springmvc+spring+mybatis+mysql整合问题
整合遇到的问题：
配置文件：spring-common.xml配置
<?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: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.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd"> <!--引入属性文件 --> <context:property-placeholder location="classpath:properties/mysql.properties" /> <!-- 1. 数据源 : DriverManagerDataSource --> <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"> <!-- <property name="driverClassName" value="com.mysql.jdbc.Driver" /> <property name="url" value="jdbc:mysql://localhost:3306/mybatis" /> <property name="username" value="root" /> <property name="password" value="1qazxsw2" /> --> <property name="driverClassName" value="${jdbc.driverClass}" /> <property name="url" value="${jdbc.jdbcUrl}"></property> <property name="username" value="${jdbc.user}"></property> <property name="password" value="${jdbc.password}"></property> </bean> <!-- 2. mybatis的SqlSession的工厂: SqlSessionFactoryBean dataSource:引用数据源 MyBatis定义数据源,同意加载配置 --> <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"> <property name="dataSource" ref="dataSource"></property> <property name="configLocation" value="classpath:config/mybatis-config.xml" /> </bean> <!-- 3. mybatis自动扫描加载Sql映射文件/接口 : MapperScannerConfigurer sqlSessionFactory basePackage:指定sql映射文件/接口所在的包（自动扫描） --> <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"> <property name="basePackage" value="com.mapper"></property> <property name="sqlSessionFactory" ref="sqlSessionFactory"></property> </bean> <!-- 4. 事务管理 : DataSourceTransactionManager dataSource:引用上面定义的数据源 --> <bean id="txManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"> <property name="dataSource" ref="dataSource"></property> </bean> <!-- 5. 使用声明式事务 transaction-manager：引用上面定义的事务管理器 --> <tx:annotation-driven transaction-manager="txManager" /> </beans>
启动程序报错：
页面错误 404
后台控制台报错：
警告: Exception encountered during context initialization - cancelling refresh attempt org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userService' defined in file [E:\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp3\wtpwebapps\springmvc_mybatis\WEB-INF\classes\springContext-beans.xml]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.ms.service.UserService]: Specified class is an interface at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1105) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1050) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:510) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:305) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:301) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:196) at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:772) at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:834) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:537) at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:446) at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:328) at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:107) at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4729) at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5167) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1408) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1398) at java.util.concurrent.FutureTask.run(Unknown Source) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.ms.service.UserService]: Specified class is an interface at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:68) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1098) ... 22 more 四月 07, 2016 2:16:49 下午 org.springframework.web.context.ContextLoader initWebApplicationContext 严重: Context initialization failed org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userService' defined in file [E:\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp3\wtpwebapps\springmvc_mybatis\WEB-INF\classes\springContext-beans.xml]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.ms.service.UserService]: Specified class is an interface at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1105) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1050) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:510) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:305) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:301) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:196) at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:772) at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:834) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:537) at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:446) at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:328) at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:107) at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4729) at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5167) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1408) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1398) at java.util.concurrent.FutureTask.run(Unknown Source) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.ms.service.UserService]: Specified class is an interface at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:68) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1098) ... 22 more 四月 07, 2016 2:16:49 下午 org.apache.catalina.core.StandardContext listenerStart 严重: Exception sending context initialized event to listener instance of class org.springframework.web.context.ContextLoaderListener org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userService' defined in file [E:\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp3\wtpwebapps\springmvc_mybatis\WEB-INF\classes\springContext-beans.xml]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.ms.service.UserService]: Specified class is an interface at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1105) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1050) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:510) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:305) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:301) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:196) at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:772) at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:834) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:537) at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:446) at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:328) at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:107) at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4729) at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5167) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1408) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1398) at java.util.concurrent.FutureTask.run(Unknown Source) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.ms.service.UserService]: Specified class is an interface at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:68) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1098) ... 22 more 四月 07, 2016 2:16:49 下午 org.apache.catalina.core.StandardContext startInternal 严重: One or more listeners failed to start. Full details will be found in the appropriate container log file 四月 07, 2016 2:16:49 下午 org.apache.catalina.core.StandardContext startInternal 严重: Context [/springmvc_mybatis] startup failed due to previous errors 四月 07, 2016 2:16:49 下午 org.apache.catalina.core.ApplicationContext log 信息: Closing Spring root WebApplicationContext 四月 07, 2016 2:16:50 下午 org.apache.jasper.servlet.TldScanner scanJars 信息: At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time. 四月 07, 2016 2:16:50 下午 org.apache.catalina.core.ApplicationContext log 信息: No Spring WebApplicationInitializer types detected on classpath 四月 07, 2016 2:16:51 下午 org.apache.catalina.core.ApplicationContext log 信息: Initializing Spring root WebApplicationContext log4j:WARN No appenders could be found for logger (org.springframework.web.context.ContextLoader). log4j:WARN Please initialize the log4j system properly. log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info. 四月 07, 2016 2:16:51 下午 org.apache.catalina.core.StandardContext listenerStart 严重: Exception sending context initialized event to listener instance of class org.springframework.web.context.ContextLoaderListener org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.mybatis.spring.mapper.MapperScannerConfigurer#0' defined in file [E:\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp3\wtpwebapps\ssm_2\WEB-INF\classes\config\spring-common.xml]: Cannot resolve reference to bean 'sqlSessionFactory' while setting bean property 'sqlSessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sqlSessionFactory' defined in file [E:\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp3\wtpwebapps\ssm_2\WEB-INF\classes\config\spring-common.xml]: Cannot resolve reference to bean 'dataSource' while setting bean property 'dataSource'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in file [E:\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp3\wtpwebapps\ssm_2\WEB-INF\classes\config\spring-common.xml]: Error setting property values; nested exception is org.springframework.beans.PropertyBatchUpdateException; nested PropertyAccessExceptions (1) are: PropertyAccessException 1: org.springframework.beans.MethodInvocationException: Property 'driverClassName' threw exception; nested exception is java.lang.IllegalStateException: Could not load JDBC driver class [${jdbc.driverClass}] at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:328) at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:107) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1456) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1197) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:200) at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:116) at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:609) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:464) at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:381) at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:293) at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:106) at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4729) at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5167) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1408) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1398) at java.util.concurrent.FutureTask.run(Unknown Source) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sqlSessionFactory' defined in file [E:\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp3\wtpwebapps\ssm_2\WEB-INF\classes\config\spring-common.xml]: Cannot resolve reference to bean 'dataSource' while setting bean property 'dataSource'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in file [E:\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp3\wtpwebapps\ssm_2\WEB-INF\classes\config\spring-common.xml]: Error setting property values; nested exception is org.springframework.beans.PropertyBatchUpdateException; nested PropertyAccessExceptions (1) are: PropertyAccessException 1: org.springframework.beans.MethodInvocationException: Property 'driverClassName' threw exception; nested exception is java.lang.IllegalStateException: Could not load JDBC driver class [${jdbc.driverClass}] at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:328) at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:107) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1456) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1197) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195) at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:320) ... 24 more Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in file [E:\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp3\wtpwebapps\ssm_2\WEB-INF\classes\config\spring-common.xml]: Error setting property values; nested exception is org.springframework.beans.PropertyBatchUpdateException; nested PropertyAccessExceptions (1) are: PropertyAccessException 1: org.springframework.beans.MethodInvocationException: Property 'driverClassName' threw exception; nested exception is java.lang.IllegalStateException: Could not load JDBC driver class [${jdbc.driverClass}] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1493) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1197) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195) at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:320) ... 34 more Caused by: org.springframework.beans.PropertyBatchUpdateException; nested PropertyAccessExceptions (1) are: PropertyAccessException 1: org.springframework.beans.MethodInvocationException: Property 'driverClassName' threw exception; nested exception is java.lang.IllegalStateException: Could not load JDBC driver class [${jdbc.driverClass}] at org.springframework.beans.AbstractPropertyAccessor.setPropertyValues(AbstractPropertyAccessor.java:108) at org.springframework.beans.AbstractPropertyAccessor.setPropertyValues(AbstractPropertyAccessor.java:62) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1489) ... 42 more 四月 07, 2016 2:16:51 下午 org.apache.catalina.core.StandardContext startInternal 严重: One or more listeners failed to start. Full details will be found in the appropriate container log file 四月 07, 2016 2:16:51 下午 org.apache.catalina.core.StandardContext startInternal 严重: Context [/ssm_2] startup failed due to previous errors 四月 07, 2016 2:16:51 下午 org.apache.catalina.core.ApplicationContext log 信息: Closing Spring root WebApplicationContext 四月 07, 2016 2:16:51 下午 org.apache.coyote.AbstractProtocol start 信息: Starting ProtocolHandler ["http-nio-8080"] 四月 07, 2016 2:16:51 下午 org.apache.coyote.AbstractProtocol start 信息: Starting ProtocolHandler ["ajp-nio-8009"] 四月 07, 2016 2:16:51 下午 org.apache.catalina.startup.Catalina start 信息: Server startup in 6981 ms
经查原因是：
在spring里使用org.mybatis.spring.mapper.MapperScannerConfigurer 进行自动扫描的时候，设置了sqlSessionFactory 的话，可能会导致PropertyPlaceholderConfigurer失效，也就是用${jdbc.username}这样之类的表达式，将无法获取到properties文件里的内容。 导致这一原因是因为，MapperScannerConigurer实际是在解析加载bean定义阶段的，这个时候要是设置sqlSessionFactory的话，会导致提前初始化一些类，这个时候，PropertyPlaceholderConfigurer还没来得及替换定义中的变量，导致把表达式当作字符串复制了。 但如果不设置sqlSessionFactory 属性的话，就必须要保证sessionFactory在spring中名称一定要是sqlSessionFactory ，否则就无法自动注入。又或者直接定义 MapperFactoryBean ，再或者放弃自动代理接口方式。
解决方法：
将
1. <property name="sqlSessionFactory" ref="sqlSessionFactory"></property>
改为 <property name="sqlSessionFactoryBeanName" value="ysSqlSessionFactory" />
2.将 <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
的引用改为
<bean id="ysSqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
