spring整合mybatis，ioc容器及声明式事务配置

步骤：

1.创建jdbc.properties文件，用来管理存放连接数据库的相关信息

jdbc.properties：

jdbc.user=root
jdbc.password=123456
jdbc.url=jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=UTF-8
jdbc.driver=com.mysql.jdbc.Driver

2.创建spring的配置文件，配置Spring和Mybatis整合相关

ApplicationContext.xml：

<?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:aop="http://www.springframework.org/schema/aop"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="
       http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/aop
       http://www.springframework.org/schema/aop/spring-aop.xsd
       http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context.xsd
       http://www.springframework.org/schema/tx
       http://www.springframework.org/schema/tx/spring-tx.xsd">

</beans>

3.在spring的配置文件中加载jdbc.properties文件，通过<context:property-placeholder>标签

ApplicationContext.xml：

<?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:aop="http://www.springframework.org/schema/aop"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="
       http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/aop
       http://www.springframework.org/schema/aop/spring-aop.xsd
       http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context.xsd
       http://www.springframework.org/schema/tx
       http://www.springframework.org/schema/tx/spring-tx.xsd">

    <context:property-placeholder location="classpath:jdbc.properties"/>
</beans>

4.在spring配置文件中配置数据源（数据库连接池）

ApplicationContext.xml：

<?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:aop="http://www.springframework.org/schema/aop"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="
       http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/aop
       http://www.springframework.org/schema/aop/spring-aop.xsd
       http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context.xsd
       http://www.springframework.org/schema/tx
       http://www.springframework.org/schema/tx/spring-tx.xsd">

    <context:property-placeholder location="classpath:jdbc.properties"/>

    <bean class="com.alibaba.druid.pool.DruidDataSource" name="dataSource">
        <property name="driverClassName" value="${jdbc.driver}"/>
        <property name="url" value="${jdbc.url}"/>
        <property name="username" value="${jdbc.user}"/>
        <property name="password" value="${jdbc.password}"/>
    </bean>
</beans>

5.在spring配置文件中配置SqlSessionFactoryBean

作用：用于指定Xxxmapper.xml的位置，然后根据xml文件生成代理对象

其作用相当于原来mybatis主配置文件，原来mybatis主配置文件有的功能，在这里都可以实现，如取别名、开启二级缓存等。

ApplicationContext.xml：

<?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:aop="http://www.springframework.org/schema/aop"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="
       http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/aop
       http://www.springframework.org/schema/aop/spring-aop.xsd
       http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context.xsd
       http://www.springframework.org/schema/tx
       http://www.springframework.org/schema/tx/spring-tx.xsd">

    <context:property-placeholder location="classpath:jdbc.properties"/>

    <bean class="com.alibaba.druid.pool.DruidDataSource" name="dataSource">
        <property name="driverClassName" value="${jdbc.driver}"/>
        <property name="url" value="${jdbc.url}"/>
        <property name="username" value="${jdbc.user}"/>
        <property name="password" value="${jdbc.password}"/>
    </bean>

    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
        <property name="mapperLocations" value="classpath:com/xj/mapper/*Mapper.xml"/>
    </bean>
</beans>

6.在spring配置文件中配置MapperScannerConfigurer

作用：扫描dao层的接口类，将第五步动态生成的代理对象加入到ioc容器中。

ApplicationContext.xml：

?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:aop="http://www.springframework.org/schema/aop"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="
       http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/aop
       http://www.springframework.org/schema/aop/spring-aop.xsd
       http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context.xsd
       http://www.springframework.org/schema/tx
       http://www.springframework.org/schema/tx/spring-tx.xsd">

    <context:property-placeholder location="classpath:jdbc.properties"/>

    <bean class="com.alibaba.druid.pool.DruidDataSource" name="dataSource">
        <property name="driverClassName" value="${jdbc.driver}"/>
        <property name="url" value="${jdbc.url}"/>
        <property name="username" value="${jdbc.user}"/>
        <property name="password" value="${jdbc.password}"/>
    </bean>

    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
        <property name="mapperLocations" value="classpath:com/xj/mapper/*Mapper.xml"/>
    </bean>

    <bean id="mapperScannerConfigurer" class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.xj.mapper"/>
    </bean>
</beans>

相关依赖：

    <dependencies>
        <!--mybatis相关依赖-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.5</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.6</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.0.31</version>
        </dependency>

        <!--单元测试-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>

        <!--spring相关依赖-->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.0.2.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
            <version>5.0.2.RELEASE</version>
        </dependency>

        <!--spring整合mybatis相关依赖-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>1.3.0</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.0.2.RELEASE</version>
        </dependency>
    </dependencies>

二、基于xml的声明式事务配置

步骤：

1.配置自动扫描的包：为了把Service扫描到IOC容器中

<context:component-scan base-package="com.xj.service"/>

2.配置事务管理器

    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"/>
    </bean>

3.配置事务的通知

    <!-- 配置事务通知 -->
    <tx:advice id="txAdvice" transaction-manager="transactionManager">
        <!-- 配置事务属性 -->
        <tx:attributes>
            <!-- 查询方法：配置只读属性，让数据库知道这是一个查询操作，能够进行一定优化 -->
            <tx:method name="find*" read-only="true"/>
            <!-- 增删改方法：配置事务传播行为、回滚异常 -->
            <tx:method name="*" propagation="REQUIRES_NEW" rollback-for="java.lang.Exception"/>
        </tx:attributes>
    </tx:advice>

propagation属性：
    REQUIRED：默认值，表示当前方法必须工作在事务中，如果当前线程上没有已经开启的事务，则自己开新事务。如果有已开启的事务，那么就使用这个已有的事务。
　　　　顾虑：用别人的事务有可能“被”回滚。

    REQUIRES_NEW：建议使用的值，表示不管当前线程上有没有事务，都要自己开事务，在自己的事务中运行。
        好处：不会受到其他事务回滚的影响。

4.配置事务的切面

    <!-- 配置事务切面 -->
    <aop:config>
        <aop:pointcut id="txPointCut" expression="execution(* *..*ServiceImpl.*(..))"/>
        <!-- 将切入点表达式和事务通知关联起来 -->
        <aop:advisor advice-ref="txAdvice" pointcut-ref="txPointCut"/>
    </aop:config>