这段代码是什么意思
<?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:aop="http://www.springframework.org/schema/aop"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-4.0.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
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd">
<!-- 配置数据源,记得去掉myBatis-config.xml的数据源相关配置 -->
<bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="location" value="classpath:jdbc.properties"></property>
</bean>
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
<property name="driverClassName" value="${driverClassName}" />
<property name="url" value="${url}" />
<property name="username" value="${username}" />
<property name="password" value="${password}" />
<!--initialSize: 初始化连接-->
<property name="initialSize" value="5"/>
<!--maxIdle: 最大空闲连接-->
<property name="maxIdle" value="10"/>
<!--minIdle: 最小空闲连接-->
<property name="minIdle" value="5"/>
<!--maxActive: 最大连接数量-->
<property name="maxActive" value="15"/>
</bean>
<!-- 配置session工厂 -->
<bean id="SessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="configLocation" value="classpath:myBatis-config.xml" />
<property name="mapperLocations">
<list>
<value>classpath:manage/dao/mapper/*.xml</value>
</list>
</property>
</bean>
<!-- 配置事务管理器,管理数据源事务处理-->
<bean id="transActionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource" />
</bean>
<bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
<property name="messageConverters">
<list>
<ref bean="jsonHttpMessageConverter" />
</list>
</property>
</bean>
<bean id="jsonHttpMessageConverter" class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter">
<property name="supportedMediaTypes">
<list>
<value>application/json;charset=UTF-8</value>
</list>
</property>
</bean>
<!-- 配置事务通知 -->
<tx:advice id="advice" transaction-manager="transActionManager">
<tx:attributes>
<!-- 默认只处理运行时异常,可加rollback-for="Exception/Throwable"等处理所有异常或包括错误 -->
<tx:method name="insert*" propagation="REQUIRED" isolation="DEFAULT" rollback-for="Exception"/>
<tx:method name="update*" propagation="REQUIRED" isolation="DEFAULT" rollback-for="Exception"/>
<tx:method name="delete*" propagation="REQUIRED" isolation="DEFAULT" rollback-for="Exception"/>
<tx:method name="*" propagation="SUPPORTS" isolation="DEFAULT" read-only="true"/>
</tx:attributes>
</tx:advice>
<!-- 配置切面织入的范围,后边要把事务边界定在service层 -->
<aop:config>
<aop:pointcut id="services"
expression="execution(* manage.service..*.*(..))" />
<aop:advisor pointcut-ref="services" advice-ref="advice" />
</aop:config>
<!-- 自动扫描组件,要把controller去除,他们是在spring-mvc.xml中配置,如果不去除会影响事务管理。 -->
<context:component-scan base-package="manage">
<context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller" />
</context:component-scan>
<!-- 配置 转换器,对于在basePackage设置的包(包括子包)下的接口类,如果在Mapper.xml文件中定义过,
将被转换成spring的BEAN,在调用 的地方通过@Autowired方式将可以注入接口实例-->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="sqlSessionFactoryBeanName" value="SessionFactory" />
<property name="basePackage" value="manage.dao"/>
</bean>
<!-- 配置SessionTemplate,已封装了繁琐的数据操作-->
<bean id="sqlSessionTemplate" class="org.mybatis.spring.SqlSessionTemplate">
<constructor-arg name="sqlSessionFactory" ref="SessionFactory"/>
</bean>
<!-- 用spring默认的提示信息,账号密码验证错误等-->
<!-- <bean id="messageSource" class="org.springframework.context.support.ReloadableResourceBundleMessageSource">
<property name="basenames" value="classpath:messages_zh_CN"></property>
</bean> -->
</beans>