle:thin:@10.16.17.40:1531:addb"></property> <property name="username" value="trac"></property> <property name="password" value="trac"></property> </bean> <bean id="dataSource" class="com.trac.dao.datasource.DataSources"> <property name="targetDataSources"> <map key-type="java.lang.String"> <entry value-ref="mySqlDataSource" key="MYSQL"></entry> <entry value-ref="oracleDataSource" key="ORACLE"></entry> </map> </property> <property name="defaultTargetDataSource" ref="oracleDataSource"></property> </bean> <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"> <property name="dataSource" ref="dataSource" /> </bean> <!-- 创建SqlSessionFactory，同时指定数据源和mapper --> <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"> <property name="dataSource" ref="dataSource" /> <property name="mapperLocations" value="classpath*:com/trac/ibatis/dbcp/*.xml" /> </bean> <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate"> <constructor-arg index="0" ref="sqlSessionFactory" /> </bean> <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"> <property name="basePackage" value="com.trac.dao" /> </bean> </beans>
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
public class DataSourceInstances{ public static final String MYSQL="MYSQL"; public static final String ORACLE="ORACLE"; }
定义数据源的标识, 和applicationContext.xml中 DataSources 的 targetDataSources 的key对应。
DataSourceSwitch.java
public class DataSourceSwitch{ private static final ThreadLocal contextHolder=new ThreadLocal(); public static void setDataSourceType(String dataSourceType){ contextHolder.set(dataSourceType); } public static String getDataSourceType(){ return (String) contextHolder.get(); } public static void clearDataSourceType(){ contextHolder.remove(); } }
DataSources.java
import org.springframework.jdbc.datasource.lookup.AbstractRoutingDataSource; public class DataSources extends AbstractRoutingDataSource{ @Override protected Object determineCurrentLookupKey() { return DataSourceSwitch.getDataSourceType(); } }
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
@Controller @SuppressWarnings("unused") public class TestAction { @Autowired TestMapper testMapper; @RequestMapping("/test.action") public ModelAndView test( HttpServletRequest request, HttpServletResponse resp){ ModelAndView model = new ModelAndView("test"); model.addObject("test1", "这是一个测试,获取默认数据连接MYSQL:"+testMapper.test()); DataSourceSwitch.setDataSourceType(DataSourceInstances.ORACLE); model.addObject("test2", "这是一个测试,获取数据连接ORACLE:"+testMapper.test()); DataSourceSwitch.setDataSourceType(DataSourceInstances.MYSQL); model.addObject("test3", "这是一个测试,获取数据连接MYSQL:"+testMapper.test()); return model; } }
本文转自：http://leoyy.iteye.com/blog/1624704
