1.spring整合dao层，关联数据库配置文件，配置数据库连接池。

<?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: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
        https://www.springframework.org/schema/context/spring-context.xsd">
    <!--1.关联数据库配置文件-->
    <context:property-placeholder location="classpath:db.properties"/>
    <!--2.连接池-->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="${driver}"/>
        <property name="jdbcUrl" value="${url}"/>
        <property name="user" value="${username}"/>
        <property name="password" value="${password}"/>
        <!--c3p0连接池的私有属性-->
        <property name="maxPoolSize" value="30"/>
        <property name="minPoolSize" value="10"/>
        <!--关闭连接后不自动commit-->
        <property name="autoCommitOnClose" value="false"/>
        <!--获取连接超时时间-->
        <property name="checkoutTimeout" value="10000"/>
        <!--当获取连接失败重试次数-->
        <property name="acquireRetryAttempts" value="2"/>
    </bean>
    <!--3.sqlSessionFactory-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
    </bean>
    <!--配置dao接口扫描包，动态实现了Dao接口可以注入到Spring容器中-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
    <!--注入 sqlSessionFactory-->
     <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
    <!--扫描的dao包-->
    <property name="basePackage" value="com.wyw.dao"/>
    </bean>


</beans>

2.spring整合service层，扫描service下的包，将所有的业务类注入到spring中。

<?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: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 
       https://www.springframework.org/schema/context/spring-context.xsd">
    <!--1.扫描service下的包-->
    <context:component-scan base-package="com.wyw.service"/>
    <!--2.将我们的所有业务类，注入到Spring，可以通过配置，或者注解-->
    <bean id="BookServiceImpl" class="com.wyw.service.BookServiceImpl">
        <property name="bookMapper" ref="bookMapper"/>
    </bean>
    <!--3.声明式事务配置-->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <!--注入数据源-->
        <property name="dataSource" ref="dataSource"/>
    </bean>



</beans>