1. pom.xml

     <dependency>
            <groupId>com.mchange</groupId>
            <artifactId>c3p0</artifactId>
            <version>0.9.5.4</version>
        </dependency>

2.  在com.imooc.mybatis.datasource下新增一个数据源C3P0DataSourceFactory.java

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>

    <settings>
        <!-- goods_id ==> goodsId 驼峰命名转换 -->
        <setting name="mapUnderscoreToCamelCase" value="true"/>
    </settings>

    <!--启用Pagehelper分页插件-->
    <plugins>
        <plugin interceptor="com.github.pagehelper.PageInterceptor">
            <!--设置数据库类型-->
            <property name="helperDialect" value="mysql"/>
            <!--分页合理化-->
            <property name="reasonable" value="true"/>
        </plugin>
    </plugins>

    <!-- 环境，可以配置多个，default：指定采用哪个环境 -->
    <environments default="dev">
        <!-- id：唯一标识 -->
        <environment id="dev">
            <!--采用JDBC进行事务的管理commit/rollback-->
            <transactionManager type="JDBC"/>
            <!-- 数据源，连接池类型的数据源 -->
            <!--<dataSource type="POOLED">-->
            <dataSource type="com.imooc.mybatis.datasource.C3P0DataSourceFactory">
                <property name="driverClass" value="com.mysql.cj.jdbc.Driver"/>
                <property name="jdbcUrl"
                          value="jdbc:mysql://localhost:3306/babytun?useUnicode=true&amp;characterEncoding=UTF-8&amp;serverTimezone=UTC"/>
                <property name="user" value="root"/>
                <property name="password" value="root"/>

　　　　　　　　　　　<property name="initialPoolSize" value="5"/>
　　　　　　　　　　　<property name="maxPoolSize" value="20"/>
                  <property name="minPoolSize" value="5"/>

            </dataSource>
        </environment>

    </environments>

    <!--声明mapper的配置文件-->
    <mappers>
        <mapper resource="mappers/goods.xml"/>
        <mapper resource="mappers/goods_detail.xml"/>
    </mappers>
</configuration>