Spring and database programming

Configure database resources in xml mode

• Use SimpleDriverDataSource to connect, it does not support database connection.

<!-- 配置数据源 -->
    <bean id="dataSource" class="org.springframework.jdbc.datasource.SimpleDriverDataSource">
        <property name="driverClass" value="com.mysql.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://localhost:3306/test"/>
        <property name="username" value="root"/>
        <property name="password" value="root"/>
   </bean>

• Use third-party database connection pool
  Use DBCP database connection pool
  Dependencies that need to be imported:

<dependency>
     <groupId>commons-dbcp</groupId>
      <artifactId>commons-dbcp</artifactId>
      <version>1.4</version>
</dependency>

<!-- 配置数据源 -->
    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://localhost:3306/test"/>
        <property name="username" value="root"/>
        <property name="password" value="root"/>
        <!--连接池的最大数据库连接数-->
        <property name="maxActive" value="255"/>
        <!--最大等待连接中的数量-->
        <property name="maxIdle" value="5"/>
        <!--最大等待毫秒数-->
        <property name="maxWait" value="10000"/>
   </bean>

Use c3p0 database connection pool
The dependencies that need to be imported:

<dependency>
     <groupId>c3p0</groupId>
     <artifactId>c3p0</artifactId>
     <version>0.9.1.2</version>
     <type>jar</type>
     <scope>compile</scope>
</dependency>

<!--配置连接池-->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="com.mysql.jdbc.Driver"/>
        <property name="jdbcUrl" value="jdbc:mysql:///mybatis_form"/>
        <property name="user" value="root"/>
        <property name="password" value="root"/>
   </bean>

Configure SqlSessionFactory component

    <!--配置SqlSessionFactory组件-->
    <bean id="SqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <!--引入mybatis的主配置文件-->
        <property name="configLocation" value="classpath:sqlMapConfig.xml"/>
    </bean>

SqlSessionTemplate component

SqlSessionTemplate is not a component that must be configured. It is a thread-safe class. It is necessary to create objects through the construction method with parameters. The commonly used parameters are the types of SqlSessionFactory and Mybatis executors (SIMPLE, REUSE, BATCH)

  <!--配置SqlSessionTemplate-->
    <bean id="sqlSessionTemplate" class="org.mybatis.spring.SqlSessionTemplate">
        <constructor-arg ref="SqlSessionFactory"/>
        <constructor-arg value="BATCH"/>
    </bean>

When both SqlSessionFactory and SqlSessionTemplate are configured at the same time, the priority of SqlSessionTemplate is greater than that of SqlSessionFactory.

Configure MapperFactoryBean

mapperInterface: the interface of the mapper

    <bean class="org.mybatis.spring.mapper.MapperFactoryBean">
        <property name="mapperInterface" value="com.example.dao.AccountDao"/>
        <property name="SqlSessionFactoryBeanName" value="SqlSessionFactory"/>
    </bean>

Configure MapperScannerConfigurer

This is a class that configures the Mapper in the form of scanning, and does not need to be configured one by one.
Attribute: annotationClass, scan only if the class is identified by this annotation. That is, the dao interface, and the annotation @Repository indicates that this is a data access layer.

 <!--配置MapperScannerConfigurer-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.example.dao"/>
        <property name="SqlSessionFactoryBeanName" value="SqlSessionFactory"/>
        <property name="annotationClass" value="org.springframework.stereotype.Repository"/>
    </bean>

Complete spring+mybatis xml configuration

  <!-- 配置数据源 -->
    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://localhost:3306/test"/>
        <property name="username" value="root"/>
        <property name="password" value="root"/>
        <!--连接池的最大数据库连接数-->
        <property name="maxActive" value="255"/>
        <!--最大等待连接中的数量-->
        <property name="maxIdle" value="5"/>
        <!--最大等待毫秒数-->
        <property name="maxWait" value="10000"/>
    </bean>
    <!--配置SqlSessionFactory组件-->
    <bean id="SqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <!--引入mybatis的主配置文件-->
        <property name="configLocation" value="classpath:sqlMapConfig.xml"/>
    </bean>
    <!--配置SqlSessionTemplate-->
    <bean id="sqlSessionTemplate" class="org.mybatis.spring.SqlSessionTemplate">
        <constructor-arg ref="SqlSessionFactory"/>
        <constructor-arg value="BATCH"/>
    </bean>
     <!--配置MapperScannerConfigurer-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.example.dao"/>
        <property name="SqlSessionFactoryBeanName" value="SqlSessionFactory"/>
<!--        <property name="sqlSessionTemplateBeanName" value="sqlSessionTemplate"/>-->
        <property name="annotationClass" value="org.springframework.stereotype.Repository"/>
    </bean>